[nem-en] 0000898: 'int' treated as an identifier even if usedwithout verbatim specifier (@)

[vc]

> This clearly does not make sense, since it is still possible to do:
> 
> using System;
> 
> match (x) {
>   | x as String => ...
> }
> 
> The point is that user will be warned that the variable name "String"
> or "int" (in case of | x as int => )  is not used. So I don't think
> this is a real problem.

This is real problem. At least we should prevent use type names for pattern
bound variable. In my option variable redefinition also bad choice, but it
is widely used in code.