auto merge of #12338 : edwardw/rust/hygienic-break-continue, r=cmr

Makes labelled loops hygiene by performing renaming of the labels defined in e.g. `'x: loop { ... }` and then used in break and continue statements within loop body so that they act hygienically when used with macros.
    
Closes #12262.

src/librustc/middle/cfg/construct.rs

@@ -490,7 +490,7 @@ impl CFGBuilder {
 
     fn find_scope(&self,
                   expr: @ast::Expr,
-                  label: Option<ast::Name>) -> LoopScope {
+                  label: Option<ast::Ident>) -> LoopScope {
         match label {
             None => {
                 return *self.loop_scopes.last().unwrap();

src/librustc/middle/dataflow.rs

@@ -770,7 +770,7 @@ impl<'a, O:DataFlowOperator> PropagationContext<'a, O> {
 
     fn find_scope<'a>(&self,
                       expr: &ast::Expr,
-                      label: Option<ast::Name>,
+                      label: Option<ast::Ident>,
                       loop_scopes: &'a mut ~[LoopScope]) -> &'a mut LoopScope {
         let index = match label {
             None => {

src/librustc/middle/liveness.rs

@@ -747,7 +747,7 @@ impl Liveness {
     }
 
     pub fn find_loop_scope(&self,
-                           opt_label: Option<Name>,
+                           opt_label: Option<Ident>,
                            id: NodeId,
                            sp: Span)
                            -> NodeId {

src/librustc/middle/resolve.rs

@@ -5206,13 +5206,13 @@ impl Resolver {
             ExprLoop(_, Some(label)) => {
                 self.with_label_rib(|this| {
                     let def_like = DlDef(DefLabel(expr.id));
-                    // plain insert (no renaming)
                     {
                         let mut label_ribs = this.label_ribs.borrow_mut();
                         let rib = label_ribs.get()[label_ribs.get().len() -
                                                    1];
                         let mut bindings = rib.bindings.borrow_mut();
-                        bindings.get().insert(label.name, def_like);
+                        let renamed = mtwt_resolve(label);
+                        bindings.get().insert(renamed, def_like);
                     }
 
                     visit::walk_expr(this, expr, ());
@@ -5223,11 +5223,12 @@ impl Resolver {
 
             ExprBreak(Some(label)) | ExprAgain(Some(label)) => {
                 let mut label_ribs = self.label_ribs.borrow_mut();
-                match self.search_ribs(label_ribs.get(), label, expr.span) {
+                let renamed = mtwt_resolve(label);
+                match self.search_ribs(label_ribs.get(), renamed, expr.span) {
                     None =>
                         self.resolve_error(expr.span,
                                               format!("use of undeclared label `{}`",
-                                                   token::get_name(label))),
+                                                   token::get_ident(label))),
                     Some(DlDef(def @ DefLabel(_))) => {
                         // Since this def is a label, it is never read.
                         self.record_def(expr.id, (def, LastMod(AllPublic)))

src/librustc/middle/trans/controlflow.rs

@@ -25,7 +25,7 @@ use util::ppaux::Repr;
 use middle::trans::type_::Type;
 
 use syntax::ast;
-use syntax::ast::Name;
+use syntax::ast::Ident;
 use syntax::ast_util;
 use syntax::codemap::Span;
 use syntax::parse::token::InternedString;
@@ -260,7 +260,7 @@ pub fn trans_loop<'a>(bcx:&'a Block<'a>,
 
 pub fn trans_break_cont<'a>(bcx: &'a Block<'a>,
                             expr_id: ast::NodeId,
-                            opt_label: Option<Name>,
+                            opt_label: Option<Ident>,
                             exit: uint)
                             -> &'a Block<'a> {
     let _icx = push_ctxt("trans_break_cont");
@@ -293,14 +293,14 @@ pub fn trans_break_cont<'a>(bcx: &'a Block<'a>,
 
 pub fn trans_break<'a>(bcx: &'a Block<'a>,
                        expr_id: ast::NodeId,
-                       label_opt: Option<Name>)
+                       label_opt: Option<Ident>)
                        -> &'a Block<'a> {
     return trans_break_cont(bcx, expr_id, label_opt, cleanup::EXIT_BREAK);
 }
 
 pub fn trans_cont<'a>(bcx: &'a Block<'a>,
                       expr_id: ast::NodeId,
-                      label_opt: Option<Name>)
+                      label_opt: Option<Ident>)
                       -> &'a Block<'a> {
     return trans_break_cont(bcx, expr_id, label_opt, cleanup::EXIT_LOOP);
 }