cmd/compile: recognize embedded field in inlined function

There was already special code to recognize "?" in hidden_structdcl,
which is used for inlined types and variables.  This recognizes "?" in
structdcl as well, a case that arises when a struct type appears
within an inlined function body.

Fixes #10219.

Change-Id: Ic5257ae54f817e0d4a189c2294dcd633c9f2101a
Reviewed-on: https://go-review.googlesource.com/12241
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>

src/cmd/compile/internal/gc/go.y

@@ -1632,7 +1632,7 @@ structdcl:
 
 		var n *Node
 		l = $1;
-		if l == nil {
+		if l == nil || l.N.Sym.Name == "?" {
 			// ? symbol, during import (list1(nil) == nil)
 			n = $2;
 			if n.Op == OIND {

src/cmd/compile/internal/gc/y.go

@@ -2791,7 +2791,7 @@ yydefault:
 
 			var n *Node
 			l = yyDollar[1].list
-			if l == nil {
+			if l == nil || l.N.Sym.Name == "?" {
 				// ? symbol, during import (list1(nil) == nil)
 				n = yyDollar[2].node
 				if n.Op == OIND {

test/fixedbugs/issue10219.dir/a.go

+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package a
+
+type m struct {
+	S string
+}
+
+var g = struct {
+	m
+	P string
+}{
+	m{"a"},
+	"",
+}
+
+type S struct{}
+
+func (s *S) M(p string) {
+	r := g
+	r.P = p
+}

test/fixedbugs/issue10219.dir/b.go

+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package b
+
+import "./a"
+
+func F() *a.S {
+	return &a.S{}
+}

test/fixedbugs/issue10219.dir/c.go

+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package c
+
+import "./b"
+
+func F() {
+	s := b.F()
+	s.M("c")
+}

test/fixedbugs/issue10219.go

+// compiledir
+
+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Issue 10219: failure of inlinable function that uses embedded types
+// in an anonymous struct via :=.
+
+package ignored