diff --git a/src/go/printer/printer.go b/src/go/printer/printer.go
index 32be3d67dd..5a6127c6b4 100644
--- a/src/go/printer/printer.go
+++ b/src/go/printer/printer.go
@@ -45,9 +45,9 @@ const (
 )
 
 type commentInfo struct {
-	cindex         int               // current comment index
-	comment        *ast.CommentGroup // = printer.comments[cindex]; or nil
-	commentOffset  int               // = printer.posFor(printer.comments[cindex].List[0].Pos()).Offset; or infinity
+	cindex         int               // index of the next comment
+	comment        *ast.CommentGroup // = printer.comments[cindex-1]; or nil
+	commentOffset  int               // = printer.posFor(printer.comments[cindex-1].List[0].Pos()).Offset; or infinity
 	commentNewline bool              // true if the comment group contains newlines
 }