From 236aff31c5aac324849886f08b03922d8fd2ea5b Mon Sep 17 00:00:00 2001
From: Russ Cox <rsc@golang.org>
Date: Fri, 14 Oct 2011 15:54:45 -0400
Subject: [PATCH] gofmt: fix //line handling

Fixes #2369.

R=gri
CC=golang-dev
https://golang.org/cl/5275048
---
 src/cmd/gofmt/gofmt_test.go            | 1 +
 src/cmd/gofmt/testdata/comments.golden | 9 +++++++++
 src/cmd/gofmt/testdata/comments.input  | 9 +++++++++
 src/pkg/go/scanner/scanner.go          | 2 +-
 4 files changed, 20 insertions(+), 1 deletion(-)
 create mode 100644 src/cmd/gofmt/testdata/comments.golden
 create mode 100644 src/cmd/gofmt/testdata/comments.input

diff --git a/src/cmd/gofmt/gofmt_test.go b/src/cmd/gofmt/gofmt_test.go
index 87b02dad7df..6587f06a02d 100644
--- a/src/cmd/gofmt/gofmt_test.go
+++ b/src/cmd/gofmt/gofmt_test.go
@@ -77,6 +77,7 @@ var tests = []struct {
 	{"testdata/rewrite1.input", "-r=Foo->Bar"},
 	{"testdata/rewrite2.input", "-r=int->bool"},
 	{"testdata/stdin*.input", "-stdin"},
+	{"testdata/comments.input", ""},
 }
 
 func TestRewrite(t *testing.T) {
diff --git a/src/cmd/gofmt/testdata/comments.golden b/src/cmd/gofmt/testdata/comments.golden
new file mode 100644
index 00000000000..ad6bcafafa2
--- /dev/null
+++ b/src/cmd/gofmt/testdata/comments.golden
@@ -0,0 +1,9 @@
+package main
+
+func main() {}
+
+// comment here
+
+func f() {}
+
+//line foo.go:1
diff --git a/src/cmd/gofmt/testdata/comments.input b/src/cmd/gofmt/testdata/comments.input
new file mode 100644
index 00000000000..ad6bcafafa2
--- /dev/null
+++ b/src/cmd/gofmt/testdata/comments.input
@@ -0,0 +1,9 @@
+package main
+
+func main() {}
+
+// comment here
+
+func f() {}
+
+//line foo.go:1
diff --git a/src/pkg/go/scanner/scanner.go b/src/pkg/go/scanner/scanner.go
index 9f855fc197f..589ec68a678 100644
--- a/src/pkg/go/scanner/scanner.go
+++ b/src/pkg/go/scanner/scanner.go
@@ -151,7 +151,7 @@ func (S *Scanner) interpretLineComment(text []byte) {
 					filename = filepath.Join(S.dir, filename)
 				}
 				// update scanner position
-				S.file.AddLineInfo(S.lineOffset, filename, line-1) // -1 since comment applies to next line
+				S.file.AddLineInfo(S.lineOffset+len(text)+1, filename, line) // +len(text)+1 since comment applies to next line
 			}
 		}
 	}