Perform type checking on the AST

[lmderval]

In order to verify the input program, we need to check that gates and registers are correctly used. This is done during type checking.

The purpose of type checking is to:

• detect the use of register in a wrong context, for instance, applying a gate on a classical register
• detect operand size mismatch during a measure
• detect if a gate is not correctly used
• detect if all parameters have been passed to a gate