ChainCallJoinLinesHandler: disable when builder variable is self-referenced

java/java-impl/src/com/intellij/codeInsight/editorActions/ChainCallJoinLinesHandler.java

@@ -4,6 +4,8 @@ package com.intellij.codeInsight.editorActions;
 import com.intellij.codeInsight.PsiEquivalenceUtil;
 import com.intellij.openapi.editor.Document;
 import com.intellij.psi.*;
+import com.intellij.psi.search.LocalSearchScope;
+import com.intellij.psi.search.searches.ReferencesSearch;
 import com.intellij.psi.util.PsiTreeUtil;
 import com.siyeh.ig.psiutils.ExpressionUtils;
 import org.jetbrains.annotations.NotNull;
@@ -53,6 +55,7 @@ public class ChainCallJoinLinesHandler implements JoinLinesHandlerDelegate {
     if (!ExpressionUtils.isReferenceTo(qualifier, var)) return false;
     PsiType type = nextCall.getType();
     if (type == null || !type.equals(initializer.getType())) return false;
+    if (ReferencesSearch.search(var, new LocalSearchScope(nextCall)).findAll().size() > 1) return false;
     qualifier.replace(initializer);
     initializer.replace(nextCall);
     return true;

java/java-tests/testData/codeInsight/joinLines/DeclarationAndCallSelfRef.java

@@ -0,0 +1,8 @@
+class Foo {
+    void test() {
+        <caret>StringBuilder sb = new StringBuilder();
+        sb.append(sb);
+        sb.append("bar");
+        sb.append("baz");
+    }
+}

java/java-tests/testData/codeInsight/joinLines/DeclarationAndCallSelfRef_after.java

@@ -0,0 +1,7 @@
+class Foo {
+    void test() {
+        StringBuilder sb = new StringBuilder();<caret>sb.append(sb);
+        sb.append("bar");
+        sb.append("baz");
+    }
+}

java/java-tests/testSrc/com/intellij/java/codeInsight/JoinLinesTest.java

@@ -44,6 +44,7 @@ public class JoinLinesTest extends LightCodeInsightTestCase {
   public void testCallChain2() { doTest(); }
   public void testCallChainWrong() { doTest(); }
   public void testDeclarationAndCall() { doTest(); }
+  public void testDeclarationAndCallSelfRef() { doTest(); }
   public void testAssignmentAndCall() { doTest(); }
 
   public void testSCR3493() {