If a type variable T is used in an `is` or `as` expression (e.g.
`42 is T` or `42 as T`) or is part of a subtype check, then any types
which may be substituted for T via instantiation must also be treated as
participating in a type check.
This CL ensures that the RTI need computation includes type arguments
for those substituted types and that those types are included in the
list of implicit checks.
Additionally, in order for this to work, this CL fixes a bug in which
the impact transformer was failing to register generic instantiations
occurring in (partial) constants.
Fixes: https://github.com/dart-lang/sdk/issues/45046
Change-Id: I98ae0eca0adcbbb26cdd664318da0da578b289b5
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/190460
Reviewed-by: Stephen Adams <sra@google.com>
Commit-Queue: Mayank Patke <fishythefish@google.com>
Mayank Patke