From c42b3e21c30c354a5a2fdc840a0824fb71c10368 Mon Sep 17 00:00:00 2001
From: Robert Griesemer <gri@golang.org>
Date: Fri, 1 Apr 2011 20:51:55 -0700
Subject: [PATCH] go/parser: package name must not be the blank identifier

R=r, r2, rsc1
CC=golang-dev
https://golang.org/cl/4343045
---
 src/pkg/go/parser/parser.go | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/pkg/go/parser/parser.go b/src/pkg/go/parser/parser.go
index fd9ad0f1b52..84a0da6ae7b 100644
--- a/src/pkg/go/parser/parser.go
+++ b/src/pkg/go/parser/parser.go
@@ -2209,6 +2209,9 @@ func (p *parser) parseFile() *ast.File {
 	// Go spec: The package clause is not a declaration;
 	// the package name does not appear in any scope.
 	ident := p.parseIdent()
+	if ident.Name == "_" {
+		p.error(p.pos, "invalid package name _")
+	}
 	p.expectSemi()
 
 	var decls []ast.Decl