CC @rsc

Go's regexp isn't trying to be at performance parity with RE2, which is overengineered. The issue of ambiguity is mostly an internal matter. Is all this code worthwhile for the core library? RE2 is available for wrapping if you need it.

Fair call. I had observed that Go already supports factoring out common prefixes of alternations as per https://github.com/golang/go/blob/master/src/regexp/syntax/parse.go#L394, so I figured that I would at least offer. :)

It's good to know it's there, but I think we can wait until a need arises. Thanks.

@adg, how does one decline a proposal?

@rsc say "Thanks, but we'll decline for now." and close the issue. (like so :-))