Kotlin编译调校之WarningsAsErrors

//Code to be added
kotlinOptions {
    allWarningsAsErrors = true
}

@Suppress("NOTHING_TO_INLINE")
inline fun String?.isNotNullNorEmpty(): Boolean {
    //Expected performance impact of inlining 
    // 'public inline fun String?.isNotNullNorEmpty(): Boolean 
    // defined in com.example.warningsaserrorscases in file NothingToInlineWarnings.kt'
    // is insignificant. 
    // Inlining works best for functions with parameters of functional types
    return this != null && this.isNotEmpty()
}

public class RequestManager {
    public static RequestManager sInstance = new RequestManager();

    private static class TimelineRequest {
        public String from;
    }

    public TimelineRequest getTimelineRequest() {
        return new TimelineRequest();
    }
}

fun testInaccessibleType() {
    //Type RequestManager.TimelineRequest! is inaccessible in this context
    // due to: private open class TimelineRequest defined
    // in com.example.warningsaserrorscases.RequestManager
    @Suppress("INACCESSIBLE_TYPE")
    RequestManager.sInstance.timelineRequest
}

fun <T> Any.toType(): T? {
    //Unchecked cast: Any to T
    @Suppress("UNCHECKED_CAST")
    return this as? T
}

//a better way
inline fun <reified T> Any.toType(): T? {
    return if (this is T) {
        this
    } else {
        null
    }
}

fun testEnum1() {
    //Enum argument can be null in Java, but exhaustive when contains no null branch
    when(SeasonUtil.getCurrentSeason()) {
        Season.SPRING -> println("Spring")
        Season.SUMMER -> println("Summer")
        Season.FALL -> println("Fall")
        Season.WINTER -> println("Winter")
        //else -> println("unknown")
    }
}

fun testEnum2() {
    //Enum argument can be null in Java, but exhaustive when contains no null branch
    @Suppress("WHEN_ENUM_CAN_BE_NULL_IN_JAVA")
    when(SeasonUtil.getCurrentSeason()) {
        Season.SPRING -> println("Spring")
        Season.SUMMER -> println("Summer")
        Season.FALL -> println("Fall")
        Season.WINTER -> println("Winter")
    }
}

interface OnViewClickedListener {
    fun onViewClicked(viewId: Int)
}

fun testParameterNameChangedOnOverride() {
    // The corresponding parameter in the supertype 'OnViewClickedListener'
    // is named 'viewId'.
    // This may cause problems when calling this function with named arguments.
    object : OnViewClickedListener {
        override fun onViewClicked(@Suppress("PARAMETER_NAME_CHANGED_ON_OVERRIDE") id: Int) {
            println("onViewClicked id=$id")
        }
    }
}

fun testNameShadowing(message: String) {
    run {
        //Name shadowed: message
        @Suppress("NAME_SHADOWING") val message = "Hello World"
        println(message)
    }
}

fun testUnnecessarySafeCall(message: String) {
    @Suppress("UNNECESSARY_SAFE_CALL")
    println(message?.toIntOrNull())
}

fun testSenselessComparison(message: String) {
    //Condition 'message != null' is always 'true'
    @Suppress("SENSELESS_COMPARISON")
    if (message != null) {

    }
}

fun testUncessaryNotNullAssertion(message: String) {
    //Unnecessary non-null assertion (!!) on a non-null receiver
    // of type String
    @Suppress("UNNECESSARY_NOT_NULL_ASSERTION")
    println(message!!.toIntOrNull())
}

fun testUselessIsCheck(message: String) {
    //Check for instance is always 'true'
    @Suppress("USELESS_IS_CHECK")
    if (message is String) {

    }
}

fun testVariableWithRedundantInitializer() {
    //Variable 'message' initializer is redundant
    @Suppress("VARIABLE_WITH_REDUNDANT_INITIALIZER") var message: String? = null;
    message = System.currentTimeMillis().toString()
    println(message)
}

fun testGetDrawable(context: Context) {
    @Suppress("DEPRECATION")
    context.resources.getDrawable(R.mipmap.ic_launcher)
}

fun showMessage(message: String, extra: String?) {
    println(message)
}

fun forEachList() {
    listOf<String>("Hello", "World").forEachIndexed { index, s ->
        println(s)
    }
}

fun unusedVariable() {
    @Suppress("UNUSED_VARIABLE") val currentTimeStamp = System.currentTimeMillis()
    println("unusedVariable")
}

fun test(status: Int) {
    when(status) {
        1 -> "First"
        2 -> "Second"
        else -> "Else"
    }
}

fun testUnusedValue() {
    // The value '"Hello"' assigned to 'var message: String?
    // defined in com.example.warningsaserrorscases.test' is never used
    @Suppress("ASSIGNED_BUT_NEVER_ACCESSED_VARIABLE") var message: String? = null
    @Suppress("UNUSED_VALUE")
    message = "Hello"
}