From 707ca18d97ccc769d78f9d16bdf94b992858977d Mon Sep 17 00:00:00 2001 From: Robert Griesemer Date: Tue, 19 Jun 2018 10:20:35 -0700 Subject: [PATCH] cmd/compile: more accurate position for select case error message Fixes #25958. Change-Id: I1f4808a70c20334ecfc4eb1789f5389d94dcf00e Reviewed-on: https://go-review.googlesource.com/119755 Reviewed-by: Ian Lance Taylor --- src/cmd/compile/internal/gc/select.go | 10 +++++++++- test/fixedbugs/issue25958.go | 17 +++++++++++++++++ 2 files changed, 26 insertions(+), 1 deletion(-) create mode 100644 test/fixedbugs/issue25958.go diff --git a/src/cmd/compile/internal/gc/select.go b/src/cmd/compile/internal/gc/select.go index eb37e32bf1..4445edbe92 100644 --- a/src/cmd/compile/internal/gc/select.go +++ b/src/cmd/compile/internal/gc/select.go @@ -33,7 +33,15 @@ func typecheckselect(sel *Node) { ncase.List.Set(nil) switch n.Op { default: - yyerrorl(n.Pos, "select case must be receive, send or assign recv") + pos := n.Pos + if n.Op == ONAME { + // We don't have the right position for ONAME nodes (see #15459 and + // others). Using ncase.Pos for now as it will provide the correct + // line number (assuming the expression follows the "case" keyword + // on the same line). This matches the approach before 1.10. + pos = ncase.Pos + } + yyerrorl(pos, "select case must be receive, send or assign recv") // convert x = <-c into OSELRECV(x, <-c). // remove implicit conversions; the eventual assignment diff --git a/test/fixedbugs/issue25958.go b/test/fixedbugs/issue25958.go new file mode 100644 index 0000000000..ba7ee82230 --- /dev/null +++ b/test/fixedbugs/issue25958.go @@ -0,0 +1,17 @@ +// errorcheck + +// Copyright 2018 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 + +// Verify that the "must be receive" error for "case done:" appears +// on the line of the case clause, not the line of the done declaration. + +func f(done chan struct{}) { + select { + case done: // ERROR "must be receive", "not used" + case (chan struct{})(done): // ERROR "must be receive" + } +}