Fix NullAnnotationsRewriteOperations to handle AnnotatableType (eclipse-jdt#2080)

- add new test to QuickFixTest1d8
- fixes eclipse-jdt#2076

Author: jjohnstn

org.eclipse.jdt.ui.tests/ui/org/eclipse/jdt/ui/tests/quickfix/QuickFixTest1d8.java

@@ -1822,6 +1822,52 @@ public class E {
 		assertEqualString(preview, str);
 	}
 
+	// remove redundant @NonNull on type
+	@Test
+	public void testRemoveRedundantNonNull2() throws Exception {
+		Hashtable<String, String> options= JavaCore.getOptions();
+		options.put(JavaCore.COMPILER_ANNOTATION_NULL_ANALYSIS, JavaCore.ENABLED);
+		JavaCore.setOptions(options);
+
+		JavaProjectHelper.addLibrary(fJProject1, new Path(Java1d8ProjectTestSetup.getJdtAnnotations20Path()));
+		IPackageFragment pack1= fSourceFolder.createPackageFragment("test1", false, null);
+		String str1= """
+			package test1;
+			import java.util.List;
+			import org.eclipse.jdt.annotation.NonNull;
+			import org.eclipse.jdt.annotation.NonNullByDefault;
+			@NonNullByDefault
+			public class E {
+				void m(@NonNull List<String> l) {
+					// empty block
+				}
+			}
+			""";
+		ICompilationUnit cu= pack1.createCompilationUnit("E.java", str1, false, null);
+
+		CompilationUnit astRoot= getASTRoot(cu);
+		int offset= str1.indexOf("@NonNull ");
+		AssistContext context= new AssistContext(cu, offset, 0);
+		ArrayList<IJavaCompletionProposal> proposals= collectCorrections(cu, astRoot, 1, context);
+		assertNumberOfProposals(proposals, 4);
+		CUCorrectionProposal proposal= (CUCorrectionProposal)proposals.get(0);
+		String preview= getPreviewContent(proposal);
+
+		String str= """
+			package test1;
+			import java.util.List;
+
+			import org.eclipse.jdt.annotation.NonNullByDefault;
+			@NonNullByDefault
+			public class E {
+				void m(List<String> l) {
+					// empty block
+				}
+			}
+			""";
+		assertEqualString(preview, str);
+	}
+
 	@Test
 	public void testBug514580_avoidRedundantNonNullInChangeMethodSignatureFix() throws Exception {
 		Hashtable<String, String> options= JavaCore.getOptions();

org.eclipse.jdt.ui/core extension/org/eclipse/jdt/internal/corext/fix/NullAnnotationsRewriteOperations.java

@@ -34,6 +34,7 @@
 import org.eclipse.jdt.core.compiler.IProblem;
 import org.eclipse.jdt.core.dom.AST;
 import org.eclipse.jdt.core.dom.ASTNode;
+import org.eclipse.jdt.core.dom.AnnotatableType;
 import org.eclipse.jdt.core.dom.Annotation;
 import org.eclipse.jdt.core.dom.ArrayType;
 import org.eclipse.jdt.core.dom.ChildListPropertyDescriptor;
@@ -72,6 +73,7 @@
 import org.eclipse.jdt.internal.corext.dom.Bindings;
 import org.eclipse.jdt.internal.corext.fix.CompilationUnitRewriteOperationsFixCore.CompilationUnitRewriteOperationWithSourceRange;
 import org.eclipse.jdt.internal.corext.refactoring.structure.CompilationUnitRewrite;
+import org.eclipse.jdt.internal.corext.refactoring.structure.ImportRemover;
 import org.eclipse.jdt.internal.corext.util.Messages;
 
 import org.eclipse.jdt.ui.text.java.IProblemLocation;
@@ -342,6 +344,7 @@ public RemoveRedundantAnnotationRewriteOperation(CompilationUnit compilationUnit
 		public void rewriteASTInternal(CompilationUnitRewrite cuRewrite, LinkedProposalModelCore linkedModel) throws CoreException {
 			TextEditGroup group= createTextEditGroup(FixMessages.NullAnnotationsRewriteOperations_remove_redundant_nullness_annotation, cuRewrite);
 			ASTRewrite astRewrite= cuRewrite.getASTRewrite();
+			ImportRemover remover= cuRewrite.getImportRemover();
 
 			CompilationUnit astRoot= fCompilationUnit;
 			ASTNode selectedNode= fProblem.getCoveringNode(astRoot);
@@ -357,6 +360,8 @@ public void rewriteASTInternal(CompilationUnitRewrite cuRewrite, LinkedProposalM
 				} else if (selectedNode instanceof MethodDeclaration) {
 					MethodDeclaration methodDeclaration= (MethodDeclaration) selectedNode;
 					modifiers= methodDeclaration.modifiers();
+				} else if (selectedNode instanceof AnnotatableType annotatableType) {
+					modifiers= annotatableType.annotations();
 				} else {
 					return;
 				}
@@ -368,6 +373,7 @@ public void rewriteASTInternal(CompilationUnitRewrite cuRewrite, LinkedProposalM
 						String name= annotationBinding.getName();
 						if (name.equals(NullAnnotationsFix.getNonNullAnnotationName(fCompilationUnit.getJavaElement(), true))) {
 							astRewrite.remove(annotation, group);
+							remover.registerRemovedNode(annotation);
 						}
 					}
 				}