}
    }

    @Override
    public void set(@Nullable T value) {
        if (value == null) {
            discardValue();
        } else {
            setSupplier(Providers.fixedValue(getValidationDisplayName(), value, type, sanitizer));
        }
    }

    @Override
    public Property<T> value(@Nullable T value) {
        set(value);
        return this;
    }

    @Override

        }

        @Override
        public void calculateExecutionTimeValue(Action<? super ExecutionTimeValue<? extends Iterable<? extends T>>> visitor) {
            visitor.execute(ExecutionTimeValue.fixedValue(ImmutableList.of(element)));
        }

        @Override
        public ValueProducer getProducer() {
            return ValueProducer.unknown();
        }

        @Override

                writeByte(2)
                write(value.fixedValue)
            }

            value.hasFixedValue() && sideEffect != null -> {
                // Can serialize a fixed value and discard the provider
                // TODO - should preserve information about the source, for diagnostics at execution time
                writeByte(3)
                write(value.fixedValue)
                write(sideEffect)
            }

            return this;
        }

        @Override
        public ExecutionTimeValue<? extends C> calculateExecutionTimeValue() {
            return ExecutionTimeValue.fixedValue(emptyCollection());
        }

        @Override
        public ValueProducer getProducer() {
            return ValueProducer.noProducer();
        }

        @Override

            return new CollectingSupplier(collector);
        }

        @Override
        public ExecutionTimeValue<? extends Map<K, V>> calculateExecutionTimeValue() {
            return ExecutionTimeValue.fixedValue(ImmutableMap.of());
        }

        @Override
        public ValueProducer getProducer() {
            return ValueProducer.noProducer();
        }

        @Override

        property.addAll(["c"])

        expect:
        assertHasNoProducer(property)
        def value = property.calculateExecutionTimeValue()
        value.hasFixedValue()
        value.fixedValue == toImmutable(["a", "b", "c"])
    }

    def "has no producer and fixed execution time value when element provider added"() {
        given:
        property.add(supplierWithValues("a"))

        def mapped = property.map { someOtherValue() }

        expect:
        assertHasNoProducer(mapped)
        def value = mapped.calculateExecutionTimeValue()
        value.hasFixedValue()
        value.fixedValue == someOtherValue()

        property.attachProducer(owner(task))

        assertHasProducer(mapped, task)
        def value2 = mapped.calculateExecutionTimeValue()
        value2.isChangingValue()