From: Robert Griesemer <gri@golang.org>
Date: Fri, 24 Sep 2010 19:58:08 +0000 (-0700)
Subject: gofmt: don't substitute invalid positions with valid ones in rewrites
X-Git-Tag: weekly.2010-09-29~53
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=daf64bf567354167aa0f60a7e4688892e55825dd;p=gostls13.git

gofmt: don't substitute invalid positions with valid ones in rewrites

Fixes rewrite bug: 'f(x) -> f(0)' where functions "picked up" ... arguments.

R=rsc
CC=golang-dev
https://golang.org/cl/2279041
---

diff --git a/src/cmd/gofmt/rewrite.go b/src/cmd/gofmt/rewrite.go
index 3aaaebdd1a..6170a64f4d 100644
--- a/src/cmd/gofmt/rewrite.go
+++ b/src/cmd/gofmt/rewrite.go
@@ -203,6 +203,10 @@ func subst(m map[string]reflect.Value, pattern reflect.Value, pos reflect.Value)
 	}
 
 	if pos != nil && pattern.Type() == positionType {
+		// use new position only if old position was valid in the first place
+		if old := pattern.Interface().(token.Position); !old.IsValid() {
+			return pattern
+		}
 		return pos
 	}