package org.checkerframework.checker.nullness.qual;
import java.lang.annotation.Documented;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
import org.checkerframework.framework.qual.DefaultInUncheckedCodeFor;
import org.checkerframework.framework.qual.ImplicitFor;
import org.checkerframework.framework.qual.LiteralKind;
import org.checkerframework.framework.qual.SubtypeOf;
import org.checkerframework.framework.qual.TypeUseLocation;
/**
* {@link Nullable} is a type annotation that indicates that the value is not known to be non-null
* (see {@link NonNull}). Only if an expression has a {@link Nullable} type may it be assigned
* {@code null}.
*
* <p>This annotation is associated with the {@link
* org.checkerframework.checker.nullness.AbstractNullnessChecker}.
*
* @see NonNull
* @see MonotonicNonNull
* @see org.checkerframework.checker.nullness.AbstractNullnessChecker
* @checker_framework.manual #nullness-checker Nullness Checker
*/
@SubtypeOf({})
@ImplicitFor(literals = LiteralKind.NULL, typeNames = java.lang.Void.class)
@DefaultInUncheckedCodeFor({TypeUseLocation.RETURN, TypeUseLocation.UPPER_BOUND})
@Documented
@Retention(RetentionPolicy.RUNTIME)
@Target({ElementType.TYPE_USE, ElementType.TYPE_PARAMETER})
public @interface Nullable {}