diff --git a/src/pkg/go/scanner/scanner.go b/src/pkg/go/scanner/scanner.go
index 82b9aba0d68..60ac45c86e0 100644
--- a/src/pkg/go/scanner/scanner.go
+++ b/src/pkg/go/scanner/scanner.go
@@ -22,7 +22,6 @@ package scanner
 
 import (
 	"bytes"
-	"fmt"
 	"go/token"
 	"path/filepath"
 	"strconv"
@@ -671,7 +670,7 @@ scanAgain:
 			tok = S.switch3(token.OR, token.OR_ASSIGN, '|', token.LOR)
 		default:
 			if S.mode&AllowIllegalChars == 0 {
-				S.error(offs, fmt.Sprintf("illegal character '%c' (%U)", ch, ch))
+				S.error(offs, "illegal character "+strconv.QuoteRune(ch))
 			}
 			insertSemi = S.insertSemi // preserve insertSemi info
 		}
diff --git a/src/pkg/go/scanner/scanner_test.go b/src/pkg/go/scanner/scanner_test.go
index 657e85122e9..5b99bede118 100644
--- a/src/pkg/go/scanner/scanner_test.go
+++ b/src/pkg/go/scanner/scanner_test.go
@@ -650,8 +650,9 @@ var errors = []struct {
 	pos int
 	err string
 }{
-	{"\a", token.ILLEGAL, 0, "illegal character '\a' (U+0007)"},
-	{`#`, token.ILLEGAL, 0, "illegal character '#' (U+0023)"},
+	{"\a", token.ILLEGAL, 0, "illegal character '\\a'"},
+	{`#`, token.ILLEGAL, 0, "illegal character '#'"},
+	{`…`, token.ILLEGAL, 0, "illegal character '\\u2026'"},
 	{`' '`, token.CHAR, 0, ""},
 	{`''`, token.CHAR, 0, "illegal character literal"},
 	{`'\8'`, token.CHAR, 2, "unknown escape sequence"},