com.google.errorprone.bugpatterns.DiscardedPostfixExpression Maven / Gradle / Ivy
/*
* Copyright 2018 The Error Prone Authors.
*
* 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.bugpatterns;
import static com.google.errorprone.matchers.Description.NO_MATCH;
import com.google.errorprone.BugPattern;
import com.google.errorprone.BugPattern.SeverityLevel;
import com.google.errorprone.VisitorState;
import com.google.errorprone.bugpatterns.BugChecker.UnaryTreeMatcher;
import com.google.errorprone.fixes.SuggestedFix;
import com.google.errorprone.matchers.Description;
import com.google.errorprone.util.ASTHelpers;
import com.sun.source.tree.Tree;
import com.sun.source.tree.Tree.Kind;
import com.sun.source.tree.UnaryTree;
import com.sun.tools.javac.code.Symbol;
import com.sun.tools.javac.tree.JCTree.JCLambda;
/** A {@link BugChecker}; see the associated {@link BugPattern} annotation for details. */
@BugPattern(
summary = "The result of this unary operation on a lambda parameter is discarded",
severity = SeverityLevel.ERROR)
public class DiscardedPostfixExpression extends BugChecker implements UnaryTreeMatcher {
@Override
public Description matchUnary(UnaryTree tree, VisitorState state) {
switch (tree.getKind()) {
case POSTFIX_INCREMENT:
case POSTFIX_DECREMENT:
break;
default:
return NO_MATCH;
}
Tree parent = state.getPath().getParentPath().getLeaf();
if (parent.getKind() != Kind.LAMBDA_EXPRESSION) {
return NO_MATCH;
}
JCLambda lambda = (JCLambda) parent;
Symbol sym = ASTHelpers.getSymbol(tree.getExpression());
if (lambda.getParameters().stream().noneMatch(p -> ASTHelpers.getSymbol(p) == sym)) {
return NO_MATCH;
}
return describeMatch(
tree,
SuggestedFix.replace(
tree,
String.format(
"%s %s 1",
state.getSourceForNode(tree.getExpression()),
tree.getKind() == Kind.POSTFIX_INCREMENT ? "+" : "-")));
}
}