// accessed.
	methods []*Func

	// loader may be provided to lazily load type parameters, underlying type, and methods.
	loader func(*Named) (tparams []*TypeParam, underlying Type, methods []*Func)
}

// instance holds information that is only necessary for instantiated named
// types.
type instance struct {
	orig            *Named    // original, uninstantiated type

      return Types.newArtificialTypeVariable(WildcardCapturer.class, name, upperBounds);
    }

    private WildcardCapturer forTypeVariable(TypeVariable<?> typeParam) {
      return new WildcardCapturer(id) {
        @Override
        TypeVariable<?> captureAsTypeVariable(Type[] upperBounds) {
          Set<Type> combined = new LinkedHashSet<>(asList(upperBounds));

        when:
        fails()

        then:
        failure.assertHasCause("Please use the ObjectFactory.$method method to create a property of type $type$typeParam.")

        where:
        prop    | method                | type          | typeParam
        'prop1' | 'listProperty()'      | 'List'        | '<T>'
        'prop2' | 'setProperty()'       | 'Set'         | '<T>'

		if t, _ := t.(*Interface); t != nil {
			t.implicit = true
		}
		return t
	}
	return check.typ(x)
}

func (check *Checker) declareTypeParams(tparams []*TypeParam, names []*ast.Ident, scopePos token.Pos) []*TypeParam {
	// Use Typ[Invalid] for the type constraint to ensure that a type
	// is present even if the actual constraint has not been assigned
	// yet.

      return Types.newArtificialTypeVariable(WildcardCapturer.class, name, upperBounds);
    }

    private WildcardCapturer forTypeVariable(TypeVariable<?> typeParam) {
      return new WildcardCapturer(id) {
        @Override
        TypeVariable<?> captureAsTypeVariable(Type[] upperBounds) {
          Set<Type> combined = new LinkedHashSet<>(asList(upperBounds));

		}
	}

	testenv.MustHaveGoBuild(t)

	tmpdir := mktmpdir(t)
	defer os.RemoveAll(tmpdir)

	// Check go files in test/typeparam, except those that fail for a known
	// reason.
	rootDir := filepath.Join(gorootTest, "typeparam")
	list, err := os.ReadDir(rootDir)
	if err != nil {
		t.Fatal(err)
	}

	for _, entry := range list {

	if typ == nil || seen[typ] {
		return nil
	}
	if seen == nil {
		seen = make(map[types.Type]bool)
	}
	seen[typ] = true

	if tpar, ok := aliases.Unalias(typ).(*types.TypeParam); ok {
		terms, err := typeparams.StructuralTerms(tpar)
		if err != nil {
			return nil // invalid type
		}
		for _, term := range terms {
			subpath := lockPath(tpkg, term.Type(), seen)

		// TODO(gri) report detailed failure cause for better error messages
		var key, elem Type // key != nil: we must have all maps
		mode := variable   // non-maps result mode
		// TODO(gri) factor out closure and use it for non-typeparam cases as well
		if typ.typeSet().underIs(func(u Type) bool {
			l := int64(-1) // valid if >= 0
			var k, e Type  // k is only set for maps
			switch t := u.(type) {
			case *Basic:
				if isString(t) {

		// TODO(gri) report detailed failure cause for better error messages
		var key, elem Type // key != nil: we must have all maps
		mode := variable   // non-maps result mode
		// TODO(gri) factor out closure and use it for non-typeparam cases as well
		if typ.typeSet().underIs(func(u Type) bool {
			l := int64(-1) // valid if >= 0
			var k, e Type  // k is only set for maps
			switch t := u.(type) {
			case *Basic:
				if isString(t) {

	if check != nil {
		check.error(atPos(pos), WrongTypeArgCount, msg)
		return false
	}

	panic(fmt.Sprintf("%v: %s", pos, msg))
}

func (check *Checker) verify(pos syntax.Pos, tparams []*TypeParam, targs []Type, ctxt *Context) (int, error) {
	smap := makeSubstMap(tparams, targs)
	for i, tpar := range tparams {
		// Ensure that we have a (possibly implicit) interface as type bound (go.dev/issue/51048).
		tpar.iface()