regexp/syntax: replace internal error on unexpected ) w/ ErrUnexpectedParen
Unbalanced extra right parenthesis produced an internal error instead of
a more descriptive one.
Fixes #3406.
R=r, rsc
CC=golang-dev
https://golang.org/cl/6201063
diff --git a/src/pkg/regexp/syntax/parse_test.go b/src/pkg/regexp/syntax/parse_test.go
index c6e6339..81fd9dc 100644
--- a/src/pkg/regexp/syntax/parse_test.go
+++ b/src/pkg/regexp/syntax/parse_test.go
@@ -441,10 +441,18 @@
`(`,
`)`,
`(a`,
+ `a)`,
+ `(a))`,
`(a|b|`,
+ `a|b|)`,
+ `(a|b|))`,
`(a|b`,
+ `a|b)`,
+ `(a|b))`,
`[a-z`,
`([a-z)`,
+ `[a-z)`,
+ `([a-z]))`,
`x{1001}`,
`x{9876543210}`,
`x{2,1}`,
