Rollup merge of #136891 - compiler-errors:unconstrained-anon-lt, r=lqd

Check sig for errors before checking for unconstrained anonymous lifetime

Fixes #136841

compiler/rustc_hir_analysis/src/hir_ty_lowering/mod.rs

@@ -2561,6 +2561,7 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
         // reject function types that violate cmse ABI requirements
         cmse::validate_cmse_abi(self.tcx(), self.dcx(), hir_id, abi, bare_fn_ty);
 
+        if !bare_fn_ty.references_error() {
             // Find any late-bound regions declared in return type that do
             // not appear in the arguments. These are not well-formed.
             //
@@ -2582,6 +2583,7 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
                     br_name
                 )
             });
+        }
 
         bare_fn_ty
     }

tests/ui/async-await/unconstrained-lifetimes.rs

@@ -0,0 +1,9 @@
+//@ edition: 2021
+
+// Make sure we don't complain about the implicit `-> impl Future` capturing an
+// unconstrained anonymous lifetime.
+
+async fn foo(_: Missing<'_>) {}
+//~^ ERROR cannot find type `Missing` in this scope
+
+fn main() {}

tests/ui/async-await/unconstrained-lifetimes.stderr

@@ -0,0 +1,9 @@
+error[E0412]: cannot find type `Missing` in this scope
+  --> $DIR/unconstrained-lifetimes.rs:6:17
+   |
+LL | async fn foo(_: Missing<'_>) {}
+   |                 ^^^^^^^ not found in this scope
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0412`.