add test for #113381

Fixes #113381

r? fee1-dead

tests/ui/rfcs/rfc-2632-const-trait-impl/effects/const_closure-const_trait_impl-ice-113381.rs

@@ -0,0 +1,15 @@
+#![feature(const_closures, const_trait_impl, effects)]
+#![allow(incomplete_features)]
+
+trait Foo {
+    fn foo(&self);
+}
+
+impl Foo for () {
+    fn foo(&self) {}
+}
+
+fn main() {
+    (const || { (()).foo() })();
+    //~^ ERROR: cannot call non-const fn
+}

tests/ui/rfcs/rfc-2632-const-trait-impl/effects/const_closure-const_trait_impl-ice-113381.stderr

@@ -0,0 +1,11 @@
+error[E0015]: cannot call non-const fn `<() as Foo>::foo` in constant functions
+  --> $DIR/const_closure-const_trait_imp-ice-113381.rs:13:22
+   |
+LL |     (const || { (()).foo() })();
+   |                      ^^^^^
+   |
+   = note: calls in constant functions are limited to constant functions, tuple structs and tuple variants
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0015`.