IDEA-231427 Extract method produces incompilable code when extracting expression that produces a pattern variable

GitOrigin-RevId: 3fbd29e6543e21af934c4de8899bd6ed5bda6965

java/java-psi-impl/src/com/intellij/psi/controlFlow/ControlFlowAnalyzer.java

@@ -1599,6 +1599,15 @@ class ControlFlowAnalyzer extends JavaElementVisitor {
     final PsiExpression operand = expression.getOperand();
     operand.accept(this);
 
+    PsiPattern pattern = expression.getPattern();
+    if (pattern instanceof PsiTypeTestPattern) {
+      PsiPatternVariable variable = ((PsiTypeTestPattern)pattern).getPatternVariable();
+
+      if (variable != null) {
+        myCurrentFlow.addInstruction(new WriteVariableInstruction(variable));
+      }
+    }
+
     finishElement(expression);
   }
 

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

@@ -0,0 +1,7 @@
+class X {
+    void test(Object obj) {
+        if (<selection>obj instanceof String s</selection> && s.length() > 5) {
+            System.out.println(s);
+        }
+    }
+}

java/java-tests/testData/refactoring/extractMethod/PatternVariableIntroduced2.java

@@ -0,0 +1,7 @@
+class X {
+    void test(Object obj) {
+        if (<selection>obj instanceof String s && s.length() > 5</selection>) {
+            System.out.println(s);
+        }
+    }
+}

java/java-tests/testData/refactoring/extractMethod/PatternVariableIntroduced3.java

@@ -0,0 +1,7 @@
+class X {
+    void test(Object obj) {
+        if (<selection>obj instanceof String s && s.length() > 5</selection>) {
+            System.out.println("found");
+        }
+    }
+}

java/java-tests/testData/refactoring/extractMethod/PatternVariableIntroduced3_after.java

@@ -0,0 +1,11 @@
+class X {
+    void test(Object obj) {
+        if (newMethod(obj)) {
+            System.out.println("found");
+        }
+    }
+
+    private boolean newMethod(Object obj) {
+        return obj instanceof String s && s.length() > 5;
+    }
+}

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

@@ -945,6 +945,18 @@ public class ExtractMethodTest extends LightJavaCodeInsightTestCase {
     doTestWithLanguageLevel(LanguageLevel.JDK_14_PREVIEW);
   }
 
+  public void testPatternVariableIntroduced() throws Exception {
+    doExitPointsTest(false);
+  }
+
+  public void testPatternVariableIntroduced2() throws Exception {
+    doExitPointsTest(false);
+  }
+
+  public void testPatternVariableIntroduced3() throws Exception {
+    doTestWithLanguageLevel(LanguageLevel.JDK_14_PREVIEW);
+  }
+
   public void testSuggestChangeSignatureWithChangedParameterName() throws Exception {
     configureByFile(BASE_PATH + getTestName(false) + ".java");
     boolean success = performExtractMethod(true, true, getEditor(), getFile(), getProject(), false, null, false, "p");