Compute item_generics_num_lifetimes during resolution.

4 files changed, 30 insertions, 54 deletions

diff --git a/compiler/rustc_ast_lowering/src/lib.rs b/compiler/rustc_ast_lowering/src/lib.rs
index 196d48faf51..5d3a5fc20e0 100644
--- a/compiler/rustc_ast_lowering/src/lib.rs
+++ b/compiler/rustc_ast_lowering/src/lib.rs
@@ -39,7 +39,6 @@ use rustc_ast::node_id::NodeMap;
 use rustc_ast::token::{self, Token};
 use rustc_ast::tokenstream::{CanSynthesizeMissingTokens, TokenStream, TokenTree};
 use rustc_ast::visit::{self, AssocCtxt, Visitor};
-use rustc_ast::walk_list;
 use rustc_ast::{self as ast, *};
 use rustc_ast_pretty::pprust;
 use rustc_data_structures::captures::Captures;
@@ -48,7 +47,7 @@ use rustc_data_structures::sync::Lrc;
 use rustc_errors::{struct_span_err, Applicability};
 use rustc_hir as hir;
 use rustc_hir::def::{DefKind, Namespace, PartialRes, PerNS, Res};
-use rustc_hir::def_id::{DefId, DefIdMap, DefPathHash, LocalDefId, CRATE_DEF_ID};
+use rustc_hir::def_id::{DefId, DefPathHash, LocalDefId, CRATE_DEF_ID};
 use rustc_hir::definitions::{DefKey, DefPathData, Definitions};
 use rustc_hir::intravisit;
 use rustc_hir::{ConstArg, GenericArg, InferKind, ParamName};
@@ -159,8 +158,6 @@ struct LoweringContext<'a, 'hir: 'a> {
 
     current_module: LocalDefId,
 
-    type_def_lifetime_params: DefIdMap<usize>,
-
     current_hir_id_owner: (LocalDefId, u32),
     item_local_id_counters: NodeMap<u32>,
     node_id_to_hir_id: IndexVec<NodeId, Option<hir::HirId>>,
@@ -172,7 +169,7 @@ struct LoweringContext<'a, 'hir: 'a> {
 pub trait ResolverAstLowering {
     fn def_key(&mut self, id: DefId) -> DefKey;
 
-    fn item_generics_num_lifetimes(&self, def: DefId, sess: &Session) -> usize;
+    fn item_generics_num_lifetimes(&self, def: DefId) -> usize;
 
     fn legacy_const_generic_args(&mut self, expr: &Expr) -> Option<Vec<usize>>;
 
@@ -336,7 +333,6 @@ pub fn lower_crate<'a, 'hir>(
         is_in_trait_impl: false,
         is_in_dyn_type: false,
         anonymous_lifetime_mode: AnonymousLifetimeMode::PassThrough,
-        type_def_lifetime_params: Default::default(),
         current_module: CRATE_DEF_ID,
         current_hir_id_owner: (CRATE_DEF_ID, 0),
         item_local_id_counters: Default::default(),
@@ -452,26 +448,8 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
             fn visit_item(&mut self, item: &'tcx Item) {
                 self.lctx.allocate_hir_id_counter(item.id);
 
-                match item.kind {
-                    ItemKind::Struct(_, ref generics)
-                    | ItemKind::Union(_, ref generics)
-                    | ItemKind::Enum(_, ref generics)
-                    | ItemKind::TyAlias(box TyAliasKind(_, ref generics, ..))
-                    | ItemKind::Trait(box TraitKind(_, _, ref generics, ..)) => {
-                        let def_id = self.lctx.resolver.local_def_id(item.id);
-                        let count = generics
-                            .params
-                            .iter()
-                            .filter(|param| {
-                                matches!(param.kind, ast::GenericParamKind::Lifetime { .. })
-                            })
-                            .count();
-                        self.lctx.type_def_lifetime_params.insert(def_id.to_def_id(), count);
-                    }
-                    ItemKind::Use(ref use_tree) => {
-                        self.allocate_use_tree_hir_id_counters(use_tree);
-                    }
-                    _ => {}
+                if let ItemKind::Use(ref use_tree) = item.kind {
+                    self.allocate_use_tree_hir_id_counters(use_tree);
                 }
 
                 visit::walk_item(self, item);
@@ -486,23 +464,6 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                 self.lctx.allocate_hir_id_counter(item.id);
                 visit::walk_foreign_item(self, item);
             }
-
-            fn visit_ty(&mut self, t: &'tcx Ty) {
-                match t.kind {
-                    // Mirrors the case in visit::walk_ty
-                    TyKind::BareFn(ref f) => {
-                        walk_list!(self, visit_generic_param, &f.generic_params);
-                        // Mirrors visit::walk_fn_decl
-                        for parameter in &f.decl.inputs {
-                            // We don't lower the ids of argument patterns
-                            self.visit_pat(&parameter.pat);
-                            self.visit_ty(&parameter.ty)
-                        }
-                        self.visit_fn_ret_ty(&f.decl.output)
-                    }
-                    _ => visit::walk_ty(self, t),
-                }
-            }
         }
 
         self.lower_node_id(CRATE_NODE_ID);
diff --git a/compiler/rustc_ast_lowering/src/path.rs b/compiler/rustc_ast_lowering/src/path.rs
index a11d020c931..90a22b5c209 100644
--- a/compiler/rustc_ast_lowering/src/path.rs
+++ b/compiler/rustc_ast_lowering/src/path.rs
@@ -90,15 +90,8 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                         _ => ParenthesizedGenericArgs::Err,
                     };
 
-                    let num_lifetimes = type_def_id.map_or(0, |def_id| {
-                        if let Some(&n) = self.type_def_lifetime_params.get(&def_id) {
-                            return n;
-                        }
-                        assert!(!def_id.is_local());
-                        let n = self.resolver.item_generics_num_lifetimes(def_id, self.sess);
-                        self.type_def_lifetime_params.insert(def_id, n);
-                        n
-                    });
+                    let num_lifetimes = type_def_id
+                        .map_or(0, |def_id| self.resolver.item_generics_num_lifetimes(def_id));
                     self.lower_path_segment(
                         p.span,
                         segment,
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(),
         };