// error type
	DeferCheckSize()
	ErrorType = defBasic(TFORW, BuiltinPkg, "error")
	ErrorType.SetUnderlying(makeErrorInterface())
	ResumeCheckSize()

	// comparable type (interface)
	DeferCheckSize()
	ComparableType = defBasic(TFORW, BuiltinPkg, "comparable")
	ComparableType.SetUnderlying(makeComparableInterface())
	ResumeCheckSize()

	// any type (interface)
	DeferCheckSize()

		// interface{ Error() string }
		ityp := &Interface{methods: []*Func{err}, complete: true}
		computeInterfaceTypeSet(nil, nopos, ityp) // prevent races due to lazy computation of tset

		typ.SetUnderlying(ityp)
		def(obj)
	}

	// type comparable interface{} // marked as comparable
	{
		obj := NewTypeName(nopos, nil, "comparable", nil)
		obj.setColor(black)
		typ := NewNamed(obj, nil, nil)

		// interface{ Error() string }
		ityp := &Interface{methods: []*Func{err}, complete: true}
		computeInterfaceTypeSet(nil, nopos, ityp) // prevent races due to lazy computation of tset

		typ.SetUnderlying(ityp)
		def(obj)
	}

	// type comparable interface{} // marked as comparable
	{
		obj := NewTypeName(nopos, nil, "comparable", nil)
		obj.setColor(black)
		typ := NewNamed(obj, nil, nil)

	// We need to call iface.Complete(), but if there are any embedded
	// defined types, then we may not have set their underlying
	// interface type yet. So we need to defer calling Complete until
	// after we've called SetUnderlying everywhere.
	//
	// TODO(mdempsky): After CL 424876 lands, it should be safe to call
	// iface.Complete() immediately.
	r.p.ifaces = append(r.p.ifaces, iface)

	return iface
}

		rtyp = NewPointer(t)
	} else {
		rtyp = t
	}

	sig.recv = substVar(origSig.recv, rtyp)
	return substFunc(origm, sig)
}

// SetUnderlying sets the underlying type and marks t as complete.
// t must not have type arguments.
func (t *Named) SetUnderlying(underlying Type) {
	assert(t.inst == nil)
	if underlying == nil {
		panic("underlying type must not be nil")
	}
	if asNamed(underlying) != nil {

		rtyp = NewPointer(t)
	} else {
		rtyp = t
	}

	sig.recv = substVar(origSig.recv, rtyp)
	return substFunc(origm, sig)
}

// SetUnderlying sets the underlying type and marks t as complete.
// t must not have type arguments.
func (t *Named) SetUnderlying(underlying Type) {
	assert(t.inst == nil)
	if underlying == nil {
		panic("underlying type must not be nil")
	}
	if asNamed(underlying) != nil {

func (t *Type) Obj() Object {
	return t.obj
}

// SetUnderlying sets the underlying type of an incomplete type (i.e. type whose kind
// is currently TFORW). SetUnderlying automatically updates any types that were waiting
// for this type to be completed.
func (t *Type) SetUnderlying(underlying *Type) {
	if underlying.kind == TFORW {
		// This type isn't computed yet; when it is, update n.

func scasetype() *types.Type {
	if scase == nil {
		n := ir.NewDeclNameAt(src.NoXPos, ir.OTYPE, ir.Pkgs.Runtime.Lookup("scase"))
		scase = types.NewNamed(n)
		n.SetType(scase)
		n.SetTypecheck(1)

		scase.SetUnderlying(types.NewStruct([]*types.Field{
			types.NewField(base.Pos, typecheck.Lookup("c"), types.Types[types.TUNSAFEPTR]),
			types.NewField(base.Pos, typecheck.Lookup("elem"), types.Types[types.TUNSAFEPTR]),
		}))
	}

	T2 := NewNamed(n2, nil, nil)
	s1 := NewStruct([]*Var{NewField(nopos, nil, "_", T2, false)}, nil)
	T1.SetUnderlying(s1)
	s2 := NewStruct([]*Var{NewField(nopos, nil, "_", T2, false)}, nil)
	s3 := NewStruct([]*Var{NewField(nopos, nil, "_", s2, false)}, nil)
	T2.SetUnderlying(s3)

	// These calls must terminate (no endless recursion).
	Comparable(T1)
	Comparable(T2)
}

	T2 := NewNamed(n2, nil, nil)
	s1 := NewStruct([]*Var{NewField(nopos, nil, "_", T2, false)}, nil)
	T1.SetUnderlying(s1)
	s2 := NewStruct([]*Var{NewField(nopos, nil, "_", T2, false)}, nil)
	s3 := NewStruct([]*Var{NewField(nopos, nil, "_", s2, false)}, nil)
	T2.SetUnderlying(s3)

	// These calls must terminate (no endless recursion).
	Comparable(T1)
	Comparable(T2)
}