From golang/go#11187:

regexp/syntax: fix handling of \Q...\E

It's not a group: must handle the inside as a sequence of literal chars,
not a single literal string.

That is, \Qab\E+ is the same as ab+, not (ab)+.

Repro:

• Add {"\\Qab\\E+", "cat{lit{a}plus{lit{b}}}"}, to https://github.com/google/re2j/blob/master/javatests/com/google/re2j/ParserTest.java#L88
• Test output is parse/dump of \Qab\E+ expected cat{lit{a}plus{lit{b}}}, got plus{str{ab}} expected:<[cat{lit{a}plus{lit{b}]}}> but was:<[plus{str{ab]}}>