Auto merge of #7428 - Wafflespeanut:tidy, r=Ms2ger

tidy will now show its expectation of uses!

closes #7427

(pretty errors "inherited" from rust's type checker) :P

![screenshot](https://cloud.githubusercontent.com/assets/6691262/9543298/8cabfdaa-4d95-11e5-9101-14e62781e74e.png)

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python/tidy.py

@@ -253,7 +253,10 @@ def is_associated_type(match, line, index):
             sorted_uses = sorted(uses)
             for i in range(len(uses)):
                 if sorted_uses[i] != uses[i]:
-                    yield (idx + 1 - len(uses) + i, "use statement is not in alphabetical order")
+                    message = "use statement is not in alphabetical order"
+                    expected = "\n\t\033[93mexpected: {}\033[0m".format(sorted_uses[i])
+                    found = "\n\t\033[91mfound: {}\033[0m".format(uses[i])
+                    yield (idx + 1 - len(uses) + i, message + expected + found)
             uses = []