move instance method with method ref: ensure qualifier is not deleted

IDEA-181919

java/java-impl/src/com/intellij/refactoring/move/moveInstanceMethod/MoveInstanceMethodProcessor.java

@@ -500,8 +500,13 @@ public class MoveInstanceMethodProcessor extends BaseRefactoringProcessor{
                     }
                   }
                 }
-                //Target is a field, replace target.m -> m
-                qualifier.delete();
+                if (expression instanceof PsiMethodReferenceExpression) {
+                  qualifier.replace(factory.createExpressionFromText("this", null));
+                }
+                else {
+                  //Target is a field, replace target.m -> m
+                  qualifier.delete();
+                }
                 return;
               }
               if (myTargetVariable.equals(resolved)) {

java/java-tests/testData/refactoring/moveInstanceMethod/MethodReferenceWithThisTarget.java

@@ -0,0 +1,12 @@
+import java.util.function.Consumer;
+
+class Source {
+  public void f<caret>oo(Destination destination) {
+    Consumer<String> doSomething = destination::doSomething;
+  }
+}
+
+class Destination {
+  public void doSomething(String s) {
+  }
+}

java/java-tests/testData/refactoring/moveInstanceMethod/MethodReferenceWithThisTarget.java.after

@@ -0,0 +1,13 @@
+import java.util.function.Consumer;
+
+class Source {
+}
+
+class Destination {
+  public void doSomething(String s) {
+  }
+
+    public void foo() {
+      Consumer<String> doSomething = this::doSomething;
+    }
+}

java/java-tests/testSrc/com/intellij/java/refactoring/moveMethod/MoveInstanceMethodTest.java

@@ -116,6 +116,10 @@ public class MoveInstanceMethodTest extends LightRefactoringTestCase {
     doTest(false, 0);
   }
 
+  public void testMethodReferenceWithThisTarget() {
+    BaseRefactoringProcessor.ConflictsInTestsException.withIgnoredConflicts(() -> doTest(true, 0));
+  }
+
   public void testMethodReferenceToExpandToLambda() {
     BaseRefactoringProcessor.ConflictsInTestsException.withIgnoredConflicts(() -> doTest(true, 1));
   }