Fix ICE when using return type notation through trait alias

Add DefKind::TraitAlias to two locations in resolve_bound_vars.rs that
only checked for DefKind::Trait, causing an ICE when RTN was used
through a trait alias.

Author: rynewang

compiler/rustc_hir_analysis/src/collect/resolve_bound_vars.rs

@@ -1695,7 +1695,8 @@ impl<'a, 'tcx> BoundVarContext<'a, 'tcx> {
                 | DefKind::Union
                 | DefKind::Enum
                 | DefKind::TyAlias
-                | DefKind::Trait,
+                | DefKind::Trait
+                | DefKind::TraitAlias,
                 def_id,
             ) if depth == 0 => Some(def_id),
             _ => None,
@@ -1865,7 +1866,10 @@ impl<'a, 'tcx> BoundVarContext<'a, 'tcx> {
             if constraint.gen_args.parenthesized == hir::GenericArgsParentheses::ReturnTypeNotation
             {
                 let bound_vars = if let Some(type_def_id) = type_def_id
-                    && self.tcx.def_kind(type_def_id) == DefKind::Trait
+                    && matches!(
+                        self.tcx.def_kind(type_def_id),
+                        DefKind::Trait | DefKind::TraitAlias
+                    )
                     && let Some((mut bound_vars, assoc_fn)) = BoundVarContext::supertrait_hrtb_vars(
                         self.tcx,
                         type_def_id,

tests/ui/associated-type-bounds/return-type-notation/trait-alias.rs

@@ -0,0 +1,15 @@
+// Regression test for #152158.
+
+//@ check-pass
+
+#![feature(return_type_notation, trait_alias)]
+
+trait Tr {
+    fn f() -> impl Sized;
+}
+
+trait Al = Tr;
+
+fn f<T: Al<f(..): Copy>>() {}
+
+fn main() {}