import (
	"fmt"
	"internal/testenv"
	"strings"
	"testing"

	. "go/types"
)

func TestIsAlias(t *testing.T) {
	check := func(obj *TypeName, want bool) {
		if got := obj.IsAlias(); got != want {
			t.Errorf("%v: got IsAlias = %v; want %v", obj, got, want)
		}
	}

	// predeclared types
	check(Unsafe.Scope().Lookup("Pointer").(*TypeName), false)
	for _, name := range Universe.Names() {

	"fmt"
	"internal/testenv"
	"strings"
	"testing"

	. "cmd/compile/internal/types2"
)

func TestIsAlias(t *testing.T) {
	check := func(obj *TypeName, want bool) {
		if got := obj.IsAlias(); got != want {
			t.Errorf("%v: got IsAlias = %v; want %v", obj, got, want)
		}
	}

	// predeclared types
	check(Unsafe.Scope().Lookup("Pointer").(*TypeName), false)
	for _, name := range Universe.Names() {

	obj := NewTypeName(pos, pkg, name, nil)
	NewNamed(obj, nil, nil).loader = load
	return obj
}

// IsAlias reports whether obj is an alias name for a type.
func (obj *TypeName) IsAlias() bool {
	switch t := obj.typ.(type) {
	case nil:
		return false
	// case *Alias:
	//	handled by default case
	case *Basic:
		// unsafe.Pointer is not an alias.

	obj := NewTypeName(pos, pkg, name, nil)
	NewNamed(obj, nil, nil).loader = load
	return obj
}

// IsAlias reports whether obj is an alias name for a type.
func (obj *TypeName) IsAlias() bool {
	switch t := obj.typ.(type) {
	case nil:
		return false
	// case *Alias:
	//	handled by default case
	case *Basic:
		// unsafe.Pointer is not an alias.

			// this information explicitly in the object.
			var alias bool
			if check.conf._EnableAlias {
				alias = obj.IsAlias()
			} else {
				if d := check.objMap[obj]; d != nil {
					alias = d.tdecl.Assign.IsValid() // package-level object
				} else {
					alias = obj.IsAlias() // function local object
				}
			}
			if !alias {
				ndef++
			}
		case *Func:
			// ignored for now

			// this information explicitly in the object.
			var alias bool
			if check.conf.EnableAlias {
				alias = obj.IsAlias()
			} else {
				if d := check.objMap[obj]; d != nil {
					alias = d.tdecl.Alias // package-level object
				} else {
					alias = obj.IsAlias() // function local object
				}
			}
			if !alias {
				ndef++
			}
		case *Func:
			// ignored for now
		default:

	// parameters that it's implicitly parameterized by.
	for scope := obj.Parent(); scope != root; scope = scope.Parent() {
		for _, elem := range scope.elems {
			if elem, ok := elem.(*TypeName); ok && !elem.IsAlias() && cmpPos(elem.Pos(), obj.Pos()) < 0 {
				if tpar, ok := elem.Type().(*TypeParam); ok {
					if idx < 0 {
						idx = len(w.vertices)
						w.vertices = append(w.vertices, monoVertex{obj: obj})
					}

	}

	switch x := x.(type) {
	case *Basic:
		// Basic types are singletons except for the rune and byte
		// aliases, thus we cannot solely rely on the x == y check
		// above. See also comment in TypeName.IsAlias.
		if y, ok := y.(*Basic); ok {
			return x.kind == y.kind
		}

	case *Array:
		// Two array types are identical if they have identical element types
		// and the same array length.

	}

	switch x := x.(type) {
	case *Basic:
		// Basic types are singletons except for the rune and byte
		// aliases, thus we cannot solely rely on the x == y check
		// above. See also comment in TypeName.IsAlias.
		if y, ok := y.(*Basic); ok {
			return x.kind == y.kind
		}

	case *Array:
		// Two array types are identical if they have identical element types
		// and the same array length.

		tname, ok := o.(*types.TypeName)
		if !ok {
			continue // handle non-types in second pass
		}

		path := append(empty, o.Name()...)
		path = append(path, opType)

		T := o.Type()

		if tname.IsAlias() {
			// type alias
			if r := find(obj, T, path, nil); r != nil {
				return Path(r), nil
			}
		} else {
			if named, _ := T.(*types.Named); named != nil {