reflect: use cgo.Incomplete instead of go:notinheap in tests

go:notinheap will be replaced by runtime/internal/sys.NotInHeap, and for
longer term, we want to restrict all of its usages inside the runtime
package only.

Updates #46731

Change-Id: I267adc2a19f0dc8a1ed29b5b4aeec1a7dc7318d5
Reviewed-on: https://go-review.googlesource.com/c/go/+/421880
Run-TryBot: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: David Chase <drchase@google.com>
Reviewed-by: Keith Randall <khr@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>

src/reflect/all_test.go

@@ -8003,28 +8003,6 @@ func TestSetIter(t *testing.T) {
 	}
 }
 
-//go:notinheap
-type nih struct{ x int }
-
-var global_nih = nih{x: 7}
-
-func TestNotInHeapDeref(t *testing.T) {
-	// See issue 48399.
-	v := ValueOf((*nih)(nil))
-	v.Elem()
-	shouldPanic("reflect: call of reflect.Value.Field on zero Value", func() { v.Elem().Field(0) })
-
-	v = ValueOf(&global_nih)
-	if got := v.Elem().Field(0).Int(); got != 7 {
-		t.Fatalf("got %d, want 7", got)
-	}
-
-	v = ValueOf((*nih)(unsafe.Pointer(new(int))))
-	shouldPanic("reflect: reflect.Value.Elem on an invalid notinheap pointer", func() { v.Elem() })
-	shouldPanic("reflect: reflect.Value.Pointer on an invalid notinheap pointer", func() { v.Pointer() })
-	shouldPanic("reflect: reflect.Value.UnsafePointer on an invalid notinheap pointer", func() { v.UnsafePointer() })
-}
-
 func TestMethodCallValueCodePtr(t *testing.T) {
 	m := ValueOf(Point{}).Method(1)
 	want := MethodValueCallCodePtr()

src/reflect/deepequal.go

@@ -40,9 +40,9 @@ func deepValueEqual(v1, v2 Value, visited map[visit]bool) bool {
 		switch v1.Kind() {
 		case Pointer:
 			if v1.typ.ptrdata == 0 {
-				// go:notinheap pointers can't be cyclic.
+				// not-in-heap pointers can't be cyclic.
-				// At least, all of our current uses of go:notinheap have
+				// At least, all of our current uses of runtime/internal/sys.NotInHeap
-				// that property. The runtime ones aren't cyclic (and we don't use
+				// have that property. The runtime ones aren't cyclic (and we don't use
 				// DeepEqual on them anyway), and the cgo-generated ones are
 				// all empty structs.
 				return false

src/reflect/nih_test.go

@@ -0,0 +1,38 @@
+// Copyright 2009 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.
+
+//go:build cgo
+
+package reflect_test
+
+import (
+	. "reflect"
+	"runtime/cgo"
+	"testing"
+	"unsafe"
+)
+
+type nih struct {
+	_ cgo.Incomplete
+	x int
+}
+
+var global_nih = nih{x: 7}
+
+func TestNotInHeapDeref(t *testing.T) {
+	// See issue 48399.
+	v := ValueOf((*nih)(nil))
+	v.Elem()
+	shouldPanic("reflect: call of reflect.Value.Field on zero Value", func() { v.Elem().Field(0) })
+
+	v = ValueOf(&global_nih)
+	if got := v.Elem().Field(1).Int(); got != 7 {
+		t.Fatalf("got %d, want 7", got)
+	}
+
+	v = ValueOf((*nih)(unsafe.Pointer(new(int))))
+	shouldPanic("reflect: reflect.Value.Elem on an invalid notinheap pointer", func() { v.Elem() })
+	shouldPanic("reflect: reflect.Value.Pointer on an invalid notinheap pointer", func() { v.Pointer() })
+	shouldPanic("reflect: reflect.Value.UnsafePointer on an invalid notinheap pointer", func() { v.UnsafePointer() })
+}

src/reflect/value.go

@@ -92,7 +92,7 @@ func (f flag) ro() flag {
 
 // pointer returns the underlying pointer represented by v.
 // v.Kind() must be Pointer, Map, Chan, Func, or UnsafePointer
-// if v.Kind() == Pointer, the base type must not be go:notinheap.
+// if v.Kind() == Pointer, the base type must not be not-in-heap.
 func (v Value) pointer() unsafe.Pointer {
 	if v.typ.size != goarch.PtrSize || !v.typ.pointers() {
 		panic("can't call pointer on a non-pointer Value")
@@ -3156,7 +3156,7 @@ func New(typ Type) Value {
 	t := typ.(*rtype)
 	pt := t.ptrTo()
 	if ifaceIndir(pt) {
-		// This is a pointer to a go:notinheap type.
+		// This is a pointer to a not-in-heap type.
 		panic("reflect: New of type that may not be allocated in heap (possibly undefined cgo C type)")
 	}
 	ptr := unsafe_New(t)