GrReassignedInClosureLocalVarInspection.java

/*
 * Copyright 2000-2016 JetBrains s.r.o.
 *
 * 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 org.jetbrains.plugins.groovy.codeInspection.confusing;

import com.intellij.codeInspection.LocalQuickFix;
import com.intellij.codeInspection.ProblemHighlightType;
import com.intellij.psi.PsiElement;
import com.intellij.psi.PsiType;
import org.jetbrains.annotations.Nls;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.plugins.groovy.codeInspection.BaseInspection;
import org.jetbrains.plugins.groovy.codeInspection.BaseInspectionVisitor;
import org.jetbrains.plugins.groovy.codeInspection.GroovyInspectionBundle;
import org.jetbrains.plugins.groovy.codeInspection.utils.ControlFlowUtils;
import org.jetbrains.plugins.groovy.lang.psi.GrControlFlowOwner;
import org.jetbrains.plugins.groovy.lang.psi.GrNamedElement;
import org.jetbrains.plugins.groovy.lang.psi.api.statements.blocks.GrClosableBlock;
import org.jetbrains.plugins.groovy.lang.psi.api.statements.expressions.GrReferenceExpression;
import org.jetbrains.plugins.groovy.lang.psi.api.statements.typedef.GrAnonymousClassDefinition;
import org.jetbrains.plugins.groovy.lang.psi.impl.GrReassignedLocalVarsChecker;
import org.jetbrains.plugins.groovy.lang.psi.impl.statements.expressions.TypesUtil;
import org.jetbrains.plugins.groovy.lang.psi.util.PsiUtil;

/**
 * @author Max Medvedev
 */
public class GrReassignedInClosureLocalVarInspection extends BaseInspection {

  @Override
  @Nls
  @NotNull
  public String getGroupDisplayName() {
    return CONFUSING_CODE_CONSTRUCTS;
  }

  @Override
  @Nls
  @NotNull
  public String getDisplayName() {
    return "Local variable is reassigned in closure or anonymous class";
  }

  @Override
  public boolean isEnabledByDefault() {
    return true;
  }

  @NotNull
  @Override
  protected BaseInspectionVisitor buildVisitor() {
    return new BaseInspectionVisitor() {
      @Override
      public void visitReferenceExpression(@NotNull GrReferenceExpression referenceExpression) {
        super.visitReferenceExpression(referenceExpression);

        if (!PsiUtil.isLValue(referenceExpression)) return;
        final PsiElement resolved = referenceExpression.resolve();
        if (!PsiUtil.isLocalVariable(resolved)) return;

        final PsiType checked = GrReassignedLocalVarsChecker.getReassignedVarType(referenceExpression, false);
        if (checked == null) return;

        final GrControlFlowOwner varFlowOwner = ControlFlowUtils.findControlFlowOwner(resolved);
        final GrControlFlowOwner refFlorOwner = ControlFlowUtils.findControlFlowOwner(referenceExpression);
        if (isOtherScopeAndType(referenceExpression, checked, varFlowOwner, refFlorOwner)) {
          String flowDescription = getFlowDescription(refFlorOwner);
          final String message = GroovyInspectionBundle
            .message("local.var.0.is.reassigned", ((GrNamedElement)resolved).getName(), flowDescription);
          registerError(referenceExpression, message, LocalQuickFix.EMPTY_ARRAY, ProblemHighlightType.GENERIC_ERROR_OR_WARNING);
        }
      }
    };
  }

  private static boolean isOtherScopeAndType(GrReferenceExpression referenceExpression,
                                             PsiType checked,
                                             GrControlFlowOwner varFlowOwner,
                                             GrControlFlowOwner refFlorOwner) {
    return varFlowOwner != refFlorOwner && !TypesUtil.isAssignable(referenceExpression.getType(), checked, referenceExpression);
  }

  private static String getFlowDescription(GrControlFlowOwner refFlorOwner) {
    String flowDescription;
    if (refFlorOwner instanceof GrClosableBlock) {
      flowDescription = GroovyInspectionBundle.message("closure");
    }
    else if (refFlorOwner instanceof GrAnonymousClassDefinition) {
      flowDescription = GroovyInspectionBundle.message("anonymous.class");
    }
    else {
      flowDescription = GroovyInspectionBundle.message("other.scope");
    }
    return flowDescription;
  }
}