// unnecessary, but we leave it for hash readability. It can be removed later
	// if performance is an issue.
	h.typ(orig)
	if len(targs) > 0 {
		// TODO(rfindley): consider asserting on isGeneric(typ) here, if and when
		// isGeneric handles *Signature types.
		h.typeList(targs)
	}

	return strings.ReplaceAll(buf.String(), " ", "#")
}

// lookup returns an existing instantiation of orig with targs, if it exists.

	// unnecessary, but we leave it for hash readability. It can be removed later
	// if performance is an issue.
	h.typ(orig)
	if len(targs) > 0 {
		// TODO(rfindley): consider asserting on isGeneric(typ) here, if and when
		// isGeneric handles *Signature types.
		h.typeList(targs)
	}

	return strings.ReplaceAll(buf.String(), " ", "#")
}

// lookup returns an existing instantiation of orig with targs, if it exists.

// 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 iface != nil && iface.tset != nil && iface.tset.IsEmpty()
	}
	return false
}

// isGeneric reports whether a type is a generic, uninstantiated type
// (generic signatures are not included).
// TODO(gri) should we include signatures or assert that they are not present?
func isGeneric(t Type) bool {
	// A parameterized type is only generic if it doesn't have an instantiation already.

		return iface != nil && iface.tset != nil && iface.tset.IsEmpty()
	}
	return false
}

// isGeneric reports whether a type is a generic, uninstantiated type
// (generic signatures are not included).
// TODO(gri) should we include signatures or assert that they are not present?
func isGeneric(t Type) bool {
	// A parameterized type is only generic if it doesn't have an instantiation already.

	if x.mode == constant_ {
		if s := x.val.String(); s != expr {
			buf.WriteByte(' ')
			buf.WriteString(s)
		}
	}

	// <typ>
	if hasType {
		if isValid(x.typ) {
			var intro string
			if isGeneric(x.typ) {
				intro = " of generic type "
			} else {
				intro = " of type "
			}
			buf.WriteString(intro)
			WriteType(&buf, x.typ, qf)
			if tpar, _ := Unalias(x.typ).(*TypeParam); tpar != nil {

	if x.mode == constant_ {
		if s := x.val.String(); s != expr {
			buf.WriteByte(' ')
			buf.WriteString(s)
		}
	}

	// <typ>
	if hasType {
		if isValid(x.typ) {
			var intro string
			if isGeneric(x.typ) {
				intro = " of generic type "
			} else {
				intro = " of type "
			}
			buf.WriteString(intro)
			WriteType(&buf, x.typ, qf)
			if tpar, _ := Unalias(x.typ).(*TypeParam); tpar != nil {

		case *TypeName:
			// If we reach a generic type that is part of a cycle
			// and we are in a type parameter list, we have a cycle
			// through a type parameter list, which is invalid.
			if check.inTParamList && isGeneric(obj.typ) {
				tparCycle = true
				break loop
			}

			// Determine if the type name is an alias or not. For
			// package-level objects, use the object map which

		case *TypeName:
			// If we reach a generic type that is part of a cycle
			// and we are in a type parameter list, we have a cycle
			// through a type parameter list, which is invalid.
			if check.inTParamList && isGeneric(obj.typ) {
				tparCycle = true
				break loop
			}

			// Determine if the type name is an alias or not. For
			// package-level objects, use the object map which