kotlin-fork/compiler/testData/diagnostics

Several directives can be added in the beginning of a test file in the syntax:

// !DIRECTIVE

Directives:

1. DIAGNOSTICS

Must be

'([ + - ! ] DIAGNOSTIC_FACTORY_NAME | ERROR | WARNING | INFO ) +'

where

• + means 'include';

• - means 'exclude';

• ! means 'exclude everything but this'.

  Directives are applied in the order of appearance, i.e. !FOO +BAR means include only FOO and BAR.

Examples:

// !DIAGNOSTICS: -WARNING +CAST_NEVER_SUCCEEDS

// !DIAGNOSTICS: -UNUSED_EXPRESSION -UNUSED_PARAMETER -UNUSED_VARIABLE

2. CHECK_TYPE

The directive adds the following declarations to the file:

fun <T> checkSubtype(t: T) = t

class Inv<T>
fun <E> Inv<E>._() {}
infix fun <T> T.checkType(f: Inv<T>.() -> Unit) {}

With that, an exact type of an expression can be checked in the following way:

fun test(expr: A) {
   expr checkType { _<A>() }
}

Usage:

// !CHECK_TYPE

3. FILE

The directive lets you compose a test consisting of several files in one actual file.

Usage:

// FILE: A.java
/* Java code */

// FILE: B.kt
/* Kotlin code */

4. LANGUAGE

This directive lets you enable or disable certain language features. Language features are named as parameters of the primary constructor of the class LanguageFeatureSettings. Each feature can be enabled with + or disabled with -.

Usage:

// !LANGUAGE: -topLevelSealedInheritance

// !LANGUAGE: +typeAliases -localDelegatedProperties