diff options
| -rw-r--r-- | src/cmd/compile/internal/syntax/parser.go | 6 | ||||
| -rw-r--r-- | src/cmd/compile/internal/syntax/testdata/issue47704.src | 18 |
2 files changed, 23 insertions, 1 deletions
diff --git a/src/cmd/compile/internal/syntax/parser.go b/src/cmd/compile/internal/syntax/parser.go index acffd84885..29f5c88d0f 100644 --- a/src/cmd/compile/internal/syntax/parser.go +++ b/src/cmd/compile/internal/syntax/parser.go @@ -1049,7 +1049,11 @@ loop: } // x[i:... - p.want(_Colon) + // For better error message, don't use p.want(_Colon) here (issue #47704). + if !p.got(_Colon) { + p.syntaxError("expecting : or ]") + p.advance(_Colon, _Rbrack) + } p.xnest++ t := new(SliceExpr) t.pos = pos diff --git a/src/cmd/compile/internal/syntax/testdata/issue47704.src b/src/cmd/compile/internal/syntax/testdata/issue47704.src new file mode 100644 index 0000000000..0156af7d8d --- /dev/null +++ b/src/cmd/compile/internal/syntax/testdata/issue47704.src @@ -0,0 +1,18 @@ +// Copyright 2021 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package p + +// error messages for parser in non-generic mode +func _() { + _ = m[] // ERROR expecting operand + _ = m[x,] // ERROR unexpected comma, expecting \: or \] + _ = m[x /* ERROR unexpected a */ a b c d] +} + +// test case from the issue +func f(m map[int]int) int { + return m[0 // ERROR expecting \: or \] + ] +} |