From 17ff23f7c8d6a3310e1fa59fced2fc584b68ac7c Mon Sep 17 00:00:00 2001 From: griesemer Date: Mon, 6 Nov 2017 15:01:33 -0800 Subject: [PATCH] cmd/compile/internal/syntax: better syntax errors for typos in if/switch/for headers Be more pessimistic when parsing if/switch/for headers for better error messages when things go wrong. Fixes #22581. Change-Id: Ibb99925291ff53f35021bc0a59a4c9a7f695a194 Reviewed-on: https://go-review.googlesource.com/76290 Run-TryBot: Robert Griesemer Reviewed-by: Matthew Dempsky --- src/cmd/compile/internal/syntax/parser.go | 4 ++-- test/fixedbugs/issue22581.go | 27 +++++++++++++++++++++++ 2 files changed, 29 insertions(+), 2 deletions(-) create mode 100644 test/fixedbugs/issue22581.go diff --git a/src/cmd/compile/internal/syntax/parser.go b/src/cmd/compile/internal/syntax/parser.go index 8e47d8e723..7047266a70 100644 --- a/src/cmd/compile/internal/syntax/parser.go +++ b/src/cmd/compile/internal/syntax/parser.go @@ -1766,10 +1766,10 @@ func (p *parser) header(keyword token) (init SimpleStmt, cond Expr, post SimpleS pos src.Pos lit string // valid if pos.IsKnown() } - if p.tok == _Semi { + if p.tok != _Lbrace { semi.pos = p.pos() semi.lit = p.lit - p.next() + p.want(_Semi) if keyword == _For { if p.tok != _Semi { if p.tok == _Lbrace { diff --git a/test/fixedbugs/issue22581.go b/test/fixedbugs/issue22581.go new file mode 100644 index 0000000000..2b637f2ec6 --- /dev/null +++ b/test/fixedbugs/issue22581.go @@ -0,0 +1,27 @@ +// errorcheck + +// Copyright 2017 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 + +func f() { + if i := g()); i == j { // ERROR "unexpected \)" + } + + if i == g()] { // ERROR "unexpected \]" + } + + switch i := g()); i { // ERROR "unexpected \)" + } + + switch g()] { // ERROR "unexpected \]" + } + + for i := g()); i < y; { // ERROR "unexpected \)" + } + + for g()] { // ERROR "unexpected \]" + } +}