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)+.

Fixes #11187.

Change-Id: I5406d05ccf7efff3a7f15395bdb0cfb2bd23a8ed
Reviewed-on: https://go-review.googlesource.com/17233
Reviewed-by: David Crawshaw <crawshaw@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

1 files changed, 2 insertions, 0 deletions

diff --git a/src/regexp/syntax/parse_test.go b/src/regexp/syntax/parse_test.go
index c4a1117ff8..626ceeadf6 100644
--- a/src/regexp/syntax/parse_test.go
+++ b/src/regexp/syntax/parse_test.go
@@ -144,6 +144,7 @@ var parseTests = []parseTest{
 	// Test Perl quoted literals
 	{`\Q+|*?{[\E`, `str{+|*?{[}`},
 	{`\Q+\E+`, `plus{lit{+}}`},
+	{`\Qab\E+`, `cat{lit{a}plus{lit{b}}}`},
 	{`\Q\\E`, `lit{\}`},
 	{`\Q\\\E`, `str{\\}`},
 
@@ -479,6 +480,7 @@ var invalidRegexps = []string{
 	`a{100000}`,
 	`a{100000,}`,
 	"((((((((((x{2}){2}){2}){2}){2}){2}){2}){2}){2}){2})",
+	`\Q\E*`,
 }
 
 var onlyPerl = []string{