* std.meta: correct use of `default_value` in reification. stage1
accepted a wrong type for `null`.
* Sema: after instantiating a generic function, if the return type ends
up being a comptime-known type, then we return an error, undoing the
generic function instantiation, and making a comptime function call
instead.
- We also needed to clean up the dependency graph in this case.
* Sema: reified enums set tag_ty_inferred to false since an integer tag
type is provided. This is a limitation of the `@Type` builtin which
will be addressed with #10710.
* Sema: fix resolveInferredErrorSet incorrectly calling
ensureFuncBodyAnalyzed on generic functions.
2af69710a7