functional expressions: push down conflicts

java/java-impl/src/com/intellij/refactoring/memberPushDown/PushDownProcessor.java

@@ -29,6 +29,7 @@ import com.intellij.psi.*;
 import com.intellij.psi.codeStyle.JavaCodeStyleManager;
 import com.intellij.psi.javadoc.PsiDocComment;
 import com.intellij.psi.search.searches.ClassInheritorsSearch;
+import com.intellij.psi.search.searches.FunctionalExpressionSearch;
 import com.intellij.psi.search.searches.ReferencesSearch;
 import com.intellij.psi.util.MethodSignatureUtil;
 import com.intellij.psi.util.PsiTreeUtil;
@@ -46,6 +47,7 @@ import com.intellij.usageView.UsageInfo;
 import com.intellij.usageView.UsageViewDescriptor;
 import com.intellij.util.Function;
 import com.intellij.util.IncorrectOperationException;
+import com.intellij.util.Processor;
 import com.intellij.util.containers.HashSet;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
@@ -117,11 +119,32 @@ public class PushDownProcessor extends BaseRefactoringProcessor {
   @NotNull
   protected UsageInfo[] findUsages() {
     final PsiClass[] inheritors = ClassInheritorsSearch.search(myClass, false).toArray(PsiClass.EMPTY_ARRAY);
-    UsageInfo[] usages = new UsageInfo[inheritors.length];
-    for (int i = 0; i < inheritors.length; i++) {
-      usages[i] = new UsageInfo(inheritors[i]);
+    final List<UsageInfo> usages = new ArrayList<UsageInfo>(inheritors.length);
+    for (PsiClass inheritor : inheritors) {
+      usages.add(new UsageInfo(inheritor));
     }
-    return usages;
+
+    final PsiMethod interfaceMethod = LambdaUtil.getFunctionalInterfaceMethod(myClass);
+    if (interfaceMethod != null && isMoved(interfaceMethod)) {
+      FunctionalExpressionSearch.search(myClass).forEach(new Processor<PsiFunctionalExpression>() {
+        @Override
+        public boolean process(PsiFunctionalExpression expression) {
+          usages.add(new UsageInfo(expression));
+          return true;
+        }
+      });
+    }
+
+    return usages.toArray(new UsageInfo[usages.size()]);
+  }
+
+  private boolean isMoved(PsiMember member) {
+    for (MemberInfo info : myMemberInfos) {
+      if (member == info.getMember()) {
+        return true;
+      }
+    }
+    return false;
   }
 
   protected boolean preprocessUsages(final Ref<UsageInfo[]> refUsages) {
@@ -167,6 +190,13 @@ public class PushDownProcessor extends BaseRefactoringProcessor {
     if (!ProgressManager.getInstance().runProcessWithProgressSynchronously(runnable, RefactoringBundle.message("detecting.possible.conflicts"), true, myProject)) {
       return false;
     }
+
+    for (UsageInfo info : usagesIn) {
+      final PsiElement element = info.getElement();
+      if (element instanceof PsiFunctionalExpression) {
+        pushDownConflicts.getConflicts().putValue(element, RefactoringBundle.message("functional.interface.broken"));
+      }
+    }
     return showConflicts(pushDownConflicts.getConflicts(), usagesIn);
   }
 

java/java-tests/testData/refactoring/pushDown/FunctionalExpression.java

@@ -0,0 +1,12 @@
+interface Base {
+    default void foo() {
+        System.out.println("Hi there.");
+    }
+    void ba<caret>r();
+}
+
+class Test {
+  {
+    Base base = () -> {};
+  }
+}

java/java-tests/testData/refactoring/pushDown/FunctionalExpressionDefaultMethod.java

@@ -0,0 +1,14 @@
+interface Base {
+    default void foo<caret>() {
+        System.out.println("Hi there.");
+    }
+    void bar();
+}
+
+class Test {
+  {
+    Base base = () -> {};
+  }
+}
+
+class Child implements Base {}

java/java-tests/testData/refactoring/pushDown/FunctionalExpressionDefaultMethod_after.java

@@ -0,0 +1,15 @@
+interface Base {
+    void bar();
+}
+
+class Test {
+  {
+    Base base = () -> {};
+  }
+}
+
+class Child implements Base {
+    public void foo() {
+    System.out.println("Hi there.");
+}
+}

java/java-tests/testData/refactoring/pushDown/FunctionalExpression_after.java

@@ -0,0 +1,11 @@
+interface Base {
+    default void foo() {
+        System.out.println("Hi there.");
+    }
+}
+
+class Test {
+  {
+    Base base = () -> {};
+  }
+}

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

@@ -54,6 +54,9 @@ public class PushDownTest extends LightRefactoringTestCase {
   public void testExtensionMethodToInterface() { doTest(); }
   public void testExtensionMethodToClass() { doTest(); }
 
+  public void testFunctionalExpression() { doTest(true);}
+  public void testFunctionalExpressionDefaultMethod() { doTest();}
+
   private void doTest() {
     doTest(false);
   }

platform/platform-resources-en/src/messages/RefactoringBundle.properties

@@ -494,6 +494,7 @@ keep.abstract.column.header=Keep abstract
 push.down.javadoc.panel.title=JavaDoc for abstracts
 push.down.members.elements.header=Push down members from
 interface.0.does.not.have.inheritors=Interface {0} does not have inheritors
+functional.interface.broken=Functional expression demands functional interface to have exact one method
 class.0.does.not.have.inheritors=Class {0} does not have inheritors
 push.down.will.delete.members=Pushing members down will result in them being deleted. Would you like to create a new subclass?
 edit.migration.map.title=Edit Migration Map