process diamonds on safe delete of type parameter (IDEA-73968)

java/java-impl/src/com/intellij/refactoring/safeDelete/JavaSafeDeleteProcessor.java

@@ -367,22 +367,27 @@ public class JavaSafeDeleteProcessor implements SafeDeleteProcessorDelegate {
   private static void findTypeParameterExternalUsages(final PsiTypeParameter typeParameter, final Collection<UsageInfo> usages) {
     PsiTypeParameterListOwner owner = typeParameter.getOwner();
     if (owner != null) {
-      final int index = owner.getTypeParameterList().getTypeParameterIndex(typeParameter);
+      final PsiTypeParameterList parameterList = owner.getTypeParameterList();
+      if (parameterList != null) {
+        final int paramsCount = parameterList.getTypeParameters().length;
+        final int index = parameterList.getTypeParameterIndex(typeParameter);
 
-      ReferencesSearch.search(owner).forEach(new Processor<PsiReference>() {
-        public boolean process(final PsiReference reference) {
-          if (reference instanceof PsiJavaCodeReferenceElement) {
-            final PsiReferenceParameterList parameterList = ((PsiJavaCodeReferenceElement)reference).getParameterList();
-            if (parameterList != null) {
-              PsiTypeElement[] typeArgs = parameterList.getTypeParameterElements();
-              if (typeArgs.length > index) {
-                usages.add(new SafeDeleteReferenceJavaDeleteUsageInfo(typeArgs[index], typeParameter, true));
+        ReferencesSearch.search(owner).forEach(new Processor<PsiReference>() {
+          public boolean process(final PsiReference reference) {
+            if (reference instanceof PsiJavaCodeReferenceElement) {
+              final PsiReferenceParameterList parameterList = ((PsiJavaCodeReferenceElement)reference).getParameterList();
+              if (parameterList != null) {
+                PsiTypeElement[] typeArgs = parameterList.getTypeParameterElements();
+                if (typeArgs.length > index) {
+                  if (typeArgs.length == 1 && paramsCount > 1 && typeArgs[0].getType() instanceof PsiDiamondType) return true;
+                  usages.add(new SafeDeleteReferenceJavaDeleteUsageInfo(typeArgs[index], typeParameter, true));
+                }
               }
             }
+            return true;
           }
-          return true;
-        }
-      });
+        });
+      }
     }
   }
 

java/java-tests/testData/refactoring/safeDelete/LastTypeParam.java

@@ -0,0 +1,8 @@
+public class Test<T<caret>T> {}
+
+class Foo {
+        void test() {
+                Test<String> test = new Test<>();
+                Test<String> test2 = new Test<String>();
+        }
+}

java/java-tests/testData/refactoring/safeDelete/LastTypeParam_after.java

@@ -0,0 +1,8 @@
+public class Test {}
+
+class Foo {
+        void test() {
+                Test test = new Test();
+                Test test2 = new Test();
+        }
+}

java/java-tests/testData/refactoring/safeDelete/TypeParamFromDiamond.java

@@ -0,0 +1,8 @@
+public class Test<<caret>T, U> {}
+
+class Foo {
+        void test() {
+                Test<String, Long> test = new Test<>();
+                Test<String, Long> test2 = new Test<String, Long>();
+        }
+}

java/java-tests/testData/refactoring/safeDelete/TypeParamFromDiamond_after.java

@@ -0,0 +1,8 @@
+public class Test<U> {}
+
+class Foo {
+        void test() {
+                Test<Long> test = new Test<>();
+                Test<Long> test2 = new Test<Long>();
+        }
+}

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

@@ -134,6 +134,16 @@ public class SafeDeleteTest extends MultiFileTestCase {
     doSingleFileTest();
   }
 
+  public void testLastTypeParam() throws Exception {
+    LanguageLevelProjectExtension.getInstance(getProject()).setLanguageLevel(LanguageLevel.JDK_1_7);
+    doSingleFileTest();
+  }
+
+  public void testTypeParamFromDiamond() throws Exception {
+    LanguageLevelProjectExtension.getInstance(getProject()).setLanguageLevel(LanguageLevel.JDK_1_7);
+    doSingleFileTest();
+  }
+
   private void doTest(@NonNls final String qClassName) throws Exception {
     doTest(new PerformAction() {
       @Override