Simplify ResolveLiftimes creation.

Author: cjgillot

src/librustc/middle/resolve_lifetime.rs

@@ -5,7 +5,7 @@ use crate::hir::{GenericParam, ItemLocalId};
 use crate::hir::{GenericParamKind, LifetimeParamKind};
 use crate::ty;
 
-use crate::util::nodemap::{FxHashMap, FxHashSet, HirIdMap, HirIdSet};
+use crate::util::nodemap::{FxHashMap, FxHashSet};
 use rustc_macros::HashStable;
 
 /// The origin of a named lifetime definition.
@@ -68,60 +68,19 @@ pub type ObjectLifetimeDefault = Set1<Region>;
 
 /// Maps the id of each lifetime reference to the lifetime decl
 /// that it corresponds to.
-#[derive(HashStable)]
+#[derive(Default, HashStable)]
 pub struct ResolveLifetimes {
-    defs: FxHashMap<LocalDefId, FxHashMap<ItemLocalId, Region>>,
-    late_bound: FxHashMap<LocalDefId, FxHashSet<ItemLocalId>>,
-    object_lifetime_defaults:
-        FxHashMap<LocalDefId, FxHashMap<ItemLocalId, Vec<ObjectLifetimeDefault>>>,
-}
+    /// Maps from every use of a named (not anonymous) lifetime to a
+    /// `Region` describing how that region is bound
+    pub defs: FxHashMap<LocalDefId, FxHashMap<ItemLocalId, Region>>,
 
-impl ResolveLifetimes {
-    pub fn new(
-        defs: HirIdMap<Region>,
-        late_bound: HirIdSet,
-        object_lifetime_defaults: HirIdMap<Vec<ObjectLifetimeDefault>>,
-    ) -> Self {
-        let defs = {
-            let mut map = FxHashMap::<_, FxHashMap<_, _>>::default();
-            for (hir_id, v) in defs {
-                let map = map.entry(hir_id.owner_local_def_id()).or_default();
-                map.insert(hir_id.local_id, v);
-            }
-            map
-        };
-        let late_bound = {
-            let mut map = FxHashMap::<_, FxHashSet<_>>::default();
-            for hir_id in late_bound {
-                let map = map.entry(hir_id.owner_local_def_id()).or_default();
-                map.insert(hir_id.local_id);
-            }
-            map
-        };
-        let object_lifetime_defaults = {
-            let mut map = FxHashMap::<_, FxHashMap<_, _>>::default();
-            for (hir_id, v) in object_lifetime_defaults {
-                let map = map.entry(hir_id.owner_local_def_id()).or_default();
-                map.insert(hir_id.local_id, v);
-            }
-            map
-        };
-
-        Self { defs, late_bound, object_lifetime_defaults }
-    }
+    /// Set of lifetime def ids that are late-bound; a region can
+    /// be late-bound if (a) it does NOT appear in a where-clause and
+    /// (b) it DOES appear in the arguments.
+    pub late_bound: FxHashMap<LocalDefId, FxHashSet<ItemLocalId>>,
 
-    pub fn named_region_map(&self, id: &LocalDefId) -> Option<&FxHashMap<ItemLocalId, Region>> {
-        self.defs.get(id)
-    }
-
-    pub fn is_late_bound_map(&self, id: &LocalDefId) -> Option<&FxHashSet<ItemLocalId>> {
-        self.late_bound.get(id)
-    }
-
-    pub fn object_lifetime_defaults_map(
-        &self,
-        id: &LocalDefId,
-    ) -> Option<&FxHashMap<ItemLocalId, Vec<ObjectLifetimeDefault>>> {
-        self.object_lifetime_defaults.get(id)
-    }
+    /// For each type and trait definition, maps type parameters
+    /// to the trait object lifetime defaults computed from them.
+    pub object_lifetime_defaults:
+        FxHashMap<LocalDefId, FxHashMap<ItemLocalId, Vec<ObjectLifetimeDefault>>>,
 }

src/librustc_resolve/lifetimes.rs

@@ -280,17 +280,17 @@ pub fn provide(providers: &mut ty::query::Providers<'_>) {
 
         named_region_map: |tcx, id| {
             let id = LocalDefId::from_def_id(DefId::local(id)); // (*)
-            tcx.resolve_lifetimes(LOCAL_CRATE).named_region_map(&id)
+            tcx.resolve_lifetimes(LOCAL_CRATE).defs.get(&id)
         },
 
         is_late_bound_map: |tcx, id| {
             let id = LocalDefId::from_def_id(DefId::local(id)); // (*)
-            tcx.resolve_lifetimes(LOCAL_CRATE).is_late_bound_map(&id)
+            tcx.resolve_lifetimes(LOCAL_CRATE).late_bound.get(&id)
         },
 
         object_lifetime_defaults_map: |tcx, id| {
             let id = LocalDefId::from_def_id(DefId::local(id)); // (*)
-            tcx.resolve_lifetimes(LOCAL_CRATE).object_lifetime_defaults_map(&id)
+            tcx.resolve_lifetimes(LOCAL_CRATE).object_lifetime_defaults.get(&id)
         },
 
         ..*providers
@@ -308,11 +308,21 @@ fn resolve_lifetimes(tcx: TyCtxt<'_>, for_krate: CrateNum) -> &ResolveLifetimes
 
     let named_region_map = krate(tcx);
 
-    let rl = ResolveLifetimes::new(
-        named_region_map.defs,
-        named_region_map.late_bound,
-        named_region_map.object_lifetime_defaults,
-    );
+    let mut rl = ResolveLifetimes::default();
+
+    for (hir_id, v) in named_region_map.defs {
+        let map = rl.defs.entry(hir_id.owner_local_def_id()).or_default();
+        map.insert(hir_id.local_id, v);
+    }
+    for hir_id in named_region_map.late_bound {
+        let map = rl.late_bound.entry(hir_id.owner_local_def_id()).or_default();
+        map.insert(hir_id.local_id);
+    }
+    for (hir_id, v) in named_region_map.object_lifetime_defaults {
+        let map = rl.object_lifetime_defaults.entry(hir_id.owner_local_def_id()).or_default();
+        map.insert(hir_id.local_id, v);
+    }
+
     tcx.arena.alloc(rl)
 }