Extra leading underscore in type parameter names

[azz]

What version of TypeScript are you using?

2.3.2

What version of typescript-eslint-parser are you using?

master

What code were you trying to parse?

class A<__P> {}

What did you expect to happen?

assert(require('.').parse('class A<__P> {}').body[0].typeParameters.params[0].name === "__P");

What happened?

The name if the parameter is ___P (notice the extra leading underscore. This continues if there are more than two leading _ characters (always N+1 reported).

[soda0289]

This is a feature of the typescript AST. We remove the extra underscore in Identifiers but have missed this case. Should be easy fix we have function to handle this case.