Extract function trait_may_define_assoc_type

compiler/rustc_middle/src/ty/context.rs

@@ -51,7 +51,7 @@ use rustc_session::config::{BorrowckMode, CrateType, OutputFilenames};
 use rustc_session::lint::{Level, Lint};
 use rustc_session::Session;
 use rustc_span::source_map::MultiSpan;
-use rustc_span::symbol::{kw, sym, Symbol};
+use rustc_span::symbol::{kw, sym, Ident, Symbol};
 use rustc_span::{Span, DUMMY_SP};
 use rustc_target::abi::{Layout, TargetDataLayout, VariantIdx};
 use rustc_target::spec::abi;
@@ -2085,6 +2085,16 @@ impl<'tcx> TyCtxt<'tcx> {
         self.mk_fn_ptr(sig.map_bound(|sig| ty::FnSig { unsafety: hir::Unsafety::Unsafe, ..sig }))
     }
 
+    /// Given the def_id of a Trait `trait_def_id` and the name of an associated item `assoc_name`
+    /// returns true if the `trait_def_id` defines an associated item of name `assoc_name`.
+    pub fn trait_may_define_assoc_type(self, trait_def_id: DefId, assoc_name: Ident) -> bool {
+        self.super_traits_of(trait_def_id).iter().any(|trait_did| {
+            self.associated_items(*trait_did)
+                .find_by_name_and_kind(self, assoc_name, ty::AssocKind::Type, *trait_did)
+                .is_some()
+        })
+    }
+
     /// Given a closure signature, returns an equivalent fn signature. Detuples
     /// and so forth -- so e.g., if we have a sig with `Fn<(u32, i32)>` then
     /// you would get a `fn(u32, i32)`.

compiler/rustc_typeck/src/astconv/mod.rs

@@ -909,7 +909,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
         for ast_bound in ast_bounds {
             if let Some(trait_ref) = ast_bound.trait_ref() {
                 if let Some(trait_did) = trait_ref.trait_def_id() {
-                    if self.trait_may_define_assoc_type(trait_did, assoc_name) {
+                    if self.tcx().trait_may_define_assoc_type(trait_did, assoc_name) {
                         result.push(ast_bound);
                     }
                 }
@@ -919,17 +919,6 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
         self.compute_bounds(param_ty, &result, sized_by_default, span)
     }
 
-    /// Given the def_id of a Trait `trait_def_id` and the name of an associated item `assoc_name`
-    /// returns true if the `trait_def_id` defines an associated item of name `assoc_name`.
-    fn trait_may_define_assoc_type(&self, trait_def_id: DefId, assoc_name: Ident) -> bool {
-        self.tcx().super_traits_of(trait_def_id).iter().any(|trait_did| {
-            self.tcx()
-                .associated_items(*trait_did)
-                .find_by_name_and_kind(self.tcx(), assoc_name, ty::AssocKind::Type, *trait_did)
-                .is_some()
-        })
-    }
-
     /// Given an HIR binding like `Item = Foo` or `Item: Foo`, pushes the corresponding predicates
     /// onto `bounds`.
     ///

compiler/rustc_typeck/src/collect.rs

@@ -654,17 +654,7 @@ impl ItemCtxt<'tcx> {
             hir::GenericBound::Trait(poly_trait_ref, _) => {
                 let trait_ref = &poly_trait_ref.trait_ref;
                 if let Some(trait_did) = trait_ref.trait_def_id() {
-                    self.tcx.super_traits_of(trait_did).iter().any(|trait_did| {
+                    self.tcx.trait_may_define_assoc_type(trait_did, assoc_name)
-                        self.tcx
-                            .associated_items(*trait_did)
-                            .find_by_name_and_kind(
-                                self.tcx,
-                                assoc_name,
-                                ty::AssocKind::Type,
-                                *trait_did,
-                            )
-                            .is_some()
-                    })
                 } else {
                     false
                 }