Rollup merge of #104615 - spastorino:create-async-def-id-in-lowering, r=compiler-errors

Create def_id for async fns during lowering

r? `@compiler-errors`

compiler/rustc_ast_lowering/src/lib.rs

@@ -1817,9 +1817,11 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
 
         let opaque_ty_span = self.mark_span_with_reason(DesugaringKind::Async, span, None);
 
-        let opaque_ty_def_id = self.local_def_id(opaque_ty_node_id);
         let fn_def_id = self.local_def_id(fn_node_id);
 
+        let opaque_ty_def_id =
+            self.create_def(fn_def_id, opaque_ty_node_id, DefPathData::ImplTrait);
+
         // When we create the opaque type for this async fn, it is going to have
         // to capture all the lifetimes involved in the signature (including in the
         // return type). This is done by introducing lifetime parameters for: