Auto merge of #26351 - eddyb:tls-tcx, r=nikomatsakis

Pre-requisite for splitting the type context into global and local parts.
The `Repr` and `UserString` traits were also replaced by `Debug` and `Display`.

src/librustc/lib.rs

@@ -51,6 +51,7 @@
 #![feature(ref_slice)]
 #![feature(rustc_diagnostic_macros)]
 #![feature(rustc_private)]
+#![feature(scoped_tls)]
 #![feature(slice_bytes)]
 #![feature(slice_extras)]
 #![feature(slice_patterns)]

src/librustc/metadata/tydecode.rs

@@ -898,7 +898,7 @@ fn parse_builtin_bounds<F>(st: &mut PState, mut _conv: F) -> ty::BuiltinBounds w
 fn parse_builtin_bounds_<F>(st: &mut PState, _conv: &mut F) -> ty::BuiltinBounds where
     F: FnMut(DefIdSource, ast::DefId) -> ast::DefId,
 {
-    let mut builtin_bounds = ty::empty_builtin_bounds();
+    let mut builtin_bounds = ty::BuiltinBounds::empty();
 
     loop {
         match next(st) {

src/librustc/middle/astconv_util.rs

@@ -17,7 +17,6 @@
 use middle::def;
 use middle::ty::{self, Ty};
 use syntax::ast;
-use util::ppaux::Repr;
 
 pub const NO_REGIONS: usize = 1;
 pub const NO_TPS: usize = 2;
@@ -63,7 +62,7 @@ pub fn ast_ty_to_prim_ty<'tcx>(tcx: &ty::ctxt<'tcx>, ast_ty: &ast::Ty)
         let def = match tcx.def_map.borrow().get(&ast_ty.id) {
             None => {
                 tcx.sess.span_bug(ast_ty.span,
-                                  &format!("unbound path {}", path.repr(tcx)))
+                                  &format!("unbound path {:?}", path))
             }
             Some(d) => d.full_def()
         };

src/librustc/middle/astencode.rs

@@ -31,7 +31,6 @@ use middle::privacy::{AllPublic, LastMod};
 use middle::subst;
 use middle::subst::VecPerParamSpace;
 use middle::ty::{self, Ty, MethodCall, MethodCallee, MethodOrigin};
-use util::ppaux::ty_to_string;
 
 use syntax::{ast, ast_util, codemap, fold};
 use syntax::codemap::Span;
@@ -1623,8 +1622,8 @@ fn decode_side_tables(dcx: &DecodeContext,
                     }
                     c::tag_table_node_type => {
                         let ty = val_dsr.read_ty(dcx);
-                        debug!("inserting ty for node {}: {}",
-                               id, ty_to_string(dcx.tcx, ty));
+                        debug!("inserting ty for node {}: {:?}",
+                               id,  ty);
                         dcx.tcx.node_type_insert(id, ty);
                     }
                     c::tag_table_item_subst => {

src/librustc/middle/check_const.rs

@@ -33,7 +33,6 @@ use middle::mem_categorization as mc;
 use middle::traits;
 use middle::ty::{self, Ty};
 use util::nodemap::NodeMap;
-use util::ppaux::Repr;
 
 use syntax::ast;
 use syntax::codemap::Span;
@@ -300,7 +299,7 @@ impl<'a, 'tcx> CheckCrateVisitor<'a, 'tcx> {
 
 impl<'a, 'tcx, 'v> Visitor<'v> for CheckCrateVisitor<'a, 'tcx> {
     fn visit_item(&mut self, i: &ast::Item) {
-        debug!("visit_item(item={})", i.repr(self.tcx));
+        debug!("visit_item(item={})", self.tcx.map.node_to_string(i.id));
         match i.node {
             ast::ItemStatic(_, ast::MutImmutable, ref expr) => {
                 self.check_static_type(&**expr);

src/librustc/middle/check_match.rs

@@ -36,7 +36,6 @@ use syntax::print::pprust::pat_to_string;
 use syntax::parse::token;
 use syntax::ptr::P;
 use syntax::visit::{self, Visitor, FnKind};
-use util::ppaux::ty_to_string;
 use util::nodemap::FnvHashMap;
 
 pub const DUMMY_WILD_PAT: &'static Pat = &Pat {
@@ -209,9 +208,8 @@ fn check_expr(cx: &mut MatchCheckCtxt, ex: &ast::Expr) {
                 if !type_is_empty(cx.tcx, pat_ty) {
                     // We know the type is inhabited, so this must be wrong
                     span_err!(cx.tcx.sess, ex.span, E0002,
-                        "non-exhaustive patterns: type {} is non-empty",
-                        ty_to_string(cx.tcx, pat_ty)
-                    );
+                              "non-exhaustive patterns: type {} is non-empty",
+                              pat_ty);
                 }
                 // If the type *is* empty, it's vacuously exhaustive
                 return;
@@ -244,11 +242,11 @@ fn check_for_bindings_named_the_same_as_variants(cx: &MatchCheckCtxt, pat: &Pat)
                             span_warn!(cx.tcx.sess, p.span, E0170,
                                 "pattern binding `{}` is named the same as one \
                                  of the variants of the type `{}`",
-                                &token::get_ident(ident.node), ty_to_string(cx.tcx, pat_ty));
+                                &token::get_ident(ident.node), pat_ty);
                             fileline_help!(cx.tcx.sess, p.span,
                                 "if you meant to match on a variant, \
                                  consider making the path in the pattern qualified: `{}::{}`",
-                                ty_to_string(cx.tcx, pat_ty), &token::get_ident(ident.node));
+                                pat_ty, &token::get_ident(ident.node));
                         }
                     }
                 }

src/librustc/middle/check_rvalues.rs

@@ -15,7 +15,6 @@ use middle::expr_use_visitor as euv;
 use middle::mem_categorization as mc;
 use middle::ty::ParameterEnvironment;
 use middle::ty;
-use util::ppaux::ty_to_string;
 
 use syntax::ast;
 use syntax::codemap::Span;
@@ -59,11 +58,11 @@ impl<'a, 'tcx> euv::Delegate<'tcx> for RvalueContextDelegate<'a, 'tcx> {
                span: Span,
                cmt: mc::cmt<'tcx>,
                _: euv::ConsumeMode) {
-        debug!("consume; cmt: {:?}; type: {}", *cmt, ty_to_string(self.tcx, cmt.ty));
+        debug!("consume; cmt: {:?}; type: {:?}", *cmt, cmt.ty);
         if !ty::type_is_sized(Some(self.param_env), self.tcx, span, cmt.ty) {
             span_err!(self.tcx.sess, span, E0161,
                 "cannot move a value of type {0}: the size of {0} cannot be statically determined",
-                ty_to_string(self.tcx, cmt.ty));
+                cmt.ty);
         }
     }
 

src/librustc/middle/const_eval.rs

@@ -23,7 +23,6 @@ use middle::pat_util::def_to_path;
 use middle::ty::{self, Ty};
 use middle::astconv_util::ast_ty_to_prim_ty;
 use util::num::ToPrimitive;
-use util::ppaux::Repr;
 
 use syntax::ast::{self, Expr};
 use syntax::ast_util;
@@ -1030,8 +1029,8 @@ fn resolve_trait_associated_const<'a, 'tcx: 'a>(tcx: &'a ty::ctxt<'tcx>,
                                                            rcvr_self,
                                                            Vec::new()));
     let trait_substs = tcx.mk_substs(trait_substs);
-    debug!("resolve_trait_associated_const: trait_substs={}",
-           trait_substs.repr(tcx));
+    debug!("resolve_trait_associated_const: trait_substs={:?}",
+           trait_substs);
     let trait_ref = ty::Binder(ty::TraitRef { def_id: trait_id,
                                               substs: trait_substs });
 
@@ -1052,10 +1051,10 @@ fn resolve_trait_associated_const<'a, 'tcx: 'a>(tcx: &'a ty::ctxt<'tcx>,
         }
         Err(e) => {
             tcx.sess.span_bug(ti.span,
-                              &format!("Encountered error `{}` when trying \
+                              &format!("Encountered error `{:?}` when trying \
                                         to select an implementation for \
                                         constant trait item reference.",
-                                       e.repr(tcx)))
+                                       e))
         }
     };
 

src/librustc/middle/effect.rs

@@ -15,7 +15,6 @@ use self::UnsafeContext::*;
 use middle::def;
 use middle::ty::{self, Ty};
 use middle::ty::MethodCall;
-use util::ppaux;
 
 use syntax::ast;
 use syntax::codemap::Span;
@@ -66,8 +65,8 @@ impl<'a, 'tcx> EffectCheckVisitor<'a, 'tcx> {
             ast::ExprIndex(ref base, _) => ty::node_id_to_type(self.tcx, base.id),
             _ => return
         };
-        debug!("effect: checking index with base type {}",
-                ppaux::ty_to_string(self.tcx, base_type));
+        debug!("effect: checking index with base type {:?}",
+                 base_type);
         match base_type.sty {
             ty::TyBox(ty) | ty::TyRef(_, ty::mt{ty, ..}) => if ty::TyStr == ty.sty {
                 span_err!(self.tcx.sess, e.span, E0134,
@@ -142,8 +141,8 @@ impl<'a, 'tcx, 'v> Visitor<'v> for EffectCheckVisitor<'a, 'tcx> {
             ast::ExprMethodCall(_, _, _) => {
                 let method_call = MethodCall::expr(expr.id);
                 let base_type = self.tcx.method_map.borrow().get(&method_call).unwrap().ty;
-                debug!("effect: method call case, base type is {}",
-                       ppaux::ty_to_string(self.tcx, base_type));
+                debug!("effect: method call case, base type is {:?}",
+                        base_type);
                 if type_is_unsafe_function(base_type) {
                     self.require_unsafe(expr.span,
                                         "invocation of unsafe method")
@@ -151,16 +150,16 @@ impl<'a, 'tcx, 'v> Visitor<'v> for EffectCheckVisitor<'a, 'tcx> {
             }
             ast::ExprCall(ref base, _) => {
                 let base_type = ty::node_id_to_type(self.tcx, base.id);
-                debug!("effect: call case, base type is {}",
-                       ppaux::ty_to_string(self.tcx, base_type));
+                debug!("effect: call case, base type is {:?}",
+                        base_type);
                 if type_is_unsafe_function(base_type) {
                     self.require_unsafe(expr.span, "call to unsafe function")
                 }
             }
             ast::ExprUnary(ast::UnDeref, ref base) => {
                 let base_type = ty::node_id_to_type(self.tcx, base.id);
-                debug!("effect: unary case, base type is {}",
-                       ppaux::ty_to_string(self.tcx, base_type));
+                debug!("effect: unary case, base type is {:?}",
+                        base_type);
                 if let ty::TyRawPtr(_) = base_type.sty {
                     self.require_unsafe(expr.span, "dereference of raw pointer")
                 }

src/librustc/middle/expr_use_visitor.rs

@@ -27,7 +27,6 @@ use middle::ty::{self};
 use middle::ty::{MethodCall, MethodObject, MethodTraitObject};
 use middle::ty::{MethodOrigin, MethodParam, MethodTypeParam};
 use middle::ty::{MethodStatic, MethodStaticClosure};
-use util::ppaux::Repr;
 
 use syntax::{ast, ast_util};
 use syntax::ptr::P;
@@ -362,8 +361,8 @@ impl<'d,'t,'tcx,TYPER:mc::Typer<'tcx>> ExprUseVisitor<'d,'t,'tcx,TYPER> {
                         consume_id: ast::NodeId,
                         consume_span: Span,
                         cmt: mc::cmt<'tcx>) {
-        debug!("delegate_consume(consume_id={}, cmt={})",
-               consume_id, cmt.repr(self.tcx()));
+        debug!("delegate_consume(consume_id={}, cmt={:?})",
+               consume_id, cmt);
 
         let mode = copy_or_move(self.typer, &cmt, DirectRefMove);
         self.delegate.consume(consume_id, consume_span, cmt, mode);
@@ -376,7 +375,7 @@ impl<'d,'t,'tcx,TYPER:mc::Typer<'tcx>> ExprUseVisitor<'d,'t,'tcx,TYPER> {
     }
 
     pub fn consume_expr(&mut self, expr: &ast::Expr) {
-        debug!("consume_expr(expr={})", expr.repr(self.tcx()));
+        debug!("consume_expr(expr={:?})", expr);
 
         let cmt = return_if_err!(self.mc.cat_expr(expr));
         self.delegate_consume(expr.id, expr.span, cmt);
@@ -397,8 +396,8 @@ impl<'d,'t,'tcx,TYPER:mc::Typer<'tcx>> ExprUseVisitor<'d,'t,'tcx,TYPER> {
                    r: ty::Region,
                    bk: ty::BorrowKind,
                    cause: LoanCause) {
-        debug!("borrow_expr(expr={}, r={}, bk={})",
-               expr.repr(self.tcx()), r.repr(self.tcx()), bk.repr(self.tcx()));
+        debug!("borrow_expr(expr={:?}, r={:?}, bk={:?})",
+               expr, r, bk);
 
         let cmt = return_if_err!(self.mc.cat_expr(expr));
         self.delegate.borrow(expr.id, expr.span, cmt, r, bk, cause);
@@ -414,7 +413,7 @@ impl<'d,'t,'tcx,TYPER:mc::Typer<'tcx>> ExprUseVisitor<'d,'t,'tcx,TYPER> {
     }
 
     pub fn walk_expr(&mut self, expr: &ast::Expr) {
-        debug!("walk_expr(expr={})", expr.repr(self.tcx()));
+        debug!("walk_expr(expr={:?})", expr);
 
         self.walk_adjustment(expr);
 
@@ -618,8 +617,8 @@ impl<'d,'t,'tcx,TYPER:mc::Typer<'tcx>> ExprUseVisitor<'d,'t,'tcx,TYPER> {
 
     fn walk_callee(&mut self, call: &ast::Expr, callee: &ast::Expr) {
         let callee_ty = return_if_err!(self.typer.expr_ty_adjusted(callee));
-        debug!("walk_callee: callee={} callee_ty={}",
-               callee.repr(self.tcx()), callee_ty.repr(self.tcx()));
+        debug!("walk_callee: callee={:?} callee_ty={:?}",
+               callee, callee_ty);
         let call_scope = region::CodeExtent::from_node_id(call.id);
         match callee_ty.sty {
             ty::TyBareFn(..) => {
@@ -637,7 +636,7 @@ impl<'d,'t,'tcx,TYPER:mc::Typer<'tcx>> ExprUseVisitor<'d,'t,'tcx,TYPER> {
                         None => {
                             self.tcx().sess.span_bug(
                                 callee.span,
-                                &format!("unexpected callee type {}", callee_ty.repr(self.tcx())))
+                                &format!("unexpected callee type {}", callee_ty))
                         }
                     };
                 match overloaded_call_type {
@@ -811,7 +810,7 @@ impl<'d,'t,'tcx,TYPER:mc::Typer<'tcx>> ExprUseVisitor<'d,'t,'tcx,TYPER> {
     fn walk_autoderefs(&mut self,
                        expr: &ast::Expr,
                        autoderefs: usize) {
-        debug!("walk_autoderefs expr={} autoderefs={}", expr.repr(self.tcx()), autoderefs);
+        debug!("walk_autoderefs expr={:?} autoderefs={}", expr, autoderefs);
 
         for i in 0..autoderefs {
             let deref_id = ty::MethodCall::autoderef(expr.id, i as u32);
@@ -828,8 +827,8 @@ impl<'d,'t,'tcx,TYPER:mc::Typer<'tcx>> ExprUseVisitor<'d,'t,'tcx,TYPER> {
                     let (m, r) = match self_ty.sty {
                         ty::TyRef(r, ref m) => (m.mutbl, r),
                         _ => self.tcx().sess.span_bug(expr.span,
-                                &format!("bad overloaded deref type {}",
-                                    method_ty.repr(self.tcx())))
+                                &format!("bad overloaded deref type {:?}",
+                                    method_ty))
                     };
                     let bk = ty::BorrowKind::from_mutbl(m);
                     self.delegate.borrow(expr.id, expr.span, cmt,
@@ -842,9 +841,9 @@ impl<'d,'t,'tcx,TYPER:mc::Typer<'tcx>> ExprUseVisitor<'d,'t,'tcx,TYPER> {
     fn walk_autoderefref(&mut self,
                          expr: &ast::Expr,
                          adj: &ty::AutoDerefRef<'tcx>) {
-        debug!("walk_autoderefref expr={} adj={}",
-               expr.repr(self.tcx()),
-               adj.repr(self.tcx()));
+        debug!("walk_autoderefref expr={:?} adj={:?}",
+               expr,
+               adj);
 
         self.walk_autoderefs(expr, adj.autoderefs);
 
@@ -875,9 +874,9 @@ impl<'d,'t,'tcx,TYPER:mc::Typer<'tcx>> ExprUseVisitor<'d,'t,'tcx,TYPER> {
                     opt_autoref: Option<ty::AutoRef<'tcx>>)
                     -> mc::cmt<'tcx>
     {
-        debug!("walk_autoref(expr.id={} cmt_derefd={} opt_autoref={:?})",
+        debug!("walk_autoref(expr.id={} cmt_derefd={:?} opt_autoref={:?})",
                expr.id,
-               cmt_base.repr(self.tcx()),
+               cmt_base,
                opt_autoref);
 
         let cmt_base_ty = cmt_base.ty;
@@ -901,9 +900,9 @@ impl<'d,'t,'tcx,TYPER:mc::Typer<'tcx>> ExprUseVisitor<'d,'t,'tcx,TYPER> {
             }
 
             ty::AutoUnsafe(m) => {
-                debug!("walk_autoref: expr.id={} cmt_base={}",
+                debug!("walk_autoref: expr.id={} cmt_base={:?}",
                        expr.id,
-                       cmt_base.repr(self.tcx()));
+                       cmt_base);
 
                 // Converting from a &T to *T (or &mut T to *mut T) is
                 // treated as borrowing it for the enclosing temporary
@@ -1011,8 +1010,8 @@ impl<'d,'t,'tcx,TYPER:mc::Typer<'tcx>> ExprUseVisitor<'d,'t,'tcx,TYPER> {
                                cmt_discr: mc::cmt<'tcx>,
                                pat: &ast::Pat,
                                mode: &mut TrackMatchMode) {
-        debug!("determine_pat_move_mode cmt_discr={} pat={}", cmt_discr.repr(self.tcx()),
-               pat.repr(self.tcx()));
+        debug!("determine_pat_move_mode cmt_discr={:?} pat={:?}", cmt_discr,
+               pat);
         return_if_err!(self.mc.cat_pattern(cmt_discr, pat, |_mc, cmt_pat, pat| {
             let tcx = self.tcx();
             let def_map = &self.tcx().def_map;
@@ -1043,8 +1042,8 @@ impl<'d,'t,'tcx,TYPER:mc::Typer<'tcx>> ExprUseVisitor<'d,'t,'tcx,TYPER> {
                 cmt_discr: mc::cmt<'tcx>,
                 pat: &ast::Pat,
                 match_mode: MatchMode) {
-        debug!("walk_pat cmt_discr={} pat={}", cmt_discr.repr(self.tcx()),
-               pat.repr(self.tcx()));
+        debug!("walk_pat cmt_discr={:?} pat={:?}", cmt_discr,
+               pat);
 
         let mc = &self.mc;
         let typer = self.typer;
@@ -1054,9 +1053,9 @@ impl<'d,'t,'tcx,TYPER:mc::Typer<'tcx>> ExprUseVisitor<'d,'t,'tcx,TYPER> {
             if pat_util::pat_is_binding(def_map, pat) {
                 let tcx = typer.tcx();
 
-                debug!("binding cmt_pat={} pat={} match_mode={:?}",
-                       cmt_pat.repr(tcx),
-                       pat.repr(tcx),
+                debug!("binding cmt_pat={:?} pat={:?} match_mode={:?}",
+                       cmt_pat,
+                       pat,
                        match_mode);
 
                 // pat_ty: the type of the binding being produced.
@@ -1160,9 +1159,9 @@ impl<'d,'t,'tcx,TYPER:mc::Typer<'tcx>> ExprUseVisitor<'d,'t,'tcx,TYPER> {
                                     mc.cat_downcast(pat, cmt_pat, cmt_pat_ty, variant_did)
                                 };
 
-                            debug!("variant downcast_cmt={} pat={}",
-                                   downcast_cmt.repr(tcx),
-                                   pat.repr(tcx));
+                            debug!("variant downcast_cmt={:?} pat={:?}",
+                                   downcast_cmt,
+                                   pat);
 
                             delegate.matched_pat(pat, downcast_cmt, match_mode);
                         }
@@ -1172,9 +1171,9 @@ impl<'d,'t,'tcx,TYPER:mc::Typer<'tcx>> ExprUseVisitor<'d,'t,'tcx,TYPER> {
                             // namespace; we encounter the former on
                             // e.g. patterns for unit structs).
 
-                            debug!("struct cmt_pat={} pat={}",
-                                   cmt_pat.repr(tcx),
-                                   pat.repr(tcx));
+                            debug!("struct cmt_pat={:?} pat={:?}",
+                                   cmt_pat,
+                                   pat);
 
                             delegate.matched_pat(pat, cmt_pat, match_mode);
                         }
@@ -1192,9 +1191,9 @@ impl<'d,'t,'tcx,TYPER:mc::Typer<'tcx>> ExprUseVisitor<'d,'t,'tcx,TYPER> {
                             // pattern.
 
                             if !tcx.sess.has_errors() {
-                                let msg = format!("Pattern has unexpected type: {:?} and type {}",
+                                let msg = format!("Pattern has unexpected type: {:?} and type {:?}",
                                                   def,
-                                                  cmt_pat.ty.repr(tcx));
+                                                  cmt_pat.ty);
                                 tcx.sess.span_bug(pat.span, &msg)
                             }
                         }
@@ -1209,9 +1208,9 @@ impl<'d,'t,'tcx,TYPER:mc::Typer<'tcx>> ExprUseVisitor<'d,'t,'tcx,TYPER> {
                             // reported.
 
                             if !tcx.sess.has_errors() {
-                                let msg = format!("Pattern has unexpected def: {:?} and type {}",
+                                let msg = format!("Pattern has unexpected def: {:?} and type {:?}",
                                                   def,
-                                                  cmt_pat.ty.repr(tcx));
+                                                  cmt_pat.ty);
                                 tcx.sess.span_bug(pat.span, &msg[..])
                             }
                         }
@@ -1237,7 +1236,7 @@ impl<'d,'t,'tcx,TYPER:mc::Typer<'tcx>> ExprUseVisitor<'d,'t,'tcx,TYPER> {
     }
 
     fn walk_captures(&mut self, closure_expr: &ast::Expr) {
-        debug!("walk_captures({})", closure_expr.repr(self.tcx()));
+        debug!("walk_captures({:?})", closure_expr);
 
         ty::with_freevars(self.tcx(), closure_expr.id, |freevars| {
             for freevar in freevars {

src/librustc/middle/free_region.rs

@@ -14,7 +14,6 @@ use middle::implicator::Implication;
 use middle::ty::{self, FreeRegion};
 use util::common::can_reach;
 use util::nodemap::FnvHashMap;
-use util::ppaux::Repr;
 
 #[derive(Clone)]
 pub struct FreeRegionMap {
@@ -29,11 +28,10 @@ impl FreeRegionMap {
     }
 
     pub fn relate_free_regions_from_implications<'tcx>(&mut self,
-                                                       tcx: &ty::ctxt<'tcx>,
                                                        implications: &[Implication<'tcx>])
     {
         for implication in implications {
-            debug!("implication: {}", implication.repr(tcx));
+            debug!("implication: {:?}", implication);
             match *implication {
                 Implication::RegionSubRegion(_, ty::ReFree(free_a), ty::ReFree(free_b)) => {
                     self.relate_free_regions(free_a, free_b);
@@ -50,7 +48,7 @@ impl FreeRegionMap {
     pub fn relate_free_regions_from_predicates<'tcx>(&mut self,
                                                      tcx: &ty::ctxt<'tcx>,
                                                      predicates: &[ty::Predicate<'tcx>]) {
-        debug!("relate_free_regions_from_predicates(predicates={})", predicates.repr(tcx));
+        debug!("relate_free_regions_from_predicates(predicates={:?})", predicates);
         for predicate in predicates {
             match *predicate {
                 ty::Predicate::Projection(..) |
@@ -68,9 +66,9 @@ impl FreeRegionMap {
                         _ => {
                             // All named regions are instantiated with free regions.
                             tcx.sess.bug(
-                                &format!("record_region_bounds: non free region: {} / {}",
-                                         r_a.repr(tcx),
-                                         r_b.repr(tcx)));
+                                &format!("record_region_bounds: non free region: {:?} / {:?}",
+                                         r_a,
+                                         r_b));
                         }
                     }
                 }

src/librustc/middle/implicator.rs

@@ -21,10 +21,10 @@ use syntax::codemap::Span;
 
 use util::common::ErrorReported;
 use util::nodemap::FnvHashSet;
-use util::ppaux::Repr;
 
 // Helper functions related to manipulating region types.
 
+#[derive(Debug)]
 pub enum Implication<'tcx> {
     RegionSubRegion(Option<Ty<'tcx>>, ty::Region, ty::Region),
     RegionSubGeneric(Option<Ty<'tcx>>, ty::Region, GenericKind<'tcx>),
@@ -53,10 +53,10 @@ pub fn implications<'a,'tcx>(
     span: Span)
     -> Vec<Implication<'tcx>>
 {
-    debug!("implications(body_id={}, ty={}, outer_region={})",
+    debug!("implications(body_id={}, ty={:?}, outer_region={:?})",
            body_id,
-           ty.repr(closure_typer.tcx()),
-           outer_region.repr(closure_typer.tcx()));
+           ty,
+           outer_region);
 
     let mut stack = Vec::new();
     stack.push((outer_region, None));
@@ -68,7 +68,7 @@ pub fn implications<'a,'tcx>(
                               out: Vec::new(),
                               visited: FnvHashSet() };
     wf.accumulate_from_ty(ty);
-    debug!("implications: out={}", wf.out.repr(closure_typer.tcx()));
+    debug!("implications: out={:?}", wf.out);
     wf.out
 }
 
@@ -78,8 +78,8 @@ impl<'a, 'tcx> Implicator<'a, 'tcx> {
     }
 
     fn accumulate_from_ty(&mut self, ty: Ty<'tcx>) {
-        debug!("accumulate_from_ty(ty={})",
-               ty.repr(self.tcx()));
+        debug!("accumulate_from_ty(ty={:?})",
+               ty);
 
         // When expanding out associated types, we can visit a cyclic
         // set of types. Issue #23003.
@@ -312,8 +312,8 @@ impl<'a, 'tcx> Implicator<'a, 'tcx> {
     fn accumulate_from_assoc_types_transitive(&mut self,
                                               data: &ty::PolyTraitPredicate<'tcx>)
     {
-        debug!("accumulate_from_assoc_types_transitive({})",
-               data.repr(self.tcx()));
+        debug!("accumulate_from_assoc_types_transitive({:?})",
+               data);
 
         for poly_trait_ref in traits::supertraits(self.tcx(), data.to_poly_trait_ref()) {
             match ty::no_late_bound_regions(self.tcx(), &poly_trait_ref) {
@@ -326,8 +326,8 @@ impl<'a, 'tcx> Implicator<'a, 'tcx> {
     fn accumulate_from_assoc_types(&mut self,
                                    trait_ref: ty::TraitRef<'tcx>)
     {
-        debug!("accumulate_from_assoc_types({})",
-               trait_ref.repr(self.tcx()));
+        debug!("accumulate_from_assoc_types({:?})",
+               trait_ref);
 
         let trait_def_id = trait_ref.def_id;
         let trait_def = ty::lookup_trait_def(self.tcx(), trait_def_id);
@@ -336,8 +336,8 @@ impl<'a, 'tcx> Implicator<'a, 'tcx> {
                      .iter()
                      .map(|&name| ty::mk_projection(self.tcx(), trait_ref.clone(), name))
                      .collect();
-        debug!("accumulate_from_assoc_types: assoc_type_projections={}",
-               assoc_type_projections.repr(self.tcx()));
+        debug!("accumulate_from_assoc_types: assoc_type_projections={:?}",
+               assoc_type_projections);
         let tys = match self.fully_normalize(&assoc_type_projections) {
             Ok(tys) => { tys }
             Err(ErrorReported) => { return; }
@@ -400,7 +400,7 @@ impl<'a, 'tcx> Implicator<'a, 'tcx> {
     }
 
     fn fully_normalize<T>(&self, value: &T) -> Result<T,ErrorReported>
-        where T : TypeFoldable<'tcx> + ty::HasProjectionTypes + Clone + Repr<'tcx>
+        where T : TypeFoldable<'tcx> + ty::HasProjectionTypes
     {
         let value =
             traits::fully_normalize(self.infcx,
@@ -454,34 +454,3 @@ pub fn object_region_bounds<'tcx>(
     let predicates = ty::predicates(tcx, open_ty, &param_bounds);
     ty::required_region_bounds(tcx, open_ty, predicates)
 }
-
-impl<'tcx> Repr<'tcx> for Implication<'tcx> {
-    fn repr(&self, tcx: &ty::ctxt<'tcx>) -> String {
-        match *self {
-            Implication::RegionSubRegion(_, ref r_a, ref r_b) => {
-                format!("RegionSubRegion({}, {})",
-                        r_a.repr(tcx),
-                        r_b.repr(tcx))
-            }
-
-            Implication::RegionSubGeneric(_, ref r, ref p) => {
-                format!("RegionSubGeneric({}, {})",
-                        r.repr(tcx),
-                        p.repr(tcx))
-            }
-
-            Implication::RegionSubClosure(_, ref a, ref b, ref c) => {
-                format!("RegionSubClosure({}, {}, {})",
-                        a.repr(tcx),
-                        b.repr(tcx),
-                        c.repr(tcx))
-            }
-
-            Implication::Predicate(ref def_id, ref p) => {
-                format!("Predicate({}, {})",
-                        def_id.repr(tcx),
-                        p.repr(tcx))
-            }
-        }
-    }
-}

src/librustc/middle/infer/bivariate.rs

@@ -31,7 +31,6 @@ use super::type_variable::{BiTo};
 use middle::ty::{self, Ty};
 use middle::ty::TyVar;
 use middle::ty_relate::{Relate, RelateResult, TypeRelation};
-use util::ppaux::{Repr};
 
 pub struct Bivariate<'a, 'tcx: 'a> {
     fields: CombineFields<'a, 'tcx>
@@ -73,8 +72,8 @@ impl<'a, 'tcx> TypeRelation<'a, 'tcx> for Bivariate<'a, 'tcx> {
     }
 
     fn tys(&mut self, a: Ty<'tcx>, b: Ty<'tcx>) -> RelateResult<'tcx, Ty<'tcx>> {
-        debug!("{}.tys({}, {})", self.tag(),
-               a.repr(self.fields.infcx.tcx), b.repr(self.fields.infcx.tcx));
+        debug!("{}.tys({:?}, {:?})", self.tag(),
+               a, b);
         if a == b { return Ok(a); }
 
         let infcx = self.fields.infcx;

src/librustc/middle/infer/combine.rs

@@ -47,7 +47,6 @@ use middle::ty::{self, Ty};
 use middle::ty_fold;
 use middle::ty_fold::{TypeFolder, TypeFoldable};
 use middle::ty_relate::{self, Relate, RelateResult, TypeRelation};
-use util::ppaux::Repr;
 
 use syntax::ast;
 use syntax::codemap::Span;
@@ -187,7 +186,6 @@ impl<'a, 'tcx> CombineFields<'a, 'tcx> {
                        b_vid: ty::TyVid)
                        -> RelateResult<'tcx, ()>
     {
-        let tcx = self.infcx.tcx;
         let mut stack = Vec::new();
         stack.push((a_ty, dir, b_vid));
         loop {
@@ -213,10 +211,10 @@ impl<'a, 'tcx> CombineFields<'a, 'tcx> {
                 Some(e) => e,
             };
 
-            debug!("instantiate(a_ty={} dir={:?} b_vid={})",
-                   a_ty.repr(tcx),
+            debug!("instantiate(a_ty={:?} dir={:?} b_vid={:?})",
+                   a_ty,
                    dir,
-                   b_vid.repr(tcx));
+                   b_vid);
 
             // Check whether `vid` has been instantiated yet.  If not,
             // make a generalized form of `ty` and instantiate with
@@ -230,10 +228,10 @@ impl<'a, 'tcx> CombineFields<'a, 'tcx> {
                         EqTo => self.generalize(a_ty, b_vid, false),
                         BiTo | SupertypeOf | SubtypeOf => self.generalize(a_ty, b_vid, true),
                     });
-                    debug!("instantiate(a_ty={}, dir={:?}, \
-                                        b_vid={}, generalized_ty={})",
-                           a_ty.repr(tcx), dir, b_vid.repr(tcx),
-                           generalized_ty.repr(tcx));
+                    debug!("instantiate(a_ty={:?}, dir={:?}, \
+                                        b_vid={:?}, generalized_ty={:?})",
+                           a_ty, dir, b_vid,
+                           generalized_ty);
                     self.infcx.type_variables
                         .borrow_mut()
                         .instantiate_and_push(
@@ -335,8 +333,8 @@ impl<'cx, 'tcx> ty_fold::TypeFolder<'tcx> for Generalizer<'cx, 'tcx> {
             ty::ReEarlyBound(..) => {
                 self.tcx().sess.span_bug(
                     self.span,
-                    &format!("Encountered early bound region when generalizing: {}",
-                            r.repr(self.tcx())));
+                    &format!("Encountered early bound region when generalizing: {:?}",
+                            r));
             }
 
             // Always make a fresh region variable for skolemized regions;

src/librustc/middle/infer/equate.rs

@@ -16,7 +16,6 @@ use super::type_variable::{EqTo};
 use middle::ty::{self, Ty};
 use middle::ty::TyVar;
 use middle::ty_relate::{Relate, RelateResult, TypeRelation};
-use util::ppaux::{Repr};
 
 pub struct Equate<'a, 'tcx: 'a> {
     fields: CombineFields<'a, 'tcx>
@@ -45,8 +44,8 @@ impl<'a, 'tcx> TypeRelation<'a,'tcx> for Equate<'a, 'tcx> {
     }
 
     fn tys(&mut self, a: Ty<'tcx>, b: Ty<'tcx>) -> RelateResult<'tcx, Ty<'tcx>> {
-        debug!("{}.tys({}, {})", self.tag(),
-               a.repr(self.fields.infcx.tcx), b.repr(self.fields.infcx.tcx));
+        debug!("{}.tys({:?}, {:?})", self.tag(),
+               a, b);
         if a == b { return Ok(a); }
 
         let infcx = self.fields.infcx;
@@ -75,10 +74,10 @@ impl<'a, 'tcx> TypeRelation<'a,'tcx> for Equate<'a, 'tcx> {
     }
 
     fn regions(&mut self, a: ty::Region, b: ty::Region) -> RelateResult<'tcx, ty::Region> {
-        debug!("{}.regions({}, {})",
+        debug!("{}.regions({:?}, {:?})",
                self.tag(),
-               a.repr(self.fields.infcx.tcx),
-               b.repr(self.fields.infcx.tcx));
+               a,
+               b);
         let origin = Subtype(self.fields.trace.clone());
         self.fields.infcx.region_vars.make_eqregion(origin, a, b);
         Ok(a)

src/librustc/middle/infer/error_reporting.rs

@@ -75,25 +75,141 @@ use std::collections::HashSet;
 use ast_map;
 use middle::def;
 use middle::infer;
+use middle::region;
 use middle::subst;
 use middle::ty::{self, Ty};
 use middle::ty::{Region, ReFree};
+
 use std::cell::{Cell, RefCell};
 use std::char::from_u32;
-use std::string::String;
+use std::fmt;
 use syntax::ast;
 use syntax::ast_util::name_to_dummy_lifetime;
 use syntax::owned_slice::OwnedSlice;
-use syntax::codemap;
+use syntax::codemap::{Pos, Span};
 use syntax::parse::token;
 use syntax::print::pprust;
 use syntax::ptr::P;
-use util::ppaux::bound_region_to_string;
-use util::ppaux::note_and_explain_region;
 
-// Note: only import UserString, not Repr, since user-facing error
-// messages shouldn't include debug serializations.
-use util::ppaux::UserString;
+pub fn note_and_explain_region(tcx: &ty::ctxt,
+                               prefix: &str,
+                               region: ty::Region,
+                               suffix: &str) {
+    fn item_scope_tag(item: &ast::Item) -> &'static str {
+        match item.node {
+            ast::ItemImpl(..) => "impl",
+            ast::ItemStruct(..) => "struct",
+            ast::ItemEnum(..) => "enum",
+            ast::ItemTrait(..) => "trait",
+            ast::ItemFn(..) => "function body",
+            _ => "item"
+        }
+    }
+
+    fn explain_span(tcx: &ty::ctxt, heading: &str, span: Span)
+                    -> (String, Option<Span>) {
+        let lo = tcx.sess.codemap().lookup_char_pos_adj(span.lo);
+        (format!("the {} at {}:{}", heading, lo.line, lo.col.to_usize()),
+         Some(span))
+    }
+
+    let (description, span) = match region {
+        ty::ReScope(scope) => {
+            let new_string;
+            let unknown_scope = || {
+                format!("{}unknown scope: {:?}{}.  Please report a bug.",
+                        prefix, scope, suffix)
+            };
+            let span = match scope.span(&tcx.map) {
+                Some(s) => s,
+                None => return tcx.sess.note(&unknown_scope())
+            };
+            let tag = match tcx.map.find(scope.node_id()) {
+                Some(ast_map::NodeBlock(_)) => "block",
+                Some(ast_map::NodeExpr(expr)) => match expr.node {
+                    ast::ExprCall(..) => "call",
+                    ast::ExprMethodCall(..) => "method call",
+                    ast::ExprMatch(_, _, ast::MatchSource::IfLetDesugar { .. }) => "if let",
+                    ast::ExprMatch(_, _, ast::MatchSource::WhileLetDesugar) =>  "while let",
+                    ast::ExprMatch(_, _, ast::MatchSource::ForLoopDesugar) =>  "for",
+                    ast::ExprMatch(..) => "match",
+                    _ => "expression",
+                },
+                Some(ast_map::NodeStmt(_)) => "statement",
+                Some(ast_map::NodeItem(it)) => item_scope_tag(&*it),
+                Some(_) | None => {
+                    return tcx.sess.span_note(span, &unknown_scope());
+                }
+            };
+            let scope_decorated_tag = match scope {
+                region::CodeExtent::Misc(_) => tag,
+                region::CodeExtent::ParameterScope { .. } => {
+                    "scope of parameters for function"
+                }
+                region::CodeExtent::DestructionScope(_) => {
+                    new_string = format!("destruction scope surrounding {}", tag);
+                    &new_string[..]
+                }
+                region::CodeExtent::Remainder(r) => {
+                    new_string = format!("block suffix following statement {}",
+                                         r.first_statement_index);
+                    &new_string[..]
+                }
+            };
+            explain_span(tcx, scope_decorated_tag, span)
+        }
+
+        ty::ReFree(ref fr) => {
+            let prefix = match fr.bound_region {
+                ty::BrAnon(idx) => {
+                    format!("the anonymous lifetime #{} defined on", idx + 1)
+                }
+                ty::BrFresh(_) => "an anonymous lifetime defined on".to_owned(),
+                _ => {
+                    format!("the lifetime {} as defined on",
+                            fr.bound_region)
+                }
+            };
+
+            match tcx.map.find(fr.scope.node_id) {
+                Some(ast_map::NodeBlock(ref blk)) => {
+                    let (msg, opt_span) = explain_span(tcx, "block", blk.span);
+                    (format!("{} {}", prefix, msg), opt_span)
+                }
+                Some(ast_map::NodeItem(it)) => {
+                    let tag = item_scope_tag(&*it);
+                    let (msg, opt_span) = explain_span(tcx, tag, it.span);
+                    (format!("{} {}", prefix, msg), opt_span)
+                }
+                Some(_) | None => {
+                    // this really should not happen
+                    (format!("{} unknown free region bounded by scope {:?}",
+                             prefix, fr.scope), None)
+                }
+            }
+        }
+
+        ty::ReStatic => ("the static lifetime".to_owned(), None),
+
+        ty::ReEmpty => ("the empty lifetime".to_owned(), None),
+
+        ty::ReEarlyBound(ref data) => {
+            (format!("{}", token::get_name(data.name)), None)
+        }
+
+        // I believe these cases should not occur (except when debugging,
+        // perhaps)
+        ty::ReInfer(_) | ty::ReLateBound(..) => {
+            (format!("lifetime {:?}", region), None)
+        }
+    };
+    let message = format!("{}{}{}", prefix, description, suffix);
+    if let Some(span) = span {
+        tcx.sess.span_note(span, &message);
+    } else {
+        tcx.sess.note(&message);
+    }
+}
 
 pub trait ErrorReporting<'tcx> {
     fn report_region_errors(&self,
@@ -110,7 +226,7 @@ pub trait ErrorReporting<'tcx> {
 
     fn values_str(&self, values: &ValuePairs<'tcx>) -> Option<String>;
 
-    fn expected_found_str<T: UserString<'tcx> + Resolvable<'tcx>>(
+    fn expected_found_str<T: fmt::Display + Resolvable<'tcx>>(
         &self,
         exp_found: &ty::expected_found<T>)
         -> Option<String>;
@@ -162,7 +278,7 @@ trait ErrorReportingHelpers<'tcx> {
                                 ident: ast::Ident,
                                 opt_explicit_self: Option<&ast::ExplicitSelf_>,
                                 generics: &ast::Generics,
-                                span: codemap::Span);
+                                span: Span);
 }
 
 impl<'a, 'tcx> ErrorReporting<'tcx> for InferCtxt<'a, 'tcx> {
@@ -361,7 +477,7 @@ impl<'a, 'tcx> ErrorReporting<'tcx> for InferCtxt<'a, 'tcx> {
             "{}: {} ({})",
                  trace.origin,
                  expected_found_str,
-                 ty::type_err_to_str(self.tcx, terr));
+                 terr);
 
         match trace.origin {
             infer::MatchExpressionArm(_, arm_span) =>
@@ -388,7 +504,7 @@ impl<'a, 'tcx> ErrorReporting<'tcx> for InferCtxt<'a, 'tcx> {
         }
     }
 
-    fn expected_found_str<T: UserString<'tcx> + Resolvable<'tcx>>(
+    fn expected_found_str<T: fmt::Display + Resolvable<'tcx>>(
         &self,
         exp_found: &ty::expected_found<T>)
         -> Option<String>
@@ -404,8 +520,8 @@ impl<'a, 'tcx> ErrorReporting<'tcx> for InferCtxt<'a, 'tcx> {
         }
 
         Some(format!("expected `{}`, found `{}`",
-                     expected.user_string(self.tcx),
-                     found.user_string(self.tcx)))
+                     expected,
+                     found))
     }
 
     fn report_generic_bound_failure(&self,
@@ -421,9 +537,9 @@ impl<'a, 'tcx> ErrorReporting<'tcx> for InferCtxt<'a, 'tcx> {
 
         let labeled_user_string = match bound_kind {
             GenericKind::Param(ref p) =>
-                format!("the parameter type `{}`", p.user_string(self.tcx)),
+                format!("the parameter type `{}`", p),
             GenericKind::Projection(ref p) =>
-                format!("the associated type `{}`", p.user_string(self.tcx)),
+                format!("the associated type `{}`", p),
         };
 
         match sub {
@@ -435,8 +551,8 @@ impl<'a, 'tcx> ErrorReporting<'tcx> for InferCtxt<'a, 'tcx> {
                     origin.span(),
                     &format!(
                         "consider adding an explicit lifetime bound `{}: {}`...",
-                        bound_kind.user_string(self.tcx),
-                        sub.user_string(self.tcx)));
+                        bound_kind,
+                        sub));
             }
 
             ty::ReStatic => {
@@ -447,7 +563,7 @@ impl<'a, 'tcx> ErrorReporting<'tcx> for InferCtxt<'a, 'tcx> {
                     origin.span(),
                     &format!(
                         "consider adding an explicit lifetime bound `{}: 'static`...",
-                        bound_kind.user_string(self.tcx)));
+                        bound_kind));
             }
 
             _ => {
@@ -459,7 +575,7 @@ impl<'a, 'tcx> ErrorReporting<'tcx> for InferCtxt<'a, 'tcx> {
                     origin.span(),
                     &format!(
                         "consider adding an explicit lifetime bound for `{}`",
-                        bound_kind.user_string(self.tcx)));
+                        bound_kind));
                 note_and_explain_region(
                     self.tcx,
                     &format!("{} must be valid for ", labeled_user_string),
@@ -1431,7 +1547,7 @@ impl<'a, 'tcx> ErrorReportingHelpers<'tcx> for InferCtxt<'a, 'tcx> {
                                 ident: ast::Ident,
                                 opt_explicit_self: Option<&ast::ExplicitSelf_>,
                                 generics: &ast::Generics,
-                                span: codemap::Span) {
+                                span: Span) {
         let suggested_fn = pprust::fun_to_string(decl, unsafety, constness, ident,
                                                  opt_explicit_self, generics);
         let msg = format!("consider using an explicit lifetime \
@@ -1441,6 +1557,13 @@ impl<'a, 'tcx> ErrorReportingHelpers<'tcx> for InferCtxt<'a, 'tcx> {
 
     fn report_inference_failure(&self,
                                 var_origin: RegionVariableOrigin) {
+        let br_string = |br: ty::BoundRegion| {
+            let mut s = br.to_string();
+            if !s.is_empty() {
+                s.push_str(" ");
+            }
+            s
+        };
         let var_description = match var_origin {
             infer::MiscVariable(_) => "".to_string(),
             infer::PatternRegion(_) => " for pattern".to_string(),
@@ -1448,17 +1571,15 @@ impl<'a, 'tcx> ErrorReportingHelpers<'tcx> for InferCtxt<'a, 'tcx> {
             infer::Autoref(_) => " for autoref".to_string(),
             infer::Coercion(_) => " for automatic coercion".to_string(),
             infer::LateBoundRegion(_, br, infer::FnCall) => {
-                format!(" for {}in function call",
-                        bound_region_to_string(self.tcx, "lifetime parameter ", true, br))
+                format!(" for lifetime parameter {}in function call",
+                        br_string(br))
             }
             infer::LateBoundRegion(_, br, infer::HigherRankedType) => {
-                format!(" for {}in generic type",
-                        bound_region_to_string(self.tcx, "lifetime parameter ", true, br))
+                format!(" for lifetime parameter {}in generic type", br_string(br))
             }
             infer::LateBoundRegion(_, br, infer::AssocTypeProjection(type_name)) => {
-                format!(" for {}in trait containing associated type `{}`",
-                        bound_region_to_string(self.tcx, "lifetime parameter ", true, br),
-                        token::get_name(type_name))
+                format!(" for lifetime parameter {}in trait containing associated type `{}`",
+                        br_string(br), token::get_name(type_name))
             }
             infer::EarlyBoundRegion(_, name) => {
                 format!(" for lifetime parameter `{}`",

src/librustc/middle/infer/glb.rs

@@ -16,7 +16,6 @@ use super::Subtype;
 
 use middle::ty::{self, Ty};
 use middle::ty_relate::{Relate, RelateResult, TypeRelation};
-use util::ppaux::Repr;
 
 /// "Greatest lower bound" (common subtype)
 pub struct Glb<'a, 'tcx: 'a> {
@@ -55,10 +54,10 @@ impl<'a, 'tcx> TypeRelation<'a, 'tcx> for Glb<'a, 'tcx> {
     }
 
     fn regions(&mut self, a: ty::Region, b: ty::Region) -> RelateResult<'tcx, ty::Region> {
-        debug!("{}.regions({}, {})",
+        debug!("{}.regions({:?}, {:?})",
                self.tag(),
-               a.repr(self.fields.infcx.tcx),
-               b.repr(self.fields.infcx.tcx));
+               a,
+               b);
 
         let origin = Subtype(self.fields.trace.clone());
         Ok(self.fields.infcx.region_vars.glb_regions(origin, a, b))

src/librustc/middle/infer/higher_ranked/mod.rs

@@ -20,7 +20,6 @@ use middle::ty_fold::{self, TypeFoldable};
 use middle::ty_relate::{Relate, RelateResult, TypeRelation};
 use syntax::codemap::Span;
 use util::nodemap::{FnvHashMap, FnvHashSet};
-use util::ppaux::Repr;
 
 pub trait HigherRankedRelations<'a,'tcx> {
     fn higher_ranked_sub<T>(&self, a: &Binder<T>, b: &Binder<T>) -> RelateResult<'tcx, Binder<T>>
@@ -46,10 +45,8 @@ impl<'a,'tcx> HigherRankedRelations<'a,'tcx> for CombineFields<'a,'tcx> {
                             -> RelateResult<'tcx, Binder<T>>
         where T: Relate<'a,'tcx>
     {
-        let tcx = self.infcx.tcx;
-
-        debug!("higher_ranked_sub(a={}, b={})",
-               a.repr(tcx), b.repr(tcx));
+        debug!("higher_ranked_sub(a={:?}, b={:?})",
+               a, b);
 
         // Rather than checking the subtype relationship between `a` and `b`
         // as-is, we need to do some extra work here in order to make sure
@@ -75,8 +72,8 @@ impl<'a,'tcx> HigherRankedRelations<'a,'tcx> for CombineFields<'a,'tcx> {
             let (b_prime, skol_map) =
                 self.infcx.skolemize_late_bound_regions(b, snapshot);
 
-            debug!("a_prime={}", a_prime.repr(tcx));
-            debug!("b_prime={}", b_prime.repr(tcx));
+            debug!("a_prime={:?}", a_prime);
+            debug!("b_prime={:?}", b_prime);
 
             // Compare types now that bound regions have been replaced.
             let result = try!(self.sub().relate(&a_prime, &b_prime));
@@ -98,8 +95,8 @@ impl<'a,'tcx> HigherRankedRelations<'a,'tcx> for CombineFields<'a,'tcx> {
                 }
             }
 
-            debug!("higher_ranked_sub: OK result={}",
-                   result.repr(tcx));
+            debug!("higher_ranked_sub: OK result={:?}",
+                   result);
 
             Ok(ty::Binder(result))
         });
@@ -125,7 +122,7 @@ impl<'a,'tcx> HigherRankedRelations<'a,'tcx> for CombineFields<'a,'tcx> {
                 try!(self.lub().relate(&a_with_fresh, &b_with_fresh));
             let result0 =
                 self.infcx.resolve_type_vars_if_possible(&result0);
-            debug!("lub result0 = {}", result0.repr(self.tcx()));
+            debug!("lub result0 = {:?}", result0);
 
             // Generalize the regions appearing in result0 if possible
             let new_vars = self.infcx.region_vars_confined_to_snapshot(snapshot);
@@ -137,10 +134,10 @@ impl<'a,'tcx> HigherRankedRelations<'a,'tcx> for CombineFields<'a,'tcx> {
                     |r, debruijn| generalize_region(self.infcx, span, snapshot, debruijn,
                                                     &new_vars, &a_map, r));
 
-            debug!("lub({},{}) = {}",
-                   a.repr(self.tcx()),
-                   b.repr(self.tcx()),
-                   result1.repr(self.tcx()));
+            debug!("lub({:?},{:?}) = {:?}",
+                   a,
+                   b,
+                   result1);
 
             Ok(ty::Binder(result1))
         });
@@ -198,8 +195,8 @@ impl<'a,'tcx> HigherRankedRelations<'a,'tcx> for CombineFields<'a,'tcx> {
     fn higher_ranked_glb<T>(&self, a: &Binder<T>, b: &Binder<T>) -> RelateResult<'tcx, Binder<T>>
         where T: Relate<'a,'tcx>
     {
-        debug!("higher_ranked_glb({}, {})",
-               a.repr(self.tcx()), b.repr(self.tcx()));
+        debug!("higher_ranked_glb({:?}, {:?})",
+               a, b);
 
         // Make a snapshot so we can examine "all bindings that were
         // created as part of this type comparison".
@@ -219,7 +216,7 @@ impl<'a,'tcx> HigherRankedRelations<'a,'tcx> for CombineFields<'a,'tcx> {
                 try!(self.glb().relate(&a_with_fresh, &b_with_fresh));
             let result0 =
                 self.infcx.resolve_type_vars_if_possible(&result0);
-            debug!("glb result0 = {}", result0.repr(self.tcx()));
+            debug!("glb result0 = {:?}", result0);
 
             // Generalize the regions appearing in result0 if possible
             let new_vars = self.infcx.region_vars_confined_to_snapshot(snapshot);
@@ -233,10 +230,10 @@ impl<'a,'tcx> HigherRankedRelations<'a,'tcx> for CombineFields<'a,'tcx> {
                                                     &a_map, &a_vars, &b_vars,
                                                     r));
 
-            debug!("glb({},{}) = {}",
-                   a.repr(self.tcx()),
-                   b.repr(self.tcx()),
-                   result1.repr(self.tcx()));
+            debug!("glb({:?},{:?}) = {:?}",
+                   a,
+                   b,
+                   result1);
 
             Ok(ty::Binder(result1))
         });
@@ -451,9 +448,9 @@ impl<'a,'tcx> InferCtxtExt for InferCtxt<'a,'tcx> {
             !escaping_region_vars.contains(&r)
         });
 
-        debug!("region_vars_confined_to_snapshot: region_vars={} escaping_types={}",
-               region_vars.repr(self.tcx),
-               escaping_types.repr(self.tcx));
+        debug!("region_vars_confined_to_snapshot: region_vars={:?} escaping_types={:?}",
+               region_vars,
+               escaping_types);
 
         region_vars
     }
@@ -520,7 +517,7 @@ pub fn skolemize_late_bound_regions<'a,'tcx,T>(infcx: &InferCtxt<'a,'tcx>,
                                                binder: &ty::Binder<T>,
                                                snapshot: &CombinedSnapshot)
                                                -> (T, SkolemizationMap)
-    where T : TypeFoldable<'tcx> + Repr<'tcx>
+    where T : TypeFoldable<'tcx>
 {
     /*!
      * Replace all regions bound by `binder` with skolemized regions and
@@ -534,10 +531,10 @@ pub fn skolemize_late_bound_regions<'a,'tcx,T>(infcx: &InferCtxt<'a,'tcx>,
         infcx.region_vars.new_skolemized(br, &snapshot.region_vars_snapshot)
     });
 
-    debug!("skolemize_bound_regions(binder={}, result={}, map={})",
-           binder.repr(infcx.tcx),
-           result.repr(infcx.tcx),
-           map.repr(infcx.tcx));
+    debug!("skolemize_bound_regions(binder={:?}, result={:?}, map={:?})",
+           binder,
+           result,
+           map);
 
     (result, map)
 }
@@ -555,8 +552,8 @@ pub fn leak_check<'a,'tcx>(infcx: &InferCtxt<'a,'tcx>,
      * hold. See `README.md` for more details.
      */
 
-    debug!("leak_check: skol_map={}",
-           skol_map.repr(infcx.tcx));
+    debug!("leak_check: skol_map={:?}",
+           skol_map);
 
     let new_vars = infcx.region_vars_confined_to_snapshot(snapshot);
     for (&skol_br, &skol) in skol_map {
@@ -573,10 +570,10 @@ pub fn leak_check<'a,'tcx>(infcx: &InferCtxt<'a,'tcx>,
                 }
             };
 
-            debug!("{} (which replaced {}) is tainted by {}",
-                   skol.repr(infcx.tcx),
-                   skol_br.repr(infcx.tcx),
-                   tainted_region.repr(infcx.tcx));
+            debug!("{:?} (which replaced {:?}) is tainted by {:?}",
+                   skol,
+                   skol_br,
+                   tainted_region);
 
             // A is not as polymorphic as B:
             return Err((skol_br, tainted_region));
@@ -618,13 +615,13 @@ pub fn plug_leaks<'a,'tcx,T>(infcx: &InferCtxt<'a,'tcx>,
                              snapshot: &CombinedSnapshot,
                              value: &T)
                              -> T
-    where T : TypeFoldable<'tcx> + Repr<'tcx>
+    where T : TypeFoldable<'tcx>
 {
     debug_assert!(leak_check(infcx, &skol_map, snapshot).is_ok());
 
-    debug!("plug_leaks(skol_map={}, value={})",
-           skol_map.repr(infcx.tcx),
-           value.repr(infcx.tcx));
+    debug!("plug_leaks(skol_map={:?}, value={:?})",
+           skol_map,
+           value);
 
     // Compute a mapping from the "taint set" of each skolemized
     // region back to the `ty::BoundRegion` that it originally
@@ -640,8 +637,8 @@ pub fn plug_leaks<'a,'tcx,T>(infcx: &InferCtxt<'a,'tcx>,
         })
         .collect();
 
-    debug!("plug_leaks: inv_skol_map={}",
-           inv_skol_map.repr(infcx.tcx));
+    debug!("plug_leaks: inv_skol_map={:?}",
+           inv_skol_map);
 
     // Remove any instantiated type variables from `value`; those can hide
     // references to regions from the `fold_regions` code below.
@@ -669,8 +666,8 @@ pub fn plug_leaks<'a,'tcx,T>(infcx: &InferCtxt<'a,'tcx>,
         }
     });
 
-    debug!("plug_leaks: result={}",
-           result.repr(infcx.tcx));
+    debug!("plug_leaks: result={:?}",
+           result);
 
     result
 }

src/librustc/middle/infer/lattice.rs

@@ -35,7 +35,6 @@ use super::InferCtxt;
 use middle::ty::TyVar;
 use middle::ty::{self, Ty};
 use middle::ty_relate::{RelateResult, TypeRelation};
-use util::ppaux::Repr;
 
 pub trait LatticeDir<'f,'tcx> : TypeRelation<'f,'tcx> {
     fn infcx(&self) -> &'f InferCtxt<'f, 'tcx>;
@@ -51,10 +50,10 @@ pub fn super_lattice_tys<'a,'tcx,L:LatticeDir<'a,'tcx>>(this: &mut L,
                                                         -> RelateResult<'tcx, Ty<'tcx>>
     where 'tcx: 'a
 {
-    debug!("{}.lattice_tys({}, {})",
+    debug!("{}.lattice_tys({:?}, {:?})",
            this.tag(),
-           a.repr(this.tcx()),
-           b.repr(this.tcx()));
+           a,
+           b);
 
     if a == b {
         return Ok(a);

src/librustc/middle/infer/lub.rs

@@ -16,7 +16,6 @@ use super::Subtype;
 
 use middle::ty::{self, Ty};
 use middle::ty_relate::{Relate, RelateResult, TypeRelation};
-use util::ppaux::Repr;
 
 /// "Least upper bound" (common supertype)
 pub struct Lub<'a, 'tcx: 'a> {
@@ -55,10 +54,10 @@ impl<'a, 'tcx> TypeRelation<'a, 'tcx> for Lub<'a, 'tcx> {
     }
 
     fn regions(&mut self, a: ty::Region, b: ty::Region) -> RelateResult<'tcx, ty::Region> {
-        debug!("{}.regions({}, {})",
+        debug!("{}.regions({:?}, {:?})",
                self.tag(),
-               a.repr(self.tcx()),
-               b.repr(self.tcx()));
+               a,
+               b);
 
         let origin = Subtype(self.fields.trace.clone());
         Ok(self.fields.infcx.region_vars.lub_regions(origin, a, b))

src/librustc/middle/infer/mod.rs

@@ -36,8 +36,6 @@ use syntax::ast;
 use syntax::codemap;
 use syntax::codemap::Span;
 use util::nodemap::FnvHashMap;
-use util::ppaux::ty_to_string;
-use util::ppaux::{Repr, UserString};
 
 use self::combine::CombineFields;
 use self::region_inference::{RegionVarBindings, RegionSnapshot};
@@ -161,7 +159,7 @@ pub enum ValuePairs<'tcx> {
 /// encounter an error or subtyping constraint.
 ///
 /// See `error_reporting.rs` for more details.
-#[derive(Clone, Debug)]
+#[derive(Clone)]
 pub struct TypeTrace<'tcx> {
     origin: TypeOrigin,
     values: ValuePairs<'tcx>,
@@ -331,8 +329,8 @@ pub fn common_supertype<'a, 'tcx>(cx: &InferCtxt<'a, 'tcx>,
                                   b: Ty<'tcx>)
                                   -> Ty<'tcx>
 {
-    debug!("common_supertype({}, {})",
-           a.repr(cx.tcx), b.repr(cx.tcx));
+    debug!("common_supertype({:?}, {:?})",
+           a, b);
 
     let trace = TypeTrace {
         origin: origin,
@@ -356,7 +354,7 @@ pub fn mk_subty<'a, 'tcx>(cx: &InferCtxt<'a, 'tcx>,
                           b: Ty<'tcx>)
                           -> UnitResult<'tcx>
 {
-    debug!("mk_subty({} <: {})", a.repr(cx.tcx), b.repr(cx.tcx));
+    debug!("mk_subty({:?} <: {:?})", a, b);
     cx.sub_types(a_is_expected, origin, a, b)
 }
 
@@ -364,7 +362,7 @@ pub fn can_mk_subty<'a, 'tcx>(cx: &InferCtxt<'a, 'tcx>,
                               a: Ty<'tcx>,
                               b: Ty<'tcx>)
                               -> UnitResult<'tcx> {
-    debug!("can_mk_subty({} <: {})", a.repr(cx.tcx), b.repr(cx.tcx));
+    debug!("can_mk_subty({:?} <: {:?})", a, b);
     cx.probe(|_| {
         let trace = TypeTrace {
             origin: Misc(codemap::DUMMY_SP),
@@ -384,7 +382,7 @@ pub fn mk_subr<'a, 'tcx>(cx: &InferCtxt<'a, 'tcx>,
                          origin: SubregionOrigin<'tcx>,
                          a: ty::Region,
                          b: ty::Region) {
-    debug!("mk_subr({} <: {})", a.repr(cx.tcx), b.repr(cx.tcx));
+    debug!("mk_subr({:?} <: {:?})", a, b);
     let snapshot = cx.region_vars.start_snapshot();
     cx.region_vars.make_subregion(origin, a, b);
     cx.region_vars.commit(snapshot);
@@ -397,7 +395,7 @@ pub fn mk_eqty<'a, 'tcx>(cx: &InferCtxt<'a, 'tcx>,
                          b: Ty<'tcx>)
                          -> UnitResult<'tcx>
 {
-    debug!("mk_eqty({} <: {})", a.repr(cx.tcx), b.repr(cx.tcx));
+    debug!("mk_eqty({:?} <: {:?})", a, b);
     cx.commit_if_ok(|_| cx.eq_types(a_is_expected, origin, a, b))
 }
 
@@ -408,8 +406,8 @@ pub fn mk_sub_poly_trait_refs<'a, 'tcx>(cx: &InferCtxt<'a, 'tcx>,
                                    b: ty::PolyTraitRef<'tcx>)
                                    -> UnitResult<'tcx>
 {
-    debug!("mk_sub_trait_refs({} <: {})",
-           a.repr(cx.tcx), b.repr(cx.tcx));
+    debug!("mk_sub_trait_refs({:?} <: {:?})",
+           a, b);
     cx.commit_if_ok(|_| cx.sub_poly_trait_refs(a_is_expected, origin, a.clone(), b.clone()))
 }
 
@@ -638,7 +636,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
                      b: Ty<'tcx>)
                      -> UnitResult<'tcx>
     {
-        debug!("sub_types({} <: {})", a.repr(self.tcx), b.repr(self.tcx));
+        debug!("sub_types({:?} <: {:?})", a, b);
         self.commit_if_ok(|_| {
             let trace = TypeTrace::types(origin, a_is_expected, a, b);
             self.sub(a_is_expected, trace).relate(&a, &b).map(|_| ())
@@ -665,9 +663,9 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
                           b: ty::TraitRef<'tcx>)
                           -> UnitResult<'tcx>
     {
-        debug!("sub_trait_refs({} <: {})",
-               a.repr(self.tcx),
-               b.repr(self.tcx));
+        debug!("sub_trait_refs({:?} <: {:?})",
+               a,
+               b);
         self.commit_if_ok(|_| {
             let trace = TypeTrace {
                 origin: origin,
@@ -684,9 +682,9 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
                                b: ty::PolyTraitRef<'tcx>)
                                -> UnitResult<'tcx>
     {
-        debug!("sub_poly_trait_refs({} <: {})",
-               a.repr(self.tcx),
-               b.repr(self.tcx));
+        debug!("sub_poly_trait_refs({:?} <: {:?})",
+               a,
+               b);
         self.commit_if_ok(|_| {
             let trace = TypeTrace {
                 origin: origin,
@@ -709,7 +707,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
                                            value: &ty::Binder<T>,
                                            snapshot: &CombinedSnapshot)
                                            -> (T, SkolemizationMap)
-        where T : TypeFoldable<'tcx> + Repr<'tcx>
+        where T : TypeFoldable<'tcx>
     {
         /*! See `higher_ranked::skolemize_late_bound_regions` */
 
@@ -734,7 +732,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
                          snapshot: &CombinedSnapshot,
                          value: &T)
                          -> T
-        where T : TypeFoldable<'tcx> + Repr<'tcx>
+        where T : TypeFoldable<'tcx>
     {
         /*! See `higher_ranked::plug_leaks` */
 
@@ -862,8 +860,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
     }
 
     pub fn ty_to_string(&self, t: Ty<'tcx>) -> String {
-        ty_to_string(self.tcx,
-                     self.resolve_type_vars_if_possible(&t))
+        self.resolve_type_vars_if_possible(&t).to_string()
     }
 
     pub fn tys_to_string(&self, ts: &[Ty<'tcx>]) -> String {
@@ -872,8 +869,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
     }
 
     pub fn trait_ref_to_string(&self, t: &ty::TraitRef<'tcx>) -> String {
-        let t = self.resolve_type_vars_if_possible(t);
-        t.user_string(self.tcx)
+        self.resolve_type_vars_if_possible(t).to_string()
     }
 
     pub fn shallow_resolve(&self, typ: Ty<'tcx>) -> Ty<'tcx> {
@@ -981,7 +977,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
             Some(t) if ty::type_is_error(t) => (),
             _ => {
                 let error_str = err.map_or("".to_string(), |t_err| {
-                    format!(" ({})", ty::type_err_to_str(self.tcx, t_err))
+                    format!(" ({})", t_err)
                 });
 
                 self.tcx.sess.span_err(sp, &format!("{}{}",
@@ -1035,7 +1031,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
         lbrct: LateBoundRegionConversionTime,
         value: &ty::Binder<T>)
         -> (T, FnvHashMap<ty::BoundRegion,ty::Region>)
-        where T : TypeFoldable<'tcx> + Repr<'tcx>
+        where T : TypeFoldable<'tcx>
     {
         ty_fold::replace_late_bound_regions(
             self.tcx,
@@ -1049,18 +1045,18 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
                                 kind: GenericKind<'tcx>,
                                 a: ty::Region,
                                 bs: Vec<ty::Region>) {
-        debug!("verify_generic_bound({}, {} <: {})",
-               kind.repr(self.tcx),
-               a.repr(self.tcx),
-               bs.repr(self.tcx));
+        debug!("verify_generic_bound({:?}, {:?} <: {:?})",
+               kind,
+               a,
+               bs);
 
         self.region_vars.verify_generic_bound(origin, kind, a, bs);
     }
 
     pub fn can_equate<'b,T>(&'b self, a: &T, b: &T) -> UnitResult<'tcx>
-        where T: Relate<'b,'tcx> + Repr<'tcx>
+        where T: Relate<'b,'tcx> + fmt::Debug
     {
-        debug!("can_equate({}, {})", a.repr(self.tcx), b.repr(self.tcx));
+        debug!("can_equate({:?}, {:?})", a, b);
         self.probe(|_| {
             // Gin up a dummy trace, since this won't be committed
             // anyhow. We should make this typetrace stuff more
@@ -1101,9 +1097,9 @@ impl<'tcx> TypeTrace<'tcx> {
     }
 }
 
-impl<'tcx> Repr<'tcx> for TypeTrace<'tcx> {
-    fn repr(&self, tcx: &ty::ctxt) -> String {
-        format!("TypeTrace({})", self.origin.repr(tcx))
+impl<'tcx> fmt::Debug for TypeTrace<'tcx> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "TypeTrace({:?})", self.origin)
     }
 }
 
@@ -1125,44 +1121,6 @@ impl TypeOrigin {
     }
 }
 
-impl<'tcx> Repr<'tcx> for TypeOrigin {
-    fn repr(&self, tcx: &ty::ctxt) -> String {
-        match *self {
-            MethodCompatCheck(a) => {
-                format!("MethodCompatCheck({})", a.repr(tcx))
-            }
-            ExprAssignable(a) => {
-                format!("ExprAssignable({})", a.repr(tcx))
-            }
-            Misc(a) => format!("Misc({})", a.repr(tcx)),
-            RelateTraitRefs(a) => {
-                format!("RelateTraitRefs({})", a.repr(tcx))
-            }
-            RelateSelfType(a) => {
-                format!("RelateSelfType({})", a.repr(tcx))
-            }
-            RelateOutputImplTypes(a) => {
-                format!("RelateOutputImplTypes({})", a.repr(tcx))
-            }
-            MatchExpressionArm(a, b) => {
-                format!("MatchExpressionArm({}, {})", a.repr(tcx), b.repr(tcx))
-            }
-            IfExpression(a) => {
-                format!("IfExpression({})", a.repr(tcx))
-            }
-            IfExpressionWithNoElse(a) => {
-                format!("IfExpressionWithNoElse({})", a.repr(tcx))
-            }
-            RangeExpression(a) => {
-                format!("RangeExpression({})", a.repr(tcx))
-            }
-            EquatePredicate(a) => {
-                format!("EquatePredicate({})", a.repr(tcx))
-            }
-        }
-    }
-}
-
 impl<'tcx> SubregionOrigin<'tcx> {
     pub fn span(&self) -> Span {
         match *self {
@@ -1192,70 +1150,6 @@ impl<'tcx> SubregionOrigin<'tcx> {
     }
 }
 
-impl<'tcx> Repr<'tcx> for SubregionOrigin<'tcx> {
-    fn repr(&self, tcx: &ty::ctxt<'tcx>) -> String {
-        match *self {
-            Subtype(ref a) => {
-                format!("Subtype({})", a.repr(tcx))
-            }
-            InfStackClosure(a) => {
-                format!("InfStackClosure({})", a.repr(tcx))
-            }
-            InvokeClosure(a) => {
-                format!("InvokeClosure({})", a.repr(tcx))
-            }
-            DerefPointer(a) => {
-                format!("DerefPointer({})", a.repr(tcx))
-            }
-            FreeVariable(a, b) => {
-                format!("FreeVariable({}, {})", a.repr(tcx), b)
-            }
-            IndexSlice(a) => {
-                format!("IndexSlice({})", a.repr(tcx))
-            }
-            RelateObjectBound(a) => {
-                format!("RelateObjectBound({})", a.repr(tcx))
-            }
-            RelateParamBound(a, b) => {
-                format!("RelateParamBound({},{})",
-                        a.repr(tcx),
-                        b.repr(tcx))
-            }
-            RelateRegionParamBound(a) => {
-                format!("RelateRegionParamBound({})",
-                        a.repr(tcx))
-            }
-            RelateDefaultParamBound(a, b) => {
-                format!("RelateDefaultParamBound({},{})",
-                        a.repr(tcx),
-                        b.repr(tcx))
-            }
-            Reborrow(a) => format!("Reborrow({})", a.repr(tcx)),
-            ReborrowUpvar(a, b) => {
-                format!("ReborrowUpvar({},{:?})", a.repr(tcx), b)
-            }
-            ReferenceOutlivesReferent(_, a) => {
-                format!("ReferenceOutlivesReferent({})", a.repr(tcx))
-            }
-            ExprTypeIsNotInScope(a, b) => {
-                format!("ExprTypeIsNotInScope({}, {})",
-                        a.repr(tcx),
-                        b.repr(tcx))
-            }
-            BindingTypeIsNotValidAtDecl(a) => {
-                format!("BindingTypeIsNotValidAtDecl({})", a.repr(tcx))
-            }
-            CallRcvr(a) => format!("CallRcvr({})", a.repr(tcx)),
-            CallArg(a) => format!("CallArg({})", a.repr(tcx)),
-            CallReturn(a) => format!("CallReturn({})", a.repr(tcx)),
-            Operand(a) => format!("Operand({})", a.repr(tcx)),
-            AddrOf(a) => format!("AddrOf({})", a.repr(tcx)),
-            AutoBorrow(a) => format!("AutoBorrow({})", a.repr(tcx)),
-            SafeDestructor(a) => format!("SafeDestructor({})", a.repr(tcx)),
-        }
-    }
-}
-
 impl RegionVariableOrigin {
     pub fn span(&self) -> Span {
         match *self {
@@ -1271,33 +1165,3 @@ impl RegionVariableOrigin {
         }
     }
 }
-
-impl<'tcx> Repr<'tcx> for RegionVariableOrigin {
-    fn repr(&self, tcx: &ty::ctxt<'tcx>) -> String {
-        match *self {
-            MiscVariable(a) => {
-                format!("MiscVariable({})", a.repr(tcx))
-            }
-            PatternRegion(a) => {
-                format!("PatternRegion({})", a.repr(tcx))
-            }
-            AddrOfRegion(a) => {
-                format!("AddrOfRegion({})", a.repr(tcx))
-            }
-            Autoref(a) => format!("Autoref({})", a.repr(tcx)),
-            Coercion(a) => format!("Coercion({})", a.repr(tcx)),
-            EarlyBoundRegion(a, b) => {
-                format!("EarlyBoundRegion({},{})", a.repr(tcx), b.repr(tcx))
-            }
-            LateBoundRegion(a, b, c) => {
-                format!("LateBoundRegion({},{},{:?})", a.repr(tcx), b.repr(tcx), c)
-            }
-            BoundRegionInCoherence(a) => {
-                format!("bound_regionInCoherence({})", a.repr(tcx))
-            }
-            UpvarRegion(a, b) => {
-                format!("UpvarRegion({}, {})", a.repr(tcx), b.repr(tcx))
-            }
-        }
-    }
-}

src/librustc/middle/infer/region_inference/graphviz.rs

@@ -24,7 +24,6 @@ use super::Constraint;
 use middle::infer::SubregionOrigin;
 use middle::infer::region_inference::RegionVarBindings;
 use util::nodemap::{FnvHashMap, FnvHashSet};
-use util::ppaux::Repr;
 
 use std::borrow::Cow;
 use std::collections::hash_map::Entry::Vacant;
@@ -191,13 +190,13 @@ impl<'a, 'tcx> dot::Labeller<'a, Node, Edge> for ConstraintGraph<'a, 'tcx> {
             Node::RegionVid(n_vid) =>
                 dot::LabelText::label(format!("{:?}", n_vid)),
             Node::Region(n_rgn) =>
-                dot::LabelText::label(format!("{}", n_rgn.repr(self.tcx))),
+                dot::LabelText::label(format!("{:?}", n_rgn)),
         }
     }
     fn edge_label(&self, e: &Edge) -> dot::LabelText {
         match *e {
             Edge::Constraint(ref c) =>
-                dot::LabelText::label(format!("{}", self.map.get(c).unwrap().repr(self.tcx))),
+                dot::LabelText::label(format!("{:?}", self.map.get(c).unwrap())),
             Edge::EnclScope(..) =>
                 dot::LabelText::label(format!("(enclosed)")),
         }

src/librustc/middle/infer/region_inference/mod.rs

@@ -30,10 +30,10 @@ use middle::ty::{ReLateBound, ReScope, ReVar, ReSkolemized, BrFresh};
 use middle::ty_relate::RelateResult;
 use util::common::indenter;
 use util::nodemap::{FnvHashMap, FnvHashSet};
-use util::ppaux::{Repr, UserString};
 
 use std::cell::{Cell, RefCell};
 use std::cmp::Ordering::{self, Less, Greater, Equal};
+use std::fmt;
 use std::iter::repeat;
 use std::u32;
 use syntax::ast;
@@ -68,7 +68,7 @@ pub enum Verify<'tcx> {
     VerifyGenericBound(GenericKind<'tcx>, SubregionOrigin<'tcx>, Region, Vec<Region>),
 }
 
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Clone, PartialEq, Eq)]
 pub enum GenericKind<'tcx> {
     Param(ty::ParamTy),
     Projection(ty::ProjectionTy<'tcx>),
@@ -323,8 +323,8 @@ impl<'a, 'tcx> RegionVarBindings<'a, 'tcx> {
         if self.in_snapshot() {
             self.undo_log.borrow_mut().push(AddVar(vid));
         }
-        debug!("created new region variable {:?} with origin {}",
-               vid, origin.repr(self.tcx));
+        debug!("created new region variable {:?} with origin {:?}",
+               vid, origin);
         return vid;
     }
 
@@ -391,8 +391,8 @@ impl<'a, 'tcx> RegionVarBindings<'a, 'tcx> {
         // cannot add constraints once regions are resolved
         assert!(self.values_are_none());
 
-        debug!("RegionVarBindings: add_constraint({})",
-               constraint.repr(self.tcx));
+        debug!("RegionVarBindings: add_constraint({:?})",
+               constraint);
 
         if self.constraints.borrow_mut().insert(constraint, origin).is_none() {
             if self.in_snapshot() {
@@ -406,8 +406,8 @@ impl<'a, 'tcx> RegionVarBindings<'a, 'tcx> {
         // cannot add verifys once regions are resolved
         assert!(self.values_are_none());
 
-        debug!("RegionVarBindings: add_verify({})",
-               verify.repr(self.tcx));
+        debug!("RegionVarBindings: add_verify({:?})",
+               verify);
 
         let mut verifys = self.verifys.borrow_mut();
         let index = verifys.len();
@@ -425,8 +425,8 @@ impl<'a, 'tcx> RegionVarBindings<'a, 'tcx> {
 
         let mut givens = self.givens.borrow_mut();
         if givens.insert((sub, sup)) {
-            debug!("add_given({} <= {:?})",
-                   sub.repr(self.tcx),
+            debug!("add_given({:?} <= {:?})",
+                   sub,
                    sup);
 
             self.undo_log.borrow_mut().push(AddGiven(sub, sup));
@@ -452,10 +452,10 @@ impl<'a, 'tcx> RegionVarBindings<'a, 'tcx> {
         // cannot add constraints once regions are resolved
         assert!(self.values_are_none());
 
-        debug!("RegionVarBindings: make_subregion({}, {}) due to {}",
-               sub.repr(self.tcx),
-               sup.repr(self.tcx),
-               origin.repr(self.tcx));
+        debug!("RegionVarBindings: make_subregion({:?}, {:?}) due to {:?}",
+               sub,
+               sup,
+               origin);
 
         match (sub, sup) {
           (ReEarlyBound(..), ReEarlyBound(..)) => {
@@ -471,9 +471,9 @@ impl<'a, 'tcx> RegionVarBindings<'a, 'tcx> {
           (_, ReLateBound(..)) => {
             self.tcx.sess.span_bug(
                 origin.span(),
-                &format!("cannot relate bound region: {} <= {}",
-                        sub.repr(self.tcx),
-                        sup.repr(self.tcx)));
+                &format!("cannot relate bound region: {:?} <= {:?}",
+                        sub,
+                        sup));
           }
           (_, ReStatic) => {
             // all regions are subregions of static, so we can ignore this
@@ -510,9 +510,9 @@ impl<'a, 'tcx> RegionVarBindings<'a, 'tcx> {
         // cannot add constraints once regions are resolved
         assert!(self.values_are_none());
 
-        debug!("RegionVarBindings: lub_regions({}, {})",
-               a.repr(self.tcx),
-               b.repr(self.tcx));
+        debug!("RegionVarBindings: lub_regions({:?}, {:?})",
+               a,
+               b);
         match (a, b) {
             (ReStatic, _) | (_, ReStatic) => {
                 ReStatic // nothing lives longer than static
@@ -535,9 +535,9 @@ impl<'a, 'tcx> RegionVarBindings<'a, 'tcx> {
         // cannot add constraints once regions are resolved
         assert!(self.values_are_none());
 
-        debug!("RegionVarBindings: glb_regions({}, {})",
-               a.repr(self.tcx),
-               b.repr(self.tcx));
+        debug!("RegionVarBindings: glb_regions({:?}, {:?})",
+               a,
+               b);
         match (a, b) {
             (ReStatic, r) | (r, ReStatic) => {
                 // static lives longer than everything else
@@ -563,7 +563,7 @@ impl<'a, 'tcx> RegionVarBindings<'a, 'tcx> {
             }
             Some(ref values) => {
                 let r = lookup(values, rid);
-                debug!("resolve_var({:?}) = {}", rid, r.repr(self.tcx));
+                debug!("resolve_var({:?}) = {:?}", rid, r);
                 r
             }
         }
@@ -620,7 +620,7 @@ impl<'a, 'tcx> RegionVarBindings<'a, 'tcx> {
     /// made---`r0` itself will be the first entry. This is used when checking whether skolemized
     /// regions are being improperly related to other regions.
     pub fn tainted(&self, mark: &RegionSnapshot, r0: Region) -> Vec<Region> {
-        debug!("tainted(mark={:?}, r0={})", mark, r0.repr(self.tcx));
+        debug!("tainted(mark={:?}, r0={:?})", mark, r0);
         let _indenter = indenter();
 
         // `result_set` acts as a worklist: we explore all outgoing
@@ -731,9 +731,9 @@ impl<'a, 'tcx> RegionVarBindings<'a, 'tcx> {
           (ReEarlyBound(..), _) |
           (_, ReEarlyBound(..)) => {
             self.tcx.sess.bug(
-                &format!("cannot relate bound region: LUB({}, {})",
-                        a.repr(self.tcx),
-                        b.repr(self.tcx)));
+                &format!("cannot relate bound region: LUB({:?}, {:?})",
+                        a,
+                        b));
           }
 
           (ReStatic, _) | (_, ReStatic) => {
@@ -836,9 +836,9 @@ impl<'a, 'tcx> RegionVarBindings<'a, 'tcx> {
             (ReEarlyBound(..), _) |
             (_, ReEarlyBound(..)) => {
               self.tcx.sess.bug(
-                  &format!("cannot relate bound region: GLB({}, {})",
-                          a.repr(self.tcx),
-                          b.repr(self.tcx)));
+                  &format!("cannot relate bound region: GLB({:?}, {:?})",
+                          a,
+                          b));
             }
 
             (ReStatic, r) | (r, ReStatic) => {
@@ -959,7 +959,7 @@ impl<'a, 'tcx> RegionVarBindings<'a, 'tcx> {
 #[derive(Copy, Clone, PartialEq, Debug)]
 enum Classification { Expanding, Contracting }
 
-#[derive(Copy, Clone)]
+#[derive(Copy, Clone, Debug)]
 pub enum VarValue { NoValue, Value(Region), ErrorValue }
 
 struct VarData {
@@ -1013,18 +1013,18 @@ impl<'a, 'tcx> RegionVarBindings<'a, 'tcx> {
     fn dump_constraints(&self) {
         debug!("----() Start constraint listing ()----");
         for (idx, (constraint, _)) in self.constraints.borrow().iter().enumerate() {
-            debug!("Constraint {} => {}", idx, constraint.repr(self.tcx));
+            debug!("Constraint {} => {:?}", idx, constraint);
         }
     }
 
     fn expansion(&self, free_regions: &FreeRegionMap, var_data: &mut [VarData]) {
         self.iterate_until_fixed_point("Expansion", |constraint| {
-            debug!("expansion: constraint={} origin={}",
-                   constraint.repr(self.tcx),
+            debug!("expansion: constraint={:?} origin={:?}",
+                   constraint,
                    self.constraints.borrow()
                                    .get(constraint)
                                    .unwrap()
-                                   .repr(self.tcx));
+                                   );
             match *constraint {
               ConstrainRegSubVar(a_region, b_vid) => {
                 let b_data = &mut var_data[b_vid.index as usize];
@@ -1054,10 +1054,10 @@ impl<'a, 'tcx> RegionVarBindings<'a, 'tcx> {
                    b_data: &mut VarData)
                    -> bool
     {
-        debug!("expand_node({}, {:?} == {})",
-               a_region.repr(self.tcx),
+        debug!("expand_node({:?}, {:?} == {:?})",
+               a_region,
                b_vid,
-               b_data.value.repr(self.tcx));
+               b_data.value);
 
         // Check if this relationship is implied by a given.
         match a_region {
@@ -1073,8 +1073,8 @@ impl<'a, 'tcx> RegionVarBindings<'a, 'tcx> {
         b_data.classification = Expanding;
         match b_data.value {
           NoValue => {
-            debug!("Setting initial value of {:?} to {}",
-                   b_vid, a_region.repr(self.tcx));
+            debug!("Setting initial value of {:?} to {:?}",
+                   b_vid, a_region);
 
             b_data.value = Value(a_region);
             return true;
@@ -1086,10 +1086,10 @@ impl<'a, 'tcx> RegionVarBindings<'a, 'tcx> {
                 return false;
             }
 
-            debug!("Expanding value of {:?} from {} to {}",
+            debug!("Expanding value of {:?} from {:?} to {:?}",
                    b_vid,
-                   cur_region.repr(self.tcx),
-                   lub.repr(self.tcx));
+                   cur_region,
+                   lub);
 
             b_data.value = Value(lub);
             return true;
@@ -1105,12 +1105,12 @@ impl<'a, 'tcx> RegionVarBindings<'a, 'tcx> {
                    free_regions: &FreeRegionMap,
                    var_data: &mut [VarData]) {
         self.iterate_until_fixed_point("Contraction", |constraint| {
-            debug!("contraction: constraint={} origin={}",
-                   constraint.repr(self.tcx),
+            debug!("contraction: constraint={:?} origin={:?}",
+                   constraint,
                    self.constraints.borrow()
                                    .get(constraint)
                                    .unwrap()
-                                   .repr(self.tcx));
+                                   );
             match *constraint {
               ConstrainRegSubVar(..) => {
                 // This is an expansion constraint.  Ignore.
@@ -1139,9 +1139,9 @@ impl<'a, 'tcx> RegionVarBindings<'a, 'tcx> {
                      a_data: &mut VarData,
                      b_region: Region)
                      -> bool {
-        debug!("contract_node({:?} == {}/{:?}, {})",
-               a_vid, a_data.value.repr(self.tcx),
-               a_data.classification, b_region.repr(self.tcx));
+        debug!("contract_node({:?} == {:?}/{:?}, {:?})",
+               a_vid, a_data.value,
+               a_data.classification, b_region);
 
         return match a_data.value {
             NoValue => {
@@ -1171,10 +1171,10 @@ impl<'a, 'tcx> RegionVarBindings<'a, 'tcx> {
                       -> bool
         {
             if !free_regions.is_subregion_of(this.tcx, a_region, b_region) {
-                debug!("Setting {:?} to ErrorValue: {} not subregion of {}",
+                debug!("Setting {:?} to ErrorValue: {:?} not subregion of {:?}",
                        a_vid,
-                       a_region.repr(this.tcx),
-                       b_region.repr(this.tcx));
+                       a_region,
+                       b_region);
                 a_data.value = ErrorValue;
             }
             false
@@ -1192,19 +1192,19 @@ impl<'a, 'tcx> RegionVarBindings<'a, 'tcx> {
                     if glb == a_region {
                         false
                     } else {
-                        debug!("Contracting value of {:?} from {} to {}",
+                        debug!("Contracting value of {:?} from {:?} to {:?}",
                                a_vid,
-                               a_region.repr(this.tcx),
-                               glb.repr(this.tcx));
+                               a_region,
+                               glb);
                         a_data.value = Value(glb);
                         true
                     }
                 }
                 Err(_) => {
-                    debug!("Setting {:?} to ErrorValue: no glb of {}, {}",
+                    debug!("Setting {:?} to ErrorValue: no glb of {:?}, {:?}",
                            a_vid,
-                           a_region.repr(this.tcx),
-                           b_region.repr(this.tcx));
+                           a_region,
+                           b_region);
                     a_data.value = ErrorValue;
                     false
                 }
@@ -1229,9 +1229,9 @@ impl<'a, 'tcx> RegionVarBindings<'a, 'tcx> {
                         continue;
                     }
 
-                    debug!("ConcreteFailure: !(sub <= sup): sub={}, sup={}",
-                           sub.repr(self.tcx),
-                           sup.repr(self.tcx));
+                    debug!("ConcreteFailure: !(sub <= sup): sub={:?}, sup={:?}",
+                           sub,
+                           sup);
                     errors.push(ConcreteFailure((*origin).clone(), sub, sup));
                 }
 
@@ -1431,10 +1431,10 @@ impl<'a, 'tcx> RegionVarBindings<'a, 'tcx> {
         self.tcx.sess.span_bug(
             (*self.var_origins.borrow())[node_idx.index as usize].span(),
             &format!("collect_error_for_expanding_node() could not find error \
-                    for var {:?}, lower_bounds={}, upper_bounds={}",
+                    for var {:?}, lower_bounds={:?}, upper_bounds={:?}",
                     node_idx,
-                    lower_bounds.repr(self.tcx),
-                    upper_bounds.repr(self.tcx)));
+                    lower_bounds,
+                    upper_bounds));
     }
 
     fn collect_error_for_contracting_node(
@@ -1478,9 +1478,9 @@ impl<'a, 'tcx> RegionVarBindings<'a, 'tcx> {
         self.tcx.sess.span_bug(
             (*self.var_origins.borrow())[node_idx.index as usize].span(),
             &format!("collect_error_for_contracting_node() could not find error \
-                     for var {:?}, upper_bounds={}",
+                     for var {:?}, upper_bounds={:?}",
                     node_idx,
-                    upper_bounds.repr(self.tcx)));
+                    upper_bounds));
     }
 
     fn collect_concrete_regions(&self,
@@ -1578,8 +1578,8 @@ impl<'a, 'tcx> RegionVarBindings<'a, 'tcx> {
             for (constraint, _) in self.constraints.borrow().iter() {
                 let edge_changed = body(constraint);
                 if edge_changed {
-                    debug!("Updated due to constraint {}",
-                           constraint.repr(self.tcx));
+                    debug!("Updated due to constraint {:?}",
+                           constraint);
                     changed = true;
                 }
             }
@@ -1589,31 +1589,14 @@ impl<'a, 'tcx> RegionVarBindings<'a, 'tcx> {
 
 }
 
-impl<'tcx> Repr<'tcx> for Constraint {
-    fn repr(&self, tcx: &ty::ctxt) -> String {
-        match *self {
-            ConstrainVarSubVar(a, b) => {
-                format!("ConstrainVarSubVar({}, {})", a.repr(tcx), b.repr(tcx))
-            }
-            ConstrainRegSubVar(a, b) => {
-                format!("ConstrainRegSubVar({}, {})", a.repr(tcx), b.repr(tcx))
-            }
-            ConstrainVarSubReg(a, b) => {
-                format!("ConstrainVarSubReg({}, {})", a.repr(tcx), b.repr(tcx))
-            }
-        }
-    }
-}
-
-impl<'tcx> Repr<'tcx> for Verify<'tcx> {
-    fn repr(&self, tcx: &ty::ctxt<'tcx>) -> String {
+impl<'tcx> fmt::Debug for Verify<'tcx> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         match *self {
             VerifyRegSubReg(_, ref a, ref b) => {
-                format!("VerifyRegSubReg({}, {})", a.repr(tcx), b.repr(tcx))
+                write!(f, "VerifyRegSubReg({:?}, {:?})", a, b)
             }
             VerifyGenericBound(_, ref p, ref a, ref bs) => {
-                format!("VerifyGenericBound({}, {}, {})",
-                        p.repr(tcx), a.repr(tcx), bs.repr(tcx))
+                write!(f, "VerifyGenericBound({:?}, {:?}, {:?})", p, a, bs)
             }
         }
     }
@@ -1634,38 +1617,28 @@ fn lookup(values: &Vec<VarValue>, rid: ty::RegionVid) -> ty::Region {
     }
 }
 
-impl<'tcx> Repr<'tcx> for VarValue {
-    fn repr(&self, tcx: &ty::ctxt) -> String {
+impl<'tcx> fmt::Debug for RegionAndOrigin<'tcx> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "RegionAndOrigin({:?},{:?})",
+               self.region,
+               self.origin)
+    }
+}
+
+impl<'tcx> fmt::Debug for GenericKind<'tcx> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         match *self {
-            NoValue => format!("NoValue"),
-            Value(r) => format!("Value({})", r.repr(tcx)),
-            ErrorValue => format!("ErrorValue"),
+            GenericKind::Param(ref p) => write!(f, "{:?}", p),
+            GenericKind::Projection(ref p) => write!(f, "{:?}", p),
         }
     }
 }
 
-impl<'tcx> Repr<'tcx> for RegionAndOrigin<'tcx> {
-    fn repr(&self, tcx: &ty::ctxt<'tcx>) -> String {
-        format!("RegionAndOrigin({},{})",
-                self.region.repr(tcx),
-                self.origin.repr(tcx))
-    }
-}
-
-impl<'tcx> Repr<'tcx> for GenericKind<'tcx> {
-    fn repr(&self, tcx: &ty::ctxt<'tcx>) -> String {
+impl<'tcx> fmt::Display for GenericKind<'tcx> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         match *self {
-            GenericKind::Param(ref p) => p.repr(tcx),
-            GenericKind::Projection(ref p) => p.repr(tcx),
-        }
-    }
-}
-
-impl<'tcx> UserString<'tcx> for GenericKind<'tcx> {
-    fn user_string(&self, tcx: &ty::ctxt<'tcx>) -> String {
-        match *self {
-            GenericKind::Param(ref p) => p.user_string(tcx),
-            GenericKind::Projection(ref p) => p.user_string(tcx),
+            GenericKind::Param(ref p) => write!(f, "{}", p),
+            GenericKind::Projection(ref p) => write!(f, "{}", p),
         }
     }
 }

src/librustc/middle/infer/resolve.rs

@@ -11,7 +11,6 @@
 use super::{InferCtxt, fixup_err, fres, unresolved_ty, unresolved_int_ty, unresolved_float_ty};
 use middle::ty::{self, Ty};
 use middle::ty_fold::{self, TypeFoldable};
-use util::ppaux::Repr;
 
 ///////////////////////////////////////////////////////////////////////////
 // OPPORTUNISTIC TYPE RESOLVER
@@ -95,8 +94,8 @@ impl<'a, 'tcx> ty_fold::TypeFolder<'tcx> for FullTypeResolver<'a, 'tcx> {
                 }
                 ty::TyInfer(_) => {
                     self.infcx.tcx.sess.bug(
-                        &format!("Unexpected type in full type resolver: {}",
-                                t.repr(self.infcx.tcx)));
+                        &format!("Unexpected type in full type resolver: {:?}",
+                                t));
                 }
                 _ => {
                     ty_fold::super_fold_ty(self, t)

src/librustc/middle/infer/sub.rs

@@ -16,7 +16,6 @@ use super::type_variable::{SubtypeOf, SupertypeOf};
 use middle::ty::{self, Ty};
 use middle::ty::TyVar;
 use middle::ty_relate::{Relate, RelateResult, TypeRelation};
-use util::ppaux::{Repr};
 
 /// "Greatest lower bound" (common subtype)
 pub struct Sub<'a, 'tcx: 'a> {
@@ -49,7 +48,7 @@ impl<'a, 'tcx> TypeRelation<'a, 'tcx> for Sub<'a, 'tcx> {
     }
 
     fn tys(&mut self, a: Ty<'tcx>, b: Ty<'tcx>) -> RelateResult<'tcx, Ty<'tcx>> {
-        debug!("{}.tys({}, {})", self.tag(), a.repr(self.tcx()), b.repr(self.tcx()));
+        debug!("{}.tys({:?}, {:?})", self.tag(), a, b);
 
         if a == b { return Ok(a); }
 
@@ -85,10 +84,10 @@ impl<'a, 'tcx> TypeRelation<'a, 'tcx> for Sub<'a, 'tcx> {
     }
 
     fn regions(&mut self, a: ty::Region, b: ty::Region) -> RelateResult<'tcx, ty::Region> {
-        debug!("{}.regions({}, {})",
+        debug!("{}.regions({:?}, {:?})",
                self.tag(),
-               a.repr(self.tcx()),
-               b.repr(self.tcx()));
+               a,
+               b);
         let origin = Subtype(self.fields.trace.clone());
         self.fields.infcx.region_vars.make_subregion(origin, a, b);
         Ok(a)

src/librustc/middle/intrinsicck.rs

@@ -14,7 +14,8 @@ use middle::def::DefFn;
 use middle::subst::{Subst, Substs, EnumeratedItems};
 use middle::ty::{TransmuteRestriction, ctxt, TyBareFn};
 use middle::ty::{self, Ty};
-use util::ppaux::Repr;
+
+use std::fmt;
 
 use syntax::abi::RustIntrinsic;
 use syntax::ast::DefId;
@@ -202,15 +203,15 @@ impl<'a, 'tcx> IntrinsicCheckingVisitor<'a, 'tcx> {
 
         match types_in_scope.next() {
             None => {
-                debug!("with_each_combination(substs={})",
-                       substs.repr(self.tcx));
+                debug!("with_each_combination(substs={:?})",
+                       substs);
 
                 callback(substs);
             }
 
             Some((space, index, &param_ty)) => {
-                debug!("with_each_combination: space={:?}, index={}, param_ty={}",
-                       space, index, param_ty.repr(self.tcx));
+                debug!("with_each_combination: space={:?}, index={}, param_ty={:?}",
+                       space, index, param_ty);
 
                 if !ty::type_is_sized(Some(param_env), self.tcx, span, param_ty) {
                     debug!("with_each_combination: param_ty is not known to be sized");
@@ -228,7 +229,7 @@ impl<'a, 'tcx> IntrinsicCheckingVisitor<'a, 'tcx> {
     }
 
     fn push_transmute_restriction(&self, restriction: TransmuteRestriction<'tcx>) {
-        debug!("Pushing transmute restriction: {}", restriction.repr(self.tcx));
+        debug!("Pushing transmute restriction: {:?}", restriction);
         self.tcx.transmute_restrictions.borrow_mut().push(restriction);
     }
 }
@@ -277,13 +278,13 @@ impl<'a, 'tcx, 'v> Visitor<'v> for IntrinsicCheckingVisitor<'a, 'tcx> {
     }
 }
 
-impl<'tcx> Repr<'tcx> for TransmuteRestriction<'tcx> {
-    fn repr(&self, tcx: &ty::ctxt<'tcx>) -> String {
-        format!("TransmuteRestriction(id={}, original=({},{}), substituted=({},{}))",
-                self.id,
-                self.original_from.repr(tcx),
-                self.original_to.repr(tcx),
-                self.substituted_from.repr(tcx),
-                self.substituted_to.repr(tcx))
+impl<'tcx> fmt::Debug for TransmuteRestriction<'tcx> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "TransmuteRestriction(id={}, original=({:?},{:?}), substituted=({:?},{:?}))",
+               self.id,
+               self.original_from,
+               self.original_to,
+               self.substituted_from,
+               self.substituted_to)
     }
 }

src/librustc/middle/mem_categorization.rs

@@ -78,18 +78,16 @@ use middle::def;
 use middle::region;
 use middle::ty::{self, Ty};
 use util::nodemap::NodeMap;
-use util::ppaux::{Repr, UserString};
 
 use syntax::ast::{MutImmutable, MutMutable};
 use syntax::ast;
 use syntax::codemap::Span;
-use syntax::print::pprust;
-use syntax::parse::token;
 
 use std::cell::RefCell;
+use std::fmt;
 use std::rc::Rc;
 
-#[derive(Clone, PartialEq, Debug)]
+#[derive(Clone, PartialEq)]
 pub enum categorization<'tcx> {
     cat_rvalue(ty::Region),                    // temporary val, argument is its scope
     cat_static_item,
@@ -103,14 +101,14 @@ pub enum categorization<'tcx> {
 }
 
 // Represents any kind of upvar
-#[derive(Clone, Copy, PartialEq, Debug)]
+#[derive(Clone, Copy, PartialEq)]
 pub struct Upvar {
     pub id: ty::UpvarId,
     pub kind: ty::ClosureKind
 }
 
 // different kinds of pointers:
-#[derive(Clone, Copy, PartialEq, Eq, Hash, Debug)]
+#[derive(Clone, Copy, PartialEq, Eq, Hash)]
 pub enum PointerKind {
     /// `Box<T>`
     Unique,
@@ -127,7 +125,7 @@ pub enum PointerKind {
 
 // We use the term "interior" to mean "something reachable from the
 // base without a pointer dereference", e.g. a field
-#[derive(Clone, Copy, PartialEq, Eq, Hash, Debug)]
+#[derive(Clone, Copy, PartialEq, Eq, Hash)]
 pub enum InteriorKind {
     InteriorField(FieldName),
     InteriorElement(InteriorOffsetKind, ElementKind),
@@ -184,7 +182,7 @@ pub enum Note {
 // dereference, but its type is the type *before* the dereference
 // (`@T`). So use `cmt.ty` to find the type of the value in a consistent
 // fashion. For more details, see the method `cat_pattern`
-#[derive(Clone, PartialEq, Debug)]
+#[derive(Clone, PartialEq)]
 pub struct cmt_<'tcx> {
     pub id: ast::NodeId,           // id of expr/pat producing this value
     pub span: Span,                // span of same expr/pat
@@ -418,7 +416,6 @@ impl<'t,'tcx,TYPER:Typer<'tcx>> MemCategorizationContext<'t,TYPER> {
     }
 
     fn pat_ty(&self, pat: &ast::Pat) -> McResult<Ty<'tcx>> {
-        let tcx = self.typer.tcx();
         let base_ty = try!(self.typer.node_ty(pat.id));
         // FIXME (Issue #18207): This code detects whether we are
         // looking at a `ref x`, and if so, figures out what the type
@@ -436,8 +433,8 @@ impl<'t,'tcx,TYPER:Typer<'tcx>> MemCategorizationContext<'t,TYPER> {
             }
             _ => base_ty,
         };
-        debug!("pat_ty(pat={}) base_ty={} ret_ty={}",
-               pat.repr(tcx), base_ty.repr(tcx), ret_ty.repr(tcx));
+        debug!("pat_ty(pat={:?}) base_ty={:?} ret_ty={:?}",
+               pat, base_ty, ret_ty);
         Ok(ret_ty)
     }
 
@@ -460,9 +457,9 @@ impl<'t,'tcx,TYPER:Typer<'tcx>> MemCategorizationContext<'t,TYPER> {
                     ty::AdjustReifyFnPointer |
                     ty::AdjustUnsafeFnPointer |
                     ty::AdjustDerefRef(_) => {
-                        debug!("cat_expr({}): {}",
-                               adjustment.repr(self.tcx()),
-                               expr.repr(self.tcx()));
+                        debug!("cat_expr({:?}): {:?}",
+                               adjustment,
+                               expr);
                         // Result is an rvalue.
                         let expr_ty = try!(self.expr_ty_adjusted(expr));
                         Ok(self.cat_rvalue_node(expr.id(), expr.span(), expr_ty))
@@ -477,9 +474,9 @@ impl<'t,'tcx,TYPER:Typer<'tcx>> MemCategorizationContext<'t,TYPER> {
                                autoderefs: usize)
                                -> McResult<cmt<'tcx>> {
         let mut cmt = try!(self.cat_expr_unadjusted(expr));
-        debug!("cat_expr_autoderefd: autoderefs={}, cmt={}",
+        debug!("cat_expr_autoderefd: autoderefs={}, cmt={:?}",
                autoderefs,
-               cmt.repr(self.tcx()));
+               cmt);
         for deref in 1..autoderefs + 1 {
             cmt = try!(self.cat_deref(expr, cmt, deref, None));
         }
@@ -487,7 +484,7 @@ impl<'t,'tcx,TYPER:Typer<'tcx>> MemCategorizationContext<'t,TYPER> {
     }
 
     pub fn cat_expr_unadjusted(&self, expr: &ast::Expr) -> McResult<cmt<'tcx>> {
-        debug!("cat_expr: id={} expr={}", expr.id, expr.repr(self.tcx()));
+        debug!("cat_expr: id={} expr={:?}", expr.id, expr);
 
         let expr_ty = try!(self.expr_ty(expr));
         match expr.node {
@@ -498,10 +495,10 @@ impl<'t,'tcx,TYPER:Typer<'tcx>> MemCategorizationContext<'t,TYPER> {
 
           ast::ExprField(ref base, f_name) => {
             let base_cmt = try!(self.cat_expr(&**base));
-            debug!("cat_expr(cat_field): id={} expr={} base={}",
+            debug!("cat_expr(cat_field): id={} expr={:?} base={:?}",
                    expr.id,
-                   expr.repr(self.tcx()),
-                   base_cmt.repr(self.tcx()));
+                   expr,
+                   base_cmt);
             Ok(self.cat_field(expr, base_cmt, f_name.node.name, expr_ty))
           }
 
@@ -524,8 +521,8 @@ impl<'t,'tcx,TYPER:Typer<'tcx>> MemCategorizationContext<'t,TYPER> {
                     let elem_ty = match ret_ty.sty {
                         ty::TyRef(_, mt) => mt.ty,
                         _ => {
-                            debug!("cat_expr_unadjusted: return type of overloaded index is {}?",
-                                   ret_ty.repr(self.tcx()));
+                            debug!("cat_expr_unadjusted: return type of overloaded index is {:?}?",
+                                   ret_ty);
                             return Err(());
                         }
                     };
@@ -583,8 +580,8 @@ impl<'t,'tcx,TYPER:Typer<'tcx>> MemCategorizationContext<'t,TYPER> {
                    expr_ty: Ty<'tcx>,
                    def: def::Def)
                    -> McResult<cmt<'tcx>> {
-        debug!("cat_def: id={} expr={} def={:?}",
-               id, expr_ty.repr(self.tcx()), def);
+        debug!("cat_def: id={} expr={:?} def={:?}",
+               id, expr_ty, def);
 
         match def {
           def::DefStruct(..) | def::DefVariant(..) | def::DefConst(..) |
@@ -635,9 +632,9 @@ impl<'t,'tcx,TYPER:Typer<'tcx>> MemCategorizationContext<'t,TYPER> {
                   _ => {
                       self.tcx().sess.span_bug(
                           span,
-                          &format!("Upvar of non-closure {} - {}",
+                          &format!("Upvar of non-closure {} - {:?}",
                                   fn_node_id,
-                                  ty.repr(self.tcx())));
+                                  ty));
                   }
               }
           }
@@ -746,7 +743,7 @@ impl<'t,'tcx,TYPER:Typer<'tcx>> MemCategorizationContext<'t,TYPER> {
         };
 
         let ret = Rc::new(cmt_result);
-        debug!("cat_upvar ret={}", ret.repr(self.tcx()));
+        debug!("cat_upvar ret={:?}", ret);
         Ok(ret)
     }
 
@@ -817,7 +814,7 @@ impl<'t,'tcx,TYPER:Typer<'tcx>> MemCategorizationContext<'t,TYPER> {
             note: NoteClosureEnv(upvar_id)
         };
 
-        debug!("env_deref ret {}", ret.repr(self.tcx()));
+        debug!("env_deref ret {:?}", ret);
 
         ret
     }
@@ -855,7 +852,7 @@ impl<'t,'tcx,TYPER:Typer<'tcx>> MemCategorizationContext<'t,TYPER> {
             ty::ReStatic
         };
         let ret = self.cat_rvalue(id, span, re, expr_ty);
-        debug!("cat_rvalue_node ret {}", ret.repr(self.tcx()));
+        debug!("cat_rvalue_node ret {:?}", ret);
         ret
     }
 
@@ -872,7 +869,7 @@ impl<'t,'tcx,TYPER:Typer<'tcx>> MemCategorizationContext<'t,TYPER> {
             ty:expr_ty,
             note: NoteNone
         });
-        debug!("cat_rvalue ret {}", ret.repr(self.tcx()));
+        debug!("cat_rvalue ret {:?}", ret);
         ret
     }
 
@@ -890,7 +887,7 @@ impl<'t,'tcx,TYPER:Typer<'tcx>> MemCategorizationContext<'t,TYPER> {
             ty: f_ty,
             note: NoteNone
         });
-        debug!("cat_field ret {}", ret.repr(self.tcx()));
+        debug!("cat_field ret {:?}", ret);
         ret
     }
 
@@ -908,7 +905,7 @@ impl<'t,'tcx,TYPER:Typer<'tcx>> MemCategorizationContext<'t,TYPER> {
             ty: f_ty,
             note: NoteNone
         });
-        debug!("cat_tup_field ret {}", ret.repr(self.tcx()));
+        debug!("cat_tup_field ret {:?}", ret);
         ret
     }
 
@@ -925,7 +922,7 @@ impl<'t,'tcx,TYPER:Typer<'tcx>> MemCategorizationContext<'t,TYPER> {
         let method_ty = self.typer.node_method_ty(method_call);
 
         debug!("cat_deref: method_call={:?} method_ty={:?}",
-               method_call, method_ty.map(|ty| ty.repr(self.tcx())));
+               method_call, method_ty.map(|ty| ty));
 
         let base_cmt = match method_ty {
             Some(method_ty) => {
@@ -943,12 +940,12 @@ impl<'t,'tcx,TYPER:Typer<'tcx>> MemCategorizationContext<'t,TYPER> {
                                               mt.ty,
                                               deref_context,
                                                 /* implicit: */ false);
-                debug!("cat_deref ret {}", ret.repr(self.tcx()));
+                debug!("cat_deref ret {:?}", ret);
                 ret
             }
             None => {
-                debug!("Explicit deref of non-derefable type: {}",
-                       base_cmt_ty.repr(self.tcx()));
+                debug!("Explicit deref of non-derefable type: {:?}",
+                       base_cmt_ty);
                 return Err(());
             }
         }
@@ -991,7 +988,7 @@ impl<'t,'tcx,TYPER:Typer<'tcx>> MemCategorizationContext<'t,TYPER> {
             ty: deref_ty,
             note: NoteNone
         });
-        debug!("cat_deref_common ret {}", ret.repr(self.tcx()));
+        debug!("cat_deref_common ret {:?}", ret);
         Ok(ret)
     }
 
@@ -1042,7 +1039,7 @@ impl<'t,'tcx,TYPER:Typer<'tcx>> MemCategorizationContext<'t,TYPER> {
         let m = base_cmt.mutbl.inherit();
         let ret = interior(elt, base_cmt.clone(), base_cmt.ty,
                            m, context, element_ty);
-        debug!("cat_index ret {}", ret.repr(self.tcx()));
+        debug!("cat_index ret {:?}", ret);
         return Ok(ret);
 
         fn interior<'tcx, N: ast_node>(elt: &N,
@@ -1096,7 +1093,7 @@ impl<'t,'tcx,TYPER:Typer<'tcx>> MemCategorizationContext<'t,TYPER> {
                 base_cmt
             }
         };
-        debug!("deref_vec ret {}", ret.repr(self.tcx()));
+        debug!("deref_vec ret {:?}", ret);
         Ok(ret)
     }
 
@@ -1155,7 +1152,7 @@ impl<'t,'tcx,TYPER:Typer<'tcx>> MemCategorizationContext<'t,TYPER> {
             ty: interior_ty,
             note: NoteNone
         });
-        debug!("cat_imm_interior ret={}", ret.repr(self.tcx()));
+        debug!("cat_imm_interior ret={:?}", ret);
         ret
     }
 
@@ -1173,7 +1170,7 @@ impl<'t,'tcx,TYPER:Typer<'tcx>> MemCategorizationContext<'t,TYPER> {
             ty: downcast_ty,
             note: NoteNone
         });
-        debug!("cat_downcast ret={}", ret.repr(self.tcx()));
+        debug!("cat_downcast ret={:?}", ret);
         ret
     }
 
@@ -1233,9 +1230,9 @@ impl<'t,'tcx,TYPER:Typer<'tcx>> MemCategorizationContext<'t,TYPER> {
         // step out of sync again. So you'll see below that we always
         // get the type of the *subpattern* and use that.
 
-        debug!("cat_pattern: id={} pat={} cmt={}",
-               pat.id, pprust::pat_to_string(pat),
-               cmt.repr(self.tcx()));
+        debug!("cat_pattern: {:?} cmt={:?}",
+               pat,
+               cmt);
 
         (*op)(self, cmt.clone(), pat);
 
@@ -1521,7 +1518,7 @@ impl<'tcx> cmt_<'tcx> {
                 let upvar = self.upvar();
                 match upvar.as_ref().map(|i| &i.cat) {
                     Some(&cat_upvar(ref var)) => {
-                        var.user_string(tcx)
+                        var.to_string()
                     }
                     Some(_) => unreachable!(),
                     None => {
@@ -1561,7 +1558,7 @@ impl<'tcx> cmt_<'tcx> {
                 "pattern-bound indexed content".to_string()
             }
             cat_upvar(ref var) => {
-                var.user_string(tcx)
+                var.to_string()
             }
             cat_downcast(ref cmt, _) => {
                 cmt.descriptive_string(tcx)
@@ -1570,33 +1567,36 @@ impl<'tcx> cmt_<'tcx> {
     }
 }
 
-impl<'tcx> Repr<'tcx> for cmt_<'tcx> {
-    fn repr(&self, tcx: &ty::ctxt<'tcx>) -> String {
-        format!("{{{} id:{} m:{:?} ty:{}}}",
-                self.cat.repr(tcx),
-                self.id,
-                self.mutbl,
-                self.ty.repr(tcx))
+impl<'tcx> fmt::Debug for cmt_<'tcx> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "{{{:?} id:{} m:{:?} ty:{:?}}}",
+               self.cat,
+               self.id,
+               self.mutbl,
+               self.ty)
     }
 }
 
-impl<'tcx> Repr<'tcx> for categorization<'tcx> {
-    fn repr(&self, tcx: &ty::ctxt<'tcx>) -> String {
+impl<'tcx> fmt::Debug for categorization<'tcx> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         match *self {
-            cat_static_item |
-            cat_rvalue(..) |
-            cat_local(..) |
-            cat_upvar(..) => {
-                format!("{:?}", *self)
+            cat_static_item => write!(f, "static"),
+            cat_rvalue(r) => write!(f, "rvalue({:?})", r),
+            cat_local(id) => {
+               let name = ty::tls::with(|tcx| ty::local_var_name_str(tcx, id));
+               write!(f, "local({})", name)
+            }
+            cat_upvar(upvar) => {
+                write!(f, "upvar({:?})", upvar)
             }
             cat_deref(ref cmt, derefs, ptr) => {
-                format!("{}-{}{}->", cmt.cat.repr(tcx), ptr.repr(tcx), derefs)
+                write!(f, "{:?}-{:?}{}->", cmt.cat, ptr, derefs)
             }
             cat_interior(ref cmt, interior) => {
-                format!("{}.{}", cmt.cat.repr(tcx), interior.repr(tcx))
+                write!(f, "{:?}.{:?}", cmt.cat, interior)
             }
             cat_downcast(ref cmt, _) => {
-                format!("{}->(enum)", cmt.cat.repr(tcx))
+                write!(f, "{:?}->(enum)", cmt.cat)
             }
         }
     }
@@ -1615,39 +1615,33 @@ pub fn ptr_sigil(ptr: PointerKind) -> &'static str {
     }
 }
 
-impl<'tcx> Repr<'tcx> for PointerKind {
-    fn repr(&self, tcx: &ty::ctxt<'tcx>) -> String {
+impl fmt::Debug for PointerKind {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         match *self {
-            Unique => {
-                format!("Box")
-            }
+            Unique => write!(f, "Box"),
             BorrowedPtr(ty::ImmBorrow, ref r) |
             Implicit(ty::ImmBorrow, ref r) => {
-                format!("&{}", r.repr(tcx))
+                write!(f, "&{:?}", r)
             }
             BorrowedPtr(ty::MutBorrow, ref r) |
             Implicit(ty::MutBorrow, ref r) => {
-                format!("&{} mut", r.repr(tcx))
+                write!(f, "&{:?} mut", r)
             }
             BorrowedPtr(ty::UniqueImmBorrow, ref r) |
             Implicit(ty::UniqueImmBorrow, ref r) => {
-                format!("&{} uniq", r.repr(tcx))
-            }
-            UnsafePtr(_) => {
-                format!("*")
+                write!(f, "&{:?} uniq", r)
             }
+            UnsafePtr(_) => write!(f, "*")
         }
     }
 }
 
-impl<'tcx> Repr<'tcx> for InteriorKind {
-    fn repr(&self, _tcx: &ty::ctxt) -> String {
+impl fmt::Debug for InteriorKind {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         match *self {
-            InteriorField(NamedField(fld)) => {
-                token::get_name(fld).to_string()
-            }
-            InteriorField(PositionalField(i)) => format!("#{}", i),
-            InteriorElement(..) => "[]".to_string(),
+            InteriorField(NamedField(fld)) => write!(f, "{}", fld),
+            InteriorField(PositionalField(i)) => write!(f, "#{}", i),
+            InteriorElement(..) => write!(f, "[]"),
         }
     }
 }
@@ -1664,25 +1658,19 @@ fn element_kind(t: Ty) -> ElementKind {
     }
 }
 
-impl<'tcx> Repr<'tcx> for ty::ClosureKind {
-    fn repr(&self, _: &ty::ctxt) -> String {
-        format!("Upvar({:?})", self)
+impl fmt::Debug for Upvar {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "{:?}/{:?}", self.id, self.kind)
     }
 }
 
-impl<'tcx> Repr<'tcx> for Upvar {
-    fn repr(&self, tcx: &ty::ctxt) -> String {
-        format!("Upvar({})", self.kind.repr(tcx))
-    }
-}
-
-impl<'tcx> UserString<'tcx> for Upvar {
-    fn user_string(&self, _: &ty::ctxt) -> String {
+impl fmt::Display for Upvar {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         let kind = match self.kind {
             ty::FnClosureKind => "Fn",
             ty::FnMutClosureKind => "FnMut",
             ty::FnOnceClosureKind => "FnOnce",
         };
-        format!("captured outer variable in an `{}` closure", kind)
+        write!(f, "captured outer variable in an `{}` closure", kind)
     }
 }

src/librustc/middle/stability.rs

@@ -28,7 +28,6 @@ use syntax::attr::{Stability, AttrMetaMethods};
 use syntax::visit::{FnKind, Visitor};
 use syntax::feature_gate::emit_feature_err;
 use util::nodemap::{DefIdMap, FnvHashSet, FnvHashMap};
-use util::ppaux::Repr;
 
 use std::mem::replace;
 
@@ -450,7 +449,7 @@ pub fn check_expr(tcx: &ty::ctxt, e: &ast::Expr,
                     tcx.sess.span_bug(e.span,
                                       &format!("stability::check_expr: struct construction \
                                                 of non-struct, type {:?}",
-                                               type_.repr(tcx)));
+                                               type_));
                 }
             }
         }
@@ -551,7 +550,7 @@ pub fn lookup<'tcx>(tcx: &ty::ctxt<'tcx>, id: DefId) -> Option<&'tcx Stability>
 }
 
 fn lookup_uncached<'tcx>(tcx: &ty::ctxt<'tcx>, id: DefId) -> Option<&'tcx Stability> {
-    debug!("lookup(id={})", id.repr(tcx));
+    debug!("lookup(id={:?})", id);
 
     // is this definition the implementation of a trait method?
     match ty::trait_item_of_item(tcx, id) {

src/librustc/middle/subst.rs

@@ -15,7 +15,6 @@ pub use self::RegionSubsts::*;
 
 use middle::ty::{self, Ty};
 use middle::ty_fold::{self, TypeFoldable, TypeFolder};
-use util::ppaux::Repr;
 
 use std::fmt;
 use std::iter::IntoIterator;
@@ -29,7 +28,7 @@ use syntax::codemap::{Span, DUMMY_SP};
 /// identify each in-scope parameter by an *index* and a *parameter
 /// space* (which indices where the parameter is defined; see
 /// `ParamSpace`).
-#[derive(Clone, PartialEq, Eq, Hash, Debug)]
+#[derive(Clone, PartialEq, Eq, Hash)]
 pub struct Substs<'tcx> {
     pub types: VecPerParamSpace<Ty<'tcx>>,
     pub regions: RegionSubsts,
@@ -38,7 +37,7 @@ pub struct Substs<'tcx> {
 /// Represents the values to use when substituting lifetime parameters.
 /// If the value is `ErasedRegions`, then this subst is occurring during
 /// trans, and all region parameters will be replaced with `ty::ReStatic`.
-#[derive(Clone, PartialEq, Eq, Hash, Debug)]
+#[derive(Clone, PartialEq, Eq, Hash)]
 pub enum RegionSubsts {
     ErasedRegions,
     NonerasedRegions(VecPerParamSpace<ty::Region>)
@@ -240,13 +239,11 @@ pub struct SeparateVecsPerParamSpace<T> {
 }
 
 impl<T: fmt::Debug> fmt::Debug for VecPerParamSpace<T> {
-    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
-        try!(write!(fmt, "VecPerParamSpace {{"));
-        for space in &ParamSpace::all() {
-            try!(write!(fmt, "{:?}: {:?}, ", *space, self.get_slice(*space)));
-        }
-        try!(write!(fmt, "}}"));
-        Ok(())
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "[{:?};{:?};{:?}]",
+               self.get_slice(TypeSpace),
+               self.get_slice(SelfSpace),
+               self.get_slice(FnSpace))
     }
 }
 
@@ -620,10 +617,10 @@ impl<'a, 'tcx> TypeFolder<'tcx> for SubstFolder<'a, 'tcx> {
                                 self.tcx().sess.span_bug(
                                     span,
                                     &format!("Type parameter out of range \
-                                              when substituting in region {} (root type={}) \
+                                              when substituting in region {} (root type={:?}) \
                                               (space={:?}, index={})",
-                                             data.name.as_str(),
-                                             self.root_ty.repr(self.tcx()),
+                                             data.name,
+                                             self.root_ty,
                                              data.space,
                                              data.index));
                             }
@@ -675,14 +672,14 @@ impl<'a,'tcx> SubstFolder<'a,'tcx> {
                 let span = self.span.unwrap_or(DUMMY_SP);
                 self.tcx().sess.span_bug(
                     span,
-                    &format!("Type parameter `{}` ({}/{:?}/{}) out of range \
-                                 when substituting (root type={}) substs={}",
-                            p.repr(self.tcx()),
-                            source_ty.repr(self.tcx()),
+                    &format!("Type parameter `{:?}` ({:?}/{:?}/{}) out of range \
+                                 when substituting (root type={:?}) substs={:?}",
+                            p,
+                            source_ty,
                             p.space,
                             p.idx,
-                            self.root_ty.repr(self.tcx()),
-                            self.substs.repr(self.tcx())));
+                            self.root_ty,
+                            self.substs));
             }
         };
 
@@ -733,14 +730,14 @@ impl<'a,'tcx> SubstFolder<'a,'tcx> {
     /// is that only in the second case have we passed through a fn binder.
     fn shift_regions_through_binders(&self, ty: Ty<'tcx>) -> Ty<'tcx> {
         debug!("shift_regions(ty={:?}, region_binders_passed={:?}, type_has_escaping_regions={:?})",
-               ty.repr(self.tcx()), self.region_binders_passed, ty::type_has_escaping_regions(ty));
+               ty, self.region_binders_passed, ty::type_has_escaping_regions(ty));
 
         if self.region_binders_passed == 0 || !ty::type_has_escaping_regions(ty) {
             return ty;
         }
 
         let result = ty_fold::shift_regions(self.tcx(), self.region_binders_passed, &ty);
-        debug!("shift_regions: shifted result = {:?}", result.repr(self.tcx()));
+        debug!("shift_regions: shifted result = {:?}", result);
 
         result
     }

src/librustc/middle/traits/coherence.rs

@@ -22,7 +22,6 @@ use middle::ty::{self, ToPolyTraitRef, Ty};
 use middle::infer::{self, InferCtxt};
 use syntax::ast;
 use syntax::codemap::{DUMMY_SP, Span};
-use util::ppaux::Repr;
 
 #[derive(Copy, Clone)]
 struct InferIsLocal(bool);
@@ -34,10 +33,10 @@ pub fn overlapping_impls(infcx: &InferCtxt,
                          -> bool
 {
     debug!("impl_can_satisfy(\
-           impl1_def_id={}, \
-           impl2_def_id={})",
-           impl1_def_id.repr(infcx.tcx),
-           impl2_def_id.repr(infcx.tcx));
+           impl1_def_id={:?}, \
+           impl2_def_id={:?})",
+           impl1_def_id,
+           impl2_def_id);
 
     let param_env = &ty::empty_parameter_environment(infcx.tcx);
     let selcx = &mut SelectionContext::intercrate(infcx, param_env);
@@ -53,9 +52,9 @@ fn overlap(selcx: &mut SelectionContext,
            b_def_id: ast::DefId)
            -> bool
 {
-    debug!("overlap(a_def_id={}, b_def_id={})",
-           a_def_id.repr(selcx.tcx()),
-           b_def_id.repr(selcx.tcx()));
+    debug!("overlap(a_def_id={:?}, b_def_id={:?})",
+           a_def_id,
+           b_def_id);
 
     let (a_trait_ref, a_obligations) = impl_trait_ref_and_oblig(selcx,
                                                                 a_def_id,
@@ -65,9 +64,9 @@ fn overlap(selcx: &mut SelectionContext,
                                                                 b_def_id,
                                                                 util::fresh_type_vars_for_impl);
 
-    debug!("overlap: a_trait_ref={}", a_trait_ref.repr(selcx.tcx()));
+    debug!("overlap: a_trait_ref={:?}", a_trait_ref);
 
-    debug!("overlap: b_trait_ref={}", b_trait_ref.repr(selcx.tcx()));
+    debug!("overlap: b_trait_ref={:?}", b_trait_ref);
 
     // Does `a <: b` hold? If not, no overlap.
     if let Err(_) = infer::mk_sub_poly_trait_refs(selcx.infcx(),
@@ -81,7 +80,6 @@ fn overlap(selcx: &mut SelectionContext,
     debug!("overlap: subtraitref check succeeded");
 
     // Are any of the obligations unsatisfiable? If so, no overlap.
-    let tcx = selcx.tcx();
     let infcx = selcx.infcx();
     let opt_failing_obligation =
         a_obligations.iter()
@@ -90,7 +88,7 @@ fn overlap(selcx: &mut SelectionContext,
                      .find(|o| !selcx.evaluate_obligation(o));
 
     if let Some(failing_obligation) = opt_failing_obligation {
-        debug!("overlap: obligation unsatisfiable {}", failing_obligation.repr(tcx));
+        debug!("overlap: obligation unsatisfiable {:?}", failing_obligation);
         return false
     }
 
@@ -99,7 +97,7 @@ fn overlap(selcx: &mut SelectionContext,
 
 pub fn trait_ref_is_knowable<'tcx>(tcx: &ty::ctxt<'tcx>, trait_ref: &ty::TraitRef<'tcx>) -> bool
 {
-    debug!("trait_ref_is_knowable(trait_ref={})", trait_ref.repr(tcx));
+    debug!("trait_ref_is_knowable(trait_ref={:?})", trait_ref);
 
     // if the orphan rules pass, that means that no ancestor crate can
     // impl this, so it's up to us.
@@ -155,7 +153,7 @@ fn impl_trait_ref_and_oblig<'a,'tcx>(selcx: &mut SelectionContext<'a,'tcx>,
     let Normalized { value: predicates, obligations: normalization_obligations2 } =
         project::normalize(selcx, ObligationCause::dummy(), &predicates);
     let impl_obligations =
-        util::predicates_for_generics(selcx.tcx(), ObligationCause::dummy(), 0, &predicates);
+        util::predicates_for_generics(ObligationCause::dummy(), 0, &predicates);
 
     let impl_obligations: Vec<_> =
         impl_obligations.into_iter()
@@ -181,17 +179,17 @@ pub fn orphan_check<'tcx>(tcx: &ty::ctxt<'tcx>,
                           impl_def_id: ast::DefId)
                           -> Result<(), OrphanCheckErr<'tcx>>
 {
-    debug!("orphan_check({})", impl_def_id.repr(tcx));
+    debug!("orphan_check({:?})", impl_def_id);
 
     // We only except this routine to be invoked on implementations
     // of a trait, not inherent implementations.
     let trait_ref = ty::impl_trait_ref(tcx, impl_def_id).unwrap();
-    debug!("orphan_check: trait_ref={}", trait_ref.repr(tcx));
+    debug!("orphan_check: trait_ref={:?}", trait_ref);
 
     // If the *trait* is local to the crate, ok.
     if trait_ref.def_id.krate == ast::LOCAL_CRATE {
-        debug!("trait {} is local to current crate",
-               trait_ref.def_id.repr(tcx));
+        debug!("trait {:?} is local to current crate",
+               trait_ref.def_id);
         return Ok(());
     }
 
@@ -203,8 +201,8 @@ fn orphan_check_trait_ref<'tcx>(tcx: &ty::ctxt<'tcx>,
                                 infer_is_local: InferIsLocal)
                                 -> Result<(), OrphanCheckErr<'tcx>>
 {
-    debug!("orphan_check_trait_ref(trait_ref={}, infer_is_local={})",
-           trait_ref.repr(tcx), infer_is_local.0);
+    debug!("orphan_check_trait_ref(trait_ref={:?}, infer_is_local={})",
+           trait_ref, infer_is_local.0);
 
     // First, create an ordered iterator over all the type parameters to the trait, with the self
     // type appearing first.
@@ -215,14 +213,14 @@ fn orphan_check_trait_ref<'tcx>(tcx: &ty::ctxt<'tcx>,
     // some local type.
     for input_ty in input_tys {
         if ty_is_local(tcx, input_ty, infer_is_local) {
-            debug!("orphan_check_trait_ref: ty_is_local `{}`", input_ty.repr(tcx));
+            debug!("orphan_check_trait_ref: ty_is_local `{:?}`", input_ty);
 
             // First local input type. Check that there are no
             // uncovered type parameters.
             let uncovered_tys = uncovered_tys(tcx, input_ty, infer_is_local);
             for uncovered_ty in uncovered_tys {
                 if let Some(param) = uncovered_ty.walk().find(|t| is_type_parameter(t)) {
-                    debug!("orphan_check_trait_ref: uncovered type `{}`", param.repr(tcx));
+                    debug!("orphan_check_trait_ref: uncovered type `{:?}`", param);
                     return Err(OrphanCheckErr::UncoveredTy(param));
                 }
             }
@@ -235,7 +233,7 @@ fn orphan_check_trait_ref<'tcx>(tcx: &ty::ctxt<'tcx>,
         // parameters reachable.
         if !infer_is_local.0 {
             if let Some(param) = input_ty.walk().find(|t| is_type_parameter(t)) {
-                debug!("orphan_check_trait_ref: uncovered type `{}`", param.repr(tcx));
+                debug!("orphan_check_trait_ref: uncovered type `{:?}`", param);
                 return Err(OrphanCheckErr::UncoveredTy(param));
             }
         }
@@ -295,7 +293,7 @@ fn ty_is_local_constructor<'tcx>(tcx: &ty::ctxt<'tcx>,
                                  infer_is_local: InferIsLocal)
                                  -> bool
 {
-    debug!("ty_is_local_constructor({})", ty.repr(tcx));
+    debug!("ty_is_local_constructor({:?})", ty);
 
     match ty.sty {
         ty::TyBool |
@@ -336,8 +334,8 @@ fn ty_is_local_constructor<'tcx>(tcx: &ty::ctxt<'tcx>,
         ty::TyClosure(..) |
         ty::TyError => {
             tcx.sess.bug(
-                &format!("ty_is_local invoked on unexpected type: {}",
-                        ty.repr(tcx)))
+                &format!("ty_is_local invoked on unexpected type: {:?}",
+                        ty))
         }
     }
 }

src/librustc/middle/traits/error_reporting.rs

@@ -28,9 +28,9 @@ use middle::infer::InferCtxt;
 use middle::ty::{self, AsPredicate, ReferencesError, ToPolyTraitRef, TraitRef};
 use middle::ty_fold::TypeFoldable;
 use std::collections::HashMap;
+use std::fmt;
 use syntax::codemap::{DUMMY_SP, Span};
 use syntax::attr::{AttributeMethods, AttrMetaMethods};
-use util::ppaux::{Repr, UserString};
 
 pub fn report_fulfillment_errors<'a, 'tcx>(infcx: &InferCtxt<'a, 'tcx>,
                                            errors: &Vec<FulfillmentError<'tcx>>) {
@@ -68,8 +68,8 @@ pub fn report_projection_error<'a, 'tcx>(infcx: &InferCtxt<'a, 'tcx>,
     if !infcx.tcx.sess.has_errors() || !predicate.references_error() {
         span_err!(infcx.tcx.sess, obligation.cause.span, E0271,
                 "type mismatch resolving `{}`: {}",
-                predicate.user_string(infcx.tcx),
-                ty::type_err_to_str(infcx.tcx, &error.err));
+                predicate,
+                error.err);
         note_obligation_cause(infcx, obligation);
     }
 }
@@ -87,16 +87,16 @@ fn report_on_unimplemented<'a, 'tcx>(infcx: &InferCtxt<'a, 'tcx>,
                 item.meta().span
             };
             let def = ty::lookup_trait_def(infcx.tcx, def_id);
-            let trait_str = def.trait_ref.user_string(infcx.tcx);
+            let trait_str = def.trait_ref.to_string();
             if let Some(ref istring) = item.value_str() {
                 let mut generic_map = def.generics.types.iter_enumerated()
                                          .map(|(param, i, gen)| {
                                                (gen.name.as_str().to_string(),
                                                 trait_ref.substs.types.get(param, i)
-                                                         .user_string(infcx.tcx))
+                                                         .to_string())
                                               }).collect::<HashMap<String, String>>();
                 generic_map.insert("Self".to_string(),
-                                   trait_ref.self_ty().user_string(infcx.tcx));
+                                   trait_ref.self_ty().to_string());
                 let parser = Parser::new(&istring);
                 let mut errored = false;
                 let err: String = parser.filter_map(|p| {
@@ -157,13 +157,13 @@ fn report_on_unimplemented<'a, 'tcx>(infcx: &InferCtxt<'a, 'tcx>,
 pub fn report_overflow_error<'a, 'tcx, T>(infcx: &InferCtxt<'a, 'tcx>,
                                           obligation: &Obligation<'tcx, T>)
                                           -> !
-    where T: UserString<'tcx> + TypeFoldable<'tcx>
+    where T: fmt::Display + TypeFoldable<'tcx>
 {
     let predicate =
         infcx.resolve_type_vars_if_possible(&obligation.predicate);
     span_err!(infcx.tcx.sess, obligation.cause.span, E0275,
               "overflow evaluating the requirement `{}`",
-              predicate.user_string(infcx.tcx));
+              predicate);
 
     suggest_new_overflow_limit(infcx.tcx, obligation.cause.span);
 
@@ -184,7 +184,7 @@ pub fn report_selection_error<'a, 'tcx>(infcx: &InferCtxt<'a, 'tcx>,
                     span_err!(infcx.tcx.sess, obligation.cause.span, E0276,
                             "the requirement `{}` appears on the impl \
                             method but not on the corresponding trait method",
-                            obligation.predicate.user_string(infcx.tcx));;
+                            obligation.predicate);;
                 }
                 _ => {
                     match obligation.predicate {
@@ -197,8 +197,8 @@ pub fn report_selection_error<'a, 'tcx>(infcx: &InferCtxt<'a, 'tcx>,
                                 let trait_ref = trait_predicate.to_poly_trait_ref();
                                 span_err!(infcx.tcx.sess, obligation.cause.span, E0277,
                                         "the trait `{}` is not implemented for the type `{}`",
-                                        trait_ref.user_string(infcx.tcx),
-                                        trait_ref.self_ty().user_string(infcx.tcx));
+                                        trait_ref,
+                                        trait_ref.self_ty());
                                 // Check if it has a custom "#[rustc_on_unimplemented]"
                                 // error message, report with that message if it does
                                 let custom_note = report_on_unimplemented(infcx, &trait_ref.0,
@@ -216,8 +216,8 @@ pub fn report_selection_error<'a, 'tcx>(infcx: &InferCtxt<'a, 'tcx>,
                                                                &predicate).err().unwrap();
                             span_err!(infcx.tcx.sess, obligation.cause.span, E0278,
                                     "the requirement `{}` is not satisfied (`{}`)",
-                                    predicate.user_string(infcx.tcx),
-                                    ty::type_err_to_str(infcx.tcx, &err));
+                                    predicate,
+                                    err);
                         }
 
                         ty::Predicate::RegionOutlives(ref predicate) => {
@@ -226,8 +226,8 @@ pub fn report_selection_error<'a, 'tcx>(infcx: &InferCtxt<'a, 'tcx>,
                                                                       &predicate).err().unwrap();
                             span_err!(infcx.tcx.sess, obligation.cause.span, E0279,
                                     "the requirement `{}` is not satisfied (`{}`)",
-                                    predicate.user_string(infcx.tcx),
-                                    ty::type_err_to_str(infcx.tcx, &err));
+                                    predicate,
+                                    err);
                         }
 
                         ty::Predicate::Projection(..) | ty::Predicate::TypeOutlives(..) => {
@@ -235,7 +235,7 @@ pub fn report_selection_error<'a, 'tcx>(infcx: &InferCtxt<'a, 'tcx>,
                                     infcx.resolve_type_vars_if_possible(&obligation.predicate);
                                 span_err!(infcx.tcx.sess, obligation.cause.span, E0280,
                                         "the requirement `{}` is not satisfied",
-                                        predicate.user_string(infcx.tcx));
+                                        predicate);
                         }
                     }
                 }
@@ -249,10 +249,10 @@ pub fn report_selection_error<'a, 'tcx>(infcx: &InferCtxt<'a, 'tcx>,
                 span_err!(infcx.tcx.sess, obligation.cause.span, E0281,
                         "type mismatch: the type `{}` implements the trait `{}`, \
                         but the trait `{}` is required ({})",
-                        expected_trait_ref.self_ty().user_string(infcx.tcx),
-                        expected_trait_ref.user_string(infcx.tcx),
-                        actual_trait_ref.user_string(infcx.tcx),
-                        ty::type_err_to_str(infcx.tcx, e));
+                        expected_trait_ref.self_ty(),
+                        expected_trait_ref,
+                        actual_trait_ref,
+                        e);
                     note_obligation_cause(infcx, obligation);
             }
         }
@@ -282,7 +282,7 @@ pub fn report_selection_error<'a, 'tcx>(infcx: &InferCtxt<'a, 'tcx>,
                         infcx.tcx.sess.span_note(
                             obligation.cause.span,
                             &format!("method `{}` has no receiver",
-                                    method.name.user_string(infcx.tcx)));
+                                    method.name));
                     }
 
                     ObjectSafetyViolation::Method(method,
@@ -291,7 +291,7 @@ pub fn report_selection_error<'a, 'tcx>(infcx: &InferCtxt<'a, 'tcx>,
                             obligation.cause.span,
                             &format!("method `{}` references the `Self` type \
                                     in its arguments or return type",
-                                    method.name.user_string(infcx.tcx)));
+                                    method.name));
                     }
 
                     ObjectSafetyViolation::Method(method,
@@ -299,7 +299,7 @@ pub fn report_selection_error<'a, 'tcx>(infcx: &InferCtxt<'a, 'tcx>,
                         infcx.tcx.sess.span_note(
                             obligation.cause.span,
                             &format!("method `{}` has generic type parameters",
-                                    method.name.user_string(infcx.tcx)));
+                                    method.name));
                     }
                 }
             }
@@ -316,9 +316,9 @@ pub fn maybe_report_ambiguity<'a, 'tcx>(infcx: &InferCtxt<'a, 'tcx>,
 
     let predicate = infcx.resolve_type_vars_if_possible(&obligation.predicate);
 
-    debug!("maybe_report_ambiguity(predicate={}, obligation={})",
-           predicate.repr(infcx.tcx),
-           obligation.repr(infcx.tcx));
+    debug!("maybe_report_ambiguity(predicate={:?}, obligation={:?})",
+           predicate,
+           obligation);
 
     match predicate {
         ty::Predicate::Trait(ref data) => {
@@ -349,11 +349,11 @@ pub fn maybe_report_ambiguity<'a, 'tcx>(infcx: &InferCtxt<'a, 'tcx>,
                         span_err!(infcx.tcx.sess, obligation.cause.span, E0282,
                                 "unable to infer enough type information about `{}`; \
                                  type annotations or generic parameter binding required",
-                                self_ty.user_string(infcx.tcx));
+                                self_ty);
                     } else {
                         span_err!(infcx.tcx.sess, obligation.cause.span, E0283,
                                 "type annotations required: cannot resolve `{}`",
-                                predicate.user_string(infcx.tcx));;
+                                predicate);;
                         note_obligation_cause(infcx, obligation);
                     }
                 }
@@ -365,8 +365,8 @@ pub fn maybe_report_ambiguity<'a, 'tcx>(infcx: &InferCtxt<'a, 'tcx>,
                         "coherence failed to report ambiguity: \
                          cannot locate the impl of the trait `{}` for \
                          the type `{}`",
-                        trait_ref.user_string(infcx.tcx),
-                        self_ty.user_string(infcx.tcx)));
+                        trait_ref,
+                        self_ty));
             }
         }
 
@@ -374,7 +374,7 @@ pub fn maybe_report_ambiguity<'a, 'tcx>(infcx: &InferCtxt<'a, 'tcx>,
             if !infcx.tcx.sess.has_errors() {
                 span_err!(infcx.tcx.sess, obligation.cause.span, E0284,
                         "type annotations required: cannot resolve `{}`",
-                        predicate.user_string(infcx.tcx));;
+                        predicate);;
                 note_obligation_cause(infcx, obligation);
             }
         }
@@ -383,7 +383,7 @@ pub fn maybe_report_ambiguity<'a, 'tcx>(infcx: &InferCtxt<'a, 'tcx>,
 
 fn note_obligation_cause<'a, 'tcx, T>(infcx: &InferCtxt<'a, 'tcx>,
                                       obligation: &Obligation<'tcx, T>)
-    where T: UserString<'tcx>
+    where T: fmt::Display
 {
     note_obligation_cause_code(infcx,
                                &obligation.predicate,
@@ -395,7 +395,7 @@ fn note_obligation_cause_code<'a, 'tcx, T>(infcx: &InferCtxt<'a, 'tcx>,
                                            predicate: &T,
                                            cause_span: Span,
                                            cause_code: &ObligationCauseCode<'tcx>)
-    where T: UserString<'tcx>
+    where T: fmt::Display
 {
     let tcx = infcx.tcx;
     match *cause_code {
@@ -463,7 +463,7 @@ fn note_obligation_cause_code<'a, 'tcx, T>(infcx: &InferCtxt<'a, 'tcx>,
             let parent_trait_ref = infcx.resolve_type_vars_if_possible(&data.parent_trait_ref);
             span_note!(tcx.sess, cause_span,
                        "required because it appears within the type `{}`",
-                       parent_trait_ref.0.self_ty().user_string(infcx.tcx));
+                       parent_trait_ref.0.self_ty());
             let parent_predicate = parent_trait_ref.as_predicate();
             note_obligation_cause_code(infcx, &parent_predicate, cause_span, &*data.parent_code);
         }
@@ -471,8 +471,8 @@ fn note_obligation_cause_code<'a, 'tcx, T>(infcx: &InferCtxt<'a, 'tcx>,
             let parent_trait_ref = infcx.resolve_type_vars_if_possible(&data.parent_trait_ref);
             span_note!(tcx.sess, cause_span,
                        "required because of the requirements on the impl of `{}` for `{}`",
-                       parent_trait_ref.user_string(infcx.tcx),
-                       parent_trait_ref.0.self_ty().user_string(infcx.tcx));
+                       parent_trait_ref,
+                       parent_trait_ref.0.self_ty());
             let parent_predicate = parent_trait_ref.as_predicate();
             note_obligation_cause_code(infcx, &parent_predicate, cause_span, &*data.parent_code);
         }
@@ -480,7 +480,7 @@ fn note_obligation_cause_code<'a, 'tcx, T>(infcx: &InferCtxt<'a, 'tcx>,
             span_note!(tcx.sess, cause_span,
                       "the requirement `{}` appears on the impl method \
                       but not on the corresponding trait method",
-                      predicate.user_string(infcx.tcx));
+                      predicate);
         }
     }
 }

src/librustc/middle/traits/fulfill.rs

@@ -10,11 +10,11 @@
 
 use middle::infer::InferCtxt;
 use middle::ty::{self, RegionEscape, Ty};
+
 use std::collections::HashSet;
-use std::default::Default;
+use std::fmt;
 use syntax::ast;
 use util::common::ErrorReported;
-use util::ppaux::Repr;
 use util::nodemap::NodeMap;
 
 use super::CodeAmbiguity;
@@ -137,8 +137,8 @@ impl<'tcx> FulfillmentContext<'tcx> {
                                          cause: ObligationCause<'tcx>)
                                          -> Ty<'tcx>
     {
-        debug!("normalize_associated_type(projection_ty={})",
-               projection_ty.repr(infcx.tcx));
+        debug!("normalize_associated_type(projection_ty={:?})",
+               projection_ty);
 
         assert!(!projection_ty.has_escaping_regions());
 
@@ -151,7 +151,7 @@ impl<'tcx> FulfillmentContext<'tcx> {
             self.register_predicate_obligation(infcx, obligation);
         }
 
-        debug!("normalize_associated_type: result={}", normalized.value.repr(infcx.tcx));
+        debug!("normalize_associated_type: result={:?}", normalized.value);
 
         normalized.value
     }
@@ -171,12 +171,11 @@ impl<'tcx> FulfillmentContext<'tcx> {
     }
 
     pub fn register_region_obligation<'a>(&mut self,
-                                          infcx: &InferCtxt<'a,'tcx>,
                                           t_a: Ty<'tcx>,
                                           r_b: ty::Region,
                                           cause: ObligationCause<'tcx>)
     {
-        register_region_obligation(infcx.tcx, t_a, r_b, cause, &mut self.region_obligations);
+        register_region_obligation(t_a, r_b, cause, &mut self.region_obligations);
     }
 
     pub fn register_predicate_obligation<'a>(&mut self,
@@ -190,11 +189,11 @@ impl<'tcx> FulfillmentContext<'tcx> {
         assert!(!obligation.has_escaping_regions());
 
         if self.is_duplicate_or_add(infcx.tcx, &obligation.predicate) {
-            debug!("register_predicate({}) -- already seen, skip", obligation.repr(infcx.tcx));
+            debug!("register_predicate({:?}) -- already seen, skip", obligation);
             return;
         }
 
-        debug!("register_predicate({})", obligation.repr(infcx.tcx));
+        debug!("register_predicate({:?})", obligation);
         self.predicates.push(obligation);
     }
 
@@ -366,7 +365,6 @@ fn process_predicate<'a,'tcx>(selcx: &mut SelectionContext<'a,'tcx>,
      * type inference.
      */
 
-    let tcx = selcx.tcx();
     match obligation.predicate {
         ty::Predicate::Trait(ref data) => {
             let trait_obligation = obligation.with(data.clone());
@@ -379,9 +377,9 @@ fn process_predicate<'a,'tcx>(selcx: &mut SelectionContext<'a,'tcx>,
                     true
                 }
                 Err(selection_err) => {
-                    debug!("predicate: {} error: {}",
-                           obligation.repr(tcx),
-                           selection_err.repr(tcx));
+                    debug!("predicate: {:?} error: {:?}",
+                           obligation,
+                           selection_err);
                     errors.push(
                         FulfillmentError::new(
                             obligation.clone(),
@@ -430,7 +428,7 @@ fn process_predicate<'a,'tcx>(selcx: &mut SelectionContext<'a,'tcx>,
                         CodeSelectionError(Unimplemented)));
             } else {
                 let ty::OutlivesPredicate(t_a, r_b) = binder.0;
-                register_region_obligation(tcx, t_a, r_b,
+                register_region_obligation(t_a, r_b,
                                            obligation.cause.clone(),
                                            region_obligations);
             }
@@ -440,9 +438,9 @@ fn process_predicate<'a,'tcx>(selcx: &mut SelectionContext<'a,'tcx>,
         ty::Predicate::Projection(ref data) => {
             let project_obligation = obligation.with(data.clone());
             let result = project::poly_project_and_unify_type(selcx, &project_obligation);
-            debug!("process_predicate: poly_project_and_unify_type({}) returned {}",
-                   project_obligation.repr(tcx),
-                   result.repr(tcx));
+            debug!("process_predicate: poly_project_and_unify_type({:?}) returned {:?}",
+                   project_obligation,
+                   result);
             match result {
                 Ok(Some(obligations)) => {
                     new_obligations.extend(obligations);
@@ -463,16 +461,15 @@ fn process_predicate<'a,'tcx>(selcx: &mut SelectionContext<'a,'tcx>,
     }
 }
 
-impl<'tcx> Repr<'tcx> for RegionObligation<'tcx> {
-    fn repr(&self, tcx: &ty::ctxt<'tcx>) -> String {
-        format!("RegionObligation(sub_region={}, sup_type={})",
-                self.sub_region.repr(tcx),
-                self.sup_type.repr(tcx))
+impl<'tcx> fmt::Debug for RegionObligation<'tcx> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "RegionObligation(sub_region={:?}, sup_type={:?})",
+               self.sub_region,
+               self.sup_type)
     }
 }
 
-fn register_region_obligation<'tcx>(tcx: &ty::ctxt<'tcx>,
-                                    t_a: Ty<'tcx>,
+fn register_region_obligation<'tcx>(t_a: Ty<'tcx>,
                                     r_b: ty::Region,
                                     cause: ObligationCause<'tcx>,
                                     region_obligations: &mut NodeMap<Vec<RegionObligation<'tcx>>>)
@@ -481,8 +478,8 @@ fn register_region_obligation<'tcx>(tcx: &ty::ctxt<'tcx>,
                                                sub_region: r_b,
                                                cause: cause };
 
-    debug!("register_region_obligation({})",
-           region_obligation.repr(tcx));
+    debug!("register_region_obligation({:?})",
+           region_obligation);
 
     region_obligations.entry(region_obligation.cause.body_id).or_insert(vec![])
         .push(region_obligation);

src/librustc/middle/traits/mod.rs

@@ -23,7 +23,6 @@ use middle::infer::{self, fixup_err_to_string, InferCtxt};
 use std::rc::Rc;
 use syntax::ast;
 use syntax::codemap::{Span, DUMMY_SP};
-use util::ppaux::Repr;
 
 pub use self::error_reporting::report_fulfillment_errors;
 pub use self::error_reporting::report_overflow_error;
@@ -219,7 +218,7 @@ pub type SelectionResult<'tcx, T> = Result<Option<T>, SelectionError<'tcx>>;
 /// ### The type parameter `N`
 ///
 /// See explanation on `VtableImplData`.
-#[derive(Debug,Clone)]
+#[derive(Clone)]
 pub enum Vtable<'tcx, N> {
     /// Vtable identifying a particular impl.
     VtableImpl(VtableImplData<'tcx, N>),
@@ -277,13 +276,13 @@ pub struct VtableClosureData<'tcx, N> {
     pub nested: Vec<N>
 }
 
-#[derive(Debug, Clone)]
+#[derive(Clone)]
 pub struct VtableDefaultImplData<N> {
     pub trait_def_id: ast::DefId,
     pub nested: Vec<N>
 }
 
-#[derive(Debug,Clone)]
+#[derive(Clone)]
 pub struct VtableBuiltinData<N> {
     pub nested: Vec<N>
 }
@@ -300,12 +299,11 @@ pub struct VtableObjectData<'tcx> {
 }
 
 /// Creates predicate obligations from the generic bounds.
-pub fn predicates_for_generics<'tcx>(tcx: &ty::ctxt<'tcx>,
-                                     cause: ObligationCause<'tcx>,
+pub fn predicates_for_generics<'tcx>(cause: ObligationCause<'tcx>,
                                      generic_bounds: &ty::InstantiatedPredicates<'tcx>)
                                      -> PredicateObligations<'tcx>
 {
-    util::predicates_for_generics(tcx, cause, 0, generic_bounds)
+    util::predicates_for_generics(cause, 0, generic_bounds)
 }
 
 /// Determines whether the type `ty` is known to meet `bound` and
@@ -320,8 +318,8 @@ pub fn type_known_to_meet_builtin_bound<'a,'tcx>(infcx: &InferCtxt<'a,'tcx>,
                                                  span: Span)
                                                  -> bool
 {
-    debug!("type_known_to_meet_builtin_bound(ty={}, bound={:?})",
-           ty.repr(infcx.tcx),
+    debug!("type_known_to_meet_builtin_bound(ty={:?}, bound={:?})",
+           ty,
            bound);
 
     let mut fulfill_cx = FulfillmentContext::new(false);
@@ -338,16 +336,16 @@ pub fn type_known_to_meet_builtin_bound<'a,'tcx>(infcx: &InferCtxt<'a,'tcx>,
     // assume it is move; linear is always ok.
     match fulfill_cx.select_all_or_error(infcx, typer) {
         Ok(()) => {
-            debug!("type_known_to_meet_builtin_bound: ty={} bound={:?} success",
-                   ty.repr(infcx.tcx),
+            debug!("type_known_to_meet_builtin_bound: ty={:?} bound={:?} success",
+                   ty,
                    bound);
             true
         }
         Err(e) => {
-            debug!("type_known_to_meet_builtin_bound: ty={} bound={:?} errors={}",
-                   ty.repr(infcx.tcx),
+            debug!("type_known_to_meet_builtin_bound: ty={:?} bound={:?} errors={:?}",
+                   ty,
                    bound,
-                   e.repr(infcx.tcx));
+                   e);
             false
         }
     }
@@ -377,8 +375,8 @@ pub fn normalize_param_env_or_error<'a,'tcx>(unnormalized_env: ty::ParameterEnvi
     let span = cause.span;
     let body_id = cause.body_id;
 
-    debug!("normalize_param_env_or_error(unnormalized_env={})",
-           unnormalized_env.repr(tcx));
+    debug!("normalize_param_env_or_error(unnormalized_env={:?})",
+           unnormalized_env);
 
     let predicates: Vec<_> =
         util::elaborate_predicates(tcx, unnormalized_env.caller_bounds.clone())
@@ -393,8 +391,8 @@ pub fn normalize_param_env_or_error<'a,'tcx>(unnormalized_env: ty::ParameterEnvi
     // constructed, but I am not currently doing so out of laziness.
     // -nmatsakis
 
-    debug!("normalize_param_env_or_error: elaborated-predicates={}",
-           predicates.repr(tcx));
+    debug!("normalize_param_env_or_error: elaborated-predicates={:?}",
+           predicates);
 
     let elaborated_env = unnormalized_env.with_caller_bounds(predicates);
 
@@ -434,25 +432,23 @@ pub fn fully_normalize<'a,'tcx,T>(infcx: &InferCtxt<'a,'tcx>,
                                   cause: ObligationCause<'tcx>,
                                   value: &T)
                                   -> Result<T, Vec<FulfillmentError<'tcx>>>
-    where T : TypeFoldable<'tcx> + HasProjectionTypes + Clone + Repr<'tcx>
+    where T : TypeFoldable<'tcx> + HasProjectionTypes
 {
-    let tcx = closure_typer.tcx();
-
-    debug!("normalize_param_env(value={})", value.repr(tcx));
+    debug!("normalize_param_env(value={:?})", value);
 
     let mut selcx = &mut SelectionContext::new(infcx, closure_typer);
     let mut fulfill_cx = FulfillmentContext::new(false);
     let Normalized { value: normalized_value, obligations } =
         project::normalize(selcx, cause, value);
-    debug!("normalize_param_env: normalized_value={} obligations={}",
-           normalized_value.repr(tcx),
-           obligations.repr(tcx));
+    debug!("normalize_param_env: normalized_value={:?} obligations={:?}",
+           normalized_value,
+           obligations);
     for obligation in obligations {
         fulfill_cx.register_predicate_obligation(selcx.infcx(), obligation);
     }
     try!(fulfill_cx.select_all_or_error(infcx, closure_typer));
     let resolved_value = infcx.resolve_type_vars_if_possible(&normalized_value);
-    debug!("normalize_param_env: resolved_value={}", resolved_value.repr(tcx));
+    debug!("normalize_param_env: resolved_value={:?}", resolved_value);
     Ok(resolved_value)
 }
 

src/librustc/middle/traits/object_safety.rs

@@ -25,8 +25,8 @@ use middle::traits;
 use middle::ty::{self, ToPolyTraitRef, Ty};
 use std::rc::Rc;
 use syntax::ast;
-use util::ppaux::Repr;
 
+#[derive(Debug)]
 pub enum ObjectSafetyViolation<'tcx> {
     /// Self : Sized declared on the trait
     SizedSelf,
@@ -70,7 +70,7 @@ pub fn is_object_safe<'tcx>(tcx: &ty::ctxt<'tcx>,
         result
     });
 
-    debug!("is_object_safe({}) = {}", trait_def_id.repr(tcx), result);
+    debug!("is_object_safe({:?}) = {}", trait_def_id, result);
 
     result
 }
@@ -111,9 +111,9 @@ fn object_safety_violations_for_trait<'tcx>(tcx: &ty::ctxt<'tcx>,
         violations.push(ObjectSafetyViolation::SupertraitSelf);
     }
 
-    debug!("object_safety_violations_for_trait(trait_def_id={}) = {}",
-           trait_def_id.repr(tcx),
-           violations.repr(tcx));
+    debug!("object_safety_violations_for_trait(trait_def_id={:?}) = {:?}",
+           trait_def_id,
+           violations);
 
     violations
 }
@@ -352,19 +352,6 @@ fn contains_illegal_self_type_reference<'tcx>(tcx: &ty::ctxt<'tcx>,
     error
 }
 
-impl<'tcx> Repr<'tcx> for ObjectSafetyViolation<'tcx> {
-    fn repr(&self, tcx: &ty::ctxt<'tcx>) -> String {
-        match *self {
-            ObjectSafetyViolation::SizedSelf =>
-                format!("SizedSelf"),
-            ObjectSafetyViolation::SupertraitSelf =>
-                format!("SupertraitSelf"),
-            ObjectSafetyViolation::Method(ref m, code) =>
-                format!("Method({},{:?})", m.repr(tcx), code),
-        }
-    }
-}
-
 fn is_self<'tcx>(ty: Ty<'tcx>) -> bool {
     match ty.sty {
         ty::TyParam(ref data) => data.space == subst::SelfSpace,

src/librustc/middle/traits/project.rs

@@ -28,7 +28,8 @@ use middle::ty::{self, AsPredicate, ReferencesError, RegionEscape,
 use middle::ty_fold::{self, TypeFoldable, TypeFolder};
 use syntax::parse::token;
 use util::common::FN_OUTPUT_NAME;
-use util::ppaux::Repr;
+
+use std::fmt;
 
 pub type PolyProjectionObligation<'tcx> =
     Obligation<'tcx, ty::PolyProjectionPredicate<'tcx>>;
@@ -40,6 +41,7 @@ pub type ProjectionTyObligation<'tcx> =
     Obligation<'tcx, ty::ProjectionTy<'tcx>>;
 
 /// When attempting to resolve `<T as TraitRef>::Name` ...
+#[derive(Debug)]
 pub enum ProjectionTyError<'tcx> {
     /// ...we found multiple sources of information and couldn't resolve the ambiguity.
     TooManyCandidates,
@@ -53,7 +55,7 @@ pub struct MismatchedProjectionTypes<'tcx> {
     pub err: ty::type_err<'tcx>
 }
 
-#[derive(PartialEq, Eq)]
+#[derive(PartialEq, Eq, Debug)]
 enum ProjectionTyCandidate<'tcx> {
     ParamEnv(ty::PolyProjectionPredicate<'tcx>),
     Impl(VtableImplData<'tcx, PredicateObligation<'tcx>>),
@@ -76,8 +78,8 @@ pub fn poly_project_and_unify_type<'cx,'tcx>(
     obligation: &PolyProjectionObligation<'tcx>)
     -> Result<Option<Vec<PredicateObligation<'tcx>>>, MismatchedProjectionTypes<'tcx>>
 {
-    debug!("poly_project_and_unify_type(obligation={})",
-           obligation.repr(selcx.tcx()));
+    debug!("poly_project_and_unify_type(obligation={:?})",
+           obligation);
 
     let infcx = selcx.infcx();
     infcx.commit_if_ok(|snapshot| {
@@ -109,8 +111,8 @@ fn project_and_unify_type<'cx,'tcx>(
     obligation: &ProjectionObligation<'tcx>)
     -> Result<Option<Vec<PredicateObligation<'tcx>>>, MismatchedProjectionTypes<'tcx>>
 {
-    debug!("project_and_unify_type(obligation={})",
-           obligation.repr(selcx.tcx()));
+    debug!("project_and_unify_type(obligation={:?})",
+           obligation);
 
     let Normalized { value: normalized_ty, obligations } =
         match opt_normalize_projection_type(selcx,
@@ -124,9 +126,9 @@ fn project_and_unify_type<'cx,'tcx>(
             }
         };
 
-    debug!("project_and_unify_type: normalized_ty={} obligations={}",
-           normalized_ty.repr(selcx.tcx()),
-           obligations.repr(selcx.tcx()));
+    debug!("project_and_unify_type: normalized_ty={:?} obligations={:?}",
+           normalized_ty,
+           obligations);
 
     let infcx = selcx.infcx();
     let origin = infer::RelateOutputImplTypes(obligation.cause.span);
@@ -138,8 +140,8 @@ fn project_and_unify_type<'cx,'tcx>(
 
 fn consider_unification_despite_ambiguity<'cx,'tcx>(selcx: &mut SelectionContext<'cx,'tcx>,
                                                     obligation: &ProjectionObligation<'tcx>) {
-    debug!("consider_unification_despite_ambiguity(obligation={})",
-           obligation.repr(selcx.tcx()));
+    debug!("consider_unification_despite_ambiguity(obligation={:?})",
+           obligation);
 
     let def_id = obligation.predicate.projection_ty.trait_ref.def_id;
     match selcx.tcx().lang_items.fn_trait_kind(def_id) {
@@ -173,7 +175,7 @@ fn consider_unification_despite_ambiguity<'cx,'tcx>(selcx: &mut SelectionContext
                     &ty::Binder(ret_type));
 
             debug!("consider_unification_despite_ambiguity: ret_type={:?}",
-                   ret_type.repr(selcx.tcx()));
+                   ret_type);
             let origin = infer::RelateOutputImplTypes(obligation.cause.span);
             let obligation_ty = obligation.predicate.ty;
             match infer::mk_eqty(infcx, true, origin, obligation_ty, ret_type) {
@@ -193,7 +195,7 @@ pub fn normalize<'a,'b,'tcx,T>(selcx: &'a mut SelectionContext<'b,'tcx>,
                                cause: ObligationCause<'tcx>,
                                value: &T)
                                -> Normalized<'tcx, T>
-    where T : TypeFoldable<'tcx> + HasProjectionTypes + Clone + Repr<'tcx>
+    where T : TypeFoldable<'tcx> + HasProjectionTypes
 {
     normalize_with_depth(selcx, cause, 0, value)
 }
@@ -204,7 +206,7 @@ pub fn normalize_with_depth<'a,'b,'tcx,T>(selcx: &'a mut SelectionContext<'b,'tc
                                           depth: usize,
                                           value: &T)
                                           -> Normalized<'tcx, T>
-    where T : TypeFoldable<'tcx> + HasProjectionTypes + Clone + Repr<'tcx>
+    where T : TypeFoldable<'tcx> + HasProjectionTypes
 {
     let mut normalizer = AssociatedTypeNormalizer::new(selcx, cause, depth);
     let result = normalizer.fold(value);
@@ -236,7 +238,7 @@ impl<'a,'b,'tcx> AssociatedTypeNormalizer<'a,'b,'tcx> {
         }
     }
 
-    fn fold<T:TypeFoldable<'tcx> + HasProjectionTypes + Clone>(&mut self, value: &T) -> T {
+    fn fold<T:TypeFoldable<'tcx> + HasProjectionTypes>(&mut self, value: &T) -> T {
         let value = self.selcx.infcx().resolve_type_vars_if_possible(value);
 
         if !value.has_projection_types() {
@@ -354,9 +356,9 @@ fn opt_normalize_projection_type<'a,'b,'tcx>(
     -> Option<NormalizedTy<'tcx>>
 {
     debug!("normalize_projection_type(\
-           projection_ty={}, \
+           projection_ty={:?}, \
            depth={})",
-           projection_ty.repr(selcx.tcx()),
+           projection_ty,
            depth);
 
     let obligation = Obligation::with_depth(cause.clone(), depth, projection_ty.clone());
@@ -367,18 +369,17 @@ fn opt_normalize_projection_type<'a,'b,'tcx>(
             // an impl, where-clause etc) and hence we must
             // re-normalize it
 
-            debug!("normalize_projection_type: projected_ty={} depth={} obligations={}",
-                   projected_ty.repr(selcx.tcx()),
+            debug!("normalize_projection_type: projected_ty={:?} depth={} obligations={:?}",
+                   projected_ty,
                    depth,
-                   obligations.repr(selcx.tcx()));
+                   obligations);
 
             if ty::type_has_projection(projected_ty) {
-                let tcx = selcx.tcx();
                 let mut normalizer = AssociatedTypeNormalizer::new(selcx, cause, depth);
                 let normalized_ty = normalizer.fold(&projected_ty);
 
-                debug!("normalize_projection_type: normalized_ty={} depth={}",
-                       normalized_ty.repr(tcx),
+                debug!("normalize_projection_type: normalized_ty={:?} depth={}",
+                       normalized_ty,
                        depth);
 
                 obligations.extend(normalizer.obligations);
@@ -394,8 +395,8 @@ fn opt_normalize_projection_type<'a,'b,'tcx>(
             }
         }
         Ok(ProjectedTy::NoProgress(projected_ty)) => {
-            debug!("normalize_projection_type: projected_ty={} no progress",
-                   projected_ty.repr(selcx.tcx()));
+            debug!("normalize_projection_type: projected_ty={:?} no progress",
+                   projected_ty);
             Some(Normalized {
                 value: projected_ty,
                 obligations: vec!()
@@ -449,8 +450,8 @@ fn project_type<'cx,'tcx>(
     obligation: &ProjectionTyObligation<'tcx>)
     -> Result<ProjectedTy<'tcx>, ProjectionTyError<'tcx>>
 {
-    debug!("project(obligation={})",
-           obligation.repr(selcx.tcx()));
+    debug!("project(obligation={:?})",
+           obligation);
 
     let recursion_limit = selcx.tcx().sess.recursion_limit.get();
     if obligation.recursion_depth >= recursion_limit {
@@ -461,7 +462,7 @@ fn project_type<'cx,'tcx>(
     let obligation_trait_ref =
         selcx.infcx().resolve_type_vars_if_possible(&obligation.predicate.trait_ref);
 
-    debug!("project: obligation_trait_ref={}", obligation_trait_ref.repr(selcx.tcx()));
+    debug!("project: obligation_trait_ref={:?}", obligation_trait_ref);
 
     if obligation_trait_ref.references_error() {
         return Ok(ProjectedTy::Progress(selcx.tcx().types.err, vec!()));
@@ -589,12 +590,12 @@ fn assemble_candidates_from_predicates<'cx,'tcx,I>(
     env_predicates: I)
     where I: Iterator<Item=ty::Predicate<'tcx>>
 {
-    debug!("assemble_candidates_from_predicates(obligation={})",
-           obligation.repr(selcx.tcx()));
+    debug!("assemble_candidates_from_predicates(obligation={:?})",
+           obligation);
     let infcx = selcx.infcx();
     for predicate in env_predicates {
-        debug!("assemble_candidates_from_predicates: predicate={}",
-               predicate.repr(selcx.tcx()));
+        debug!("assemble_candidates_from_predicates: predicate={:?}",
+               predicate);
         match predicate {
             ty::Predicate::Projection(ref data) => {
                 let same_name = data.item_name() == obligation.predicate.item_name;
@@ -611,10 +612,9 @@ fn assemble_candidates_from_predicates<'cx,'tcx,I>(
                                               obligation_poly_trait_ref).is_ok()
                 });
 
-                debug!("assemble_candidates_from_predicates: candidate {} is_match {} same_name {}",
-                       data.repr(selcx.tcx()),
-                       is_match,
-                       same_name);
+                debug!("assemble_candidates_from_predicates: candidate={:?} \
+                                                             is_match={} same_name={}",
+                       data, is_match, same_name);
 
                 if is_match {
                     candidate_set.vec.push(
@@ -633,16 +633,15 @@ fn assemble_candidates_from_object_type<'cx,'tcx>(
     candidate_set: &mut ProjectionTyCandidateSet<'tcx>,
     object_ty: Ty<'tcx>)
 {
-    let infcx = selcx.infcx();
-    debug!("assemble_candidates_from_object_type(object_ty={})",
-           object_ty.repr(infcx.tcx));
+    debug!("assemble_candidates_from_object_type(object_ty={:?})",
+           object_ty);
     let data = match object_ty.sty {
         ty::TyTrait(ref data) => data,
         _ => {
             selcx.tcx().sess.span_bug(
                 obligation.cause.span,
-                &format!("assemble_candidates_from_object_type called with non-object: {}",
-                         object_ty.repr(selcx.tcx())));
+                &format!("assemble_candidates_from_object_type called with non-object: {:?}",
+                         object_ty));
         }
     };
     let projection_bounds = data.projection_bounds_with_self_ty(selcx.tcx(), object_ty);
@@ -672,16 +671,16 @@ fn assemble_candidates_from_impls<'cx,'tcx>(
             return Ok(());
         }
         Err(e) => {
-            debug!("assemble_candidates_from_impls: selection error {}",
-                   e.repr(selcx.tcx()));
+            debug!("assemble_candidates_from_impls: selection error {:?}",
+                   e);
             return Err(e);
         }
     };
 
     match vtable {
         super::VtableImpl(data) => {
-            debug!("assemble_candidates_from_impls: impl candidate {}",
-                   data.repr(selcx.tcx()));
+            debug!("assemble_candidates_from_impls: impl candidate {:?}",
+                   data);
 
             candidate_set.vec.push(
                 ProjectionTyCandidate::Impl(data));
@@ -731,8 +730,8 @@ fn assemble_candidates_from_impls<'cx,'tcx>(
             // These traits have no associated types.
             selcx.tcx().sess.span_bug(
                 obligation.cause.span,
-                &format!("Cannot project an associated type from `{}`",
-                         vtable.repr(selcx.tcx())));
+                &format!("Cannot project an associated type from `{:?}`",
+                         vtable));
         }
     }
 
@@ -745,11 +744,9 @@ fn confirm_candidate<'cx,'tcx>(
     candidate: ProjectionTyCandidate<'tcx>)
     -> (Ty<'tcx>, Vec<PredicateObligation<'tcx>>)
 {
-    let infcx = selcx.infcx();
-
-    debug!("confirm_candidate(candidate={}, obligation={})",
-           candidate.repr(infcx.tcx),
-           obligation.repr(infcx.tcx));
+    debug!("confirm_candidate(candidate={:?}, obligation={:?})",
+           candidate,
+           obligation);
 
     match candidate {
         ProjectionTyCandidate::ParamEnv(poly_projection) => {
@@ -813,9 +810,9 @@ fn confirm_callable_candidate<'cx,'tcx>(
 {
     let tcx = selcx.tcx();
 
-    debug!("confirm_callable_candidate({},{})",
-           obligation.repr(tcx),
-           fn_sig.repr(tcx));
+    debug!("confirm_callable_candidate({:?},{:?})",
+           obligation,
+           fn_sig);
 
     // the `Output` associated type is declared on `FnOnce`
     let fn_once_def_id = tcx.lang_items.fn_once_trait().unwrap();
@@ -865,10 +862,10 @@ fn confirm_param_env_candidate<'cx,'tcx>(
         Err(e) => {
             selcx.tcx().sess.span_bug(
                 obligation.cause.span,
-                &format!("Failed to unify `{}` and `{}` in projection: {}",
-                         obligation.repr(selcx.tcx()),
-                         projection.repr(selcx.tcx()),
-                         ty::type_err_to_str(selcx.tcx(), &e)));
+                &format!("Failed to unify `{:?}` and `{:?}` in projection: {}",
+                         obligation,
+                         projection,
+                         e));
         }
     }
 
@@ -915,34 +912,8 @@ fn confirm_impl_candidate<'cx,'tcx>(
     }
 
     selcx.tcx().sess.span_bug(obligation.cause.span,
-                              &format!("No associated type for {}",
-                                       trait_ref.repr(selcx.tcx())));
-}
-
-impl<'tcx> Repr<'tcx> for ProjectionTyError<'tcx> {
-    fn repr(&self, tcx: &ty::ctxt<'tcx>) -> String {
-        match *self {
-            ProjectionTyError::TooManyCandidates =>
-                format!("NoCandidate"),
-            ProjectionTyError::TraitSelectionError(ref e) =>
-                format!("TraitSelectionError({})", e.repr(tcx)),
-        }
-    }
-}
-
-impl<'tcx> Repr<'tcx> for ProjectionTyCandidate<'tcx> {
-    fn repr(&self, tcx: &ty::ctxt<'tcx>) -> String {
-        match *self {
-            ProjectionTyCandidate::ParamEnv(ref data) =>
-                format!("ParamEnv({})", data.repr(tcx)),
-            ProjectionTyCandidate::Impl(ref data) =>
-                format!("Impl({})", data.repr(tcx)),
-            ProjectionTyCandidate::Closure(ref data) =>
-                format!("Closure({})", data.repr(tcx)),
-            ProjectionTyCandidate::FnPointer(a) =>
-                format!("FnPointer(({}))", a.repr(tcx)),
-        }
-    }
+                              &format!("No associated type for {:?}",
+                                       trait_ref));
 }
 
 impl<'tcx, T: TypeFoldable<'tcx>> TypeFoldable<'tcx> for Normalized<'tcx, T> {
@@ -954,10 +925,10 @@ impl<'tcx, T: TypeFoldable<'tcx>> TypeFoldable<'tcx> for Normalized<'tcx, T> {
     }
 }
 
-impl<'tcx, T:Repr<'tcx>> Repr<'tcx> for Normalized<'tcx, T> {
-    fn repr(&self, tcx: &ty::ctxt<'tcx>) -> String {
-        format!("Normalized({},{})",
-                self.value.repr(tcx),
-                self.obligations.repr(tcx))
+impl<'tcx, T:fmt::Debug> fmt::Debug for Normalized<'tcx, T> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "Normalized({:?},{:?})",
+               self.value,
+               self.obligations)
     }
 }

src/librustc/middle/traits/select.rs

@@ -44,12 +44,13 @@ use middle::infer::{InferCtxt, TypeFreshener};
 use middle::ty_fold::TypeFoldable;
 use middle::ty_match;
 use middle::ty_relate::TypeRelation;
+
 use std::cell::RefCell;
+use std::fmt;
 use std::rc::Rc;
 use syntax::{abi, ast};
 use util::common::ErrorReported;
 use util::nodemap::FnvHashMap;
-use util::ppaux::Repr;
 
 pub struct SelectionContext<'cx, 'tcx:'cx> {
     infcx: &'cx InferCtxt<'cx, 'tcx>,
@@ -298,7 +299,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
     /// type environment by performing unification.
     pub fn select(&mut self, obligation: &TraitObligation<'tcx>)
                   -> SelectionResult<'tcx, Selection<'tcx>> {
-        debug!("select({})", obligation.repr(self.tcx()));
+        debug!("select({:?})", obligation);
         assert!(!obligation.predicate.has_escaping_regions());
 
         let stack = self.push_stack(TraitObligationStackList::empty(), obligation);
@@ -387,8 +388,8 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                                obligation: &PredicateObligation<'tcx>)
                                -> bool
     {
-        debug!("evaluate_obligation({})",
-               obligation.repr(self.tcx()));
+        debug!("evaluate_obligation({:?})",
+               obligation);
 
         self.evaluate_predicate_recursively(TraitObligationStackList::empty(), obligation)
             .may_apply()
@@ -440,8 +441,8 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                                           obligation: &PredicateObligation<'tcx>)
                                            -> EvaluationResult<'tcx>
     {
-        debug!("evaluate_predicate_recursively({})",
-               obligation.repr(self.tcx()));
+        debug!("evaluate_predicate_recursively({:?})",
+               obligation);
 
         // Check the cache from the tcx of predicates that we know
         // have been proven elsewhere. This cache only contains
@@ -499,8 +500,8 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                                            obligation: &TraitObligation<'tcx>)
                                            -> EvaluationResult<'tcx>
     {
-        debug!("evaluate_obligation_recursively({})",
-               obligation.repr(self.tcx()));
+        debug!("evaluate_obligation_recursively({:?})",
+               obligation);
 
         let stack = self.push_stack(previous_stack, obligation);
 
@@ -547,8 +548,8 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                   |prev| self.match_fresh_trait_refs(&stack.fresh_trait_ref,
                                                      &prev.fresh_trait_ref)))
         {
-            debug!("evaluate_stack({}) --> unbound argument, recursion -->  ambiguous",
-                   stack.fresh_trait_ref.repr(self.tcx()));
+            debug!("evaluate_stack({:?}) --> unbound argument, recursion -->  ambiguous",
+                   stack.fresh_trait_ref);
             return EvaluatedToAmbig;
         }
 
@@ -576,8 +577,8 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
             .skip(1) // skip top-most frame
             .any(|prev| stack.fresh_trait_ref == prev.fresh_trait_ref)
         {
-            debug!("evaluate_stack({}) --> recursive",
-                   stack.fresh_trait_ref.repr(self.tcx()));
+            debug!("evaluate_stack({:?}) --> recursive",
+                   stack.fresh_trait_ref);
             return EvaluatedToOk;
         }
 
@@ -595,9 +596,9 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                          obligation: &TraitObligation<'tcx>)
                          -> bool
     {
-        debug!("evaluate_impl(impl_def_id={}, obligation={})",
-               impl_def_id.repr(self.tcx()),
-               obligation.repr(self.tcx()));
+        debug!("evaluate_impl(impl_def_id={:?}, obligation={:?})",
+               impl_def_id,
+               obligation);
 
         self.infcx.probe(|snapshot| {
             match self.match_impl(impl_def_id, obligation, snapshot) {
@@ -643,16 +644,16 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
         // with fresh skolemized types starting from index 0.
         let cache_fresh_trait_pred =
             self.infcx.freshen(stack.obligation.predicate.clone());
-        debug!("candidate_from_obligation(cache_fresh_trait_pred={}, obligation={})",
-               cache_fresh_trait_pred.repr(self.tcx()),
-               stack.repr(self.tcx()));
+        debug!("candidate_from_obligation(cache_fresh_trait_pred={:?}, obligation={:?})",
+               cache_fresh_trait_pred,
+               stack);
         assert!(!stack.obligation.predicate.has_escaping_regions());
 
         match self.check_candidate_cache(&cache_fresh_trait_pred) {
             Some(c) => {
-                debug!("CACHE HIT: cache_fresh_trait_pred={}, candidate={}",
-                       cache_fresh_trait_pred.repr(self.tcx()),
-                       c.repr(self.tcx()));
+                debug!("CACHE HIT: cache_fresh_trait_pred={:?}, candidate={:?}",
+                       cache_fresh_trait_pred,
+                       c);
                 return c;
             }
             None => { }
@@ -662,8 +663,8 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
         let candidate = self.candidate_from_obligation_no_cache(stack);
 
         if self.should_update_candidate_cache(&cache_fresh_trait_pred, &candidate) {
-            debug!("CACHE MISS: cache_fresh_trait_pred={}, candidate={}",
-                   cache_fresh_trait_pred.repr(self.tcx()), candidate.repr(self.tcx()));
+            debug!("CACHE MISS: cache_fresh_trait_pred={:?}, candidate={:?}",
+                   cache_fresh_trait_pred, candidate);
             self.insert_candidate_cache(cache_fresh_trait_pred, candidate.clone());
         }
 
@@ -692,10 +693,10 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
 
         let mut candidates = candidate_set.vec;
 
-        debug!("assembled {} candidates for {}: {}",
+        debug!("assembled {} candidates for {:?}: {:?}",
                candidates.len(),
-               stack.repr(self.tcx()),
-               candidates.repr(self.tcx()));
+               stack,
+               candidates);
 
         // At this point, we know that each of the entries in the
         // candidate set is *individually* applicable. Now we have to
@@ -735,12 +736,12 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                     .any(|j| self.candidate_should_be_dropped_in_favor_of(&candidates[i],
                                                                           &candidates[j]));
                 if is_dup {
-                    debug!("Dropping candidate #{}/{}: {}",
-                           i, candidates.len(), candidates[i].repr(self.tcx()));
+                    debug!("Dropping candidate #{}/{}: {:?}",
+                           i, candidates.len(), candidates[i]);
                     candidates.swap_remove(i);
                 } else {
-                    debug!("Retaining candidate #{}/{}: {}",
-                           i, candidates.len(), candidates[i].repr(self.tcx()));
+                    debug!("Retaining candidate #{}/{}: {:?}",
+                           i, candidates.len(), candidates[i]);
                     i += 1;
                 }
             }
@@ -906,8 +907,8 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
 
         match self.tcx().lang_items.to_builtin_kind(obligation.predicate.def_id()) {
             Some(ty::BoundCopy) => {
-                debug!("obligation self ty is {}",
-                       obligation.predicate.0.self_ty().repr(self.tcx()));
+                debug!("obligation self ty is {:?}",
+                       obligation.predicate.0.self_ty());
 
                 // User-defined copy impls are permitted, but only for
                 // structs and enums.
@@ -957,9 +958,9 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
         let poly_trait_predicate =
             self.infcx().resolve_type_vars_if_possible(&obligation.predicate);
 
-        debug!("assemble_candidates_for_projected_tys({},{})",
-               obligation.repr(self.tcx()),
-               poly_trait_predicate.repr(self.tcx()));
+        debug!("assemble_candidates_for_projected_tys({:?},{:?})",
+               obligation,
+               poly_trait_predicate);
 
         // FIXME(#20297) -- just examining the self-type is very simplistic
 
@@ -981,8 +982,8 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
             _ => { return; }
         };
 
-        debug!("assemble_candidates_for_projected_tys: trait_def_id={}",
-               trait_def_id.repr(self.tcx()));
+        debug!("assemble_candidates_for_projected_tys: trait_def_id={:?}",
+               trait_def_id);
 
         let result = self.infcx.probe(|snapshot| {
             self.match_projection_obligation_against_bounds_from_trait(obligation,
@@ -1005,9 +1006,9 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
         let (skol_trait_predicate, skol_map) =
             self.infcx().skolemize_late_bound_regions(&poly_trait_predicate, snapshot);
         debug!("match_projection_obligation_against_bounds_from_trait: \
-                skol_trait_predicate={} skol_map={}",
-               skol_trait_predicate.repr(self.tcx()),
-               skol_map.repr(self.tcx()));
+                skol_trait_predicate={:?} skol_map={:?}",
+               skol_trait_predicate,
+               skol_map);
 
         let projection_trait_ref = match skol_trait_predicate.trait_ref.self_ty().sty {
             ty::TyProjection(ref data) => &data.trait_ref,
@@ -1015,19 +1016,19 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                 self.tcx().sess.span_bug(
                     obligation.cause.span,
                     &format!("match_projection_obligation_against_bounds_from_trait() called \
-                              but self-ty not a projection: {}",
-                             skol_trait_predicate.trait_ref.self_ty().repr(self.tcx())));
+                              but self-ty not a projection: {:?}",
+                             skol_trait_predicate.trait_ref.self_ty()));
             }
         };
         debug!("match_projection_obligation_against_bounds_from_trait: \
-                projection_trait_ref={}",
-               projection_trait_ref.repr(self.tcx()));
+                projection_trait_ref={:?}",
+               projection_trait_ref);
 
         let trait_predicates = ty::lookup_predicates(self.tcx(), projection_trait_ref.def_id);
         let bounds = trait_predicates.instantiate(self.tcx(), projection_trait_ref.substs);
         debug!("match_projection_obligation_against_bounds_from_trait: \
-                bounds={}",
-               bounds.repr(self.tcx()));
+                bounds={:?}",
+               bounds);
 
         let matching_bound =
             util::elaborate_predicates(self.tcx(), bounds.predicates.into_vec())
@@ -1041,8 +1042,8 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                                               snapshot)));
 
         debug!("match_projection_obligation_against_bounds_from_trait: \
-                matching_bound={}",
-               matching_bound.repr(self.tcx()));
+                matching_bound={:?}",
+               matching_bound);
         match matching_bound {
             None => false,
             Some(bound) => {
@@ -1088,8 +1089,8 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                                                   candidates: &mut SelectionCandidateSet<'tcx>)
                                                   -> Result<(),SelectionError<'tcx>>
     {
-        debug!("assemble_candidates_from_caller_bounds({})",
-               stack.obligation.repr(self.tcx()));
+        debug!("assemble_candidates_from_caller_bounds({:?})",
+               stack.obligation);
 
         let all_bounds =
             self.param_env().caller_bounds
@@ -1155,10 +1156,10 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
             _ => { return Ok(()); }
         };
 
-        debug!("assemble_unboxed_candidates: self_ty={} kind={:?} obligation={}",
-               self_ty.repr(self.tcx()),
+        debug!("assemble_unboxed_candidates: self_ty={:?} kind={:?} obligation={:?}",
+               self_ty,
                kind,
-               obligation.repr(self.tcx()));
+               obligation);
 
         match self.closure_typer.closure_kind(closure_def_id) {
             Some(closure_kind) => {
@@ -1221,7 +1222,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                                       candidates: &mut SelectionCandidateSet<'tcx>)
                                       -> Result<(), SelectionError<'tcx>>
     {
-        debug!("assemble_candidates_from_impls(obligation={})", obligation.repr(self.tcx()));
+        debug!("assemble_candidates_from_impls(obligation={:?})", obligation);
 
         let def = ty::lookup_trait_def(self.tcx(), obligation.predicate.def_id());
 
@@ -1247,7 +1248,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
     {
         // OK to skip binder here because the tests we do below do not involve bound regions
         let self_ty = self.infcx.shallow_resolve(*obligation.self_ty().skip_binder());
-        debug!("assemble_candidates_from_default_impls(self_ty={})", self_ty.repr(self.tcx()));
+        debug!("assemble_candidates_from_default_impls(self_ty={:?})", self_ty);
 
         let def_id = obligation.predicate.def_id();
 
@@ -1316,8 +1317,8 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                                           obligation: &TraitObligation<'tcx>,
                                           candidates: &mut SelectionCandidateSet<'tcx>)
     {
-        debug!("assemble_candidates_from_object_ty(self_ty={})",
-               self.infcx.shallow_resolve(*obligation.self_ty().skip_binder()).repr(self.tcx()));
+        debug!("assemble_candidates_from_object_ty(self_ty={:?})",
+               self.infcx.shallow_resolve(*obligation.self_ty().skip_binder()));
 
         // Object-safety candidates are only applicable to object-safe
         // traits. Including this check is useful because it helps
@@ -1362,8 +1363,8 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                 }
             };
 
-            debug!("assemble_candidates_from_object_ty: poly_trait_ref={}",
-                   poly_trait_ref.repr(self.tcx()));
+            debug!("assemble_candidates_from_object_ty: poly_trait_ref={:?}",
+                   poly_trait_ref);
 
             // see whether the object trait can be upcast to the trait we are looking for
             let upcast_trait_refs = self.upcast(poly_trait_ref, obligation);
@@ -1406,8 +1407,8 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
         let source = self.infcx.shallow_resolve(self_ty);
         let target = self.infcx.shallow_resolve(obligation.predicate.0.input_types()[0]);
 
-        debug!("assemble_candidates_for_unsizing(source={}, target={})",
-               source.repr(self.tcx()), target.repr(self.tcx()));
+        debug!("assemble_candidates_for_unsizing(source={:?}, target={:?})",
+               source, target);
 
         let may_apply = match (&source.sty, &target.sty) {
             // Trait+Kx+'a -> Trait+Ky+'b (upcasts).
@@ -1473,7 +1474,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                             candidate: &SelectionCandidate<'tcx>)
                             -> EvaluationResult<'tcx>
     {
-        debug!("winnow_candidate: candidate={}", candidate.repr(self.tcx()));
+        debug!("winnow_candidate: candidate={:?}", candidate);
         let result = self.infcx.probe(|_| {
             let candidate = (*candidate).clone();
             match self.confirm_candidate(stack.obligation, candidate) {
@@ -1565,8 +1566,8 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
     {
         match self.builtin_bound(bound, stack.obligation) {
             Ok(If(..)) => {
-                debug!("builtin_bound: bound={}",
-                       bound.repr(self.tcx()));
+                debug!("builtin_bound: bound={:?}",
+                       bound);
                 candidates.vec.push(BuiltinCandidate(bound));
                 Ok(())
             }
@@ -1774,8 +1775,8 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
             | ty::TyInfer(ty::FreshFloatTy(_)) => {
                 self.tcx().sess.bug(
                     &format!(
-                        "asked to assemble builtin bounds of unexpected type: {}",
-                        self_ty.repr(self.tcx())));
+                        "asked to assemble builtin bounds of unexpected type: {:?}",
+                        self_ty));
             }
         };
 
@@ -1837,8 +1838,8 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
             ty::TyInfer(ty::FreshFloatTy(_)) => {
                 self.tcx().sess.bug(
                     &format!(
-                        "asked to assemble constituent types of unexpected type: {}",
-                        t.repr(self.tcx())));
+                        "asked to assemble constituent types of unexpected type: {:?}",
+                        t));
             }
 
             ty::TyBox(referent_ty) => {  // Box<T>
@@ -1972,9 +1973,9 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                          candidate: SelectionCandidate<'tcx>)
                          -> Result<Selection<'tcx>,SelectionError<'tcx>>
     {
-        debug!("confirm_candidate({}, {})",
-               obligation.repr(self.tcx()),
-               candidate.repr(self.tcx()));
+        debug!("confirm_candidate({:?}, {:?})",
+               obligation,
+               candidate);
 
         match candidate {
             BuiltinCandidate(builtin_bound) => {
@@ -2064,9 +2065,9 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                                param: ty::PolyTraitRef<'tcx>)
                                -> Vec<PredicateObligation<'tcx>>
     {
-        debug!("confirm_param_candidate({},{})",
-               obligation.repr(self.tcx()),
-               param.repr(self.tcx()));
+        debug!("confirm_param_candidate({:?},{:?})",
+               obligation,
+               param);
 
         // During evaluation, we already checked that this
         // where-clause trait-ref could be unified with the obligation
@@ -2076,9 +2077,9 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
             Ok(obligations) => obligations,
             Err(()) => {
                 self.tcx().sess.bug(
-                    &format!("Where clause `{}` was applicable to `{}` but now is not",
-                             param.repr(self.tcx()),
-                             obligation.repr(self.tcx())));
+                    &format!("Where clause `{:?}` was applicable to `{:?}` but now is not",
+                             param,
+                             obligation));
             }
         }
     }
@@ -2089,16 +2090,16 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                                  -> Result<VtableBuiltinData<PredicateObligation<'tcx>>,
                                            SelectionError<'tcx>>
     {
-        debug!("confirm_builtin_candidate({})",
-               obligation.repr(self.tcx()));
+        debug!("confirm_builtin_candidate({:?})",
+               obligation);
 
         match try!(self.builtin_bound(bound, obligation)) {
             If(nested) => Ok(self.vtable_builtin_data(obligation, bound, nested)),
             AmbiguousBuiltin | ParameterBuiltin => {
                 self.tcx().sess.span_bug(
                     obligation.cause.span,
-                    &format!("builtin bound for {} was ambig",
-                            obligation.repr(self.tcx())));
+                    &format!("builtin bound for {:?} was ambig",
+                            obligation));
             }
         }
     }
@@ -2118,8 +2119,8 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
 
         let obligations = self.collect_predicates_for_types(obligation, trait_def, nested);
 
-        debug!("vtable_builtin_data: obligations={}",
-               obligations.repr(self.tcx()));
+        debug!("vtable_builtin_data: obligations={:?}",
+               obligations);
 
         VtableBuiltinData { nested: obligations }
     }
@@ -2134,9 +2135,9 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                                       trait_def_id: ast::DefId)
                                       -> VtableDefaultImplData<PredicateObligation<'tcx>>
     {
-        debug!("confirm_default_impl_candidate({}, {})",
-               obligation.repr(self.tcx()),
-               trait_def_id.repr(self.tcx()));
+        debug!("confirm_default_impl_candidate({:?}, {:?})",
+               obligation,
+               trait_def_id);
 
         // binder is moved below
         let self_ty = self.infcx.shallow_resolve(obligation.predicate.skip_binder().self_ty());
@@ -2145,8 +2146,8 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
             None => {
                 self.tcx().sess.bug(
                     &format!(
-                        "asked to confirm default implementation for ambiguous type: {}",
-                        self_ty.repr(self.tcx())));
+                        "asked to confirm default implementation for ambiguous type: {:?}",
+                        self_ty));
             }
         }
     }
@@ -2156,9 +2157,9 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                                              trait_def_id: ast::DefId)
                                              -> VtableDefaultImplData<PredicateObligation<'tcx>>
     {
-        debug!("confirm_default_impl_object_candidate({}, {})",
-               obligation.repr(self.tcx()),
-               trait_def_id.repr(self.tcx()));
+        debug!("confirm_default_impl_object_candidate({:?}, {:?})",
+               obligation,
+               trait_def_id);
 
         assert!(ty::has_attr(self.tcx(), trait_def_id, "rustc_reflect_like"));
 
@@ -2184,8 +2185,8 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
             _ => {
                 self.tcx().sess.bug(
                     &format!(
-                        "asked to confirm default object implementation for non-object type: {}",
-                        self_ty.repr(self.tcx())));
+                        "asked to confirm default object implementation for non-object type: {:?}",
+                        self_ty));
             }
         }
     }
@@ -2197,7 +2198,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                            nested: ty::Binder<Vec<Ty<'tcx>>>)
                            -> VtableDefaultImplData<PredicateObligation<'tcx>>
     {
-        debug!("vtable_default_impl_data: nested={}", nested.repr(self.tcx()));
+        debug!("vtable_default_impl_data: nested={:?}", nested);
 
         let mut obligations = self.collect_predicates_for_types(obligation,
                                                                 trait_def_id,
@@ -2218,7 +2219,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
         // no Errors in that code above
         obligations.append(&mut trait_obligations.unwrap());
 
-        debug!("vtable_default_impl_data: obligations={}", obligations.repr(self.tcx()));
+        debug!("vtable_default_impl_data: obligations={:?}", obligations);
 
         VtableDefaultImplData {
             trait_def_id: trait_def_id,
@@ -2232,9 +2233,9 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                               -> Result<VtableImplData<'tcx, PredicateObligation<'tcx>>,
                                         SelectionError<'tcx>>
     {
-        debug!("confirm_impl_candidate({},{})",
-               obligation.repr(self.tcx()),
-               impl_def_id.repr(self.tcx()));
+        debug!("confirm_impl_candidate({:?},{:?})",
+               obligation,
+               impl_def_id);
 
         // First, create the substitutions by matching the impl again,
         // this time not in a probe.
@@ -2242,7 +2243,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
             let (substs, skol_map) =
                 self.rematch_impl(impl_def_id, obligation,
                                   snapshot);
-            debug!("confirm_impl_candidate substs={}", substs.repr(self.tcx()));
+            debug!("confirm_impl_candidate substs={:?}", substs);
             Ok(self.vtable_impl(impl_def_id, substs, obligation.cause.clone(),
                                 obligation.recursion_depth + 1, skol_map, snapshot))
         })
@@ -2257,11 +2258,11 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                    snapshot: &infer::CombinedSnapshot)
                    -> VtableImplData<'tcx, PredicateObligation<'tcx>>
     {
-        debug!("vtable_impl(impl_def_id={}, substs={}, recursion_depth={}, skol_map={})",
-               impl_def_id.repr(self.tcx()),
-               substs.repr(self.tcx()),
+        debug!("vtable_impl(impl_def_id={:?}, substs={:?}, recursion_depth={}, skol_map={:?})",
+               impl_def_id,
+               substs,
                recursion_depth,
-               skol_map.repr(self.tcx()));
+               skol_map);
 
         let mut impl_obligations =
             self.impl_or_trait_obligations(cause,
@@ -2271,9 +2272,9 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                                            skol_map,
                                            snapshot);
 
-        debug!("vtable_impl: impl_def_id={} impl_obligations={}",
-               impl_def_id.repr(self.tcx()),
-               impl_obligations.repr(self.tcx()));
+        debug!("vtable_impl: impl_def_id={:?} impl_obligations={:?}",
+               impl_def_id,
+               impl_obligations);
 
         impl_obligations.append(&mut substs.obligations);
 
@@ -2286,8 +2287,8 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                                 obligation: &TraitObligation<'tcx>)
                                 -> VtableObjectData<'tcx>
     {
-        debug!("confirm_object_candidate({})",
-               obligation.repr(self.tcx()));
+        debug!("confirm_object_candidate({:?})",
+               obligation);
 
         // FIXME skipping binder here seems wrong -- we should
         // probably flatten the binder from the obligation and the
@@ -2328,8 +2329,8 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                                     obligation: &TraitObligation<'tcx>)
                                     -> Result<ty::Ty<'tcx>,SelectionError<'tcx>>
     {
-        debug!("confirm_fn_pointer_candidate({})",
-               obligation.repr(self.tcx()));
+        debug!("confirm_fn_pointer_candidate({:?})",
+               obligation);
 
         // ok to skip binder; it is reintroduced below
         let self_ty = self.infcx.shallow_resolve(*obligation.self_ty().skip_binder());
@@ -2355,20 +2356,20 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                                  -> Result<VtableClosureData<'tcx, PredicateObligation<'tcx>>,
                                            SelectionError<'tcx>>
     {
-        debug!("confirm_closure_candidate({},{},{})",
-               obligation.repr(self.tcx()),
-               closure_def_id.repr(self.tcx()),
-               substs.repr(self.tcx()));
+        debug!("confirm_closure_candidate({:?},{:?},{:?})",
+               obligation,
+               closure_def_id,
+               substs);
 
         let Normalized {
             value: trait_ref,
             obligations
         } = self.closure_trait_ref(obligation, closure_def_id, substs);
 
-        debug!("confirm_closure_candidate(closure_def_id={}, trait_ref={}, obligations={})",
-               closure_def_id.repr(self.tcx()),
-               trait_ref.repr(self.tcx()),
-               obligations.repr(self.tcx()));
+        debug!("confirm_closure_candidate(closure_def_id={:?}, trait_ref={:?}, obligations={:?})",
+               closure_def_id,
+               trait_ref,
+               obligations);
 
         try!(self.confirm_poly_trait_refs(obligation.cause.clone(),
                                           obligation.predicate.to_poly_trait_ref(),
@@ -2436,8 +2437,8 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
             ty::no_late_bound_regions(tcx, &obligation.self_ty()).unwrap());
         let target = self.infcx.shallow_resolve(obligation.predicate.0.input_types()[0]);
 
-        debug!("confirm_builtin_unsize_candidate(source={}, target={})",
-               source.repr(tcx), target.repr(tcx));
+        debug!("confirm_builtin_unsize_candidate(source={:?}, target={:?})",
+               source, target);
 
         let mut nested = vec![];
         match (&source.sty, &target.sty) {
@@ -2613,9 +2614,9 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
             Ok((substs, skol_map)) => (substs, skol_map),
             Err(()) => {
                 self.tcx().sess.bug(
-                    &format!("Impl {} was matchable against {} but now is not",
-                            impl_def_id.repr(self.tcx()),
-                            obligation.repr(self.tcx())));
+                    &format!("Impl {:?} was matchable against {:?} but now is not",
+                            impl_def_id,
+                            obligation));
             }
         }
     }
@@ -2654,30 +2655,28 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                                           obligation.recursion_depth + 1,
                                           &impl_trait_ref);
 
-        debug!("match_impl(impl_def_id={}, obligation={}, \
-               impl_trait_ref={}, skol_obligation_trait_ref={})",
-               impl_def_id.repr(self.tcx()),
-               obligation.repr(self.tcx()),
-               impl_trait_ref.repr(self.tcx()),
-               skol_obligation_trait_ref.repr(self.tcx()));
+        debug!("match_impl(impl_def_id={:?}, obligation={:?}, \
+               impl_trait_ref={:?}, skol_obligation_trait_ref={:?})",
+               impl_def_id,
+               obligation,
+               impl_trait_ref,
+               skol_obligation_trait_ref);
 
         let origin = infer::RelateOutputImplTypes(obligation.cause.span);
         if let Err(e) = self.infcx.sub_trait_refs(false,
                                                   origin,
                                                   impl_trait_ref.value.clone(),
                                                   skol_obligation_trait_ref) {
-            debug!("match_impl: failed sub_trait_refs due to `{}`",
-                   ty::type_err_to_str(self.tcx(), &e));
+            debug!("match_impl: failed sub_trait_refs due to `{}`", e);
             return Err(());
         }
 
         if let Err(e) = self.infcx.leak_check(&skol_map, snapshot) {
-            debug!("match_impl: failed leak check due to `{}`",
-                   ty::type_err_to_str(self.tcx(), &e));
+            debug!("match_impl: failed leak check due to `{}`", e);
             return Err(());
         }
 
-        debug!("match_impl: success impl_substs={}", impl_substs.repr(self.tcx()));
+        debug!("match_impl: success impl_substs={:?}", impl_substs);
         Ok((Normalized {
             value: impl_substs,
             obligations: impl_trait_ref.obligations
@@ -2728,9 +2727,9 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                             poly_trait_ref: ty::PolyTraitRef<'tcx>)
                             -> Result<(),()>
     {
-        debug!("match_poly_trait_ref: obligation={} poly_trait_ref={}",
-               obligation.repr(self.tcx()),
-               poly_trait_ref.repr(self.tcx()));
+        debug!("match_poly_trait_ref: obligation={:?} poly_trait_ref={:?}",
+               obligation,
+               poly_trait_ref);
 
         let origin = infer::RelateOutputImplTypes(obligation.cause.span);
         match self.infcx.sub_poly_trait_refs(false,
@@ -2769,15 +2768,15 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
         let impl_self_ty = ty::lookup_item_type(self.tcx(), impl_def_id).ty;
         let impl_self_ty = impl_self_ty.subst(self.tcx(), &impl_substs);
 
-        debug!("match_impl_self_types(obligation_self_ty={}, impl_self_ty={})",
-               obligation_self_ty.repr(self.tcx()),
-               impl_self_ty.repr(self.tcx()));
+        debug!("match_impl_self_types(obligation_self_ty={:?}, impl_self_ty={:?})",
+               obligation_self_ty,
+               impl_self_ty);
 
         match self.match_self_types(obligation_cause,
                                     impl_self_ty,
                                     obligation_self_ty) {
             Ok(()) => {
-                debug!("Matched impl_substs={}", impl_substs.repr(self.tcx()));
+                debug!("Matched impl_substs={:?}", impl_substs);
                 Ok(impl_substs)
             }
             Err(()) => {
@@ -2889,15 +2888,14 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                                  snapshot: &infer::CombinedSnapshot)
                                  -> Vec<PredicateObligation<'tcx>>
     {
-        debug!("impl_or_trait_obligations(def_id={})", def_id.repr(self.tcx()));
+        debug!("impl_or_trait_obligations(def_id={:?})", def_id);
 
         let predicates = ty::lookup_predicates(self.tcx(), def_id);
         let predicates = predicates.instantiate(self.tcx(), substs);
         let predicates = normalize_with_depth(self, cause.clone(), recursion_depth, &predicates);
         let mut predicates = self.infcx().plug_leaks(skol_map, snapshot, &predicates);
         let mut obligations =
-            util::predicates_for_generics(self.tcx(),
-                                          cause,
+            util::predicates_for_generics(cause,
                                           recursion_depth,
                                           &predicates.value);
         obligations.append(&mut predicates.obligations);
@@ -2940,9 +2938,9 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
     fn upcast(&mut self, obj_trait_ref: ty::PolyTraitRef<'tcx>, obligation: &TraitObligation<'tcx>)
               -> Vec<ty::PolyTraitRef<'tcx>>
     {
-        debug!("upcast(obj_trait_ref={}, obligation={})",
-               obj_trait_ref.repr(self.tcx()),
-               obligation.repr(self.tcx()));
+        debug!("upcast(obj_trait_ref={:?}, obligation={:?})",
+               obj_trait_ref,
+               obligation);
 
         let obligation_def_id = obligation.predicate.def_id();
         let mut upcast_trait_refs = util::upcast(self.tcx(), obj_trait_ref, obligation_def_id);
@@ -2958,33 +2956,11 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
             self.infcx.probe(|_| self.match_poly_trait_ref(obligation, upcast_trait_ref)).is_ok()
         });
 
-        debug!("upcast: upcast_trait_refs={}", upcast_trait_refs.repr(self.tcx()));
+        debug!("upcast: upcast_trait_refs={:?}", upcast_trait_refs);
         upcast_trait_refs
     }
 }
 
-impl<'tcx> Repr<'tcx> for SelectionCandidate<'tcx> {
-    fn repr(&self, tcx: &ty::ctxt<'tcx>) -> String {
-        match *self {
-            PhantomFnCandidate => format!("PhantomFnCandidate"),
-            ErrorCandidate => format!("ErrorCandidate"),
-            BuiltinCandidate(b) => format!("BuiltinCandidate({:?})", b),
-            BuiltinObjectCandidate => format!("BuiltinObjectCandidate"),
-            BuiltinUnsizeCandidate => format!("BuiltinUnsizeCandidate"),
-            ParamCandidate(ref a) => format!("ParamCandidate({})", a.repr(tcx)),
-            ImplCandidate(a) => format!("ImplCandidate({})", a.repr(tcx)),
-            DefaultImplCandidate(t) => format!("DefaultImplCandidate({:?})", t),
-            DefaultImplObjectCandidate(t) => format!("DefaultImplObjectCandidate({:?})", t),
-            ProjectionCandidate => format!("ProjectionCandidate"),
-            FnPointerCandidate => format!("FnPointerCandidate"),
-            ObjectCandidate => format!("ObjectCandidate"),
-            ClosureCandidate(c, ref s) => {
-                format!("ClosureCandidate({:?},{})", c, s.repr(tcx))
-            }
-        }
-    }
-}
-
 impl<'tcx> SelectionCache<'tcx> {
     pub fn new() -> SelectionCache<'tcx> {
         SelectionCache {
@@ -3032,10 +3008,9 @@ impl<'o,'tcx> Iterator for TraitObligationStackList<'o,'tcx>{
     }
 }
 
-impl<'o,'tcx> Repr<'tcx> for TraitObligationStack<'o,'tcx> {
-    fn repr(&self, tcx: &ty::ctxt<'tcx>) -> String {
-        format!("TraitObligationStack({})",
-                self.obligation.repr(tcx))
+impl<'o,'tcx> fmt::Debug for TraitObligationStack<'o,'tcx> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "TraitObligationStack({:?})", self.obligation)
     }
 }
 

src/librustc/middle/traits/util.rs

@@ -16,7 +16,6 @@ use syntax::ast;
 use syntax::codemap::Span;
 use util::common::ErrorReported;
 use util::nodemap::FnvHashSet;
-use util::ppaux::Repr;
 
 use super::{Obligation, ObligationCause, PredicateObligation,
             VtableImpl, VtableParam, VtableImplData, VtableDefaultImplData};
@@ -125,8 +124,8 @@ impl<'cx, 'tcx> Elaborator<'cx, 'tcx> {
                               .map(|p| p.subst_supertrait(self.tcx, &data.to_poly_trait_ref()))
                               .collect();
 
-                debug!("super_predicates: data={} predicates={}",
-                       data.repr(self.tcx), predicates.repr(self.tcx));
+                debug!("super_predicates: data={:?} predicates={:?}",
+                       data, predicates);
 
                 // Only keep those bounds that we haven't already
                 // seen.  This is necessary to prevent infinite
@@ -302,33 +301,14 @@ pub fn fresh_type_vars_for_impl<'a, 'tcx>(infcx: &InferCtxt<'a, 'tcx>,
     infcx.fresh_substs_for_generics(span, &impl_generics)
 }
 
-impl<'tcx, N> fmt::Debug for VtableImplData<'tcx, N> {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        write!(f, "VtableImpl({:?})", self.impl_def_id)
-    }
-}
-
-impl<'tcx, N> fmt::Debug for super::VtableClosureData<'tcx, N> {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        write!(f, "VtableClosure({:?})", self.closure_def_id)
-    }
-}
-
-impl<'tcx> fmt::Debug for super::VtableObjectData<'tcx> {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        write!(f, "VtableObject(...)")
-    }
-}
-
 /// See `super::obligations_for_generics`
-pub fn predicates_for_generics<'tcx>(tcx: &ty::ctxt<'tcx>,
-                                     cause: ObligationCause<'tcx>,
+pub fn predicates_for_generics<'tcx>(cause: ObligationCause<'tcx>,
                                      recursion_depth: usize,
                                      generic_bounds: &ty::InstantiatedPredicates<'tcx>)
                                      -> Vec<PredicateObligation<'tcx>>
 {
-    debug!("predicates_for_generics(generic_bounds={})",
-           generic_bounds.repr(tcx));
+    debug!("predicates_for_generics(generic_bounds={:?})",
+           generic_bounds);
 
     generic_bounds.predicates.iter().map(|predicate| {
         Obligation { cause: cause.clone(),
@@ -486,118 +466,84 @@ pub fn closure_trait_ref_and_return_type<'tcx>(
     ty::Binder((trait_ref, sig.0.output.unwrap_or(ty::mk_nil(tcx))))
 }
 
-impl<'tcx,O:Repr<'tcx>> Repr<'tcx> for super::Obligation<'tcx, O> {
-    fn repr(&self, tcx: &ty::ctxt<'tcx>) -> String {
-        format!("Obligation(predicate={},depth={})",
-                self.predicate.repr(tcx),
-                self.recursion_depth)
+impl<'tcx,O:fmt::Debug> fmt::Debug for super::Obligation<'tcx, O> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "Obligation(predicate={:?},depth={})",
+               self.predicate,
+               self.recursion_depth)
     }
 }
 
-impl<'tcx, N:Repr<'tcx>> Repr<'tcx> for super::Vtable<'tcx, N> {
-    fn repr(&self, tcx: &ty::ctxt<'tcx>) -> String {
+impl<'tcx, N:fmt::Debug> fmt::Debug for super::Vtable<'tcx, N> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         match *self {
             super::VtableImpl(ref v) =>
-                v.repr(tcx),
+                write!(f, "{:?}", v),
 
             super::VtableDefaultImpl(ref t) =>
-                t.repr(tcx),
+                write!(f, "{:?}", t),
 
             super::VtableClosure(ref d) =>
-                d.repr(tcx),
+                write!(f, "{:?}", d),
 
             super::VtableFnPointer(ref d) =>
-                format!("VtableFnPointer({})",
-                        d.repr(tcx)),
+                write!(f, "VtableFnPointer({:?})", d),
 
             super::VtableObject(ref d) =>
-                format!("VtableObject({})",
-                        d.repr(tcx)),
+                write!(f, "VtableObject({:?})", d),
 
             super::VtableParam(ref n) =>
-                format!("VtableParam({})",
-                        n.repr(tcx)),
+                write!(f, "VtableParam({:?})", n),
 
             super::VtableBuiltin(ref d) =>
-                d.repr(tcx)
+                write!(f, "{:?}", d)
         }
     }
 }
 
-impl<'tcx, N:Repr<'tcx>> Repr<'tcx> for super::VtableImplData<'tcx, N> {
-    fn repr(&self, tcx: &ty::ctxt<'tcx>) -> String {
-        format!("VtableImpl(impl_def_id={}, substs={}, nested={})",
-                self.impl_def_id.repr(tcx),
-                self.substs.repr(tcx),
-                self.nested.repr(tcx))
+impl<'tcx, N:fmt::Debug> fmt::Debug for super::VtableImplData<'tcx, N> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "VtableImpl(impl_def_id={:?}, substs={:?}, nested={:?})",
+               self.impl_def_id,
+               self.substs,
+               self.nested)
     }
 }
 
-impl<'tcx, N:Repr<'tcx>> Repr<'tcx> for super::VtableClosureData<'tcx, N> {
-    fn repr(&self, tcx: &ty::ctxt<'tcx>) -> String {
-        format!("VtableClosure(closure_def_id={}, substs={}, nested={})",
-                self.closure_def_id.repr(tcx),
-                self.substs.repr(tcx),
-                self.nested.repr(tcx))
+impl<'tcx, N:fmt::Debug> fmt::Debug for super::VtableClosureData<'tcx, N> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "VtableClosure(closure_def_id={:?}, substs={:?}, nested={:?})",
+               self.closure_def_id,
+               self.substs,
+               self.nested)
     }
 }
 
-impl<'tcx, N:Repr<'tcx>> Repr<'tcx> for super::VtableBuiltinData<N> {
-    fn repr(&self, tcx: &ty::ctxt<'tcx>) -> String {
-        format!("VtableBuiltin(nested={})",
-                self.nested.repr(tcx))
+impl<'tcx, N:fmt::Debug> fmt::Debug for super::VtableBuiltinData<N> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "VtableBuiltin(nested={:?})", self.nested)
     }
 }
 
-impl<'tcx, N:Repr<'tcx>> Repr<'tcx> for super::VtableDefaultImplData<N> {
-    fn repr(&self, tcx: &ty::ctxt<'tcx>) -> String {
-        format!("VtableDefaultImplData(trait_def_id={}, nested={})",
-                self.trait_def_id.repr(tcx),
-                self.nested.repr(tcx))
+impl<'tcx, N:fmt::Debug> fmt::Debug for super::VtableDefaultImplData<N> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "VtableDefaultImplData(trait_def_id={:?}, nested={:?})",
+               self.trait_def_id,
+               self.nested)
     }
 }
 
-impl<'tcx> Repr<'tcx> for super::VtableObjectData<'tcx> {
-    fn repr(&self, tcx: &ty::ctxt<'tcx>) -> String {
-        format!("VtableObject(object_ty={})",
-                self.object_ty.repr(tcx))
+impl<'tcx> fmt::Debug for super::VtableObjectData<'tcx> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "VtableObject(object_ty={:?})", self.object_ty)
     }
 }
 
-impl<'tcx> Repr<'tcx> for super::SelectionError<'tcx> {
-    fn repr(&self, tcx: &ty::ctxt<'tcx>) -> String {
-        match *self {
-            super::Unimplemented =>
-                format!("Unimplemented"),
-
-            super::OutputTypeParameterMismatch(ref a, ref b, ref c) =>
-                format!("OutputTypeParameterMismatch({},{},{})",
-                        a.repr(tcx),
-                        b.repr(tcx),
-                        c.repr(tcx)),
-
-            super::TraitNotObjectSafe(ref tr) =>
-                format!("TraitNotObjectSafe({})",
-                        tr.repr(tcx))
-        }
-    }
-}
-
-impl<'tcx> Repr<'tcx> for super::FulfillmentError<'tcx> {
-    fn repr(&self, tcx: &ty::ctxt<'tcx>) -> String {
-        format!("FulfillmentError({},{})",
-                self.obligation.repr(tcx),
-                self.code.repr(tcx))
-    }
-}
-
-impl<'tcx> Repr<'tcx> for super::FulfillmentErrorCode<'tcx> {
-    fn repr(&self, tcx: &ty::ctxt<'tcx>) -> String {
-        match *self {
-            super::CodeSelectionError(ref o) => o.repr(tcx),
-            super::CodeProjectionError(ref o) => o.repr(tcx),
-            super::CodeAmbiguity => format!("Ambiguity")
-        }
+impl<'tcx> fmt::Debug for super::FulfillmentError<'tcx> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "FulfillmentError({:?},{:?})",
+               self.obligation,
+               self.code)
     }
 }
 
@@ -611,14 +557,8 @@ impl<'tcx> fmt::Debug for super::FulfillmentErrorCode<'tcx> {
     }
 }
 
-impl<'tcx> Repr<'tcx> for super::MismatchedProjectionTypes<'tcx> {
-    fn repr(&self, tcx: &ty::ctxt<'tcx>) -> String {
-        self.err.repr(tcx)
-    }
-}
-
 impl<'tcx> fmt::Debug for super::MismatchedProjectionTypes<'tcx> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        write!(f, "MismatchedProjectionTypes(..)")
+        write!(f, "MismatchedProjectionTypes({:?})", self.err)
     }
 }

src/librustc/middle/ty_fold.rs

@@ -38,19 +38,20 @@ use middle::subst;
 use middle::subst::VecPerParamSpace;
 use middle::ty::{self, Ty};
 use middle::traits;
+
+use std::fmt;
 use std::rc::Rc;
 use syntax::abi;
 use syntax::ast;
 use syntax::owned_slice::OwnedSlice;
 use util::nodemap::FnvHashMap;
-use util::ppaux::Repr;
 
 ///////////////////////////////////////////////////////////////////////////
 // Two generic traits
 
 /// The TypeFoldable trait is implemented for every type that can be folded.
 /// Basically, every type that has a corresponding method in TypeFolder.
-pub trait TypeFoldable<'tcx>: Repr<'tcx> + Clone {
+pub trait TypeFoldable<'tcx>: fmt::Debug + Clone {
     fn fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self;
 }
 
@@ -74,7 +75,7 @@ pub trait TypeFolder<'tcx> : Sized {
     fn exit_region_binder(&mut self) { }
 
     fn fold_binder<T>(&mut self, t: &ty::Binder<T>) -> ty::Binder<T>
-        where T : TypeFoldable<'tcx> + Repr<'tcx> + Clone
+        where T : TypeFoldable<'tcx>
     {
         // FIXME(#20526) this should replace `enter_region_binder`/`exit_region_binder`.
         super_fold_binder(self, t)
@@ -197,7 +198,7 @@ impl<'tcx, T: TypeFoldable<'tcx>> TypeFoldable<'tcx> for Vec<T> {
     }
 }
 
-impl<'tcx, T:TypeFoldable<'tcx>+Repr<'tcx>+Clone> TypeFoldable<'tcx> for ty::Binder<T> {
+impl<'tcx, T:TypeFoldable<'tcx>> TypeFoldable<'tcx> for ty::Binder<T> {
     fn fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> ty::Binder<T> {
         folder.fold_binder(self)
     }
@@ -842,13 +843,13 @@ impl<'a, 'tcx> TypeFolder<'tcx> for RegionFolder<'a, 'tcx>
     fn fold_region(&mut self, r: ty::Region) -> ty::Region {
         match r {
             ty::ReLateBound(debruijn, _) if debruijn.depth < self.current_depth => {
-                debug!("RegionFolder.fold_region({}) skipped bound region (current depth={})",
-                       r.repr(self.tcx()), self.current_depth);
+                debug!("RegionFolder.fold_region({:?}) skipped bound region (current depth={})",
+                       r, self.current_depth);
                 r
             }
             _ => {
-                debug!("RegionFolder.fold_region({}) folding free region (current_depth={})",
-                       r.repr(self.tcx()), self.current_depth);
+                debug!("RegionFolder.fold_region({:?}) folding free region (current_depth={})",
+                       r, self.current_depth);
                 (self.fld_r)(r, self.current_depth)
             }
         }
@@ -885,9 +886,9 @@ pub fn replace_late_bound_regions<'tcx,T,F>(tcx: &ty::ctxt<'tcx>,
                                             mut f: F)
                                             -> (T, FnvHashMap<ty::BoundRegion, ty::Region>)
     where F : FnMut(ty::BoundRegion) -> ty::Region,
-          T : TypeFoldable<'tcx> + Repr<'tcx>,
+          T : TypeFoldable<'tcx>,
 {
-    debug!("replace_late_bound_regions({})", value.repr(tcx));
+    debug!("replace_late_bound_regions({:?})", value);
     let mut replacer = RegionReplacer::new(tcx, &mut f);
     let result = value.skip_binder().fold_with(&mut replacer);
     (result, replacer.map)
@@ -916,8 +917,8 @@ impl<'a, 'tcx> TypeFolder<'tcx> for RegionReplacer<'a, 'tcx>
     fn fold_region(&mut self, r: ty::Region) -> ty::Region {
         match r {
             ty::ReLateBound(debruijn, br) if debruijn.depth == self.current_depth => {
-                debug!("RegionReplacer.fold_region({}) folding region (current_depth={})",
-                       r.repr(self.tcx()), self.current_depth);
+                debug!("RegionReplacer.fold_region({:?}) folding region (current_depth={})",
+                       r, self.current_depth);
                 let fld_r = &mut self.fld_r;
                 let region = *self.map.entry(br).or_insert_with(|| fld_r(br));
                 if let ty::ReLateBound(debruijn1, br) = region {
@@ -994,10 +995,10 @@ pub fn shift_region(region: ty::Region, amount: u32) -> ty::Region {
     }
 }
 
-pub fn shift_regions<'tcx, T:TypeFoldable<'tcx>+Repr<'tcx>>(tcx: &ty::ctxt<'tcx>,
-                                                            amount: u32, value: &T) -> T {
-    debug!("shift_regions(value={}, amount={})",
-           value.repr(tcx), amount);
+pub fn shift_regions<'tcx, T:TypeFoldable<'tcx>>(tcx: &ty::ctxt<'tcx>,
+                                                 amount: u32, value: &T) -> T {
+    debug!("shift_regions(value={:?}, amount={})",
+           value, amount);
 
     value.fold_with(&mut RegionFolder::new(tcx, &mut |region, _current_depth| {
         shift_region(region, amount)

src/librustc/middle/ty_match.rs

@@ -10,7 +10,6 @@
 
 use middle::ty::{self, Ty};
 use middle::ty_relate::{self, Relate, TypeRelation, RelateResult};
-use util::ppaux::Repr;
 
 /// A type "A" *matches* "B" if the fresh types in B could be
 /// substituted with values so as to make it equal to A. Matching is
@@ -53,16 +52,16 @@ impl<'a, 'tcx> TypeRelation<'a, 'tcx> for Match<'a, 'tcx> {
     }
 
     fn regions(&mut self, a: ty::Region, b: ty::Region) -> RelateResult<'tcx, ty::Region> {
-        debug!("{}.regions({}, {})",
+        debug!("{}.regions({:?}, {:?})",
                self.tag(),
-               a.repr(self.tcx()),
-               b.repr(self.tcx()));
+               a,
+               b);
         Ok(a)
     }
 
     fn tys(&mut self, a: Ty<'tcx>, b: Ty<'tcx>) -> RelateResult<'tcx, Ty<'tcx>> {
-        debug!("{}.tys({}, {})", self.tag(),
-               a.repr(self.tcx()), b.repr(self.tcx()));
+        debug!("{}.tys({:?}, {:?})", self.tag(),
+               a, b);
         if a == b { return Ok(a); }
 
         match (&a.sty, &b.sty) {

src/librustc/middle/ty_relate/mod.rs

@@ -19,7 +19,6 @@ use middle::ty_fold::TypeFoldable;
 use std::rc::Rc;
 use syntax::abi;
 use syntax::ast;
-use util::ppaux::Repr;
 
 pub type RelateResult<'tcx, T> = Result<T, ty::type_err<'tcx>>;
 
@@ -79,10 +78,10 @@ impl<'a,'tcx:'a> Relate<'a,'tcx> for ty::mt<'tcx> {
                  -> RelateResult<'tcx, ty::mt<'tcx>>
         where R: TypeRelation<'a,'tcx>
     {
-        debug!("{}.mts({}, {})",
+        debug!("{}.mts({:?}, {:?})",
                relation.tag(),
-               a.repr(relation.tcx()),
-               b.repr(relation.tcx()));
+               a,
+               b);
         if a.mutbl != b.mutbl {
             Err(ty::terr_mutability)
         } else {
@@ -107,10 +106,10 @@ fn relate_item_substs<'a,'tcx:'a,R>(relation: &mut R,
                                     -> RelateResult<'tcx, Substs<'tcx>>
     where R: TypeRelation<'a,'tcx>
 {
-    debug!("substs: item_def_id={} a_subst={} b_subst={}",
-           item_def_id.repr(relation.tcx()),
-           a_subst.repr(relation.tcx()),
-           b_subst.repr(relation.tcx()));
+    debug!("substs: item_def_id={:?} a_subst={:?} b_subst={:?}",
+           item_def_id,
+           a_subst,
+           b_subst);
 
     let variances;
     let opt_variances = if relation.tcx().variance_computed.get() {
@@ -191,14 +190,13 @@ fn relate_region_params<'a,'tcx:'a,R>(relation: &mut R,
                                       -> RelateResult<'tcx, Vec<ty::Region>>
     where R: TypeRelation<'a,'tcx>
 {
-    let tcx = relation.tcx();
     let num_region_params = a_rs.len();
 
-    debug!("relate_region_params(a_rs={}, \
-            b_rs={}, variances={})",
-           a_rs.repr(tcx),
-           b_rs.repr(tcx),
-           variances.repr(tcx));
+    debug!("relate_region_params(a_rs={:?}, \
+            b_rs={:?}, variances={:?})",
+           a_rs,
+           b_rs,
+           variances);
 
     assert_eq!(num_region_params,
                variances.map_or(num_region_params,