Two more tests

src/test/compile-fail/closure-no-fn.rs

@@ -0,0 +1,24 @@
+// Copyright 2017 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+// Ensure that capturing closures are never coerced to fns
+// Especially interesting as non-capturing closures can be.
+
+fn main() {
+    let mut a = 0u8;
+    let foo :fn(u8) -> u8 = |v: u8| { a += v; a };
+    //~^ ERROR mismatched types
+    let b = 0u8;
+    let bar :fn() -> u8 = || { b };
+    //~^ ERROR mismatched types
+    let baz :fn() -> u8 = || { b } as fn() -> u8;
+    //~^ ERROR mismatched types
+    //~^^ ERROR non-scalar cast
+}

src/test/compile-fail/feature-gate-closure_to_fn_coercion.rs

@@ -0,0 +1,45 @@
+// Copyright 2017 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+// ignore-stage0: new feature, remove this when SNAP
+// revisions: a b
+
+#[cfg(a)]
+mod a {
+    const FOO :fn(u8) -> u8 = |v: u8| { v };
+    //[a]~^ ERROR non-capturing closure to fn coercion is experimental
+    //[a]~^^ ERROR mismatched types
+
+    const BAR: [fn(&mut u32); 1] = [
+        |v: &mut u32| *v += 1,
+    //[a]~^ ERROR non-capturing closure to fn coercion is experimental
+    //[a]~^^ ERROR mismatched types
+    ];
+}
+
+#[cfg(b)]
+mod b {
+    fn func_specific() -> (fn() -> u32) {
+        || return 42
+        //[b]~^ ERROR non-capturing closure to fn coercion is experimental
+        //[b]~^^ ERROR mismatched types
+    }
+    fn foo() {
+        // Items
+        assert_eq!(func_specific()(), 42);
+        let foo :fn(u8) -> u8 = |v: u8| { v };
+        //[b]~^ ERROR non-capturing closure to fn coercion is experimental
+        //[b]~^^ ERROR mismatched types
+    }
+
+}
+
+
+