--- a/gfx/webrender_bindings/src/moz2d_renderer.rs
+++ b/gfx/webrender_bindings/src/moz2d_renderer.rs
@@ -1,9 +1,8 @@
-#![allow(improper_ctypes)] // this is needed so that rustc doesn't complain about passing the &Arc<Vec> to an extern function
 use webrender::api::*;
 use bindings::{ByteSlice, MutByteSlice, wr_moz2d_render_cb, ArcVecU8};
 use rayon::ThreadPool;
 
 use std::collections::hash_map::{HashMap, Entry};
 use std::mem;
 use std::os::raw::c_void;
 use std::ptr;
@@ -443,18 +442,19 @@ impl BlobImageRenderer for Moz2dImageRen
         unsafe { DeleteFontData(font); }
     }
 
     fn delete_font_instance(&mut self, _key: FontInstanceKey) {
     }
 }
 
 use bindings::WrFontKey;
+
+#[allow(improper_ctypes)] // this is needed so that rustc doesn't complain about passing the &Arc<Vec> to an extern function
 extern "C" {
-    #[allow(improper_ctypes)]
     fn AddFontData(key: WrFontKey, data: *const u8, size: usize, index: u32, vec: &ArcVecU8);
     fn AddNativeFontHandle(key: WrFontKey, handle: *mut c_void, index: u32);
     fn DeleteFontData(key: WrFontKey);
 }
 
 impl Moz2dImageRenderer {
     pub fn new(workers: Arc<ThreadPool>) -> Self {
         let (tx, rx) = channel();