Add else entry for when quick fix

compiler/frontend/src/org/jetbrains/jet/lang/psi/JetPsiFactory.java

@@ -21,6 +21,7 @@ import com.intellij.openapi.project.Project;
 import com.intellij.openapi.util.Pair;
 import com.intellij.psi.PsiElement;
 import com.intellij.psi.PsiFileFactory;
+import com.intellij.psi.util.PsiTreeUtil;
 import com.intellij.util.LocalTimeCounter;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
@@ -82,6 +83,10 @@ public class JetPsiFactory {
         return property.findElementAt(3);
     }
 
+    public static PsiElement createNewLineWhiteSpace(Project project) {
+        return createWhiteSpace(project, "\n");
+    }
+
     public static JetClass createClass(Project project, String text) {
         return createDeclaration(project, text, JetClass.class);
     }
@@ -147,6 +152,11 @@ public class JetPsiFactory {
         return function.getValueParameters().get(0);
     }
 
+    public static JetWhenEntry createElseWhenEntry(Project project) {
+        JetNamedFunction function = createFunction(project, "fun foo() { when(12) { else -> { } } }");
+        return PsiTreeUtil.findChildOfType(function, JetWhenEntry.class);
+    }
+
     @NotNull
     public static JetImportDirective createImportDirective(Project project, @NotNull String path) {
         return createImportDirective(project, new ImportPath(path));

compiler/frontend/src/org/jetbrains/jet/lang/psi/JetWhenExpression.java

@@ -57,4 +57,10 @@ public class JetWhenExpression extends JetExpressionImpl {
     public PsiElement getWhenKeywordElement() {
         return findChildByType(JetTokens.WHEN_KEYWORD);
     }
+
+    @Nullable
+    public PsiElement getCloseBraceNode() {
+        ASTNode openBraceNode = getNode().findChildByType(JetTokens.RBRACE);
+        return openBraceNode != null ? openBraceNode.getPsi() : null;
+    }
 }

idea/src/org/jetbrains/jet/plugin/JetBundle.properties

@@ -94,3 +94,5 @@ options.jet.attribute.descriptor.label=Label
 change.to.function.invocation=Change to function invocation
 migrate.tuple=Migrate tuples in project\: e.g., \#(,) and \#(,,) will be replaced by Pair and Triple
 migrate.sure=Replace sure() calls by !! in project
+add.when.else.branch.action.family.name=Add Else Branch
+add.when.else.branch.action=Add else branch

idea/src/org/jetbrains/jet/plugin/quickfix/AddWhenElseBranchFix.java

@@ -0,0 +1,75 @@
+/*
+ * Copyright 2010-2012 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 org.jetbrains.jet.plugin.quickfix;
+
+import com.intellij.openapi.editor.Editor;
+import com.intellij.openapi.project.Project;
+import com.intellij.psi.PsiElement;
+import com.intellij.psi.PsiFile;
+import com.intellij.psi.util.PsiTreeUtil;
+import com.intellij.util.IncorrectOperationException;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+import org.jetbrains.jet.lang.diagnostics.Diagnostic;
+import org.jetbrains.jet.lang.psi.JetPsiFactory;
+import org.jetbrains.jet.lang.psi.JetWhenExpression;
+import org.jetbrains.jet.plugin.JetBundle;
+
+public class AddWhenElseBranchFix extends JetIntentionAction<JetWhenExpression> {
+    public AddWhenElseBranchFix(@NotNull JetWhenExpression element) {
+        super(element);
+    }
+
+    @NotNull
+    @Override
+    public String getText() {
+        return JetBundle.message("add.when.else.branch.action");
+    }
+
+    @NotNull
+    @Override
+    public String getFamilyName() {
+        return JetBundle.message("add.when.else.branch.action.family.name");
+    }
+
+    @Override
+    public boolean isAvailable(@NotNull Project project, Editor editor, PsiFile file) {
+        return super.isAvailable(project, editor, file) && element.getCloseBraceNode() != null;
+    }
+
+    @Override
+    public void invoke(@NotNull Project project, Editor editor, PsiFile file) throws IncorrectOperationException {
+        PsiElement insertBeforeAnchor = element.getCloseBraceNode();
+        if (insertBeforeAnchor != null) {
+            PsiElement insertedBranch = element.addBefore(JetPsiFactory.createElseWhenEntry(project), insertBeforeAnchor);
+            element.addAfter(JetPsiFactory.createNewLineWhiteSpace(project), insertedBranch);
+        }
+    }
+
+    public static JetIntentionActionFactory createFactory() {
+        return new JetIntentionActionFactory() {
+            @Nullable
+            @Override
+            public JetIntentionAction createAction(Diagnostic diagnostic) {
+                PsiElement element = diagnostic.getPsiElement();
+                JetWhenExpression whenExpression = PsiTreeUtil.getParentOfType(element, JetWhenExpression.class, false);
+                if (whenExpression == null) return null;
+                return new AddWhenElseBranchFix(whenExpression);
+            }
+        };
+    }
+}

idea/src/org/jetbrains/jet/plugin/quickfix/QuickFixes.java

@@ -142,5 +142,7 @@ public class QuickFixes {
         actions.put(UNNECESSARY_NOT_NULL_ASSERTION, ExclExclCallFix.removeExclExclCall());
 
         actions.put(PUBLIC_MEMBER_SHOULD_SPECIFY_TYPE, new SpecifyTypeExplicitlyFix());
+
+        factories.put(NO_ELSE_IN_WHEN, AddWhenElseBranchFix.createFactory());
     }
 }

idea/testData/quickfix/when/afterNoElseInWhenWithBranches.kt

@@ -0,0 +1,10 @@
+// "Add else branch" "true"
+fun test() {
+    val a = 12
+    wh<caret>en (a) {
+        in 0..11 -> { /* some code */ }
+        12, 13, 14 -> { /* some code */ }
+        else -> {
+        }
+    }
+}

idea/testData/quickfix/when/afterNoElseInWhenWithoutBranches.kt

@@ -0,0 +1,8 @@
+// "Add else branch" "true"
+fun test() {
+    val a = 12
+    when (a) {
+        else -> {
+        }
+    }
+}

idea/testData/quickfix/when/beforeNoElseInWhenWithBranches.kt

@@ -0,0 +1,8 @@
+// "Add else branch" "true"
+fun test() {
+    val a = 12
+    wh<caret>en (a) {
+        in 0..11 -> { /* some code */ }
+        12, 13, 14 -> { /* some code */ }
+    }
+}

idea/testData/quickfix/when/beforeNoElseInWhenWithoutBranches.kt

@@ -0,0 +1,6 @@
+// "Add else branch" "true"
+fun test() {
+    val a = 12
+    wh<caret>en (a) {
+    }
+}