test case & adapted grammar for annotated generic return type

public static <T> @Nullable T getNullableEnum() {
		return null;
	}

pmd-java/etc/grammar/Java.jjt

@@ -1488,7 +1488,7 @@ void MethodDeclaration(int modifiers) :
 {jjtThis.setModifiers(modifiers);}
 {
   [ TypeParameters() ]
-  ResultType() MethodDeclarator() [ "throws" NameList() ]
+  [(Annotation() {checkForBadTypeAnnotations();})+] ResultType() MethodDeclarator() [ "throws" NameList() ]
   ( Block() | ";" )
 }
 

pmd-java/src/test/resources/net/sourceforge/pmd/ast/ParserCornerCases18.java

@@ -180,6 +180,10 @@ public class ParserCornerCases18 {
 	public static <T extends @NonNull Enum<T>> T getEnum() {
 		return null;
 	}
+
+	public static <T> @Nullable T getNullableEnum() {
+		return null;
+	}
 	
 	public Object[] createNonNullArray() {
 		return new Object @NonNull[0];