1 files changed, 141 insertions, 0 deletions
diff --git a/plugins/InspectionGadgets/InspectionGadgetsAnalysis/src/com/siyeh/ig/assignment/BaseAssignmentToParameterInspection.java b/plugins/InspectionGadgets/InspectionGadgetsAnalysis/src/com/siyeh/ig/assignment/BaseAssignmentToParameterInspection.java
new file mode 100644
index 000000000000..7f27c6bf762a
--- /dev/null
+++ b/plugins/InspectionGadgets/InspectionGadgetsAnalysis/src/com/siyeh/ig/assignment/BaseAssignmentToParameterInspection.java
@@ -0,0 +1,141 @@
+/*
+ * Copyright 2000-2014 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 com.siyeh.ig.assignment;
+
+import com.intellij.psi.*;
+import com.intellij.psi.tree.IElementType;
+import com.siyeh.ig.BaseInspection;
+import com.siyeh.ig.BaseInspectionVisitor;
+import com.siyeh.ig.InspectionGadgetsFix;
+import com.siyeh.ig.fixes.ExtractParameterAsLocalVariableFix;
+import com.siyeh.ig.psiutils.ParenthesesUtils;
+import com.siyeh.ig.psiutils.VariableAccessUtils;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+/**
+ * @author Bas Leijdekkers
+ */
+public abstract class BaseAssignmentToParameterInspection extends BaseInspection {
+
+  @SuppressWarnings({"PublicField"})
+  public boolean ignoreTransformationOfOriginalParameter = false;
+
+  @Override
+  protected InspectionGadgetsFix buildFix(Object... infos) {
+    return new ExtractParameterAsLocalVariableFix();
+  }
+
+  protected abstract boolean isCorrectScope(PsiElement declarationScope);
+
+  @Override
+  public final BaseInspectionVisitor buildVisitor() {
+    return new AssignmentToParameterVisitor();
+  }
+
+  private class AssignmentToParameterVisitor extends BaseInspectionVisitor {
+
+    @Override
+    public void visitAssignmentExpression(@NotNull PsiAssignmentExpression expression) {
+      super.visitAssignmentExpression(expression);
+      final PsiExpression lhs = expression.getLExpression();
+      final PsiParameter parameter = getParameter(lhs);
+      if (parameter == null) {
+        return;
+      }
+      if (ignoreTransformationOfOriginalParameter) {
+        final PsiExpression rhs = expression.getRExpression();
+        if (rhs != null && VariableAccessUtils.variableIsUsed(parameter, rhs)) {
+          return;
+        }
+        final IElementType tokenType =
+          expression.getOperationTokenType();
+        if (tokenType == JavaTokenType.PLUSEQ ||
+            tokenType == JavaTokenType.MINUSEQ ||
+            tokenType == JavaTokenType.ASTERISKEQ ||
+            tokenType == JavaTokenType.DIVEQ ||
+            tokenType == JavaTokenType.ANDEQ ||
+            tokenType == JavaTokenType.OREQ ||
+            tokenType == JavaTokenType.XOREQ ||
+            tokenType == JavaTokenType.PERCEQ ||
+            tokenType == JavaTokenType.LTLTEQ ||
+            tokenType == JavaTokenType.GTGTEQ ||
+            tokenType == JavaTokenType.GTGTGTEQ) {
+          return;
+        }
+      }
+      registerError(lhs);
+    }
+
+    @Override
+    public void visitPrefixExpression(@NotNull PsiPrefixExpression expression) {
+      if (ignoreTransformationOfOriginalParameter) {
+        return;
+      }
+      super.visitPrefixExpression(expression);
+      final IElementType tokenType = expression.getOperationTokenType();
+      if (!tokenType.equals(JavaTokenType.PLUSPLUS) && !tokenType.equals(JavaTokenType.MINUSMINUS)) {
+        return;
+      }
+      final PsiExpression operand = expression.getOperand();
+      if (operand == null) {
+        return;
+      }
+      final PsiParameter parameter = getParameter(operand);
+      if (parameter == null) {
+        return;
+      }
+      registerError(operand);
+    }
+
+    @Override
+    public void visitPostfixExpression(@NotNull PsiPostfixExpression expression) {
+      if (ignoreTransformationOfOriginalParameter) {
+        return;
+      }
+      super.visitPostfixExpression(expression);
+      final IElementType tokenType = expression.getOperationTokenType();
+      if (!tokenType.equals(JavaTokenType.PLUSPLUS) && !tokenType.equals(JavaTokenType.MINUSMINUS)) {
+        return;
+      }
+      final PsiExpression operand = expression.getOperand();
+      final PsiParameter parameter = getParameter(operand);
+      if (parameter == null) {
+        return;
+      }
+      registerError(operand);
+    }
+
+    @Nullable
+    private PsiParameter getParameter(PsiExpression expression) {
+      expression = ParenthesesUtils.stripParentheses(expression);
+      if (!(expression instanceof PsiReferenceExpression)) {
+        return null;
+      }
+      final PsiReferenceExpression referenceExpression = (PsiReferenceExpression)expression;
+      final PsiElement variable = referenceExpression.resolve();
+      if (!(variable instanceof PsiParameter)) {
+        return null;
+      }
+      final PsiParameter parameter = (PsiParameter)variable;
+      final PsiElement declarationScope = parameter.getDeclarationScope();
+      if (!isCorrectScope(declarationScope)) {
+        return null;
+      }
+      return parameter;
+    }
+  }
+}