From 5827dd052c45c557b3f136e7ee466a0d9fe0f126 Mon Sep 17 00:00:00 2001
From: Robert Griesemer <gri@golang.org>
Date: Wed, 7 Mar 2012 16:57:26 -0800
Subject: [PATCH] go/scanner: better panic diagnostic

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/5787045
---
 src/pkg/go/scanner/scanner.go | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/pkg/go/scanner/scanner.go b/src/pkg/go/scanner/scanner.go
index 2395363b0e..da508747a6 100644
--- a/src/pkg/go/scanner/scanner.go
+++ b/src/pkg/go/scanner/scanner.go
@@ -109,7 +109,7 @@ const (
 func (s *Scanner) Init(file *token.File, src []byte, err ErrorHandler, mode Mode) {
 	// Explicitly initialize all fields since a scanner may be reused.
 	if file.Size() != len(src) {
-		panic("file size does not match src len")
+		panic(fmt.Sprintf("file size (%d) does not match src len (%d)", file.Size(), len(src)))
 	}
 	s.file = file
 	s.dir, _ = filepath.Split(file.Name())
-- 
2.48.1