cmd/gc: check for initialization cycles in method values

Fixes issue 7960.

LGTM=rsc
R=rsc
CC=golang-codereviews, gri
https://codereview.appspot.com/159800045

26 files changed, 538 insertions, 0 deletions

diff --git a/test/fixedbugs/issue6703a.go b/test/fixedbugs/issue6703a.go
new file mode 100644
index 000000000..d4c008f83
--- /dev/null
+++ b/test/fixedbugs/issue6703a.go
@@ -0,0 +1,16 @@
+// 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"
diff --git a/test/fixedbugs/issue6703b.go b/test/fixedbugs/issue6703b.go
new file mode 100644
index 000000000..326b5839a
--- /dev/null
+++ b/test/fixedbugs/issue6703b.go
@@ -0,0 +1,16 @@
+// 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"
diff --git a/test/fixedbugs/issue6703c.go b/test/fixedbugs/issue6703c.go
new file mode 100644
index 000000000..473576475
--- /dev/null
+++ b/test/fixedbugs/issue6703c.go
@@ -0,0 +1,18 @@
+// 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"
diff --git a/test/fixedbugs/issue6703d.go b/test/fixedbugs/issue6703d.go
new file mode 100644
index 000000000..0a1952f78
--- /dev/null
+++ b/test/fixedbugs/issue6703d.go
@@ -0,0 +1,18 @@
+// 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"
diff --git a/test/fixedbugs/issue6703e.go b/test/fixedbugs/issue6703e.go
new file mode 100644
index 000000000..416066e85
--- /dev/null
+++ b/test/fixedbugs/issue6703e.go
@@ -0,0 +1,18 @@
+// 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"
diff --git a/test/fixedbugs/issue6703f.go b/test/fixedbugs/issue6703f.go
new file mode 100644
index 000000000..30238297b
--- /dev/null
+++ b/test/fixedbugs/issue6703f.go
@@ -0,0 +1,18 @@
+// 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"
diff --git a/test/fixedbugs/issue6703g.go b/test/fixedbugs/issue6703g.go
new file mode 100644
index 000000000..002b5a636
--- /dev/null
+++ b/test/fixedbugs/issue6703g.go
@@ -0,0 +1,20 @@
+// 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" 
diff --git a/test/fixedbugs/issue6703h.go b/test/fixedbugs/issue6703h.go
new file mode 100644
index 000000000..234ccb365
--- /dev/null
+++ b/test/fixedbugs/issue6703h.go
@@ -0,0 +1,20 @@
+// 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" 
diff --git a/test/fixedbugs/issue6703i.go b/test/fixedbugs/issue6703i.go
new file mode 100644
index 000000000..78b4d4980
--- /dev/null
+++ b/test/fixedbugs/issue6703i.go
@@ -0,0 +1,20 @@
+// 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" 
diff --git a/test/fixedbugs/issue6703j.go b/test/fixedbugs/issue6703j.go
new file mode 100644
index 000000000..a7f63f748
--- /dev/null
+++ b/test/fixedbugs/issue6703j.go
@@ -0,0 +1,20 @@
+// 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"
diff --git a/test/fixedbugs/issue6703k.go b/test/fixedbugs/issue6703k.go
new file mode 100644
index 000000000..19c61078c
--- /dev/null
+++ b/test/fixedbugs/issue6703k.go
@@ -0,0 +1,21 @@
+// 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"
+)
diff --git a/test/fixedbugs/issue6703l.go b/test/fixedbugs/issue6703l.go
new file mode 100644
index 000000000..3f4ca3147
--- /dev/null
+++ b/test/fixedbugs/issue6703l.go
@@ -0,0 +1,21 @@
+// 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"
+)
diff --git a/test/fixedbugs/issue6703m.go b/test/fixedbugs/issue6703m.go
new file mode 100644
index 000000000..d80959cdc
--- /dev/null
+++ b/test/fixedbugs/issue6703m.go
@@ -0,0 +1,25 @@
+// 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"
+)
diff --git a/test/fixedbugs/issue6703n.go b/test/fixedbugs/issue6703n.go
new file mode 100644
index 000000000..2c623f219
--- /dev/null
+++ b/test/fixedbugs/issue6703n.go
@@ -0,0 +1,25 @@
+// 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"
+)
diff --git a/test/fixedbugs/issue6703o.go b/test/fixedbugs/issue6703o.go
new file mode 100644
index 000000000..efc894737
--- /dev/null
+++ b/test/fixedbugs/issue6703o.go
@@ -0,0 +1,23 @@
+// 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" 
+)
diff --git a/test/fixedbugs/issue6703p.go b/test/fixedbugs/issue6703p.go
new file mode 100644
index 000000000..dad88f634
--- /dev/null
+++ b/test/fixedbugs/issue6703p.go
@@ -0,0 +1,23 @@
+// 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" 
+)
diff --git a/test/fixedbugs/issue6703q.go b/test/fixedbugs/issue6703q.go
new file mode 100644
index 000000000..7bd748aaa
--- /dev/null
+++ b/test/fixedbugs/issue6703q.go
@@ -0,0 +1,28 @@
+// 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" 
+)
diff --git a/test/fixedbugs/issue6703r.go b/test/fixedbugs/issue6703r.go
new file mode 100644
index 000000000..669846241
--- /dev/null
+++ b/test/fixedbugs/issue6703r.go
@@ -0,0 +1,28 @@
+// 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" 
+)
diff --git a/test/fixedbugs/issue6703s.go b/test/fixedbugs/issue6703s.go
new file mode 100644
index 000000000..6aa28483a
--- /dev/null
+++ b/test/fixedbugs/issue6703s.go
@@ -0,0 +1,18 @@
+// 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"
diff --git a/test/fixedbugs/issue6703t.go b/test/fixedbugs/issue6703t.go
new file mode 100644
index 000000000..bad65ad16
--- /dev/null
+++ b/test/fixedbugs/issue6703t.go
@@ -0,0 +1,18 @@
+// 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"
diff --git a/test/fixedbugs/issue6703u.go b/test/fixedbugs/issue6703u.go
new file mode 100644
index 000000000..b6813b771
--- /dev/null
+++ b/test/fixedbugs/issue6703u.go
@@ -0,0 +1,18 @@
+// 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"
diff --git a/test/fixedbugs/issue6703v.go b/test/fixedbugs/issue6703v.go
new file mode 100644
index 000000000..a1b3711bb
--- /dev/null
+++ b/test/fixedbugs/issue6703v.go
@@ -0,0 +1,18 @@
+// 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"
diff --git a/test/fixedbugs/issue6703w.go b/test/fixedbugs/issue6703w.go
new file mode 100644
index 000000000..d4733deba
--- /dev/null
+++ b/test/fixedbugs/issue6703w.go
@@ -0,0 +1,21 @@
+// 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"
+)
diff --git a/test/fixedbugs/issue6703x.go b/test/fixedbugs/issue6703x.go
new file mode 100644
index 000000000..8008b8c37
--- /dev/null
+++ b/test/fixedbugs/issue6703x.go
@@ -0,0 +1,21 @@
+// 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"
+)
diff --git a/test/fixedbugs/issue6703y.go b/test/fixedbugs/issue6703y.go
new file mode 100644
index 000000000..ac4526dda
--- /dev/null
+++ b/test/fixedbugs/issue6703y.go
@@ -0,0 +1,23 @@
+// 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" 
diff --git a/test/fixedbugs/issue6703z.go b/test/fixedbugs/issue6703z.go
new file mode 100644
index 000000000..d4c17e13a
--- /dev/null
+++ b/test/fixedbugs/issue6703z.go
@@ -0,0 +1,23 @@
+// 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"