New "Return of instance of anonymous, local or inner class" inspection

plugins/InspectionGadgets/InspectionGadgetsAnalysis/src/META-INF/InspectionGadgets.xml

@@ -1547,6 +1547,9 @@
                      key="inner.class.may.be.static.display.name" groupBundle="messages.InspectionsBundle"
                      groupKey="group.names.memory.issues" enabledByDefault="false" level="WARNING" runForWholeFile="true"
                      implementationClass="com.siyeh.ig.memory.InnerClassMayBeStaticInspection"/>
+    <localInspection language="JAVA" shortName="ReturnOfInnerClass" bundle="com.siyeh.InspectionGadgetsBundle"
+                     key="return.of.inner.class.display.name" groupBundle="messages.InspectionsBundle"
+                     implementationClass="com.siyeh.ig.memory.ReturnOfInnerClassInspection" enabledByDefault="false" level="WARNING"/>
     <localInspection language="JAVA" shortName="StaticCollection" bundle="com.siyeh.InspectionGadgetsBundle" key="static.collection.display.name"
                      groupBundle="messages.InspectionsBundle" groupKey="group.names.memory.issues" enabledByDefault="false" level="WARNING"
                      implementationClass="com.siyeh.ig.memory.StaticCollectionInspection"/>

plugins/InspectionGadgets/InspectionGadgetsAnalysis/src/com/siyeh/InspectionGadgetsBundle.properties

@@ -2117,3 +2117,7 @@ junit3.method.naming.convention.problem.descriptor.regex.mismatch=JUnit 3 test m
 introduce.holder.class.quickfix=Introduce holder class
 double.brace.initialization.display.name=Double brace initialization
 double.brace.initialization.quickfix=Replace with regular initialization
+return.of.inner.class.display.name=Return of instance of anonymous, local or inner class
+return.of.anonymous.class.problem.descriptor=Return of instance of anonymous class #loc
+return.of.local.class.problem.descriptor=Return of instance of local class <code>{0}</code> #loc
+return.of.inner.class.problem.descriptor=Return of instance of non-static inner class <code>{0}</code> #loc

plugins/InspectionGadgets/InspectionGadgetsAnalysis/src/com/siyeh/ig/memory/ReturnOfInnerClassInspection.java

@@ -0,0 +1,107 @@
+/*
+ * 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.memory;
+
+import com.intellij.psi.*;
+import com.intellij.psi.util.PsiTreeUtil;
+import com.intellij.psi.util.PsiUtil;
+import com.siyeh.InspectionGadgetsBundle;
+import com.siyeh.ig.BaseInspection;
+import com.siyeh.ig.BaseInspectionVisitor;
+import com.siyeh.ig.psiutils.ParenthesesUtils;
+import org.jetbrains.annotations.Nls;
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * @author Bas Leijdekkers
+ */
+public class ReturnOfInnerClassInspection extends BaseInspection {
+
+  private enum ClassType { ANONYMOUS_CLASS, LOCAL_CLASS, INNER_CLASS }
+
+  @Nls
+  @NotNull
+  @Override
+  public String getDisplayName() {
+    return InspectionGadgetsBundle.message("return.of.inner.class.display.name");
+  }
+
+  @NotNull
+  @Override
+  protected String buildErrorString(Object... infos) {
+    switch ((ClassType)infos[0]) {
+      case ANONYMOUS_CLASS:
+        return InspectionGadgetsBundle.message("return.of.anonymous.class.problem.descriptor");
+      case LOCAL_CLASS: {
+        final PsiClass aClass = (PsiClass)infos[1];
+        return InspectionGadgetsBundle.message("return.of.local.class.problem.descriptor", aClass.getName());
+      }
+      case INNER_CLASS: {
+        final PsiClass aClass = (PsiClass)infos[1];
+        return InspectionGadgetsBundle.message("return.of.inner.class.problem.descriptor", aClass.getName());
+      }
+      default:
+        throw new UnsupportedOperationException();
+    }
+  }
+
+  @Override
+  public BaseInspectionVisitor buildVisitor() {
+    return new ReturnOfInnerClassVisitor();
+  }
+
+  private static class ReturnOfInnerClassVisitor extends BaseInspectionVisitor {
+
+    @Override
+    public void visitReturnStatement(PsiReturnStatement statement) {
+      super.visitReturnStatement(statement);
+      final PsiExpression expression = ParenthesesUtils.stripParentheses(statement.getReturnValue());
+      if (expression == null) {
+        return;
+      }
+      final PsiMethod method = PsiTreeUtil.getParentOfType(statement, PsiMethod.class, true, PsiLambdaExpression.class);
+      if (method == null || method.hasModifierProperty(PsiModifier.PRIVATE)) {
+        return;
+      }
+      if (expression instanceof PsiNewExpression) {
+        final PsiNewExpression newExpression = (PsiNewExpression)expression;
+        final PsiAnonymousClass anonymousClass = newExpression.getAnonymousClass();
+        if (anonymousClass != null) {
+          registerStatementError(statement, ClassType.ANONYMOUS_CLASS);
+          return;
+        }
+      }
+      final PsiType type = expression.getType();
+      if (!(type instanceof PsiClassType)) {
+        return;
+      }
+      final PsiClassType classType = (PsiClassType)type;
+      final PsiClass aClass = classType.resolve();
+      if (aClass == null) {
+        return;
+      }
+      if (PsiUtil.isLocalClass(aClass)) {
+        registerStatementError(statement, ClassType.LOCAL_CLASS, aClass);
+        return;
+      }
+      final PsiClass containingClass = aClass.getContainingClass();
+      if (containingClass == null || aClass.hasModifierProperty(PsiModifier.STATIC)) {
+        return;
+      }
+      registerStatementError(statement, ClassType.INNER_CLASS, aClass);
+    }
+  }
+}

plugins/InspectionGadgets/test/com/siyeh/igtest/memory/return_of_inner_class/ReturnOfInnerClass.java

@@ -0,0 +1,20 @@
+public class ReturnOfInnerClass {
+
+  public Object one() {
+    <warning descr="Return of instance of anonymous class">return</warning> new Object() {};
+  }
+
+  public Object two() {
+    class A {}
+    <warning descr="Return of instance of local class 'A'">return</warning> new A();
+  }
+
+  class B {}
+  public Object three() {
+    <warning descr="Return of instance of non-static inner class 'B'">return</warning> new B();
+  }
+
+  private Object four() {
+    return new B();
+  }
+}

plugins/InspectionGadgets/testsrc/com/siyeh/ig/memory/ReturnOfInnerClassInspectionTest.java

@@ -0,0 +1,35 @@
+/*
+ * 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.memory;
+
+import com.intellij.codeInspection.InspectionProfileEntry;
+import com.siyeh.ig.LightInspectionTestCase;
+import junit.framework.TestCase;
+import org.jetbrains.annotations.Nullable;
+
+/**
+ * @author Bas Leijdekkers
+ */
+public class ReturnOfInnerClassInspectionTest extends LightInspectionTestCase {
+
+  public void testReturnOfInnerClass() { doTest(); }
+
+  @Nullable
+  @Override
+  protected InspectionProfileEntry getInspection() {
+    return new ReturnOfInnerClassInspection();
+  }
+}