remove redundant else: check all then clauses (IDEA-58136)

java/java-impl/src/com/intellij/codeInsight/daemon/impl/quickfix/RemoveRedundantElseAction.java

@@ -26,6 +26,7 @@ import com.intellij.psi.controlFlow.*;
 import com.intellij.psi.util.PsiTreeUtil;
 import com.intellij.util.IncorrectOperationException;
 import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
 
 /**
  * @author ven
@@ -53,20 +54,38 @@ public class RemoveRedundantElseAction extends PsiElementBaseIntentionAction {
       if (thenBranch == null) return false;
       PsiElement block = PsiTreeUtil.getParentOfType(ifStatement, PsiCodeBlock.class);
       if (block != null) {
-        try {
-          ControlFlow controlFlow = ControlFlowFactory.getInstance(project).getControlFlow(block, LocalsOrMyInstanceFieldsControlFlowPolicy.getInstance());
-          int startOffset = controlFlow.getStartOffset(thenBranch);
-          int endOffset = controlFlow.getEndOffset(thenBranch);
-          return startOffset != -1 && endOffset != -1 && !ControlFlowUtil.canCompleteNormally(controlFlow, startOffset,endOffset);
-        }
-        catch (AnalysisCanceledException e) {
-          return false;
+        while (cantCompleteNormally(thenBranch, block)) {
+          thenBranch = getPrevThenBranch(thenBranch);
+          if (thenBranch == null) return true;
         }
+        return false;
       }
     }
     return false;
   }
 
+  @Nullable
+  private static PsiStatement getPrevThenBranch(@NotNull PsiElement thenBranch) {
+    final PsiElement ifStatement = thenBranch.getParent();
+    final PsiElement parent = ifStatement.getParent();
+    if (parent instanceof PsiIfStatement && ((PsiIfStatement)parent).getElseBranch() == ifStatement) {
+      return ((PsiIfStatement)parent).getThenBranch();
+    }
+    return null;
+  }
+
+  private static boolean cantCompleteNormally(@NotNull PsiStatement thenBranch, PsiElement block) {
+    try {
+      ControlFlow controlFlow = ControlFlowFactory.getInstance(thenBranch.getProject()).getControlFlow(block, LocalsOrMyInstanceFieldsControlFlowPolicy.getInstance());
+      int startOffset = controlFlow.getStartOffset(thenBranch);
+      int endOffset = controlFlow.getEndOffset(thenBranch);
+      return startOffset != -1 && endOffset != -1 && !ControlFlowUtil.canCompleteNormally(controlFlow, startOffset, endOffset);
+    }
+    catch (AnalysisCanceledException e) {
+      return false;
+    }
+  }
+
   public void invoke(@NotNull Project project, Editor editor, PsiFile file) throws IncorrectOperationException {
     if (!CodeInsightUtilBase.prepareFileForWrite(file)) return;
     PsiElement elementAt = file.findElementAt(editor.getCaretModel().getOffset());

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/quickFix/removeRedundantElse/after1.java

@@ -0,0 +1,13 @@
+// "Remove Redundant 'else'" "true"
+class a {
+  void foo() {
+    int a = 0;
+    int b = 0;
+    if (a != b) {
+      return;
+    }
+      a = b;
+      a++;
+  }
+}
+

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/quickFix/removeRedundantElse/before1.java

@@ -0,0 +1,14 @@
+// "Remove Redundant 'else'" "true"
+class a {
+  void foo() {
+    int a = 0;
+    int b = 0;
+    if (a != b) {
+      return;
+    } e<caret>lse {
+      a = b;
+    }
+    a++;
+  }
+}
+

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/quickFix/removeRedundantElse/beforeIfElseChain.java

@@ -0,0 +1,17 @@
+// "Remove Redundant 'else'" "false"
+class a {
+  void foo() {
+    int a = 0;
+    int b = 0;
+    if (a != b) {
+      a = 10;
+    } else if (a + 1 == b) {
+      return;
+    }
+    e<caret>lse {
+      a = b;
+    }
+    a++;
+  }
+}
+

java/java-tests/testSrc/com/intellij/codeInsight/daemon/quickFix/RemoveRedundantElseActionTest.java

@@ -0,0 +1,31 @@
+/*
+ * Copyright 2000-2010 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.intellij.codeInsight.daemon.quickFix;
+
+/**
+ * User: anna
+ * Date: Aug 30, 2010
+ */
+public class RemoveRedundantElseActionTest extends LightQuickFixTestCase {
+
+  public void test() throws Exception { doAllTests(); }
+
+  protected String getBasePath() {
+    return "/codeInsight/daemonCodeAnalyzer/quickFix/removeRedundantElse";
+  }
+
+}
+