// parameters, and results, any of which may be nil.
func NewSignature(recv *Field, params, results []*Field) *Type {
	startParams := 0
	if recv != nil {
		startParams = 1
	}
	startResults := startParams + len(params)

	allParams := make([]*Field, startResults+len(results))
	if recv != nil {
		allParams[0] = recv
	}
	copy(allParams[startParams:], params)
	copy(allParams[startResults:], results)

				}
				if cause != "" {
					check.errorf(recv, InvalidRecv, "invalid receiver type %s (%s)", rtyp, cause)
				}
			case *Basic:
				check.errorf(recv, InvalidRecv, "cannot define new methods on non-local type %s", rtyp)
			default:
				check.errorf(recv, InvalidRecv, "invalid receiver type %s", recv.typ)
			}
		}).describef(recv, "validate receiver %s", recv)
	}

	sig.params = NewTuple(params...)

//
// Example: "(*Buffer).Grow" -> (true, "Buffer", "Grow")
func (sym *Symbol) SplitMethod() (ptr bool, recv, name string) {
	if sym.Kind != Method {
		panic("not a method")
	}
	recv, name, _ = strings.Cut(sym.Name, ".")
	recv = recv[len("(") : len(recv)-len(")")]
	ptr = recv[0] == '*'
	if ptr {
		recv = recv[len("*"):]
	}
	return

func (s *Selection) Type() Type {
	switch s.kind {
	case MethodVal:
		// The type of x.f is a method with its receiver type set
		// to the type of x.
		sig := *s.obj.(*Func).typ.(*Signature)
		recv := *sig.recv
		recv.typ = s.recv
		sig.recv = &recv
		return &sig

	case MethodExpr:
		// The type of x.f is a function (without receiver)
		// and an additional first argument with the same type as x.

func (s *Selection) Type() Type {
	switch s.kind {
	case MethodVal:
		// The type of x.f is a method with its receiver type set
		// to the type of x.
		sig := *s.obj.(*Func).typ.(*Signature)
		recv := *sig.recv
		recv.typ = s.recv
		sig.recv = &recv
		return &sig

	case MethodExpr:
		// The type of x.f is a function (without receiver)
		// and an additional first argument with the same type as x.

func NewMethodType(sig *types.Type, recv *types.Type) *types.Type {
	nrecvs := 0
	if recv != nil {
		nrecvs++
	}

	// TODO(mdempsky): Move this function to types.
	// TODO(mdempsky): Preserve positions, names, and package from sig+recv.

	params := make([]*types.Field, nrecvs+sig.NumParams())
	if recv != nil {
		params[0] = types.NewField(base.Pos, nil, recv)
	}
	for i, param := range sig.Params() {

		// Call the ServeHTTP to execute the handler.
		apiRouter.ServeHTTP(recV2, reqV2)
		if recV2.Code != testCase.expectedRespStatus {
			t.Errorf("Test %d: %s: Expected the response status to be `%d`, but instead found `%d`", i+1, instanceType, testCase.expectedRespStatus, recV2.Code)
		}

		errorResponse = APIErrorResponse{}
		err = xml.Unmarshal(recV2.Body.Bytes(), &errorResponse)
		if err != nil && !testCase.shouldPass {

		argidx := -1

		recv := fn.Type().(*types.Signature).Recv()
		if fn.Name() == "Unmarshal" && recv == nil {
			// "encoding/json".Unmarshal
			// "encoding/xml".Unmarshal
			// "encoding/asn1".Unmarshal
			switch fn.Pkg().Path() {
			case "encoding/json", "encoding/xml", "encoding/asn1":
				argidx = 1 // func([]byte, interface{})
			}
		} else if fn.Name() == "Decode" && recv != nil {

		// Call the ServeHTTP to execute the handler.
		apiRouter.ServeHTTP(recV2, reqV2)
		if recV2.Code != testCase.expectedRespStatus {
			t.Errorf("Test %d: %s: Expected the response status to be `%d`, but instead found `%d`", i+1, instanceType, testCase.expectedRespStatus, recV2.Code)
		}

		// read the response body.
		actualContent, err = io.ReadAll(recV2.Body)
		if err != nil {

	if f, ok := Callee(info, call).(*types.Func); ok && !interfaceMethod(f) {
		return f
	}
	return nil
}

func interfaceMethod(f *types.Func) bool {
	recv := f.Type().(*types.Signature).Recv()
	return recv != nil && types.IsInterface(recv.Type())