diff --git a/src/lib/go/doc/doc.go b/src/lib/go/doc/doc.go
index fc890f07c7c..59b511e8f02 100644
--- a/src/lib/go/doc/doc.go
+++ b/src/lib/go/doc/doc.go
@@ -221,7 +221,7 @@ var (
 // TODO(rsc): Cannot use var initialization for regexps,
 // because Regexp constructor needs threads.
 func setupRegexps() {
-	comment_markers = makeRex("^[ \t]*(// ?| ?/\\* ?)");
+	comment_markers = makeRex("^/(/|\\*) ?");
 	trailing_whitespace = makeRex("[ \t\r]+$");
 	comment_junk = makeRex("^[ \t]*(/\\*|\\*/)[ \t]*$");
 }