org.checkerframework.common.subtyping.qual.Unqualified Maven / Gradle / Ivy
package org.checkerframework.common.subtyping.qual;
import java.lang.annotation.Documented;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
import org.checkerframework.framework.qual.InvisibleQualifier;
import org.checkerframework.framework.qual.SubtypeOf;
/**
* A special annotation intended solely for representing an unqualified type in the qualifier
* hierarchy, as an argument to {@link SubtypeOf#value()}, in a type qualifier declaration.
*
* This annotation may not be written in source code; it is an implementation detail of the
* checker.
*
*
Use this qualifier only when experimenting with very simple type systems. For any more
* realistic type systems, introduce a top and bottom qualifier that gets stored in bytecode.
*
* @checker_framework.manual #subtyping-checker Subtyping Checker
*/
@Documented
@Retention(RetentionPolicy.SOURCE) // don't store in class file
@Target({}) // empty target prevents programmers from writing this in a program.
@InvisibleQualifier
@SubtypeOf({})
public @interface Unqualified {}