anchor.diff:                                  if hasFSharpCompilerGeneratedEquality ty then
                                       if ty.IsValueType
                                           then makeEquatableDelegate ty ty typedefof<StructEquatable<DummyStructInterfaces>>
  -                                        else makeEquatableDelegate ty ty typedefof<RefTypeEquatable<DummyRefTypeInterfaces>>
  +                                        else makeEquatableDelegate ty ty typedefof<RefTypeNullableEquatable<DummyRefTypeInterfaces>>
                                   else null
                               | r when r.Equals typeof<PartialEquivalenceRelation> -> null
                               | _ -> raise (Exception "invalid logic")
  
positive.code: 
                  let equalityInterfaces (t:Type) : obj =
                      let make = makeEquatableDelegate t t
  
                      if t.IsArray || typeof<System.Array>.IsAssignableFrom t then
                          // I could do something here, but I doubt it would have any real performance impact
  
negative.code:                         else                                                                   make typedefof<NullableEquals<DummyStructInterfaces>>
  
                      elif t.IsValueType && typeof<IStructuralEquatable>.IsAssignableFrom t then make typedefof<StructStructualEquality<DummyStructInterfaces>>
                      elif t.IsValueType && equatable.IsAssignableFrom t                    then make typedefof<StructEquatable<DummyStructInterfaces>>
                      elif t.IsValueType                                                    then make typedefof<StructEquals<DummyStructInterfaces>>
  
                      elif typeof<IStructuralEquatable>.IsAssignableFrom t && notnull       then make typedefof<RefTypeStructualEquality<DummyRefTypeInterfaces>>
                      elif typeof<IStructuralEquatable>.IsAssignableFrom t                  then make typedefof<RefTypeNullableStructualEquality<DummyRefTypeInterfaces>>
  
                      // only sealed as a derived class might inherit from IStructuralEquatable
                      elif t.IsSealed && equatable.IsAssignableFrom t && notnull            then make typedefof<RefTypeEquatable<DummyRefTypeInterfaces>>
                      elif t.IsSealed && equatable.IsAssignableFrom t                       then make typedefof<RefTypeNullableEquatable<DummyRefTypeInterfaces>>
                      elif t.IsSealed && notnull                                            then make typedefof<RefTypeEquals<DummyRefTypeInterfaces>>
                      elif t.IsSealed                                                       then make typedefof<RefTypeNullableEquals<DummyRefTypeInterfaces>>
  
                      else null
  
  