[java-intentions] IDEA-381804 Error after applying Extract to method reference in the Compact Source File

GitOrigin-RevId: 9944b7f6aa92ca80a9527f5ef230fb0f30da3406

Author: Mikhail Pyltsin

java/java-impl-refactorings/src/com/siyeh/ipp/functional/ExtractToMethodReferenceIntention.java

@@ -73,6 +73,14 @@ public boolean isAvailable(@NotNull Project project, @NotNull Editor editor, @No
         return false;
       }
 
+      //not directly inside an implicitly declared class
+      PsiClass targetClass = PsiUtil.getContainingClass(lambdaExpression);
+      PsiMethod method = PsiTreeUtil.getParentOfType(lambdaExpression, PsiMethod.class, true);
+      if (targetClass == null ||
+          (targetClass instanceof PsiImplicitClass && method != null && method.hasModifierProperty(PsiModifier.STATIC))) {
+        return false;
+      }
+
       PsiExpression asMethodReference = LambdaCanBeMethodReferenceInspection
         .canBeMethodReferenceProblem(body, lambdaExpression.getParameterList().getParameters(), functionalInterfaceType, null);
       if (asMethodReference != null) return false;
@@ -82,8 +90,7 @@ public boolean isAvailable(@NotNull Project project, @NotNull Editor editor, @No
         wrapper.prepareAndCheckExitStatements(toExtract, body);
         PsiVariable[] outputVariables = wrapper.getOutputVariables();
         List<PsiVariable> inputVariables = wrapper.getInputVariables(body, toExtract, outputVariables);
-        return inputVariables.stream()
-          .allMatch(variable -> variable instanceof PsiParameter && ((PsiParameter)variable).getDeclarationScope() == lambdaExpression);
+        return ContainerUtil.and(inputVariables, variable -> variable instanceof PsiParameter && ((PsiParameter)variable).getDeclarationScope() == lambdaExpression);
       }
       catch (PrepareFailedException | ControlFlowWrapper.ExitStatementsNotSameException ignored) {
       }
@@ -102,7 +109,8 @@ public void invoke(@NotNull Project project, @NotNull Editor editor, @NotNull Ps
       PsiElement[] elements = body.getStatements();
 
       HashSet<PsiField> usedFields = new HashSet<>();
-      boolean canBeStatic = CommonJavaRefactoringUtil.canBeStatic(targetClass, lambdaExpression, elements, usedFields) && usedFields.isEmpty();
+      boolean canBeStatic = CommonJavaRefactoringUtil.canBeStatic(targetClass, lambdaExpression, elements, usedFields) &&
+                            usedFields.isEmpty() && !(targetClass instanceof PsiImplicitClass);
       PsiElementFactory elementFactory = JavaPsiFacade.getElementFactory(targetClass.getProject());
       PsiType functionalInterfaceType = lambdaExpression.getFunctionalInterfaceType();
 
@@ -144,7 +152,7 @@ private static void startInplaceRename(Editor editor, PsiMethod method, PsiMetho
     PsiIdentifier nameIdentifier = method.getNameIdentifier();
     if (nameIdentifier == null) return;
     nameIdentifier = CodeInsightUtilCore.forcePsiPostprocessAndRestoreElement(nameIdentifier);
-
+    if (nameIdentifier == null) return;
     //try to navigate to reference name
     editor.getCaretModel().moveToOffset(ObjectUtils.notNull(methodReference.getReferenceNameElement(), nameIdentifier).getTextOffset());
 

java/java-tests/testData/ipp/com/siyeh/ipp/functional/extractToMethodReference/LambdaInImplicitClass.java

@@ -0,0 +1,15 @@
+void main(String[] args) throws IOException {
+  List.of("1").forEach(line -> {
+    Person person = new Person(line);
+    IO.println(person);
+  <caret>});
+}
+
+private record Person(String name) {
+  @Override
+  public String toString() {
+    return "Person{" +
+           "name='" + name + '\'' +
+           '}';
+  }
+}

java/java-tests/testData/ipp/com/siyeh/ipp/functional/extractToMethodReference/LambdaInImplicitClass_after.java

@@ -0,0 +1,17 @@
+void main(String[] args) throws IOException {
+  List.of("1").forEach(this::<caret>accept);
+}
+
+private record Person(String name) {
+  @Override
+  public String toString() {
+    return "Person{" +
+           "name='" + name + '\'' +
+           '}';
+  }
+}
+
+private void accept(String line) {
+  Person person = new Person(line);
+  IO.println(person);
+}

java/java-tests/testData/ipp/com/siyeh/ipp/functional/extractToMethodReference/StaticLambdaInImplicitClass.java

@@ -0,0 +1,15 @@
+static void main(String[] args) throws IOException {
+  List.of("1").forEach(line -> {
+    Person person = new Person(line);
+    IO.println(person);
+  <caret>});
+}
+
+private record Person(String name) {
+  @Override
+  public String toString() {
+    return "Person{" +
+           "name='" + name + '\'' +
+           '}';
+  }
+}

java/java-tests/testSrc/com/siyeh/ipp/functional/ExtractToMethodReferenceTest.java

@@ -15,6 +15,8 @@
  */
 package com.siyeh.ipp.functional;
 
+import com.intellij.pom.java.JavaFeature;
+import com.intellij.testFramework.IdeaTestUtil;
 import com.intellij.testFramework.LightProjectDescriptor;
 import com.siyeh.IntentionPowerPackBundle;
 import com.siyeh.ipp.IPPTestCase;
@@ -86,6 +88,14 @@ public void testAnnotatedLambdaParameterVar() {
     doTest();
   }
 
+  public void testLambdaInImplicitClass() {
+    IdeaTestUtil.withLevel(getModule(), JavaFeature.IMPLICIT_CLASSES.getStandardLevel(), this::doTest);
+  }
+
+  public void testStaticLambdaInImplicitClass() {
+    IdeaTestUtil.withLevel(getModule(), JavaFeature.IMPLICIT_CLASSES.getStandardLevel(), this::assertIntentionNotAvailable);
+  }
+
   @Override
   protected String getIntentionName() {
     return IntentionPowerPackBundle.message("extract.to.method.reference.intention.name");