func isTypeLit(t Type) bool {
	switch Unalias(t).(type) {
	case *Named, *TypeParam:
		return false
	}
	return true
}

// isTyped reports whether t is typed; i.e., not an untyped
// constant or boolean.
// Safe to call from types that are not fully set up.
func isTyped(t Type) bool {
	// Alias and named types cannot denote untyped types
	// so there's no need to call Unalias or under, below.
	b, _ := t.(*Basic)

func isTypeLit(t Type) bool {
	switch Unalias(t).(type) {
	case *Named, *TypeParam:
		return false
	}
	return true
}

// isTyped reports whether t is typed; i.e., not an untyped
// constant or boolean.
// Safe to call from types that are not fully set up.
func isTyped(t Type) bool {
	// Alias and named types cannot denote untyped types
	// so there's no need to call Unalias or under, below.
	b, _ := t.(*Basic)

		} else {
			offs = -1 // f.typ or offs is too large
		}
	}
	return offsets
}

func (s *gcSizes) Sizeof(T Type) int64 {
	switch t := under(T).(type) {
	case *Basic:
		assert(isTyped(T))
		k := t.kind
		if int(k) < len(basicSizes) {
			if s := basicSizes[k]; s > 0 {
				return int64(s)
			}
		}
		if k == String {
			return s.WordSize * 2
		}
	case *Array:
		n := t.len

		} else {
			offs = -1 // f.typ or offs is too large
		}
	}
	return offsets
}

func (s *gcSizes) Sizeof(T Type) int64 {
	switch t := under(T).(type) {
	case *Basic:
		assert(isTyped(T))
		k := t.kind
		if int(k) < len(basicSizes) {
			if s := basicSizes[k]; s > 0 {
				return int64(s)
			}
		}
		if k == String {
			return s.WordSize * 2
		}
	case *Array:
		n := t.len

func (check *Checker) recordCommaOkTypes(x syntax.Expr, a []*operand) {
	assert(x != nil)
	assert(len(a) == 2)
	if a[0].mode == invalid {
		return
	}
	t0, t1 := a[0].typ, a[1].typ
	assert(isTyped(t0) && isTyped(t1) && (allBoolean(t1) || t1 == universeError))
	if m := check.Types; m != nil {
		for {
			tv := m[x]
			assert(tv.Type != nil) // should have been recorded already
			pos := x.Pos()
			tv.Type = NewTuple(

func (check *Checker) recordCommaOkTypes(x ast.Expr, a []*operand) {
	assert(x != nil)
	assert(len(a) == 2)
	if a[0].mode == invalid {
		return
	}
	t0, t1 := a[0].typ, a[1].typ
	assert(isTyped(t0) && isTyped(t1) && (allBoolean(t1) || t1 == universeError))
	if m := check.Types; m != nil {
		for {
			tv := m[x]
			assert(tv.Type != nil) // should have been recorded already
			pos := x.Pos()
			tv.Type = NewTuple(

		return
	}

	// Typed constants must be representable in
	// their type after each constant operation.
	// x.typ cannot be a type parameter (type
	// parameters cannot be constant types).
	if isTyped(x.typ) {
		check.representable(x, under(x.typ).(*Basic))
		return
	}

	// Untyped integer values must not grow arbitrarily.
	const prec = 512 // 512 is the constant precision

// before any components of e are type-checked.
func (check *Checker) definedType(e syntax.Expr, def *TypeName) Type {
	typ := check.typInternal(e, def)
	assert(isTyped(typ))
	if isGeneric(typ) {
		check.errorf(e, WrongTypeArgCount, "cannot use generic type %s without instantiation", typ)
		typ = Typ[Invalid]
	}
	check.recordTypeAndValue(e, typexpr, typ, nil)
	return typ
}

// before any components of e are type-checked.
func (check *Checker) definedType(e ast.Expr, def *TypeName) Type {
	typ := check.typInternal(e, def)
	assert(isTyped(typ))
	if isGeneric(typ) {
		check.errorf(e, WrongTypeArgCount, "cannot use generic type %s without instantiation", typ)
		typ = Typ[Invalid]
	}
	check.recordTypeAndValue(e, typexpr, typ, nil)
	return typ
}

		return
	}

	// Typed constants must be representable in
	// their type after each constant operation.
	// x.typ cannot be a type parameter (type
	// parameters cannot be constant types).
	if isTyped(x.typ) {
		check.representable(x, under(x.typ).(*Basic))
		return
	}

	// Untyped integer values must not grow arbitrarily.
	const prec = 512 // 512 is the constant precision