I managed to make diagnostics hate me and give me spurious "decoder error"

arielb1 · arielb1 · commit 7ac13bdbae0d · 2015-05-06T00:57:32.000+03:00
removing $build/tmp/extended-errors seems to fix it.
diff --git a/src/librustc/diagnostics.rs b/src/librustc/diagnostics.rs
@@ -526,7 +526,6 @@ a compile-time constant.
 
 register_diagnostics! {
     E0011,
-    E0012,
     E0014,
     E0016,
     E0017,

-Original file line number
+Diff line change
 register_diagnostics! {
     E0011,
 -    E0012,
     E0014,
     E0016,
     E0017,