test case and fix for

public static <T extends @NonNull Enum<T>> getEnum() {
		return null;
	}

pmd-java/etc/grammar/Java.jjt

@@ -1416,7 +1416,7 @@ void TypeParameter():
 void TypeBound():
 {}
 {
-   "extends" ClassOrInterfaceType() ( "&" ClassOrInterfaceType() )*
+   "extends" ((Annotation() {checkForBadTypeAnnotations();})*) ClassOrInterfaceType() ( "&" ((Annotation() {checkForBadTypeAnnotations();})*) ClassOrInterfaceType() )*
 }
 
 void ClassOrInterfaceBody():

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

@@ -177,6 +177,10 @@ public class ParserCornerCases18 {
 		return null;
 	}
 	
+	public static <T extends @NonNull Enum<T>> getEnum() {
+		return null;
+	}
+
 
     /**
      * Explicit receiver Parameters