extract method from expression: declare necessary variables inside; reassign result when it was assigned before (IDEA-63593)

java/java-impl/src/com/intellij/refactoring/extractMethod/ExtractMethodProcessor.java

@@ -718,6 +718,7 @@ public class ExtractMethodProcessor implements MatchProvider {
       deleteExtracted();
     }
     else {
+      declareNecessaryVariablesInsideBody(body);
       if (myHasExpressionOutput) {
         PsiReturnStatement returnStatement = (PsiReturnStatement)myElementFactory.createStatementFromText("return x;", null);
         final PsiExpression returnValue = RefactoringUtil.convertInitializerToNormalExpression(myExpression, myForcedReturnType);
@@ -729,7 +730,11 @@ public class ExtractMethodProcessor implements MatchProvider {
         statement.getExpression().replace(myExpression);
         body.add(statement);
       }
-      final PsiElement replacement = IntroduceVariableBase.replace(myExpression, myMethodCall, myProject);
+      PsiExpression expression2Replace = myExpression;
+      if (myExpression instanceof PsiAssignmentExpression) {
+        expression2Replace = ((PsiAssignmentExpression)myExpression).getRExpression();
+      }
+      final PsiElement replacement = IntroduceVariableBase.replace(expression2Replace, myMethodCall, myProject);
       myMethodCall = PsiTreeUtil.getParentOfType(replacement.findElementAt(replacement.getText().indexOf(myMethodCall.getText())), PsiMethodCallExpression.class);
     }
 

java/java-tests/testData/refactoring/extractMethod/ExtractAssignmentExpression.java

@@ -0,0 +1,6 @@
+class Foo {
+  void foo() {
+    int x = 0;
+    int y = <selection>x = 1</selection>;
+  }
+}

java/java-tests/testData/refactoring/extractMethod/ExtractAssignmentExpressionFromStatement.java

@@ -0,0 +1,7 @@
+
+class Foo {
+  void foo() {
+    int x = 0;
+    <selection>x = 1</selection>;
+  }
+}

java/java-tests/testData/refactoring/extractMethod/ExtractAssignmentExpressionFromStatement_after.java

@@ -0,0 +1,12 @@
+
+class Foo {
+  void foo() {
+    int x = 0;
+      newMethod();
+  }
+
+    private void newMethod() {
+        int x;
+        x = 1;
+    }
+}

java/java-tests/testData/refactoring/extractMethod/ExtractAssignmentExpression_after.java

@@ -0,0 +1,11 @@
+class Foo {
+  void foo() {
+    int x = 0;
+    int y = x = newMethod();
+  }
+
+    private int newMethod() {
+        int x;
+        return x = 1;
+    }
+}

java/java-tests/testSrc/com/intellij/refactoring/ExtractMethodTest.java

@@ -151,6 +151,14 @@ public class ExtractMethodTest extends LightCodeInsightTestCase {
     doTest();
   }
 
+  public void testExtractAssignmentExpression() throws Exception {
+    doTest();
+  }
+
+  public void testExtractAssignmentExpressionFromStatement() throws Exception {
+    doTest();
+  }
+
   public void _testExtractFromTryFinally2() throws Exception {  // IDEADEV-11844
     doTest();
   }