cmd/gc: check for initialization cycles in method values

Fixes #7960.

LGTM=rsc
R=rsc
CC=golang-codereviews, gri
https://golang.org/cl/159800045

src/cmd/gc/sinit.c

@@ -207,7 +207,7 @@ init2(Node *n, NodeList **out)
 	
 	if(n->op == OCLOSURE)
 		init2list(n->closure->nbody, out);
-	if(n->op == ODOTMETH)
+	if(n->op == ODOTMETH || n->op == OCALLPART)
 		init2(n->type->nname, out);
 }
 

test/fixedbugs/issue6703a.go

+// errorcheck
+
+// Copyright 2014 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.
+
+// Check for cycles in a function value.
+
+package funcvalue
+
+func fx() int {
+	_ = x
+	return 0
+}
+
+var x = fx // ERROR "initialization loop|depends upon itself"

test/fixedbugs/issue6703b.go

+// errorcheck
+
+// Copyright 2014 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.
+
+// Check for cycles in a function call.
+
+package funccall
+
+func fx() int {
+	_ = x
+	return 0
+}
+
+var x = fx() // ERROR "initialization loop|depends upon itself"

test/fixedbugs/issue6703c.go

+// errorcheck
+
+// Copyright 2014 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.
+
+// Check for cycles in a method expression.
+
+package methexpr
+
+type T int
+
+func (T) m() int {
+	_ = x
+	return 0
+}
+
+var x = T.m // ERROR "initialization loop|depends upon itself"

test/fixedbugs/issue6703d.go

+// errorcheck
+
+// Copyright 2014 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.
+
+// Check for cycles in a method expression call.
+
+package methexprcall
+
+type T int
+
+func (T) m() int {
+	_ = x
+	return 0
+}
+
+var x = T.m(0) // ERROR "initialization loop|depends upon itself"

test/fixedbugs/issue6703e.go

+// errorcheck
+
+// Copyright 2014 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.
+
+// Check for cycles in the method value of a value literal.
+
+package litmethvalue
+
+type T int
+
+func (T) m() int {
+	_ = x
+	return 0
+}
+
+var x = T(0).m // ERROR "initialization loop|depends upon itself"

test/fixedbugs/issue6703f.go

+// errorcheck
+
+// Copyright 2014 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.
+
+// Check for cycles in the method call of a value literal.
+
+package litmethcall
+
+type T int
+
+func (T) m() int {
+	_ = x
+	return 0
+}
+
+var x = T(0).m() // ERROR "initialization loop|depends upon itself"

test/fixedbugs/issue6703g.go

+// errorcheck
+
+// Copyright 2014 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.
+
+// Check for cycles in an embedded method expression.
+
+package embedmethexpr
+
+type T int
+
+func (T) m() int {
+	_ = x
+	return 0
+}
+
+type E struct{ T }
+
+var x = E.m // ERROR "initialization loop|depends upon itself" 

test/fixedbugs/issue6703h.go

+// errorcheck
+
+// Copyright 2014 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.
+
+// Check for cycles when calling an embedded method expression.
+
+package embedmethexprcall
+
+type T int
+
+func (T) m() int {
+	_ = x
+	return 0
+}
+
+type E struct{ T }
+
+var x = E.m(E{0}) // ERROR "initialization loop|depends upon itself" 

test/fixedbugs/issue6703i.go

+// errorcheck
+
+// Copyright 2014 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.
+
+// Check for cycles in an embedded struct literal's method value.
+
+package embedlitmethvalue
+
+type T int
+
+func (T) m() int {
+	_ = x
+	return 0
+}
+
+type E struct{ T }
+
+var x = E{}.m // ERROR "initialization loop|depends upon itself" 

test/fixedbugs/issue6703j.go

+// errorcheck
+
+// Copyright 2014 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.
+
+// Check for cycles in an embedded struct literal's method call.
+
+package embedlitmethcall
+
+type T int
+
+func (T) m() int {
+	_ = x
+	return 0
+}
+
+type E struct{ T }
+
+var x = E{}.m() // ERROR "initialization loop|depends upon itself"

test/fixedbugs/issue6703k.go

+// errorcheck
+
+// Copyright 2014 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.
+
+// Check for cycles in a method value.
+
+package methvalue
+
+type T int
+
+func (T) m() int {
+	_ = x
+	return 0
+}
+
+var (
+	t T
+	x = t.m // ERROR "initialization loop|depends upon itself"
+)

test/fixedbugs/issue6703l.go

+// errorcheck
+
+// Copyright 2014 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.
+
+// Check for cycles in a method call.
+
+package methcall
+
+type T int
+
+func (T) m() int {
+	_ = x
+	return 0
+}
+
+var (
+	t T
+	x = t.m() // ERROR "initialization loop|depends upon itself"
+)

test/fixedbugs/issue6703m.go

+// errorcheck
+
+// Copyright 2014 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.
+
+// Check for cycles in the method value of a value returned from a function call.
+
+package funcmethvalue
+
+type T int
+
+func (T) m() int {
+	_ = x
+	return 0
+}
+
+func f() T {
+	return T(0)
+}
+
+var (
+	t T
+	x = f().m // ERROR "initialization loop|depends upon itself"
+)

test/fixedbugs/issue6703n.go

+// errorcheck
+
+// Copyright 2014 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.
+
+// Check for cycles in the method call of a value returned from a function call.
+
+package funcmethcall
+
+type T int
+
+func (T) m() int {
+	_ = x
+	return 0
+}
+
+func f() T {
+	return T(0)
+}
+
+var (
+	t T
+	x = f().m() // ERROR "initialization loop|depends upon itself"
+)

test/fixedbugs/issue6703o.go

+// errorcheck
+
+// Copyright 2014 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.
+
+// Check for cycles in an embedded struct's method value.
+
+package embedmethvalue
+
+type T int
+
+func (T) m() int {
+	_ = x
+	return 0
+}
+
+type E struct{ T }
+
+var (
+	e E
+	x = e.m // ERROR "initialization loop|depends upon itself" 
+)

test/fixedbugs/issue6703p.go

+// errorcheck
+
+// Copyright 2014 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.
+
+// Check for cycles in an embedded struct's method call.
+
+package embedmethcall
+
+type T int
+
+func (T) m() int {
+	_ = x
+	return 0
+}
+
+type E struct{ T }
+
+var (
+	e E
+	x = e.m() // ERROR "initialization loop|depends upon itself" 
+)

test/fixedbugs/issue6703q.go

+// errorcheck
+
+// Copyright 2014 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.
+
+// Check for cycles in the method value of an embedded struct returned
+// from a function call.
+
+package funcembedmethvalue
+
+type T int
+
+func (T) m() int {
+	_ = x
+	return 0
+}
+
+func g() E {
+	return E{0}
+}
+
+type E struct{ T }
+
+var (
+	e E
+	x = g().m // ERROR "initialization loop|depends upon itself" 
+)

test/fixedbugs/issue6703r.go

+// errorcheck
+
+// Copyright 2014 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.
+
+// Check for cycles in the method call of an embedded struct returned
+// from a function call.
+
+package funcembedmethcall
+
+type T int
+
+func (T) m() int {
+	_ = x
+	return 0
+}
+
+func g() E {
+	return E{0}
+}
+
+type E struct{ T }
+
+var (
+	e E
+	x = g().m() // ERROR "initialization loop|depends upon itself" 
+)

test/fixedbugs/issue6703s.go

+// errorcheck
+
+// Copyright 2014 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.
+
+// Check for cycles in a pointer method expression.
+
+package ptrmethexpr
+
+type T int
+
+func (*T) pm() int {
+	_ = x
+	return 0
+}
+
+var x = (*T).pm // ERROR "initialization loop|depends upon itself"

test/fixedbugs/issue6703t.go

+// errorcheck
+
+// Copyright 2014 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.
+
+// Check for cycles in the call of a pointer method expression.
+
+package ptrmethexprcall
+
+type T int
+
+func (*T) pm() int {
+	_ = x
+	return 0
+}
+
+var x = (*T).pm(nil) // ERROR "initialization loop|depends upon itself"

test/fixedbugs/issue6703u.go

+// errorcheck
+
+// Copyright 2014 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.
+
+// Check for cycles in a pointer literal's method value.
+
+package ptrlitmethvalue
+
+type T int
+
+func (*T) pm() int {
+	_ = x
+	return 0
+}
+
+var x = (*T)(nil).pm // ERROR "initialization loop|depends upon itself"

test/fixedbugs/issue6703v.go

+// errorcheck
+
+// Copyright 2014 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.
+
+// Check for cycles in a pointer literal's method call.
+
+package ptrlitmethcall
+
+type T int
+
+func (*T) pm() int {
+	_ = x
+	return 0
+}
+
+var x = (*T)(nil).pm() // ERROR "initialization loop|depends upon itself"

test/fixedbugs/issue6703w.go

+// errorcheck
+
+// Copyright 2014 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.
+
+// Check for cycles in a pointer value's method value.
+
+package ptrmethvalue
+
+type T int
+
+func (*T) pm() int {
+	_ = x
+	return 0
+}
+
+var (
+	p *T
+	x = p.pm // ERROR "initialization loop|depends upon itself"
+)

test/fixedbugs/issue6703x.go

+// errorcheck
+
+// Copyright 2014 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.
+
+// Check for cycles in a pointer value's method call.
+
+package ptrmethcall
+
+type T int
+
+func (*T) pm() int {
+	_ = x
+	return 0
+}
+
+var (
+	p *T
+	x = p.pm() // ERROR "initialization loop|depends upon itself"
+)

test/fixedbugs/issue6703y.go

+// errorcheck
+
+// Copyright 2014 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.
+
+// Check for cycles in the method value of a pointer value returned
+// from a function call.
+
+package funcptrmethvalue
+
+type T int
+
+func (*T) pm() int {
+	_ = x
+	return 0
+}
+
+func pf() *T {
+	return nil
+}
+
+var x = pf().pm // ERROR "initialization loop|depends upon itself" 

test/fixedbugs/issue6703z.go

+// errorcheck
+
+// Copyright 2014 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.
+
+// Check for cycles in the method call of a pointer value returned
+// from a function call.
+
+package funcptrmethcall
+
+type T int
+
+func (*T) pm() int {
+	_ = x
+	return 0
+}
+
+func pf() *T {
+	return nil
+}
+
+var x = pf().pm() // ERROR "initialization loop|depends upon itself"