Custom directives with names ending "Start" or "End" will silently fail to compile

[zackbrown]

Most likely related to: e46100f

Might save some frustrating debugging if angularjs throws an exception when a /._Start$/ or /._End$/ directive is declared?

[caitp]

It is because of that, and I wrote a fix for this a while ago, #5372 --- so this is basically a duplicate issue. I can try to get that reviewed better for the next release, I guess