Reworked const fn ref tests

src/test/ui/consts/fn_trait_refs.rs

@@ -1,35 +1,80 @@
-// run-pass
+// build-pass
+
 #![feature(const_fn_trait_ref_impls)]
 #![feature(fn_traits)]
 #![feature(unboxed_closures)]
 #![feature(const_trait_impl)]
 #![feature(const_mut_refs)]
+#![feature(const_cmp)]
+#![feature(const_refs_to_cell)]
 
 use std::marker::Destruct;
 
+const fn tester_fn<T>(f: T) -> T::Output
+where
+    T: ~const Fn<()> + ~const Destruct,
+{
+    f()
+}
+
+const fn tester_fn_mut<T>(mut f: T) -> T::Output
+where
+    T: ~const FnMut<()> + ~const Destruct,
+{
+    f()
+}
+
+const fn tester_fn_once<T>(f: T) -> T::Output
+where
+    T: ~const FnOnce<()>,
+{
+    f()
+}
+
+const fn test_fn<T>(mut f: T) -> (T::Output, T::Output, T::Output)
+where
+    T: ~const Fn<()> + ~const Destruct,
+{
+    (
+        // impl<A: Tuple, F: ~const Fn + ?Sized> const Fn<A> for &F
+        tester_fn(&f),
+        // impl<A: Tuple, F: ~const Fn + ?Sized> const FnMut<A> for &F
+        tester_fn_mut(&f),
+        // impl<A: Tuple, F: ~const Fn + ?Sized> const FnOnce<A> for &F
+        tester_fn_once(&f),
+    )
+}
+
+const fn test_fn_mut<T>(mut f: T) -> (T::Output, T::Output)
+where
+    T: ~const FnMut<()> + ~const Destruct,
+{
+    (
+        // impl<A: Tuple, F: ~const FnMut + ?Sized> const FnMut<A> for &mut F
+        tester_fn_mut(&mut f),
+        // impl<A: Tuple, F: ~const FnMut + ?Sized> const FnOnce<A> for &mut F
+        tester_fn_once(&mut f),
+    )
+}
 const fn test(i: i32) -> i32 {
     i + 1
 }
 
-const fn call<F: ~const FnMut(i32) -> i32 + ~const Destruct>(mut f: F) -> F::Output {
-    f(5)
-}
-
-const fn use_fn<F: ~const FnMut(i32) -> i32 + ~const Destruct>(mut f: F) -> F::Output {
-    call(&mut f)
-}
-
-const fn test_fn() {}
-
-const fn tester<T>(_fn: T)
-where
-    T: ~const Fn() + ~const Destruct,
-{
-}
-
 const fn main() {
-    tester(test_fn);
-    let test_ref = &test_fn;
-    tester(test_ref);
-    assert!(use_fn(test) == 6);
+    const fn one() -> i32 {
+        1
+    };
+    const fn two() -> i32 {
+        2
+    };
+
+    // FIXME(const_cmp_tuple)
+    let test_one = test_fn(one);
+    assert!(test_one.0 == 1);
+    assert!(test_one.1 == 1);
+    assert!(test_one.2 == 1);
+
+    let test_two = test_fn_mut(two);
+    assert!(test_two.0 == 1);
+    assert!(test_two.1 == 1);
 }