1 files changed, 32 insertions, 0 deletions
diff --git a/tests/ui/traits/next-solver/fn-trait.rs b/tests/ui/traits/next-solver/fn-trait.rs
new file mode 100644
index 000000000..1e3d8a21c
--- /dev/null
+++ b/tests/ui/traits/next-solver/fn-trait.rs
@@ -0,0 +1,32 @@
+// compile-flags: -Znext-solver
+
+fn require_fn(_: impl Fn() -> i32) {}
+
+fn f() -> i32 {
+    1i32
+}
+
+extern "C" fn g() -> i32 {
+    2i32
+}
+
+unsafe fn h() -> i32 {
+    2i32
+}
+
+fn main() {
+    require_fn(f);
+    require_fn(f as fn() -> i32);
+    require_fn(f as unsafe fn() -> i32);
+    //~^ ERROR: expected a `Fn()` closure, found `unsafe fn() -> i32`
+    //~| ERROR: type mismatch resolving `<unsafe fn() -> i32 as FnOnce<()>>::Output == i32`
+    require_fn(g);
+    //~^ ERROR: expected a `Fn()` closure, found `extern "C" fn() -> i32 {g}`
+    //~| ERROR: type mismatch resolving `<extern "C" fn() -> i32 {g} as FnOnce<()>>::Output == i32`
+    require_fn(g as extern "C" fn() -> i32);
+    //~^ ERROR: expected a `Fn()` closure, found `extern "C" fn() -> i32`
+    //~| ERROR: type mismatch resolving `<extern "C" fn() -> i32 as FnOnce<()>>::Output == i32`
+    require_fn(h);
+    //~^ ERROR: expected a `Fn()` closure, found `unsafe fn() -> i32 {h}`
+    //~| ERROR: type mismatch resolving `<unsafe fn() -> i32 {h} as FnOnce<()>>::Output == i32`
+}