From ec96795ba20209263a0bbb17a073a9c028e74437 Mon Sep 17 00:00:00 2001
From: Robert Griesemer <gri@golang.org>
Date: Mon, 8 Sep 2014 14:54:00 -0700
Subject: [PATCH] go/parser: fix (pathological) corner case

Inside a control clause (if ... {}), composite
literals starting with a type name must be parenthesized.
A composite literal used in the array length expression
of an array composite literal is already parenthesized.
Not a valid program, but syntactically is should
be accepted.

LGTM=adonovan
R=adonovan
CC=golang-codereviews
https://golang.org/cl/142760043
---
 src/go/parser/parser.go     | 2 ++
 src/go/parser/short_test.go | 1 +
 2 files changed, 3 insertions(+)

diff --git a/src/go/parser/parser.go b/src/go/parser/parser.go
index 9c62076f25..4a005d8ffa 100644
--- a/src/go/parser/parser.go
+++ b/src/go/parser/parser.go
@@ -641,6 +641,7 @@ func (p *parser) parseArrayType() ast.Expr {
 	}
 
 	lbrack := p.expect(token.LBRACK)
+	p.exprLev++
 	var len ast.Expr
 	// always permit ellipsis for more fault-tolerant parsing
 	if p.tok == token.ELLIPSIS {
@@ -649,6 +650,7 @@ func (p *parser) parseArrayType() ast.Expr {
 	} else if p.tok != token.RBRACK {
 		len = p.parseRhs()
 	}
+	p.exprLev--
 	p.expect(token.RBRACK)
 	elt := p.parseType()
 
diff --git a/src/go/parser/short_test.go b/src/go/parser/short_test.go
index f861086ddb..05e44de28a 100644
--- a/src/go/parser/short_test.go
+++ b/src/go/parser/short_test.go
@@ -39,6 +39,7 @@ var valids = []string{
 	`package p; func ((*T),) m() {}`,
 	`package p; func (*(T),) m() {}`,
 	`package p; func _(x []int) { for range x {} }`,
+	`package p; func _() { if [T{}.n]int{} {} }`,
 }
 
 func TestValid(t *testing.T) {