Rollup merge of rust-lang#123478 - maurer:cfi-call-once-addr-taken, r=compiler-errors

CFI: Add test for `call_once` addr taken

One of the proposed ways to reduce the non-passed argument erasure would cause this test to fail. Adding this now ensures that any attempt to reduce non-passed argument erasure won't make the same mistake.

r? `@compiler-errors`

cc `@rcvalle`

Author: jhpratt

tests/ui/sanitizer/cfi-closures.rs

@@ -77,3 +77,14 @@ fn closure_addr_taken() {
     let call = Fn::<()>::call;
     use_closure(call, &f);
 }
+
+fn use_closure_once<C>(call: extern "rust-call" fn(C, ()) -> i32, f: C) -> i32 {
+    call(f, ())
+}
+
+#[test]
+fn closure_once_addr_taken() {
+    let g = || 3;
+    let call2 = FnOnce::<()>::call_once;
+    use_closure_once(call2, g);
+}