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rustc: clean up the style of middle::resolve_lifetime.

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This commit is contained in:
Eduard-Mihai Burtescu 2017-01-08 22:40:04 +02:00
parent 7a2a669bb7
commit 0682a75f44
4 changed files with 108 additions and 78 deletions
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166
src/librustc/middle/resolve_lifetime.rs
View file

@ -15,9 +15,6 @@
//! used between functions, and they operate in a purely top-down
//! way. Therefore we break lifetime name resolution into a separate pass.
pub use self::DefRegion::*;
use self::ScopeChain::*;
use dep_graph::DepNode;
use hir::map::Map;
use session::Session;
@ -36,22 +33,19 @@ use hir;
use hir::intravisit::{self, Visitor, FnKind, NestedVisitorMap};
#[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, Debug)]
pub enum DefRegion {
DefStaticRegion,
DefEarlyBoundRegion(/* index */ u32,
/* lifetime decl */ ast::NodeId),
DefLateBoundRegion(ty::DebruijnIndex,
/* lifetime decl */ ast::NodeId),
DefFreeRegion(region::CallSiteScopeData,
/* lifetime decl */ ast::NodeId),
pub enum Region {
Static,
EarlyBound(/* index */ u32, /* lifetime decl */ ast::NodeId),
LateBound(ty::DebruijnIndex, /* lifetime decl */ ast::NodeId),
Free(region::CallSiteScopeData, /* lifetime decl */ ast::NodeId),
}
// Maps the id of each lifetime reference to the lifetime decl
// that it corresponds to.
pub struct NamedRegionMap {
// maps from every use of a named (not anonymous) lifetime to a
// `DefRegion` describing how that region is bound
pub defs: NodeMap<DefRegion>,
// `Region` describing how that region is bound
pub defs: NodeMap<Region>,
// the set of lifetime def ids that are late-bound; late-bound ids
// are named regions appearing in fn arguments that do not appear
@ -63,7 +57,7 @@ struct LifetimeContext<'a, 'tcx: 'a> {
sess: &'a Session,
hir_map: &'a Map<'tcx>,
map: &'a mut NamedRegionMap,
scope: Scope<'a>,
scope: ScopeRef<'a>,
// Deep breath. Our representation for poly trait refs contains a single
// binder and thus we only allow a single level of quantification. However,
// the syntax of Rust permits quantification in two places, e.g., `T: for <'a> Foo<'a>`
@ -86,25 +80,36 @@ struct LifetimeContext<'a, 'tcx: 'a> {
}
#[derive(PartialEq, Debug)]
enum ScopeChain<'a> {
/// EarlyScope(['a, 'b, ...], start, s) extends s with early-bound
/// lifetimes, with consecutive parameter indices from `start`.
/// That is, 'a has index `start`, 'b has index `start + 1`, etc.
enum Scope<'a> {
/// Extends `s` with early-bound `lifetimes`, having consecutive parameter
/// indices from `start`, i.e. `lifetimes[i]` has index `start + i`.
/// Indices before `start` correspond to other generic parameters
/// of a parent item (trait/impl of a method), or `Self` in traits.
EarlyScope(&'a [hir::LifetimeDef], u32, Scope<'a>),
/// LateScope(['a, 'b, ...], s) extends s with late-bound
/// lifetimes introduced by the declaration binder_id.
LateScope(&'a [hir::LifetimeDef], Scope<'a>),
Early {
lifetimes: &'a [hir::LifetimeDef],
start: u32,
s: ScopeRef<'a>
},
/// lifetimes introduced by a fn are scoped to the call-site for that fn.
FnScope { fn_id: ast::NodeId, body_id: ast::NodeId, s: Scope<'a> },
RootScope
/// Extends `s` with late-bound `lifetimes`.
Late {
lifetimes: &'a [hir::LifetimeDef],
s: ScopeRef<'a>
},
/// Lifetimes introduced by a fn are scoped to the call-site for that fn.
Fn {
fn_id: ast::NodeId,
body_id: ast::NodeId,
s: ScopeRef<'a>
},
Root
}
type Scope<'a> = &'a ScopeChain<'a>;
type ScopeRef<'a> = &'a Scope<'a>;
static ROOT_SCOPE: ScopeChain<'static> = RootScope;
const ROOT_SCOPE: ScopeRef<'static> = &Scope::Root;
pub fn krate(sess: &Session,
hir_map: &Map)
@ -120,7 +125,7 @@ pub fn krate(sess: &Session,
sess: sess,
hir_map: hir_map,
map: &mut map,
scope: &ROOT_SCOPE,
scope: ROOT_SCOPE,
trait_ref_hack: false,
labels_in_fn: vec![],
}, krate);
@ -140,7 +145,7 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> {
let saved_labels_in_fn = replace(&mut self.labels_in_fn, vec![]);
// Items always introduce a new root scope
self.with(RootScope, |_, this| {
self.with(Scope::Root, |_, this| {
match item.node {
hir::ItemFn(..) => {
// Fn lifetimes get added in visit_fn below:
@ -169,7 +174,12 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> {
} else {
0
};
this.with(EarlyScope(lifetimes, start, &ROOT_SCOPE), |old_scope, this| {
let early = Scope::Early {
lifetimes: lifetimes,
start: start,
s: ROOT_SCOPE
};
this.with(early, |old_scope, this| {
this.check_lifetime_defs(old_scope, lifetimes);
intravisit::walk_item(this, item);
});
@ -187,7 +197,7 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> {
let saved = replace(&mut self.labels_in_fn, vec![]);
// Items always introduce a new root scope
self.with(RootScope, |_, this| {
self.with(Scope::Root, |_, this| {
match item.node {
hir::ForeignItemFn(ref decl, _, ref generics) => {
this.visit_early_late(item.id, decl, generics, |this| {
@ -233,7 +243,11 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> {
fn visit_ty(&mut self, ty: &'tcx hir::Ty) {
match ty.node {
hir::TyBareFn(ref c) => {
self.with(LateScope(&c.lifetimes, self.scope), |old_scope, this| {
let late = Scope::Late {
lifetimes: &c.lifetimes,
s: self.scope
};
self.with(late, |old_scope, this| {
// a bare fn has no bounds, so everything
// contained within is scoped within its binder.
this.check_lifetime_defs(old_scope, &c.lifetimes);
@ -245,7 +259,7 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> {
// a trait ref, which introduces a binding scope.
match path.def {
Def::Trait(..) => {
self.with(LateScope(&[], self.scope), |_, this| {
self.with(Scope::Late { lifetimes: &[], s: self.scope }, |_, this| {
this.visit_path(path, ty.id);
});
}
@ -283,7 +297,7 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> {
return;
}
if lifetime_ref.name == keywords::StaticLifetime.name() {
self.insert_lifetime(lifetime_ref, DefStaticRegion);
self.insert_lifetime(lifetime_ref, Region::Static);
return;
}
self.resolve_lifetime_ref(lifetime_ref);
@ -304,8 +318,11 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> {
.. }) => {
if !bound_lifetimes.is_empty() {
self.trait_ref_hack = true;
let result = self.with(LateScope(bound_lifetimes, self.scope),
|old_scope, this| {
let late = Scope::Late {
lifetimes: bound_lifetimes,
s: self.scope
};
let result = self.with(late, |old_scope, this| {
this.check_lifetime_defs(old_scope, bound_lifetimes);
this.visit_ty(&bounded_ty);
walk_list!(this, visit_ty_param_bound, bounds);
@ -346,7 +363,11 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> {
span_err!(self.sess, trait_ref.span, E0316,
"nested quantification of lifetimes");
}
self.with(LateScope(&trait_ref.bound_lifetimes, self.scope), |old_scope, this| {
let late = Scope::Late {
lifetimes: &trait_ref.bound_lifetimes,
s: self.scope
};
self.with(late, |old_scope, this| {
this.check_lifetime_defs(old_scope, &trait_ref.bound_lifetimes);
for lifetime in &trait_ref.bound_lifetimes {
this.visit_lifetime_def(lifetime);
@ -412,7 +433,7 @@ fn signal_shadowing_problem(sess: &Session, name: ast::Name, orig: Original, sha
fn extract_labels(ctxt: &mut LifetimeContext, b: hir::BodyId) {
struct GatherLabels<'a> {
sess: &'a Session,
scope: Scope<'a>,
scope: ScopeRef<'a>,
labels_in_fn: &'a mut Vec<(ast::Name, Span)>,
}
@ -471,16 +492,16 @@ fn extract_labels(ctxt: &mut LifetimeContext, b: hir::BodyId) {
}
fn check_if_label_shadows_lifetime<'a>(sess: &'a Session,
mut scope: Scope<'a>,
mut scope: ScopeRef<'a>,
label: ast::Name,
label_span: Span) {
loop {
match *scope {
FnScope { s, .. } => { scope = s; }
RootScope => { return; }
Scope::Fn { s, .. } => { scope = s; }
Scope::Root => { return; }
EarlyScope(lifetimes, _, s) |
LateScope(lifetimes, s) => {
Scope::Early { lifetimes, s, .. } |
Scope::Late { lifetimes, s } => {
for lifetime_def in lifetimes {
// FIXME (#24278): non-hygienic comparison
if label == lifetime_def.lifetime.name {
@ -524,7 +545,7 @@ impl<'a, 'tcx> LifetimeContext<'a, 'tcx> {
// `self.labels_in_fn`.
extract_labels(self, fb);
self.with(FnScope { fn_id: fn_id, body_id: fb.node_id, s: self.scope },
self.with(Scope::Fn { fn_id: fn_id, body_id: fb.node_id, s: self.scope },
|_old_scope, this| this.visit_nested_body(fb))
}
@ -535,8 +556,8 @@ impl<'a, 'tcx> LifetimeContext<'a, 'tcx> {
f(self)
}
fn with<F>(&mut self, wrap_scope: ScopeChain, f: F) where
F: for<'b> FnOnce(Scope, &mut LifetimeContext<'b, 'tcx>),
fn with<F>(&mut self, wrap_scope: Scope, f: F) where
F: for<'b> FnOnce(ScopeRef, &mut LifetimeContext<'b, 'tcx>),
{
let LifetimeContext {sess, hir_map, ref mut map, ..} = *self;
let mut this = LifetimeContext {
@ -591,7 +612,7 @@ impl<'a, 'tcx> LifetimeContext<'a, 'tcx> {
// Find the start of nested early scopes, e.g. in methods.
let mut start = 0;
if let EarlyScope(..) = *self.scope {
if let Scope::Early {..} = *self.scope {
let parent = self.hir_map.expect_item(self.hir_map.get_parent(fn_id));
if let hir::ItemTrait(..) = parent.node {
start += 1; // Self comes first.
@ -605,8 +626,17 @@ impl<'a, 'tcx> LifetimeContext<'a, 'tcx> {
}
}
self.with(EarlyScope(&early, start as u32, self.scope), move |old_scope, this| {
this.with(LateScope(&late, this.scope), move |_, this| {
let early = Scope::Early {
lifetimes: &early,
start: start as u32,
s: self.scope
};
self.with(early, move |old_scope, this| {
let late = Scope::Late {
lifetimes: &late,
s: this.scope
};
this.with(late, move |_, this| {
this.check_lifetime_defs(old_scope, &generics.lifetimes);
this.hack(walk); // FIXME(#37666) workaround in place of `walk(this)`
});
@ -624,22 +654,22 @@ impl<'a, 'tcx> LifetimeContext<'a, 'tcx> {
let mut scope = self.scope;
loop {
match *scope {
FnScope {fn_id, body_id, s } => {
Scope::Fn { fn_id, body_id, s } => {
return self.resolve_free_lifetime_ref(
region::CallSiteScopeData { fn_id: fn_id, body_id: body_id },
lifetime_ref,
s);
}
RootScope => {
Scope::Root => {
break;
}
EarlyScope(lifetimes, start, s) => {
Scope::Early { lifetimes, start, s } => {
match search_lifetimes(lifetimes, lifetime_ref) {
Some((index, lifetime_def)) => {
let decl_id = lifetime_def.id;
let def = DefEarlyBoundRegion(start + index, decl_id);
let def = Region::EarlyBound(start + index, decl_id);
self.insert_lifetime(lifetime_ref, def);
return;
}
@ -649,12 +679,12 @@ impl<'a, 'tcx> LifetimeContext<'a, 'tcx> {
}
}
LateScope(lifetimes, s) => {
Scope::Late { lifetimes, s } => {
match search_lifetimes(lifetimes, lifetime_ref) {
Some((_index, lifetime_def)) => {
let decl_id = lifetime_def.id;
let debruijn = ty::DebruijnIndex::new(late_depth + 1);
let def = DefLateBoundRegion(debruijn, decl_id);
let def = Region::LateBound(debruijn, decl_id);
self.insert_lifetime(lifetime_ref, def);
return;
}
@ -674,7 +704,7 @@ impl<'a, 'tcx> LifetimeContext<'a, 'tcx> {
fn resolve_free_lifetime_ref(&mut self,
scope_data: region::CallSiteScopeData,
lifetime_ref: &hir::Lifetime,
scope: Scope) {
scope: ScopeRef) {
debug!("resolve_free_lifetime_ref \
scope_data: {:?} lifetime_ref: {:?} scope: {:?}",
scope_data, lifetime_ref, scope);
@ -690,19 +720,19 @@ impl<'a, 'tcx> LifetimeContext<'a, 'tcx> {
scope_data: {:?} scope: {:?} search_result: {:?}",
scope_data, scope, search_result);
match *scope {
FnScope { fn_id, body_id, s } => {
Scope::Fn { fn_id, body_id, s } => {
scope_data = region::CallSiteScopeData {
fn_id: fn_id, body_id: body_id
};
scope = s;
}
RootScope => {
Scope::Root => {
break;
}
EarlyScope(lifetimes, _, s) |
LateScope(lifetimes, s) => {
Scope::Early { lifetimes, s, .. } |
Scope::Late { lifetimes, s } => {
search_result = search_lifetimes(lifetimes, lifetime_ref);
if search_result.is_some() {
break;
@ -714,7 +744,7 @@ impl<'a, 'tcx> LifetimeContext<'a, 'tcx> {
match search_result {
Some((_depth, lifetime)) => {
let def = DefFreeRegion(scope_data, lifetime.id);
let def = Region::Free(scope_data, lifetime.id);
self.insert_lifetime(lifetime_ref, def);
}
@ -732,7 +762,7 @@ impl<'a, 'tcx> LifetimeContext<'a, 'tcx> {
.emit();
}
fn check_lifetime_defs(&mut self, old_scope: Scope, lifetimes: &[hir::LifetimeDef]) {
fn check_lifetime_defs(&mut self, old_scope: ScopeRef, lifetimes: &[hir::LifetimeDef]) {
for i in 0..lifetimes.len() {
let lifetime_i = &lifetimes[i];
@ -773,7 +803,7 @@ impl<'a, 'tcx> LifetimeContext<'a, 'tcx> {
}
fn check_lifetime_def_for_shadowing(&self,
mut old_scope: Scope,
mut old_scope: ScopeRef,
lifetime: &hir::Lifetime)
{
for &(label, label_span) in &self.labels_in_fn {
@ -789,16 +819,16 @@ impl<'a, 'tcx> LifetimeContext<'a, 'tcx> {
loop {
match *old_scope {
FnScope { s, .. } => {
Scope::Fn { s, .. } => {
old_scope = s;
}
RootScope => {
Scope::Root => {
return;
}
EarlyScope(lifetimes, _, s) |
LateScope(lifetimes, s) => {
Scope::Early { lifetimes, s, .. } |
Scope::Late { lifetimes, s } => {
if let Some((_, lifetime_def)) = search_lifetimes(lifetimes, lifetime) {
signal_shadowing_problem(
self.sess,
@ -816,7 +846,7 @@ impl<'a, 'tcx> LifetimeContext<'a, 'tcx> {
fn insert_lifetime(&mut self,
lifetime_ref: &hir::Lifetime,
def: DefRegion) {
def: Region) {
if lifetime_ref.id == ast::DUMMY_NODE_ID {
span_bug!(lifetime_ref.span,
"lifetime reference not renumbered, \

10
src/librustc_typeck/astconv.rs
View file

@ -247,11 +247,11 @@ impl<'o, 'gcx: 'tcx, 'tcx> AstConv<'gcx, 'tcx>+'o {
let name = opt_lifetime.map(|l| l.name);
let resolved = opt_lifetime.and_then(|l| tcx.named_region_map.defs.get(&l.id));
let r = tcx.mk_region(match resolved {
Some(&rl::DefStaticRegion) => {
Some(&rl::Region::Static) => {
ty::ReStatic
}
Some(&rl::DefLateBoundRegion(debruijn, id)) => {
Some(&rl::Region::LateBound(debruijn, id)) => {
// If this region is declared on a function, it will have
// an entry in `late_bound`, but if it comes from
// `for<'a>` in some type or something, it won't
@ -268,15 +268,15 @@ impl<'o, 'gcx: 'tcx, 'tcx> AstConv<'gcx, 'tcx>+'o {
issue_32330))
}
Some(&rl::DefEarlyBoundRegion(index, _)) => {
Some(&rl::Region::EarlyBound(index, _)) => {
ty::ReEarlyBound(ty::EarlyBoundRegion {
index: index,
name: name.unwrap()
})
}
Some(&rl::DefFreeRegion(scope, id)) => {
// As in DefLateBoundRegion above, could be missing for some late-bound
Some(&rl::Region::Free(scope, id)) => {
// As in Region::LateBound above, could be missing for some late-bound
// regions, but also for early-bound regions.
let issue_32330 = tcx.named_region_map
.late_bound

2
src/librustc_typeck/variance/constraints.rs
View file

@ -154,7 +154,7 @@ impl<'a, 'tcx> ConstraintContext<'a, 'tcx> {
let tcx = self.terms_cx.tcx;
assert!(is_lifetime(&tcx.hir, param_id));
match tcx.named_region_map.defs.get(&param_id) {
Some(&rl::DefEarlyBoundRegion(_, lifetime_decl_id)) => lifetime_decl_id,
Some(&rl::Region::EarlyBound(_, lifetime_decl_id)) => lifetime_decl_id,
Some(_) => bug!("should not encounter non early-bound cases"),
// The lookup should only fail when `param_id` is

8
src/librustdoc/clean/mod.rs
View file

@ -28,7 +28,7 @@ use syntax::symbol::keywords;
use syntax_pos::{self, DUMMY_SP, Pos};
use rustc::middle::privacy::AccessLevels;
use rustc::middle::resolve_lifetime::DefRegion::*;
use rustc::middle::resolve_lifetime as rl;
use rustc::middle::lang_items;
use rustc::hir::def::{Def, CtorKind};
use rustc::hir::def_id::{CrateNum, DefId, CRATE_DEF_INDEX, LOCAL_CRATE};
@ -765,9 +765,9 @@ impl Clean<Lifetime> for hir::Lifetime {
fn clean(&self, cx: &DocContext) -> Lifetime {
let def = cx.tcx.named_region_map.defs.get(&self.id).cloned();
match def {
Some(DefEarlyBoundRegion(_, node_id)) |
Some(DefLateBoundRegion(_, node_id)) |
Some(DefFreeRegion(_, node_id)) => {
Some(rl::Region::EarlyBound(_, node_id)) |
Some(rl::Region::LateBound(_, node_id)) |
Some(rl::Region::Free(_, node_id)) => {
if let Some(lt) = cx.lt_substs.borrow().get(&node_id).cloned() {
return lt;
}