Java raw type selection rules not enforced

[bishabosha]

When compiling java source code, rules about Raw types are not enforced.

note that in any real project, the javac compiler will also run and check these rules so this is not super high priority

Compiler version

3.4.0-RC3

Minimized code

// RawTypes.java

package lib;

public class RawTypes {

  public class C<T> {
    public class D<U> {}
  }

  public static void m_Raw_Raw(C.D d) {}
  public static void m_Raw_Gen(C.D<Object> d) {} // should be error
  public static void m_Gen_Raw(C<Object>.D d) {} // should be error

}

Output

compiles ok

Expectation

javac compiler gives these errors:

RawTypes.java:10: error: improperly formed type, type arguments given on a raw type
  public static void m_Raw_Gen(C.D<Object> d) {} // should be error
                                  ^
RawTypes.java:11: error: improperly formed type, some parameters are missing
  public static void m_Gen_Raw(C<Object>.D d) {} // should be error
                                        ^
2 errors

JLS 4.8 states these rules

It is a compile-time error to pass type arguments to a non-static member class or interface of a raw type that is not inherited from its superclasses or superinterfaces.

^ this invalidates C.D<Object> as a type, because D is not static, and C is a raw type.

It is a compile-time error to attempt to use a member class or interface of a parameterized type as a raw type.

^ this invalidates C<Object>.D as a type, because D is not allowed to be a raw type when C is parameterized.

Notes

C.D is ok because they are all raw types.

[bishabosha]

I have been informed that we only care about correctly type checking known-valid Java code, anything else is up to the compiler

[bishabosha]

I will close this in favor of adding more examples to #19619