make method static: warn about broken method references if filed or class need to be passed; NPE (EA-66661 - NPE: MakeMethodStaticProcessor.changeExternalUsage)

java/java-impl/src/com/intellij/refactoring/makeStatic/MakeMethodStaticProcessor.java

@@ -83,7 +83,7 @@ public class MakeMethodStaticProcessor extends MakeMethodOrClassStaticProcessor<
   @Override
   protected MultiMap<PsiElement, String> getConflictDescriptions(UsageInfo[] usages) {
     MultiMap<PsiElement, String> descriptions = super.getConflictDescriptions(usages);
-    if (mySettings.isMakeClassParameter()) {
+    if (mySettings.isMakeClassParameter() || mySettings.isMakeFieldParameters()) {
       for (UsageInfo usage : usages) {
         PsiElement element = usage.getElement();
         if (element instanceof PsiMethodReferenceExpression) {
@@ -329,7 +329,7 @@ public class MakeMethodStaticProcessor extends MakeMethodOrClassStaticProcessor<
         if (anchor != null) {
           anchor = argList.addAfter(fieldRef, anchor);
         }
-        else {
+        else if (argList != null) {
           if (exprs.length > 0) {
             anchor = argList.addBefore(fieldRef, exprs[0]);
           }

java/java-tests/testData/refactoring/makeMethodStatic/afterThisMethodReference.java

@@ -0,0 +1,10 @@
+class Test4 {
+    void test() {
+        Runnable f = Test4::yyy;
+    }
+    
+    String myField = "";
+    static void yyy() {
+        System.out.println(myField);
+    }
+}

java/java-tests/testData/refactoring/makeMethodStatic/beforeThisMethodReference.java

@@ -0,0 +1,10 @@
+class Test4 {
+    void test() {
+        Runnable f = this::yyy;
+    }
+    
+    String myField = "";
+    void yy<caret>y() {
+        System.out.println(myField);
+    }
+}

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

@@ -203,6 +203,10 @@ public class MakeMethodStaticTest extends LightRefactoringTestCase {
     doTest(true);
   }
 
+  public void testThisMethodReference() throws Exception {
+    doTest(false);
+  }
+
   public void testPreserveParametersAlignment() throws Exception {
     doTest();
   }