Auto merge of #43887 - michaelwoerister:node-id-be-gone, r=eddyb

Store fewer NodeIds in crate metadata.

The first commit just replaces `NodeId` with `DefId` in `resolve_lifetime::Region`, so we don't run into problems when stable-hashing `TypeParameterDef` values from other crates.

~~The second commit is more interesting. It adds the `ReScopeAnon` variant to `ty::RegionKind`, which is semantically equivalent to `ReScope`. The only difference is that it does not contain a `CodeExtent` field. All `ReScope` occurrences are then replaced with `ReScopeAnon` upon metadata export. This way we don't end up with `NodeIds` from other crates in various things imported from metadata. `ReScopeAnon` can still be tested for equality.~~ This is fixed in a better way by @eddyb in #44171.

r? @eddyb
cc @rust-lang/compiler

src/librustc/middle/resolve_lifetime.rs

@@ -38,22 +38,24 @@ use hir::intravisit::{self, Visitor, NestedVisitorMap};
 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, Debug)]
 pub enum Region {
     Static,
-    EarlyBound(/* index */ u32, /* lifetime decl */ ast::NodeId),
-    LateBound(ty::DebruijnIndex, /* lifetime decl */ ast::NodeId),
+    EarlyBound(/* index */ u32, /* lifetime decl */ DefId),
+    LateBound(ty::DebruijnIndex, /* lifetime decl */ DefId),
     LateBoundAnon(ty::DebruijnIndex, /* anon index */ u32),
-    Free(DefId, /* lifetime decl */ ast::NodeId),
+    Free(DefId, /* lifetime decl */ DefId),
 }
 
 impl Region {
-    fn early(index: &mut u32, def: &hir::LifetimeDef) -> (ast::Name, Region) {
+    fn early(hir_map: &Map, index: &mut u32, def: &hir::LifetimeDef) -> (ast::Name, Region) {
         let i = *index;
         *index += 1;
-        (def.lifetime.name, Region::EarlyBound(i, def.lifetime.id))
+        let def_id = hir_map.local_def_id(def.lifetime.id);
+        (def.lifetime.name, Region::EarlyBound(i, def_id))
     }
 
-    fn late(def: &hir::LifetimeDef) -> (ast::Name, Region) {
+    fn late(hir_map: &Map, def: &hir::LifetimeDef) -> (ast::Name, Region) {
         let depth = ty::DebruijnIndex::new(1);
-        (def.lifetime.name, Region::LateBound(depth, def.lifetime.id))
+        let def_id = hir_map.local_def_id(def.lifetime.id);
+        (def.lifetime.name, Region::LateBound(depth, def_id))
     }
 
     fn late_anon(index: &Cell<u32>) -> Region {
@@ -63,7 +65,7 @@ impl Region {
         Region::LateBoundAnon(depth, i)
     }
 
-    fn id(&self) -> Option<ast::NodeId> {
+    fn id(&self) -> Option<DefId> {
         match *self {
             Region::Static |
             Region::LateBoundAnon(..) => None,
@@ -333,7 +335,7 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> {
                     0
                 };
                 let lifetimes = generics.lifetimes.iter().map(|def| {
-                    Region::early(&mut index, def)
+                    Region::early(self.hir_map, &mut index, def)
                 }).collect();
                 let scope = Scope::Binder {
                     lifetimes,
@@ -364,7 +366,9 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> {
         match ty.node {
             hir::TyBareFn(ref c) => {
                 let scope = Scope::Binder {
-                    lifetimes: c.lifetimes.iter().map(Region::late).collect(),
+                    lifetimes: c.lifetimes.iter().map(|def| {
+                            Region::late(self.hir_map, def)
+                        }).collect(),
                     s: self.scope
                 };
                 self.with(scope, |old_scope, this| {
@@ -463,7 +467,9 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> {
                     if !bound_lifetimes.is_empty() {
                         self.trait_ref_hack = true;
                         let scope = Scope::Binder {
-                            lifetimes: bound_lifetimes.iter().map(Region::late).collect(),
+                            lifetimes: bound_lifetimes.iter().map(|def| {
+                                    Region::late(self.hir_map, def)
+                                }).collect(),
                             s: self.scope
                         };
                         let result = self.with(scope, |old_scope, this| {
@@ -508,7 +514,9 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> {
                           "nested quantification of lifetimes");
             }
             let scope = Scope::Binder {
-                lifetimes: trait_ref.bound_lifetimes.iter().map(Region::late).collect(),
+                lifetimes: trait_ref.bound_lifetimes.iter().map(|def| {
+                        Region::late(self.hir_map, def)
+                    }).collect(),
                 s: self.scope
             };
             self.with(scope, |old_scope, this| {
@@ -643,10 +651,13 @@ fn extract_labels(ctxt: &mut LifetimeContext, body: &hir::Body) {
                 Scope::Binder { ref lifetimes, s } => {
                     // FIXME (#24278): non-hygienic comparison
                     if let Some(def) = lifetimes.get(&label) {
+                        let node_id = hir_map.as_local_node_id(def.id().unwrap())
+                                             .unwrap();
+
                         signal_shadowing_problem(
                             sess,
                             label,
-                            original_lifetime(hir_map.span(def.id().unwrap())),
+                            original_lifetime(hir_map.span(node_id)),
                             shadower_label(label_span));
                         return;
                     }
@@ -745,7 +756,8 @@ fn object_lifetime_defaults_for_item(hir_map: &Map, generics: &hir::Generics)
                     generics.lifetimes.iter().enumerate().find(|&(_, def)| {
                         def.lifetime.name == name
                     }).map_or(Set1::Many, |(i, def)| {
-                        Set1::One(Region::EarlyBound(i as u32, def.lifetime.id))
+                        let def_id = hir_map.local_def_id(def.lifetime.id);
+                        Set1::One(Region::EarlyBound(i as u32, def_id))
                     })
                 }
             }
@@ -830,9 +842,9 @@ impl<'a, 'tcx> LifetimeContext<'a, 'tcx> {
 
         let lifetimes = generics.lifetimes.iter().map(|def| {
             if self.map.late_bound.contains(&def.lifetime.id) {
-                Region::late(def)
+                Region::late(self.hir_map, def)
             } else {
-                Region::early(&mut index, def)
+                Region::early(self.hir_map, &mut index, def)
             }
         }).collect();
 
@@ -1478,10 +1490,14 @@ impl<'a, 'tcx> LifetimeContext<'a, 'tcx> {
 
                 Scope::Binder { ref lifetimes, s } => {
                     if let Some(&def) = lifetimes.get(&lifetime.name) {
+                        let node_id = self.hir_map
+                                          .as_local_node_id(def.id().unwrap())
+                                          .unwrap();
+
                         signal_shadowing_problem(
                             self.sess,
                             lifetime.name,
-                            original_lifetime(self.hir_map.span(def.id().unwrap())),
+                            original_lifetime(self.hir_map.span(node_id)),
                             shadower_lifetime(&lifetime));
                         return;
                     }

src/librustc_typeck/astconv.rs

@@ -96,35 +96,39 @@ impl<'o, 'gcx: 'tcx, 'tcx> AstConv<'gcx, 'tcx>+'o {
         -> ty::Region<'tcx>
     {
         let tcx = self.tcx();
+        let lifetime_name = |def_id| {
+            tcx.hir.name(tcx.hir.as_local_node_id(def_id).unwrap())
+        };
+
         let r = match tcx.named_region_map.defs.get(&lifetime.id) {
             Some(&rl::Region::Static) => {
                 tcx.types.re_static
             }
 
             Some(&rl::Region::LateBound(debruijn, id)) => {
-                let name = tcx.hir.name(id);
+                let name = lifetime_name(id);
                 tcx.mk_region(ty::ReLateBound(debruijn,
-                    ty::BrNamed(tcx.hir.local_def_id(id), name)))
+                    ty::BrNamed(id, name)))
             }
 
             Some(&rl::Region::LateBoundAnon(debruijn, index)) => {
                 tcx.mk_region(ty::ReLateBound(debruijn, ty::BrAnon(index)))
             }
 
             Some(&rl::Region::EarlyBound(index, id)) => {
-                let name = tcx.hir.name(id);
+                let name = lifetime_name(id);
                 tcx.mk_region(ty::ReEarlyBound(ty::EarlyBoundRegion {
-                    def_id: tcx.hir.local_def_id(id),
+                    def_id: id,
                     index,
                     name,
                 }))
             }
 
             Some(&rl::Region::Free(scope, id)) => {
-                let name = tcx.hir.name(id);
+                let name = lifetime_name(id);
                 tcx.mk_region(ty::ReFree(ty::FreeRegion {
                     scope,
-                    bound_region: ty::BrNamed(tcx.hir.local_def_id(id), name)
+                    bound_region: ty::BrNamed(id, name)
                 }))
 
                     // (*) -- not late-bound, won't change

src/librustdoc/clean/mod.rs

@@ -1807,7 +1807,8 @@ impl Clean<Type> for hir::Ty {
                     for (i, lt_param) in generics.lifetimes.iter().enumerate() {
                         if let Some(lt) = provided_params.lifetimes.get(i).cloned() {
                             if !lt.is_elided() {
-                                lt_substs.insert(lt_param.lifetime.id, lt.clean(cx));
+                                let lt_def_id = cx.tcx.hir.local_def_id(lt_param.lifetime.id);
+                                lt_substs.insert(lt_def_id, lt.clean(cx));
                             }
                         }
                     }

src/librustdoc/core.rs

@@ -25,7 +25,7 @@ use rustc_trans::back::link;
 use rustc_resolve as resolve;
 use rustc_metadata::cstore::CStore;
 
-use syntax::{ast, codemap};
+use syntax::codemap;
 use syntax::feature_gate::UnstableFeatures;
 use syntax::fold::Folder;
 use errors;
@@ -66,7 +66,7 @@ pub struct DocContext<'a, 'tcx: 'a> {
     /// Table type parameter definition -> substituted type
     pub ty_substs: RefCell<FxHashMap<Def, clean::Type>>,
     /// Table node id of lifetime parameter definition -> substituted lifetime
-    pub lt_substs: RefCell<FxHashMap<ast::NodeId, clean::Lifetime>>,
+    pub lt_substs: RefCell<FxHashMap<DefId, clean::Lifetime>>,
 }
 
 impl<'a, 'tcx> DocContext<'a, 'tcx> {
@@ -78,7 +78,7 @@ impl<'a, 'tcx> DocContext<'a, 'tcx> {
     /// the substitutions for a type alias' RHS.
     pub fn enter_alias<F, R>(&self,
                              ty_substs: FxHashMap<Def, clean::Type>,
-                             lt_substs: FxHashMap<ast::NodeId, clean::Lifetime>,
+                             lt_substs: FxHashMap<DefId, clean::Lifetime>,
                              f: F) -> R
     where F: FnOnce() -> R {
         let (old_tys, old_lts) =