fixes#4554, fixes#10900, fixes#13843, fixes#19471, fixes#19517
Instead of matching generic converters to their arguments using the full
call match bindings, a new match is created for them (from which the
bindings are used to instantiate the converter return type). Then when
instantiating generic converters, they are matched to their argument
again to get their bindings again instead of using the call bindings.
This prevents generic converters which match more than once from
interfering with each other's bindings.
(cherry picked from commit 334f96c05a)