fix `nil` literal giving itself type `untyped`/`typed` [backport] (#24165)

fixes #24164, regression from #20091

The expression `nil` as the default value of template parameter `x:
untyped` is typechecked with expected type `untyped` since #20091. The
expected type is checked if it matches the `nil` literal with a match
better than a subtype match, and the type is set to it if it does.
However `untyped` matches with a generic match which is better, so the
`nil` literal has type `untyped`. This breaks type matching for the
literal. So if the expected type is `untyped` or `typed`, it is now
ignored and the `nil` literal just has the `nil` type.

0 files changed, 0 insertions, 0 deletions