/*
* Copyright 2015 Google Inc. All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.google.errorprone.annotations;
import static java.lang.annotation.ElementType.FIELD;
import static java.lang.annotation.ElementType.LOCAL_VARIABLE;
import static java.lang.annotation.ElementType.PARAMETER;
import static java.lang.annotation.RetentionPolicy.RUNTIME;
import static javax.lang.model.element.Modifier.FINAL;
import java.lang.annotation.Retention;
import java.lang.annotation.Target;
/**
* The parameter or local variable to which this annotation is applied
* is non-final.
*
* <p>Most references are never modified, and accidentally modifying a reference
* is a potential source of bugs. To prevent accidental modifications, the
* accompanying Error Prone <a href="http://errorprone.info/bugpattern/Var">check</a>
* prevents parameters and local variables from being modified unless
* they are explicitly annotated with @Var.
*
* <p>Since Java 8 can infer whether a local variable or parameter is effectively
* {@code final}, and {@code @Var} makes it clear whether any variable is non-
* {@code final}, explicitly marking local variables and parameters as
* {@code final} is discouraged.
*
* <p>The annotation can also be applied to fields, to indicate that the field is
* deliberately non-final.
*/
@Target({FIELD, PARAMETER, LOCAL_VARIABLE})
@Retention(RUNTIME)
@IncompatibleModifiers(FINAL)
public @interface Var {}