Compute item_generics_num_lifetimes during resolution.

2 files changed, 24 insertions, 2 deletions

diff --git a/compiler/rustc_resolve/src/late.rs b/compiler/rustc_resolve/src/late.rs
index 5c7b4b02822..4a0287d83ff 100644
--- a/compiler/rustc_resolve/src/late.rs
+++ b/compiler/rustc_resolve/src/late.rs
@@ -952,6 +952,7 @@ impl<'a: 'ast, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
         match item.kind {
             ItemKind::TyAlias(box TyAliasKind(_, ref generics, _, _))
             | ItemKind::Fn(box FnKind(_, _, ref generics, _)) => {
+                self.compute_num_lifetime_params(item.id, generics);
                 self.with_generic_param_rib(generics, ItemRibKind(HasGenericParams::Yes), |this| {
                     visit::walk_item(this, item)
                 });
@@ -960,6 +961,7 @@ impl<'a: 'ast, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
             ItemKind::Enum(_, ref generics)
             | ItemKind::Struct(_, ref generics)
             | ItemKind::Union(_, ref generics) => {
+                self.compute_num_lifetime_params(item.id, generics);
                 self.resolve_adt(item, generics);
             }
 
@@ -970,10 +972,12 @@ impl<'a: 'ast, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
                 items: ref impl_items,
                 ..
             }) => {
+                self.compute_num_lifetime_params(item.id, generics);
                 self.resolve_implementation(generics, of_trait, &self_ty, item.id, impl_items);
             }
 
             ItemKind::Trait(box TraitKind(.., ref generics, ref bounds, ref trait_items)) => {
+                self.compute_num_lifetime_params(item.id, generics);
                 // Create a new rib for the trait-wide type parameters.
                 self.with_generic_param_rib(generics, ItemRibKind(HasGenericParams::Yes), |this| {
                     let local_def_id = this.r.local_def_id(item.id).to_def_id();
@@ -1025,6 +1029,7 @@ impl<'a: 'ast, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
             }
 
             ItemKind::TraitAlias(ref generics, ref bounds) => {
+                self.compute_num_lifetime_params(item.id, generics);
                 // Create a new rib for the trait-wide type parameters.
                 self.with_generic_param_rib(generics, ItemRibKind(HasGenericParams::Yes), |this| {
                     let local_def_id = this.r.local_def_id(item.id).to_def_id();
@@ -2463,6 +2468,16 @@ impl<'a: 'ast, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
             Some((ident.name, ns)),
         )
     }
+
+    fn compute_num_lifetime_params(&mut self, id: NodeId, generics: &Generics) {
+        let def_id = self.r.local_def_id(id);
+        let count = generics
+            .params
+            .iter()
+            .filter(|param| matches!(param.kind, ast::GenericParamKind::Lifetime { .. }))
+            .count();
+        self.r.item_generics_num_lifetimes.insert(def_id, count);
+    }
 }
 
 impl<'a> Resolver<'a> {
diff --git a/compiler/rustc_resolve/src/lib.rs b/compiler/rustc_resolve/src/lib.rs
index da3beac0819..2101381553b 100644
--- a/compiler/rustc_resolve/src/lib.rs
+++ b/compiler/rustc_resolve/src/lib.rs
@@ -1030,6 +1030,8 @@ pub struct Resolver<'a> {
     trait_impl_items: FxHashSet<LocalDefId>,
 
     legacy_const_generic_args: FxHashMap<DefId, Option<Vec<usize>>>,
+    /// Amount of lifetime parameters for each item in the crate.
+    item_generics_num_lifetimes: FxHashMap<LocalDefId, usize>,
 
     main_def: Option<MainDefinition>,
 }
@@ -1109,8 +1111,12 @@ impl ResolverAstLowering for Resolver<'_> {
         }
     }
 
-    fn item_generics_num_lifetimes(&self, def_id: DefId, sess: &Session) -> usize {
-        self.cstore().item_generics_num_lifetimes(def_id, sess)
+    fn item_generics_num_lifetimes(&self, def_id: DefId) -> usize {
+        if let Some(def_id) = def_id.as_local() {
+            self.item_generics_num_lifetimes[&def_id]
+        } else {
+            self.cstore().item_generics_num_lifetimes(def_id, self.session)
+        }
     }
 
     fn legacy_const_generic_args(&mut self, expr: &Expr) -> Option<Vec<usize>> {
@@ -1390,6 +1396,7 @@ impl<'a> Resolver<'a> {
             next_disambiguator: Default::default(),
             trait_impl_items: Default::default(),
             legacy_const_generic_args: Default::default(),
+            item_generics_num_lifetimes: Default::default(),
             main_def: Default::default(),
         };