The methods [Alias.Origin], [Alias.SetTypeParams], [Alias.TypeParams],

	if !Vnamed || !Tnamed {
		return types.AssignableTo(V, T)
	}

	vtparams := VN.TypeParams()
	ttparams := TN.TypeParams()
	if vtparams.Len() == 0 || vtparams.Len() != ttparams.Len() || VN.TypeArgs().Len() != 0 || TN.TypeArgs().Len() != 0 {
		return types.AssignableTo(V, T)
	}

	// V and T have the same (non-zero) number of type params. Instantiate both
	// with the type parameters of V. This must always succeed for V, and will

		// TODO(gri) do we need this for Alias types?
		if t.TypeArgs().Len() != n {
			return Typ[Invalid] // error reported elsewhere
		}

		// already instantiated
		// For each (existing) type argument determine if it needs
		// to be substituted; i.e., if it is or contains a type parameter
		// that has a type argument for it.
		targs, updated := subst.typeList(t.TypeArgs().list())
		if updated {

		// TODO(gri) do we need this for Alias types?
		if t.TypeArgs().Len() != n {
			return Typ[Invalid] // error reported elsewhere
		}

		// already instantiated
		// For each (existing) type argument determine if it needs
		// to be substituted; i.e., if it is or contains a type parameter
		// that has a type argument for it.
		targs, updated := subst.typeList(t.TypeArgs().list())
		if updated {

func (a *Alias) SetTypeParams(tparams []*TypeParam) {
	assert(a.targs == nil)
	a.tparams = bindTParams(tparams)
}

// TypeArgs returns the type arguments used to instantiate the Alias type.
// If a is not an instance of a generic alias, the result is nil.
func (a *Alias) TypeArgs() *TypeList { return a.targs }

// Rhs returns the type R on the right-hand side of an alias
// declaration "type A = R", which may be another alias.

func (a *Alias) SetTypeParams(tparams []*TypeParam) {
	assert(a.targs == nil)
	a.tparams = bindTParams(tparams)
}

// TypeArgs returns the type arguments used to instantiate the Alias type.
// If a is not an instance of a generic alias, the result is nil.
func (a *Alias) TypeArgs() *TypeList { return a.targs }

// Rhs returns the type R on the right-hand side of an alias
// declaration "type A = R", which may be another alias.

		// and so it must be resolved during type-checking so that we can report
		// errors.
		check.recordInstance(ix.Orig, inst.TypeArgs().list(), inst)

		if check.validateTArgLen(ix.Pos(), inst.obj.name, inst.TypeParams().Len(), inst.TypeArgs().Len()) {
			if i, err := check.verify(ix.Pos(), inst.TypeParams().list(), inst.TypeArgs().list(), check.context()); err != nil {
				// best position for error reporting
				pos := ix.Pos()

// t must not have type arguments.
func (t *Named) SetTypeParams(tparams []*TypeParam) {
	assert(t.inst == nil)
	t.resolve().tparams = bindTParams(tparams)
}

// TypeArgs returns the type arguments used to instantiate the named type t.
func (t *Named) TypeArgs() *TypeList {
	if t.inst == nil {
		return nil
	}
	return t.inst.targs
}

// NumMethods returns the number of explicit methods defined for t.

// t must not have type arguments.
func (t *Named) SetTypeParams(tparams []*TypeParam) {
	assert(t.inst == nil)
	t.resolve().tparams = bindTParams(tparams)
}

// TypeArgs returns the type arguments used to instantiate the named type t.
func (t *Named) TypeArgs() *TypeList {
	if t.inst == nil {
		return nil
	}
	return t.inst.targs
}

// NumMethods returns the number of explicit methods defined for t.

		// and so it must be resolved during type-checking so that we can report
		// errors.
		check.recordInstance(x, inst.TypeArgs().list(), inst)

		if check.validateTArgLen(x.Pos(), inst.obj.name, inst.TypeParams().Len(), inst.TypeArgs().Len()) {
			if i, err := check.verify(x.Pos(), inst.TypeParams().list(), inst.TypeArgs().list(), check.context()); err != nil {
				// best position for error reporting
				pos := x.Pos()
				if i < len(xlist) {