From 27b698bc2a69e30dd13df20576181031863d6e8d Mon Sep 17 00:00:00 2001
From: Robert Griesemer <gri@golang.org>
Date: Fri, 27 Sep 2013 09:33:00 -0700
Subject: [PATCH] go.tools/go/types: x.f is addressable if x is addressable or
 x.f contains an indirection

Fixes golang/go#6487.

R=adonovan
CC=golang-dev
https://golang.org/cl/14047043
---
 go/types/call.go            |  6 +++++-
 go/types/testdata/stmt0.src | 15 +++++++++++++++
 2 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/go/types/call.go b/go/types/call.go
index d57172f0..ebfd00de 100644
--- a/go/types/call.go
+++ b/go/types/call.go
@@ -286,7 +286,11 @@ func (check *checker) selector(x *operand, e *ast.SelectorExpr) {
 		switch obj := obj.(type) {
 		case *Var:
 			check.recordSelection(e, FieldVal, x.typ, obj, index, indirect)
-			x.mode = variable
+			if x.mode == variable || indirect {
+				x.mode = variable
+			} else {
+				x.mode = value
+			}
 			x.typ = obj.typ
 
 		case *Func:
diff --git a/go/types/testdata/stmt0.src b/go/types/testdata/stmt0.src
index 393af5d6..c60e0508 100644
--- a/go/types/testdata/stmt0.src
+++ b/go/types/testdata/stmt0.src
@@ -92,6 +92,21 @@ func assignments1() {
 	(_) = 0
 }
 
+func issue6487() {
+	type S struct{x int}
+	_ = &S /* ERROR "cannot take address" */ {}.x
+	_ = &( /* ERROR "cannot take address" */ S{}.x)
+	_ = (&S{}).x
+	S /* ERROR "cannot assign" */ {}.x = 0
+	(&S{}).x = 0
+
+	type M map[string]S
+	var m M
+	m /* ERROR "cannot assign" */ ["foo"].x = 0
+	_ = &( /* ERROR "cannot take address" */ m["foo"].x)
+	_ = &m /* ERROR "cannot take address" */ ["foo"].x
+}
+
 func shortVarDecls() {
 	const c = 0
 	type d int