Revert "reflect: change rtype so that it (not *rtype) implements Type"

This reverts CL 487558, which is causing test failures in Google. See
b/282133554.

Change-Id: Icafa4ffc6aaa24a363abb90b8ae0b0183aca2b89
Reviewed-on: https://go-review.googlesource.com/c/go/+/494410
TryBot-Result: Gopher Robot <[email protected]>
Auto-Submit: Austin Clements <[email protected]>
Reviewed-by: David Chase <[email protected]>
Run-TryBot: Austin Clements <[email protected]>

Author: aclements

src/reflect/all_test.go

@@ -7215,11 +7215,11 @@ func join(b ...[]byte) []byte    { return bytes.Join(b, nil) }
 func lit(x ...byte) []byte       { return x }
 
 func TestTypeOfTypeOf(t *testing.T) {
-	// Check that all the type constructors return concrete rtype implementations.
+	// Check that all the type constructors return concrete *rtype implementations.
 	// It's difficult to test directly because the reflect package is only at arm's length.
-	// The easiest thing to do is just call a function that crashes if it doesn't get an rtype.
+	// The easiest thing to do is just call a function that crashes if it doesn't get an *rtype.
 	check := func(name string, typ Type) {
-		if underlying := TypeOf(typ).String(); underlying != "reflect.rtype" {
+		if underlying := TypeOf(typ).String(); underlying != "*reflect.rtype" {
 			t.Errorf("%v returned %v, not *reflect.rtype", name, underlying)
 		}
 	}

src/reflect/benchmark_test.go

@@ -247,9 +247,10 @@ func BenchmarkPtrTo(b *testing.B) {
 	// Construct a type with a zero ptrToThis.
 	type T struct{ int }
 	t := SliceOf(TypeOf(T{}))
-	ptrToThis := ValueOf(t).Field(0).Elem().FieldByName("PtrToThis")
+	ptrToThis := ValueOf(t).Elem().FieldByName("PtrToThis")
 	if !ptrToThis.IsValid() {
-		b.Fatalf("%v has no ptrToThis field; was it removed from rtype?", t)
+		b.Skipf("%v has no ptrToThis field; was it removed from rtype?", t) // TODO fix this at top of refactoring
+		// b.Fatalf("%v has no ptrToThis field; was it removed from rtype?", t)
 	}
 	if ptrToThis.Int() != 0 {
 		b.Fatalf("%v.ptrToThis unexpectedly nonzero", t)

src/reflect/export_test.go

@@ -35,7 +35,7 @@ func FuncLayout(t Type, rcvr Type) (frametype Type, argSize, retOffset uintptr,
 	if rcvr != nil {
 		ft, _, abid = funcLayout((*funcType)(unsafe.Pointer(t.common())), rcvr.common())
 	} else {
-		ft, _, abid = funcLayout((*funcType)(unsafe.Pointer(t.common())), nil)
+		ft, _, abid = funcLayout((*funcType)(unsafe.Pointer(t.(*rtype))), nil)
 	}
 	// Extract size information.
 	argSize = abid.stackCallArgsSize
@@ -80,7 +80,7 @@ func TypeLinks() []string {
 	for i, offs := range offset {
 		rodata := sections[i]
 		for _, off := range offs {
-			typ := toRType((*abi.Type)(resolveTypeOff(unsafe.Pointer(rodata), off)))
+			typ := (*rtype)(resolveTypeOff(unsafe.Pointer(rodata), off))
 			r = append(r, typ.String())
 		}
 	}
@@ -96,11 +96,11 @@ func MapBucketOf(x, y Type) Type {
 }
 
 func CachedBucketOf(m Type) Type {
-	t := m.(rtype)
+	t := m.(*rtype)
 	if Kind(t.t.Kind_&kindMask) != Map {
 		panic("not map")
 	}
-	tt := (*mapType)(unsafe.Pointer(t.t))
+	tt := (*mapType)(unsafe.Pointer(t))
 	return toType(tt.Bucket)
 }
 
@@ -122,7 +122,7 @@ func FirstMethodNameBytes(t Type) *byte {
 		panic("type has no methods")
 	}
 	m := ut.Methods()[0]
-	mname := t.(rtype).nameOff(m.Name)
+	mname := t.(*rtype).nameOff(m.Name)
 	if *mname.DataChecked(0, "name flag field")&(1<<2) == 0 {
 		panic("method name does not have pkgPath *string")
 	}
@@ -135,7 +135,7 @@ type OtherPkgFields struct {
 }
 
 func IsExported(t Type) bool {
-	typ := t.(rtype)
+	typ := t.(*rtype)
 	n := typ.nameOff(typ.t.Str)
 	return n.IsExported()
 }

src/reflect/makefunc.go

@@ -104,7 +104,7 @@ func makeMethodValue(op string, v Value) Value {
 	rcvr := Value{v.typ, v.ptr, fl}
 
 	// v.Type returns the actual type of the method value.
-	ftyp := (*funcType)(unsafe.Pointer(v.Type().common()))
+	ftyp := (*funcType)(unsafe.Pointer(v.Type().(*rtype)))
 
 	code := methodValueCallCodePtr()