diff --git a/cmd/vet/main.go b/cmd/vet/main.go
index 07a26ba9ab..8cec83204a 100644
--- a/cmd/vet/main.go
+++ b/cmd/vet/main.go
@@ -409,17 +409,17 @@ func (f *File) loc(pos token.Pos) string {
 	// expression instead of the inner part with the actual error, the
 	// precision can mislead.
 	posn := f.fset.Position(pos)
-	return fmt.Sprintf("%s:%d", posn.Filename, posn.Line)
+	return fmt.Sprintf("%s:%d: ", posn.Filename, posn.Line)
 }
 
 // Warn reports an error but does not set the exit code.
 func (f *File) Warn(pos token.Pos, args ...interface{}) {
-	fmt.Fprint(os.Stderr, f.loc(pos)+": "+fmt.Sprintln(args...))
+	fmt.Fprint(os.Stderr, f.loc(pos)+fmt.Sprintln(args...))
 }
 
 // Warnf reports a formatted error but does not set the exit code.
 func (f *File) Warnf(pos token.Pos, format string, args ...interface{}) {
-	fmt.Fprintf(os.Stderr, f.loc(pos)+": "+format+"\n", args...)
+	fmt.Fprintf(os.Stderr, f.loc(pos)+format+"\n", args...)
 }
 
 // walkFile walks the file's tree.