diff --git a/src/test/auxiliary/const_fn_lib.rs b/src/test/auxiliary/const_fn_lib.rs
new file mode 100644
index 00000000000..b0d5a6b1272
--- /dev/null
+++ b/src/test/auxiliary/const_fn_lib.rs
@@ -0,0 +1,16 @@
+// Copyright 2015 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.
+
+// Crate that exports a const fn. Used for testing cross-crate.
+
+#![crate_type="rlib"]
+#![feature(const_fn)]
+
+pub const fn foo() -> usize { 22 } //~ ERROR const fn is unstable
diff --git a/src/test/compile-fail/const-fn-stability-calls-2.rs b/src/test/compile-fail/const-fn-stability-calls-2.rs
new file mode 100644
index 00000000000..dd9a415311e
--- /dev/null
+++ b/src/test/compile-fail/const-fn-stability-calls-2.rs
@@ -0,0 +1,21 @@
+// Copyright 2015 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.
+
+// Test use of const fn from another crate without a feature gate.
+
+// aux-build:const_fn_lib.rs
+
+extern crate const_fn_lib;
+
+use const_fn_lib::foo;
+
+fn main() {
+    let x: [usize; foo()] = []; //~ ERROR unsupported constant expr
+}
diff --git a/src/test/compile-fail/const-fn-stability-calls-3.rs b/src/test/compile-fail/const-fn-stability-calls-3.rs
new file mode 100644
index 00000000000..0f413b0bbc1
--- /dev/null
+++ b/src/test/compile-fail/const-fn-stability-calls-3.rs
@@ -0,0 +1,25 @@
+// Copyright 2015 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.
+
+// Test use of const fn from another crate without a feature gate.
+
+#![feature(rustc_attrs)]
+#![allow(unused_variables)]
+
+// aux-build:const_fn_lib.rs
+
+extern crate const_fn_lib;
+
+use const_fn_lib::foo;
+
+#[rustc_error]
+fn main() { //~ ERROR compilation successful
+    let x = foo(); // use outside a constant is ok
+}
diff --git a/src/test/compile-fail/const-fn-stability-calls.rs b/src/test/compile-fail/const-fn-stability-calls.rs
new file mode 100644
index 00000000000..609077663ef
--- /dev/null
+++ b/src/test/compile-fail/const-fn-stability-calls.rs
@@ -0,0 +1,34 @@
+// Copyright 2015 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.
+
+// Test use of const fn from another crate without a feature gate.
+
+// aux-build:const_fn_lib.rs
+
+extern crate const_fn_lib;
+
+use const_fn_lib::foo;
+
+static FOO: usize = foo(); //~ ERROR const fns are an unstable feature
+const BAR: usize = foo(); //~ ERROR const fns are an unstable feature
+
+macro_rules! constant {
+    ($n:ident: $t:ty = $v:expr) => {
+        const $n: $t = $v;
+    }
+}
+
+constant! {
+    BAZ: usize = foo() //~ ERROR const fns are an unstable feature
+}
+
+fn main() {
+//    let x: [usize; foo()] = [];
+}
diff --git a/src/test/compile-fail/const-fn-stability.rs b/src/test/compile-fail/const-fn-stability.rs
index fda2930c4a9..9913c2fa12c 100644
--- a/src/test/compile-fail/const-fn-stability.rs
+++ b/src/test/compile-fail/const-fn-stability.rs
@@ -28,6 +28,16 @@ const fn foo() -> u32 { 0 } //~ ERROR const fn is unstable
 static FOO: usize = foo();
 const BAR: usize = foo();
 
+macro_rules! constant {
+    ($n:ident: $t:ty = $v:expr) => {
+        const $n: $t = $v;
+    }
+}
+
+constant! {
+    BAZ: usize = foo()
+}
+
 fn main() {
     let x: [usize; foo()] = [];
 }
diff --git a/src/test/run-pass/const-fn-cross-crate.rs b/src/test/run-pass/const-fn-cross-crate.rs
new file mode 100644
index 00000000000..5d0c17af717
--- /dev/null
+++ b/src/test/run-pass/const-fn-cross-crate.rs
@@ -0,0 +1,25 @@
+// Copyright 2015 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.
+
+// aux-build:const_fn_lib.rs
+
+// A very basic test of const fn functionality.
+
+#![feature(const_fn)]
+
+extern crate const_fn_lib;
+
+use const_fn_lib::foo;
+
+const FOO: usize = foo();
+
+fn main() {
+    assert_eq!(FOO, 22);
+}