into:          struct{}{},
			assertOnError: assertIdenticalError(&cbor.DupMapKeyError{Key: int64(-1), Index: 1}),
		},
		{
			name:          "reject duplicate negative int keys into map",
			in:            hex("a220012002"), // {-1: 1, -1: 2}
			into:          map[int64]interface{}{},
			assertOnError: assertIdenticalError(&cbor.DupMapKeyError{Key: int64(-1), Index: 1}),
		},
		{

		if got == nil {
			t.Error("expected non-nil error")
			return
		}
		if got.Error() != want {
			t.Errorf("got error %q, want %q", got.Error(), want)
		}
	}
}

func assertIdenticalError[E error](expected E) func(*testing.T, error) {
	return assertOnConcreteError(func(t *testing.T, actual E) {
		if diff := cmp.Diff(expected, actual); diff != "" {