private final Value<? extends C> value;

        public NoValueSupplier(Value<? extends C> value) {
            assert value.isMissing();
            this.value = value.asType();
        }

        @Override
        public CollectionSupplier<T, C> absentIgnoring() {
            return Cast.uncheckedCast(emptySupplier());
        }

        @Override

		if isParameterized(tparams, par.typ) || isParameterized(tparams, arg.typ) {
			// Function parameters are always typed. Arguments may be untyped.
			// Collect the indices of untyped arguments and handle them later.
			if isTyped(arg.typ) {
				if !u.unify(par.typ, arg.typ, assign) {
					errorf(par.typ, arg.typ, arg)
					return nil
				}
			} else if _, ok := par.typ.(*TypeParam); ok && !arg.isNil() {

		if isParameterized(tparams, par.typ) || isParameterized(tparams, arg.typ) {
			// Function parameters are always typed. Arguments may be untyped.
			// Collect the indices of untyped arguments and handle them later.
			if isTyped(arg.typ) {
				if !u.unify(par.typ, arg.typ, assign) {
					errorf(par.typ, arg.typ, arg)
					return nil
				}
			} else if _, ok := par.typ.(*TypeParam); ok && !arg.isNil() {

         * CRC32C to Checksum. This may carry some performance cost
         * (https://stackoverflow.com/a/22321671/28465), but I'd have to benchmark more carefully to
         * even detect it.
         */
        return MethodHandles.lookup()
            .findConstructor(clazz, methodType(void.class))
            .asType(methodType(Checksum.class));

	// not compatible, we report a type mismatch error.
	mayConvert := func(x, y *operand) bool {
		// If both operands are typed, there's no need for an implicit conversion.
		if isTyped(x.typ) && isTyped(y.typ) {
			return false
		}
		// An untyped operand may convert to its default type when paired with an empty interface
		// TODO(gri) This should only matter for comparisons (the only binary operation that is

	// not compatible, we report a type mismatch error.
	mayConvert := func(x, y *operand) bool {
		// If both operands are typed, there's no need for an implicit conversion.
		if isTyped(x.typ) && isTyped(y.typ) {
			return false
		}
		// An untyped operand may convert to its default type when paired with an empty interface
		// TODO(gri) This should only matter for comparisons (the only binary operation that is

Working with files::
 * You can no longer cast `FileCollection` objects to other types using the `as` keyword or the `asType()` method.
 * You can no longer pass `null` as the configuration action of link:{javadocPath}/org/gradle/api/file/CopySpec.html#from-java.lang.Object-org.gradle.api.Action-[CopySpec.from(Object, Action)].

		return r
	}
	return t
}

func (t *Typed) GoString() string {
	return t.goString(0, "")
}

func (t *Typed) goString(indent int, field string) string {
	return fmt.Sprintf("%*s%sTyped:\n%s\n%s", indent, "", field,
		t.Name.goString(indent+2, "Name: "),
		t.Type.goString(indent+2, "Type: "))
}

// Qualified is a name in a scope.
type Qualified struct {
	Scope AST
	Name  AST