diff --git a/src/test/compile-fail/immut-function-arguments.rs b/src/test/compile-fail/immut-function-arguments.rs
new file mode 100644
index 00000000000..814ec64b5c0
--- /dev/null
+++ b/src/test/compile-fail/immut-function-arguments.rs
@@ -0,0 +1,20 @@
+// Copyright 2012 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.
+
+fn f(y: ~int) {
+    *y = 5; //~ ERROR assigning to dereference of immutable ~ pointer
+}
+
+fn g() {
+    let _frob: fn(~int) = |q| { *q = 2; }; //~ ERROR assigning to dereference of immutable ~ pointer
+
+}
+
+fn main() {}
\ No newline at end of file
diff --git a/src/test/run-pass/mut-function-arguments.rs b/src/test/run-pass/mut-function-arguments.rs
new file mode 100644
index 00000000000..b125db6f79c
--- /dev/null
+++ b/src/test/run-pass/mut-function-arguments.rs
@@ -0,0 +1,27 @@
+// Copyright 2012 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.
+
+fn f(mut y: ~int) {
+    *y = 5;
+    assert *y == 5;
+}
+
+fn g() {
+    let frob: fn(~int) = |mut q| { *q = 2; assert *q == 2; };
+    let w = ~37;
+    frob(w);
+
+}
+
+fn main() {
+    let z = ~17;
+    f(z);
+    g();
+}
\ No newline at end of file