error: cannot find macro `concat_idents` in this scope
   --> /wrkdirs/usr/ports/sysutils/alkane/work/alkane-0.2.0/cargo-crates/devise_core-0.2.1/src/generator.rs:29:39
    |
 29 |               $(self.$vec.push(Box::new(concat_idents!(default_, $get_f)));)*
    |                                         ^^^^^^^^^^^^^
...
193 | /     mappers! {
194 | |         (map_struct, try_map_struct, struct_mapper): Struct, struct_mappers,
195 | |         (map_enum, try_map_enum, enum_mapper): Enum, enum_mappers,
196 | |         (map_variant, try_map_variant, variant_mapper): Variant, variant_mappers,
197 | |         (map_fields, try_map_fields, fields_mapper): Fields, fields_mappers,
198 | |         (map_field, try_map_field, field_mapper): Field, field_mappers
199 | |     }
    | |_____- in this macro invocation
    |
    = note: this error originates in the macro `mappers` (in Nightly builds, run with -Z macro-backtrace for more info)

error[E0557]: feature `concat_idents` has been removed
 --> /wrkdirs/usr/ports/sysutils/alkane/work/alkane-0.2.0/cargo-crates/devise_core-0.2.1/src/lib.rs:2:12
  |
2 | #![feature(concat_idents)]
  |            ^^^^^^^^^^^^^ feature has been removed
  |
  = note: removed in 1.90.0; see <https://github.com/rust-lang/rust/issues/29599#issuecomment-2986866250> for more information
  = note: Replaced by the macro_metavar_expr_concat feature

For more information about this error, try `rustc --explain E0557`.