[m-rev.] for review: Fix check of existentially typed args in subtype definitions.

[Zoltan Somogyi]

On 2024-07-04 12:33 +10:00 AEST, "Peter Wang" <novalazy at gmail.com> wrote:
> compiler/add_type.m:
>     Use a bimap to represent the correspondence between existentially
>     quantified type variables in the subtype and supertype.
> 
>     Improve check_is_subtype_var_var with an extra check and comments.

The diff seems fine.

Zoltan.