[Form] Abstract extension, on getType() call hasType()

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | 
| License       | MIT
| Doc PR        |

If not calling hasType and duplicate code is due to performance, at least a comment should be added. And is this code called so many times that worth duplicate code?