If you are using Groovy, it's likely that you unintentionally added the `private` modifier to a property declaration:

```groovy
@InputFile
RegularFileProperty inputFile // this is a public property

@InputFile
private RegularFileProperty inputFile // this is a field, remove the `private` modifier
```

[[ignored_annotations_on_method]]
== Invalid annotation on method

        def changes = [
            inputProperty: { String property ->
                inputProperties[property] = inputProperties[property] + ' changed'
            },
            inputFile: { String property ->
                inputFiles[property] << ' changed'
            },
            outputFile: { String property ->
                outputFiles[property] << ' changed'
            }
        ]

abstract class AllTypes extends DefaultTask {

    //inputs
    @Input
    final abstract Property<String> inputString = ""
    @InputFile
    final abstract RegularFileProperty inputFile = ""
    @InputDirectory
    final abstract DirectoryProperty inputDirectory = ""
    @InputFiles
    final abstract ConfigurableFileCollection inputFileCollection = ""
    @Classpath

		skipAll: true,
	},
	{
		name:       "deprecation",
		inputFiles: []string{"testdata/deprecation.yaml"},
		analyzer:   &deprecation.FieldAnalyzer{},
		expected: []message{
			{msg.Deprecated, "VirtualService foo/productpage"},
			{msg.Deprecated, "Sidecar default/no-selector"},
		},
	},
	{
		name:       "externalControlPlaneMissingWebhooks",
		inputFiles: []string{"testdata/externalcontrolplane-missing-urls.yaml"},

    public File getInputFile() {
        return inputFile != null ? inputFile : getOutputFile();
    }

    // Workaround for when the task is given an input file that doesn't exist
    @Nullable  @Optional
    @PathSensitive(PathSensitivity.NONE)
    @InputFile
    protected File getInputFileIfExists() {
        File inputFile = getInputFile();
        if (inputFile != null && inputFile.exists()) {
            return inputFile;

        def inputFile = file("input.txt")
        buildFile << """
            def inputFile = file("input.txt")
            def outputFile = file("build/output.txt")

            task consumer {
                inputs.file(inputFile)
                outputs.file(outputFile)
                doLast {
                    outputFile.text = inputFile.text
                }

                def go() { }
            }

            class NestedBean {
                NestedBean(RegularFileProperty inputFile) {
                    this.inputFile = inputFile
                }

                @InputFile
                final RegularFileProperty inputFile
            }

            class ConsumerTask extends DefaultTask {

                @Nested

                    .solution("Annotate with @InputFile for regular files")
                    .solution("Annotate with @InputFiles for collections of files")
                    .solution("If you want to track the path, return File.absolutePath as a String and keep @Input")
            );
        }
    }

                inputFile: file(providers.gradleProperty('inputFile').get())
            )
        """
        file('inputFile.txt').text = "Test"

        expect:
        succeeds "test", "-PinputFile=inputFile.txt"

        when:
        file('different-file.txt').text = "Test"
        file("inputFile.txt").delete()
        run "test", "-PinputFile=different-file.txt"

        then:
        skipped(":test")

        when:

        when:
        task.inputFile = null

        then:
        task.inputFile == task.outputFile

        when:
        task.inputFile = inputFile

        then:
        task.inputFile == inputFile
    }

    def mergesConfigurationWhenInputFileExists() {
        def configObject = new TestConfigurationObject()
        inputFile.text = 'config'

        when:
        task.generate()