Implement the Fn trait for bare fn pointers in the compiler rather than doing it using hard-coded impls. This means that it works also for more complex fn types involving bound regions. Fixes #19126.

src/test/compile-fail/issue-15965.rs

@@ -11,8 +11,6 @@
 fn main() {
     return
         { return () } //~ ERROR the type of this value must be known in this context
-    () //~^ ERROR the type of this value must be known in this context
-//~^^ ERROR notation; the first type parameter for the function trait is neither a tuple nor unit
-//~^^^ ERROR overloaded calls are experimental
+    ()
     ;
 }

src/test/compile-fail/issue-18532.rs

@@ -17,6 +17,4 @@
 fn main() {
     (return)((),());
     //~^ ERROR the type of this value must be known
-    //~^^ ERROR the type of this value must be known
-    //~^^^ ERROR cannot use call notation
 }

src/test/compile-fail/unboxed-closures-unsafe-extern-fn.rs

@@ -0,0 +1,28 @@
+// Copyright 2014 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.
+
+// Tests that unsafe extern fn pointers do not implement any Fn traits.
+
+#![feature(unboxed_closures)]
+
+use std::ops::{Fn,FnMut,FnOnce};
+
+unsafe fn square(x: &int) -> int { (*x) * (*x) }
+
+fn call_it<F:Fn(&int)->int>(_: &F, _: int) -> int { 0 }
+fn call_it_mut<F:FnMut(&int)->int>(_: &mut F, _: int) -> int { 0 }
+fn call_it_once<F:FnOnce(&int)->int>(_: F, _: int) -> int { 0 }
+
+fn main() {
+    let x = call_it(&square, 22); //~ ERROR not implemented
+    let y = call_it_mut(&mut square, 22); //~ ERROR not implemented
+    let z = call_it_once(square, 22); //~ ERROR not implemented
+}
+

src/test/compile-fail/unboxed-closures-wrong-abi.rs

@@ -0,0 +1,28 @@
+// Copyright 2014 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.
+
+// Tests that unsafe extern fn pointers do not implement any Fn traits.
+
+#![feature(unboxed_closures)]
+
+use std::ops::{Fn,FnMut,FnOnce};
+
+extern "C" fn square(x: &int) -> int { (*x) * (*x) }
+
+fn call_it<F:Fn(&int)->int>(_: &F, _: int) -> int { 0 }
+fn call_it_mut<F:FnMut(&int)->int>(_: &mut F, _: int) -> int { 0 }
+fn call_it_once<F:FnOnce(&int)->int>(_: F, _: int) -> int { 0 }
+
+fn main() {
+    let x = call_it(&square, 22); //~ ERROR not implemented
+    let y = call_it_mut(&mut square, 22); //~ ERROR not implemented
+    let z = call_it_once(square, 22); //~ ERROR not implemented
+}
+

src/test/compile-fail/unboxed-closures-wrong-arg-type-extern-fn.rs

@@ -0,0 +1,29 @@
+// Copyright 2014 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.
+
+// Tests that unsafe extern fn pointers do not implement any Fn traits.
+
+#![feature(unboxed_closures)]
+
+use std::ops::{Fn,FnMut,FnOnce};
+
+unsafe fn square(x: int) -> int { x * x }
+// note: argument type here is `int`, not `&int`
+
+fn call_it<F:Fn(&int)->int>(_: &F, _: int) -> int { 0 }
+fn call_it_mut<F:FnMut(&int)->int>(_: &mut F, _: int) -> int { 0 }
+fn call_it_once<F:FnOnce(&int)->int>(_: F, _: int) -> int { 0 }
+
+fn main() {
+    let x = call_it(&square, 22); //~ ERROR not implemented
+    let y = call_it_mut(&mut square, 22); //~ ERROR not implemented
+    let z = call_it_once(square, 22); //~ ERROR not implemented
+}
+

src/test/run-pass/unboxed-closures-extern-fn-hr.rs

@@ -0,0 +1,45 @@
+// Copyright 2014 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.
+
+// Checks that higher-ranked extern fn pointers implement the full range of Fn traits.
+
+#![feature(unboxed_closures)]
+
+use std::ops::{Fn,FnMut,FnOnce};
+
+fn square(x: &int) -> int { (*x) * (*x) }
+
+fn call_it<F:Fn(&int)->int>(f: &F, x: int) -> int {
+    (*f)(&x)
+}
+
+fn call_it_boxed(f: &Fn(&int) -> int, x: int) -> int {
+    f.call((&x,))
+}
+
+fn call_it_mut<F:FnMut(&int)->int>(f: &mut F, x: int) -> int {
+    (*f)(&x)
+}
+
+fn call_it_once<F:FnOnce(&int)->int>(f: F, x: int) -> int {
+    f(&x)
+}
+
+fn main() {
+    let x = call_it(&square, 22);
+    let x1 = call_it_boxed(&square, 22);
+    let y = call_it_mut(&mut square, 22);
+    let z = call_it_once(square, 22);
+    assert_eq!(x, square(&22));
+    assert_eq!(x1, square(&22));
+    assert_eq!(y, square(&22));
+    assert_eq!(z, square(&22));
+}
+

src/test/run-pass/unboxed-closures-extern-fn.rs

@@ -8,7 +8,7 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-// Checks that extern fn points implement the full range of Fn traits.
+// Checks that extern fn pointers implement the full range of Fn traits.
 
 #![feature(unboxed_closures)]
 #![feature(unboxed_closures)]