introduce variable from yet standalone switch expression (IDEA-206523)

java/java-impl/src/com/intellij/refactoring/introduceVariable/IntroduceVariableBase.java

@@ -329,9 +329,18 @@ public abstract class IntroduceVariableBase extends IntroduceHandlerBase {
       if (statements.length == 1) {
         if (statements[0] instanceof PsiExpressionStatement) {
           tempExpr = ((PsiExpressionStatement) statements[0]).getExpression();
-        } else if (statements[0] instanceof PsiReturnStatement) {
+        }
+        else if (statements[0] instanceof PsiReturnStatement) {
           tempExpr = ((PsiReturnStatement)statements[0]).getReturnValue();
         }
+        else if (statements[0] instanceof PsiSwitchStatement) {
+          PsiExpression expr = JavaPsiFacade.getElementFactory(project).createExpressionFromText(statements[0].getText(), statements[0]);
+          TextRange range = statements[0].getTextRange();
+          final RangeMarker rangeMarker = FileDocumentManager.getInstance().getDocument(file.getVirtualFile()).createRangeMarker(range);
+          expr.putUserData(ElementToWorkOn.TEXT_RANGE, rangeMarker);
+          expr.putUserData(ElementToWorkOn.PARENT, statements[0]);
+          return expr;
+        }
       }
     }
 

java/java-tests/testData/refactoring/introduceVariable/FromSwitchStatementJava12Preview.after.java

@@ -0,0 +1,8 @@
+class MyTest {
+    {
+        String temp = switch (0) {
+            default:
+                break "";
+        };
+    }
+}

java/java-tests/testData/refactoring/introduceVariable/FromSwitchStatementJava12Preview.java

@@ -0,0 +1,7 @@
+class MyTest {
+    {
+        <selection>switch (0) {
+            default: break "";
+        }</selection>
+    }
+}

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

@@ -259,6 +259,10 @@ public class IntroduceVariableTest extends LightCodeInsightTestCase {
     doTest(new MockIntroduceVariableHandler("temp", true, false, false, CommonClassNames.JAVA_LANG_STRING));
   }
 
+  public void testFromSwitchStatementJava12Preview() {
+    doTest(new MockIntroduceVariableHandler("temp", true, false, false, CommonClassNames.JAVA_LANG_STRING));
+  }
+
   public void testDeclareTernary() {
     doTest(new MockIntroduceVariableHandler("temp", true, false, false, CommonClassNames.JAVA_LANG_STRING));
   }