For default member initializers in templates it's important to push into the
right context during get_nsdmi.  But for a local class that's not possible,
and trying leaves the function context we need to be in, so don't try.

gcc/cp/ChangeLog
2020-05-01  Jason Merrill  <jason@redhat.com>

	PR c++/90479
	* init.c (get_nsdmi): Don't push_to_top_level for a local class.