diff --git a/components/util/vec.rs b/components/util/vec.rs
index 049cfb49bb0..638164971e4 100644
--- a/components/util/vec.rs
+++ b/components/util/vec.rs
@@ -39,8 +39,8 @@ impl<T> FullBinarySearchMethods<T> for [T] {
             return None;
         }
 
-        let mut low : isize = 0;
-        let mut high : isize = (self.len() as isize) - 1;
+        let mut low: isize = 0;
+        let mut high: isize = (self.len() as isize) - 1;
 
         while low <= high {
             // http://googleresearch.blogspot.com/2006/06/extra-extra-read-all-about-it-nearly.html
diff --git a/ports/glutin/window.rs b/ports/glutin/window.rs
index 8d72b8f97a1..5db74cf17f6 100644
--- a/ports/glutin/window.rs
+++ b/ports/glutin/window.rs
@@ -58,19 +58,19 @@ bitflags! {
 
 // Some shortcuts use Cmd on Mac and Control on other systems.
 #[cfg(all(feature = "window", target_os="macos"))]
-const CMD_OR_CONTROL : constellation_msg::KeyModifiers = SUPER;
+const CMD_OR_CONTROL: constellation_msg::KeyModifiers = SUPER;
 #[cfg(all(feature = "window", not(target_os="macos")))]
-const CMD_OR_CONTROL : constellation_msg::KeyModifiers = CONTROL;
+const CMD_OR_CONTROL: constellation_msg::KeyModifiers = CONTROL;
 
 // Some shortcuts use Cmd on Mac and Alt on other systems.
 #[cfg(all(feature = "window", target_os="macos"))]
-const CMD_OR_ALT : constellation_msg::KeyModifiers = SUPER;
+const CMD_OR_ALT: constellation_msg::KeyModifiers = SUPER;
 #[cfg(all(feature = "window", not(target_os="macos")))]
-const CMD_OR_ALT : constellation_msg::KeyModifiers = ALT;
+const CMD_OR_ALT: constellation_msg::KeyModifiers = ALT;
 
 // This should vary by zoom level and maybe actual text size (focused or under cursor)
 #[cfg(feature = "window")]
-const LINE_HEIGHT : f32 = 38.0;
+const LINE_HEIGHT: f32 = 38.0;
 
 /// The type of a window.
 #[cfg(feature = "window")]
diff --git a/python/tidy.py b/python/tidy.py
index 903715b472a..e2583ce87ba 100644
--- a/python/tidy.py
+++ b/python/tidy.py
@@ -232,9 +232,11 @@ def check_rust(file_name, contents):
         if match:
             yield (idx + 1, "missing space after ->")
 
-        # Avoid flagging ::crate::mod
-        if line.find(" :[^:]") != -1:
-            yield (idx + 1, "extra space before :")
+        # Avoid flagging ::crate::mod and `trait Foo : Bar`
+        match = line.find(" :")
+        if match != -1:
+            if line[0:match].find('trait ') == -1 and line[match + 2] != ':':
+                yield (idx + 1, "extra space before :")
 
         # Avoid flagging crate::mod
         match = re.search(r"[^:]:[A-Za-z]", line)