diff --git a/rust-version b/rust-version
index 8ed0e6ba35..53979b82cf 100644
--- a/rust-version
+++ b/rust-version
@@ -1 +1 @@
-14b15521c52549ebbb113173b4abecd124b5a823
+e83f7563495dbe2629b0cbc738afb0808c4482e1
diff --git a/tests/compile-fail/shim_arg_size.rs b/tests/compile-fail/shim_arg_size.rs
new file mode 100644
index 0000000000..dd8d6dac51
--- /dev/null
+++ b/tests/compile-fail/shim_arg_size.rs
@@ -0,0 +1,17 @@
+#![feature(rustc_private)]
+
+fn main() {
+    extern "C" {
+        // Use the wrong type(ie. not the pointer width) for the `size`
+        // argument.
+        #[cfg(target_pointer_width="64")]
+        fn malloc(size: u32) -> *mut std::ffi::c_void;
+
+        #[cfg(target_pointer_width="32")]
+        fn malloc(size: u16) -> *mut std::ffi::c_void;
+    }
+
+    unsafe {
+        let _p1 = malloc(42); //~ ERROR Undefined Behavior: scalar size mismatch
+    };
+}