make getType nodes of generic insts have full inst type (#22655)

fixes #22639 for the third time

Nodes generated by `getType` for `tyGenericInst` types, instead of
having the original `tyGenericInst` type, will have the type of the last
child (due to the `mapTypeToAst` calls which set the type to the given
argument). This will cause subsequent `getType` calls to lose
information and think it's OK to use the sym of the instantiated type
rather than fully expand the generic instantiation.

To prevent this, update the type of the node from the `mapTypeToAst`
calls to the full generic instantiation type.

0 files changed, 0 insertions, 0 deletions