com.google.errorprone.bugpatterns.ConditionalExpressionNumericPromotion Maven / Gradle / Ivy
/*
* Copyright 2017 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.
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package com.google.errorprone.bugpatterns;
import static com.google.common.base.Preconditions.checkNotNull;
import static com.google.errorprone.BugPattern.SeverityLevel.ERROR;
import static com.google.errorprone.matchers.Description.NO_MATCH;
import com.google.errorprone.BugPattern;
import com.google.errorprone.VisitorState;
import com.google.errorprone.bugpatterns.BugChecker.ConditionalExpressionTreeMatcher;
import com.google.errorprone.fixes.SuggestedFix;
import com.google.errorprone.fixes.SuggestedFixes;
import com.google.errorprone.matchers.Description;
import com.google.errorprone.util.ASTHelpers;
import com.google.errorprone.util.ASTHelpers.TargetType;
import com.sun.source.tree.ConditionalExpressionTree;
import com.sun.source.tree.ExpressionTree;
import com.sun.tools.javac.code.Type;
/** @author [email protected] (Andy Turner) */
@BugPattern(
name = "ConditionalExpressionNumericPromotion",
summary =
"A conditional expression with numeric operands of differing types will perform binary "
+ "numeric promotion of the operands; when these operands are of reference types, "
+ "the expression's result may not be of the expected type.",
severity = ERROR)
public class ConditionalExpressionNumericPromotion extends BugChecker
implements ConditionalExpressionTreeMatcher {
@Override
public Description matchConditionalExpression(
ConditionalExpressionTree conditionalExpression, VisitorState state) {
Type expressionType = checkNotNull(ASTHelpers.getType(conditionalExpression));
if (!expressionType.isPrimitive()) {
return NO_MATCH;
}
ExpressionTree trueExpression = conditionalExpression.getTrueExpression();
ExpressionTree falseExpression = conditionalExpression.getFalseExpression();
Type trueType = checkNotNull(ASTHelpers.getType(trueExpression));
Type falseType = checkNotNull(ASTHelpers.getType(falseExpression));
if (trueType.isPrimitive() || falseType.isPrimitive()) {
return NO_MATCH;
}
if (ASTHelpers.isSameType(trueType, falseType, state)) {
return NO_MATCH;
}
TargetType targetType = ASTHelpers.targetType(state);
if (targetType == null) {
return NO_MATCH;
}
if (targetType.type().isPrimitive()) {
return NO_MATCH;
}
Type numberType = state.getTypeFromString("java.lang.Number");
if (ASTHelpers.isSubtype(targetType.type(), numberType, state)
&& !ASTHelpers.isSameType(targetType.type(), numberType, state)) {
return NO_MATCH;
}
SuggestedFix.Builder builder = SuggestedFix.builder();
String numberName = SuggestedFixes.qualifyType(state, builder, numberType);
String prefix = "((" + numberName + ") ";
builder.prefixWith(trueExpression, prefix).postfixWith(trueExpression, ")");
builder.prefixWith(falseExpression, prefix).postfixWith(falseExpression, ")");
return describeMatch(conditionalExpression, builder.build());
}
}