IPP: keep block if declarations would conflict otherwise

plugins/IntentionPowerPak/src/com/siyeh/ipp/exceptions/ConvertCatchToThrowsIntention.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2007-2014 Bas Leijdekkers
+ * Copyright 2007-2016 Bas Leijdekkers
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -20,6 +20,7 @@ import com.intellij.openapi.project.Project;
 import com.intellij.psi.*;
 import com.intellij.psi.util.PsiTreeUtil;
 import com.intellij.util.IncorrectOperationException;
+import com.siyeh.ig.psiutils.VariableSearchUtils;
 import com.siyeh.ipp.base.Intention;
 import com.siyeh.ipp.base.PsiElementPredicate;
 import org.jetbrains.annotations.NotNull;
@@ -69,12 +70,18 @@ public class ConvertCatchToThrowsIntention extends Intention {
       if (tryBlock == null) {
         return;
       }
-      final PsiElement first = tryBlock.getFirstBodyElement();
-      final PsiElement last = tryBlock.getLastBodyElement();
-      if (first != null && last != null) {
-        tryStatement.getParent().addRangeAfter(first, last, tryStatement);
+      final PsiCodeBlock parentCodeBlock = PsiTreeUtil.getParentOfType(tryStatement, PsiCodeBlock.class);
+      if (parentCodeBlock == null || !VariableSearchUtils.containsConflictingDeclarations(tryBlock, parentCodeBlock)) {
+        final PsiElement first = tryBlock.getFirstBodyElement();
+        final PsiElement last = tryBlock.getLastBodyElement();
+        if (first != null && last != null) {
+          tryStatement.getParent().addRangeAfter(first, last, tryStatement);
+        }
+        tryStatement.delete();
+      }
+      else {
+        tryStatement.replace(tryBlock);
       }
-      tryStatement.delete();
     }
   }
 

plugins/IntentionPowerPak/test/com/siyeh/ipp/exceptions/catchToThrows/TryWithConflictingDeclaration.java

@@ -0,0 +1,15 @@
+class TryWithConflictingDeclaration {
+
+  abstract void f(String s) throws Exception;
+
+  void m() {
+    try {
+            /* important comment */
+      String s = "hello";
+      f();
+      // another comment
+    } catch (Exception <caret>ignore) { }
+    String s = "bye";
+    System.out.println(s);
+  }
+}

plugins/IntentionPowerPak/test/com/siyeh/ipp/exceptions/catchToThrows/TryWithConflictingDeclaration_after.java

@@ -0,0 +1,15 @@
+class TryWithConflictingDeclaration {
+
+  abstract void f(String s) throws Exception;
+
+  void m() throws Exception {
+      {
+              /* important comment */
+        String s = "hello";
+        f();
+        // another comment
+      }
+    String s = "bye";
+    System.out.println(s);
+  }
+}

plugins/IntentionPowerPak/testSrc/com/siyeh/ipp/exceptions/ConvertCatchToThrowsTest.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2000-2014 JetBrains s.r.o.
+ * Copyright 2000-2016 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.
@@ -18,6 +18,9 @@ package com.siyeh.ipp.exceptions;
 import com.siyeh.IntentionPowerPackBundle;
 import com.siyeh.ipp.IPPTestCase;
 
+/**
+ * @see ConvertCatchToThrowsIntention
+ */
 public class ConvertCatchToThrowsTest extends IPPTestCase {
   public void testSingleCatch() { doTest(); }
   public void testPluralCatches() { doTest(); }
@@ -27,6 +30,7 @@ public class ConvertCatchToThrowsTest extends IPPTestCase {
   public void testExistingThrows() { doTest(); }
   public void testLambda() { doTest(); }
   public void testLeaveFinallySection() { doTest(); }
+  public void testTryWithConflictingDeclaration() { doTest(); }
 
   @Override
   protected String getIntentionName() {