IDEA-90103 (Provide intention for changing base type in LHS to derived type when RHS type is more specific)

plugins/IntentionPowerPak/src/META-INF/plugin.xml

@@ -211,6 +211,11 @@
       <categoryKey>intention.category.declaration</categoryKey>
     </intentionAction>
 
+    <intentionAction>
+      <className>com.siyeh.ipp.decls.ChangeVariableTypeToRhsTypeIntention</className>
+      <categoryKey>intention.category.declaration</categoryKey>
+    </intentionAction>
+
     <!-- Imports -->
 
     <intentionAction>

plugins/IntentionPowerPak/src/com/siyeh/IntentionPowerPackBundle.properties

@@ -169,6 +169,7 @@ make.protected.intention.name=Make 'protected'
 make.protected.intention.family.name=Make Protected
 make.private.intention.name=Make 'private'
 make.private.intention.family.name=Make Private
+change.variable.type.to.rhs.type.intention.family.name=Change Variable Type to Type of Initializer
 
 #hand made
 demorgans.intention.name1=Replace '\\&\\&' with '||'
@@ -202,6 +203,7 @@ flip.setter.call.intention.name=Flip Setter Call
 adapter.to.listener.intention.name=Replace extension of ''{0}'' with ''Listener'' implementation
 obscure.thrown.exceptions.intention.name=Replace with ''throws {0}''
 add.array.creation.expression.intention.name=Add ''new {0}''
+change.variable.type.to.rhs.type.intention.name=Declare ''{0}'' with type ''{1}''
 
 
 #categories

plugins/IntentionPowerPak/src/com/siyeh/ipp/decls/ChangeVariableTypeToRhsTypeIntention.java

@@ -0,0 +1,75 @@
+/*
+ * Copyright 2000-2012 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.
+ */
+
+/*
+ * (c) 2012 Desert Island BV
+ * created: 14 08 2012
+ */
+package com.siyeh.ipp.decls;
+
+import com.intellij.psi.*;
+import com.intellij.util.IncorrectOperationException;
+import com.siyeh.IntentionPowerPackBundle;
+import com.siyeh.ipp.base.MutablyNamedIntention;
+import com.siyeh.ipp.base.PsiElementPredicate;
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * @author Bas Leijdekkers
+ */
+public class ChangeVariableTypeToRhsTypeIntention extends MutablyNamedIntention {
+
+  @NotNull
+  @Override
+  protected PsiElementPredicate getElementPredicate() {
+    return new ChangeVariableTypeToRhsTypePredicate();
+  }
+
+  @Override
+  protected String getTextForElement(PsiElement element) {
+    final PsiVariable variable = (PsiVariable)element.getParent();
+    final PsiExpression initializer = variable.getInitializer();
+    assert initializer != null;
+    final PsiType type = initializer.getType();
+    assert type != null;
+    return IntentionPowerPackBundle.message("change.variable.type.to.rhs.type.intention.name",
+                                            variable.getName(), type.getPresentableText());
+  }
+
+  @Override
+  protected void processIntention(@NotNull PsiElement element) throws IncorrectOperationException {
+    final PsiElement parent = element.getParent();
+    if (!(parent instanceof PsiVariable)) {
+      return;
+    }
+    final PsiVariable variable = (PsiVariable)parent;
+    final PsiExpression initializer = variable.getInitializer();
+    if (initializer == null) {
+      return;
+    }
+    final PsiType type = initializer.getType();
+    if (type == null) {
+      return;
+    }
+    final PsiElementFactory factory = JavaPsiFacade.getElementFactory(element.getProject());
+    final PsiTypeElement typeElement = factory.createTypeElement(type);
+    final PsiTypeElement variableTypeElement = variable.getTypeElement();
+    if (variableTypeElement == null) {
+      return;
+    }
+    variableTypeElement.replace(typeElement);
+  }
+}

plugins/IntentionPowerPak/src/com/siyeh/ipp/decls/ChangeVariableTypeToRhsTypePredicate.java

@@ -0,0 +1,60 @@
+/*
+ * Copyright 2000-2012 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.ipp.decls;
+
+import com.intellij.psi.*;
+import com.siyeh.ipp.base.PsiElementPredicate;
+
+/**
+ * @author Bas Leijdekkers
+ */
+class ChangeVariableTypeToRhsTypePredicate implements PsiElementPredicate {
+
+  @Override
+  public boolean satisfiedBy(PsiElement element) {
+    if (!(element instanceof PsiTypeElement)) {
+      return false;
+    }
+    final PsiElement parent = element.getParent();
+    if (!(parent instanceof PsiVariable)) {
+      return false;
+    }
+    final PsiVariable variable = (PsiVariable)parent;
+    final PsiExpression initializer = variable.getInitializer();
+    if (!(initializer instanceof PsiNewExpression)) {
+      return false;
+    }
+    final PsiType type = variable.getType();
+    if (!(type instanceof PsiClassType)) {
+      return false;
+    }
+    final PsiType initializerType = initializer.getType();
+    if (!(initializerType instanceof PsiClassType)) {
+      return false;
+    }
+    final PsiClassType initializerClassType = (PsiClassType)initializerType;
+    final PsiClass initializerClass = initializerClassType.resolve();
+    if (initializerClass == null) {
+      return false;
+    }
+    final PsiClassType classType = (PsiClassType)type;
+    final PsiClass variableClass = classType.resolve();
+    if (variableClass == null) {
+      return false;
+    }
+    return initializerClass.isInheritor(variableClass, true);
+  }
+}

plugins/IntentionPowerPak/src/intentionDescriptions/ChangeVariableTypeToRhsTypeIntention/after.java.template

@@ -0,0 +1,3 @@
+public class X {
+  private ArrayList<String> ss = new ArrayList<>();
+}

plugins/IntentionPowerPak/src/intentionDescriptions/ChangeVariableTypeToRhsTypeIntention/before.java.template

@@ -0,0 +1,3 @@
+public class X {
+  private <spot>List<String></spot> ss = new ArrayList<>();
+}

plugins/IntentionPowerPak/src/intentionDescriptions/ChangeVariableTypeToRhsTypeIntention/description.html

@@ -0,0 +1,5 @@
+<html>
+<body>
+This intention changes the type of a variable to the type of its initializer if that is more specific.
+</body>
+</html>

plugins/IntentionPowerPak/test/com/siyeh/ipp/decls/change_variable_type_to_rhs_type/SameType.java

@@ -0,0 +1,5 @@
+import java.util.ArrayList;
+
+class X {
+  private <caret>ArrayList<String> ss = new ArrayList<String>();
+}

plugins/IntentionPowerPak/test/com/siyeh/ipp/decls/change_variable_type_to_rhs_type/Simple.java

@@ -0,0 +1,6 @@
+import java.util.ArrayList;
+import java.util.List;
+
+class X {
+  private <caret>List<String> ss = new ArrayList<>();
+}

plugins/IntentionPowerPak/test/com/siyeh/ipp/decls/change_variable_type_to_rhs_type/Simple_after.java

@@ -0,0 +1,6 @@
+import java.util.ArrayList;
+import java.util.List;
+
+class X {
+  private ArrayList<String> ss = new ArrayList<>();
+}

plugins/IntentionPowerPak/testSrc/com/siyeh/ipp/decls/ChangeVariableTypeToRhsTypeIntentionTest.java

@@ -0,0 +1,24 @@
+package com.siyeh.ipp.decls;
+
+import com.siyeh.IntentionPowerPackBundle;
+import com.siyeh.ipp.IPPTestCase;
+
+/**
+ * @author Bas Leijdekkers
+ */
+public class ChangeVariableTypeToRhsTypeIntentionTest extends IPPTestCase {
+
+  public void testSimple() { doTest("Declare 'ss' with type 'ArrayList<String>'"); }
+
+  public void testSameType() { assertIntentionNotAvailable(); }
+
+  @Override
+  protected String getIntentionName() {
+    return IntentionPowerPackBundle.message("change.variable.type.to.rhs.type.intention.name", "ss", "ArrayList<String>");
+  }
+
+  @Override
+  protected String getRelativePath() {
+    return "decls/change_variable_type_to_rhs_type";
+  }
+}