this
        }
    }

    static class UnsupportedNotation extends ValidationMessageDisplayConfiguration<UnsupportedNotation> {
        String type
        String value
        String targetType

        UnsupportedNotation(ValidationMessageChecker checker) {
            super(checker)
        }

        UnsupportedNotation value(String value, String type = 'DefaultTask') {

        """

        expect:
        fails "test"
        failure.assertHasDescription("A problem was found with the configuration of task ':test' (type 'DefaultTask').")
        failureDescriptionContains(unsupportedNotation {
            property('input')
                .value("task ':dependencyTask'")
                .cannotBeConvertedTo(targetType)
                .candidates(

Possible solution: Make sure that the root of the file tree 'output' is configured to a directory.

${validationMessage("cannot_write_output")}
"""
    }

    def "tests output of unsupportedNotation"() {
        when:
        render unsupportedNotation {
            type('Human').property('face')
            value('visible', 'person')
            candidates("a mask", "a vaccine")
            cannotBeConvertedTo('safe person')

            reportUnsupportedValue(propertyName, context, targetType, value.get(), unsupportedNotationException.getCandidates());
        }
    }

    private static final String UNSUPPORTED_NOTATION = "UNSUPPORTED_NOTATION";

    private static void reportUnsupportedValue(String propertyName, PropertyValidationContext context, String targetType, Object value, Collection<String> candidates) {

If you didn't intend to write in this directory, you should simply setup your task to write in a different location.

[[unsupported_notation]]
== Unsupported notation in file inputs

This error indicates that a file, directory, collection of files, or a nested collection of files property, refers to an element that Gradle cannot convert to a file.