test thread-local key with no dtor

src/terminator/mod.rs

@@ -727,7 +727,6 @@ fn call_c_abi(
                 
                 // Extract the function type out of the signature (that seems easier than constructing it ourselves...)
                 let dtor_ptr = args[1].read_ptr(&self.memory)?;
-                // TODO: The null-pointer case here is entirely untested
                 let dtor = if dtor_ptr.is_null_ptr() { None } else { Some(self.memory.get_fn(dtor_ptr.alloc_id)?) };
                 
                 // Figure out how large a pthread TLS key actually is. This is libc::pthread_key_t.

tests/run-pass/thread-local-no-dtor.rs

@@ -0,0 +1,16 @@
+#![feature(libc)]
+extern crate libc;
+
+use std::mem;
+
+pub type Key = libc::pthread_key_t;
+
+pub unsafe fn create(dtor: Option<unsafe extern fn(*mut u8)>) -> Key {
+    let mut key = 0;
+    assert_eq!(libc::pthread_key_create(&mut key, mem::transmute(dtor)), 0);
+    key
+}
+
+fn main() {
+    let _ = unsafe { create(None) };
+}