func (t *Interface) cleanup() {
	t.typeSet() // any interface that escapes type checking must be safe for concurrent use
	t.check = nil
	t.embedPos = nil
}

func (check *Checker) interfaceType(ityp *Interface, iface *syntax.InterfaceType, def *TypeName) {
	addEmbedded := func(pos syntax.Pos, typ Type) {
		ityp.embeddeds = append(ityp.embeddeds, typ)
		if ityp.embedPos == nil {
			ityp.embedPos = new([]syntax.Pos)
		}

				m = n.ElemList[0]
				continue
			}
			return n.Pos()
		// types
		// case *ArrayType:
		// case *SliceType:
		// case *DotsType:
		// case *StructType:
		// case *Field:
		// case *InterfaceType:
		// case *FuncType:
		// case *MapType:
		// case *ChanType:

		// statements
		// case *EmptyStmt:
		// case *LabeledStmt:
		// case *BlockStmt:
		// case *ExprStmt:
		case *SendStmt:

func (t *Interface) cleanup() {
	t.typeSet() // any interface that escapes type checking must be safe for concurrent use
	t.check = nil
	t.embedPos = nil
}

func (check *Checker) interfaceType(ityp *Interface, iface *ast.InterfaceType, def *TypeName) {
	addEmbedded := func(pos token.Pos, typ Type) {
		ityp.embeddeds = append(ityp.embeddeds, typ)
		if ityp.embedPos == nil {
			ityp.embedPos = new([]token.Pos)
		}

	"go/token"
	"io/fs"
	"os"
	"path/filepath"
	"runtime"
	"strings"
	"sync"
	"testing"
)

var typeNames = []string{
	"uncommonType",
	"arrayType",
	"chanType",
	"funcType",
	"interfaceType",
	"ptrType",
	"sliceType",
	"structType",
}

type visitor struct {
	m map[string]map[string]bool
}

func newVisitor() visitor {
	v := visitor{}
	v.m = make(map[string]map[string]bool)

		return 1 << nImportSpec
	case *ast.IncDecStmt:
		return 1 << nIncDecStmt
	case *ast.IndexExpr:
		return 1 << nIndexExpr
	case *ast.IndexListExpr:
		return 1 << nIndexListExpr
	case *ast.InterfaceType:
		return 1 << nInterfaceType
	case *ast.KeyValueExpr:
		return 1 << nKeyValueExpr
	case *ast.LabeledStmt:
		return 1 << nLabeledStmt
	case *ast.MapType:
		return 1 << nMapType
	case *ast.Package:

		buf.WriteString("struct{")
		writeFieldList(buf, x.Fields.List, "; ", false)
		buf.WriteByte('}')

	case *ast.FuncType:
		buf.WriteString("func")
		writeSigExpr(buf, x)

	case *ast.InterfaceType:
		buf.WriteString("interface{")
		writeFieldList(buf, x.Methods.List, "; ", true)
		buf.WriteByte('}')

	case *ast.MapType:
		buf.WriteString("map[")
		WriteExpr(buf, x.Key)
		buf.WriteByte(']')

		}
		return fmt.Sprintf("types.NewChan(%s, %s)", i.subtype(t.Value), dir)
	case *ast.FuncType:
		return fmt.Sprintf("newSig(%s, %s)", i.fields(t.Params, false), i.fields(t.Results, false))
	case *ast.InterfaceType:
		if len(t.Methods.List) != 0 {
			log.Fatal("non-empty interfaces unsupported")
		}
		return "types.Types[types.TINTER]"
	case *ast.MapType:

		for _, t := range n.TagList {
			if t != nil {
				w.node(t)
			}
		}

	case *Field:
		if n.Name != nil {
			w.node(n.Name)
		}
		w.node(n.Type)

	case *InterfaceType:
		w.fieldList(n.MethodList)

	case *FuncType:
		w.fieldList(n.ParamList)
		w.fieldList(n.ResultList)

	case *MapType:
		w.node(n.Key)
		w.node(n.Value)

	case *ChanType:

	case *FuncType:
		if n.TypeParams != nil {
			Walk(v, n.TypeParams)
		}
		if n.Params != nil {
			Walk(v, n.Params)
		}
		if n.Results != nil {
			Walk(v, n.Results)
		}

	case *InterfaceType:
		Walk(v, n.Methods)

	case *MapType:
		Walk(v, n.Key)
		Walk(v, n.Value)

	case *ChanType:
		Walk(v, n.Value)

	// Statements
	case *BadStmt:
		// nothing to do

		Type Expr  // field names declared in a list share the same Type (identical pointers)
		node
	}

	// interface { MethodList[0]; MethodList[1]; ... }
	InterfaceType struct {
		MethodList []*Field
		expr
	}

	FuncType struct {
		ParamList  []*Field
		ResultList []*Field
		expr
	}

	// map[Key]Value
	MapType struct {
		Key, Value Expr