return nil, err
	}

	bodyLen := t.body.Len()

	class := ClassUniversal
	if params.tag != nil {
		if params.application {
			class = ClassApplication
		} else if params.private {
			class = ClassPrivate
		} else {
			class = ClassContextSpecific
		}

		if params.explicit {
			t.tag = bytesEncoder(appendTagAndLength(t.scratch[:0], tagAndLength{ClassUniversal, tag, bodyLen, isCompound}))

		expectedClass = ClassApplication
		expectedTag = *params.tag
		matchAnyClassAndTag = false
	}

	if !params.explicit && params.private && params.tag != nil {
		expectedClass = ClassPrivate
		expectedTag = *params.tag
		matchAnyClassAndTag = false
	}

	// We have unwrapped any explicit tagging at this point.
	if !matchAnyClassAndTag && (t.class != expectedClass || t.tag != expectedTag) ||

		{true, []byte{0x30, 3, (ClassContextSpecific << 6) | tag | isCompound, 1, 1}},
		{false, []byte{0x30, 3, (ClassApplication << 6) | tag | isCompound, 1, 1}},
		{false, []byte{0x30, 3, (ClassPrivate << 6) | tag | isCompound, 1, 1}},
	}

	for i, test := range tests {
		var tagged taggedRawValue
		if _, err := Unmarshal(test.derBytes, &tagged); (err == nil) != test.shouldMatch {

		{"BitString", Type, 0},
		{"BitString.BitLength", Field, 0},
		{"BitString.Bytes", Field, 0},
		{"ClassApplication", Const, 6},
		{"ClassContextSpecific", Const, 6},
		{"ClassPrivate", Const, 6},
		{"ClassUniversal", Const, 6},
		{"Enumerated", Type, 0},
		{"Flag", Type, 0},
		{"Marshal", Func, 0},
		{"MarshalWithParams", Func, 10},
		{"NullBytes", Var, 9},