Attribute rustc_dump_generics 

Dumps the generics of the annotated item.

See generics_of and ty::Generics for what “generics” means here.

See AttributeKind::RustcDumpGenerics for the internal representation of this attribute.

Example

//@ dont-require-annotations: ERROR
//@ compile-flags: --crate-type lib -Z ui-testing=no
//@ normalize-stderr: "DefId\((\d+):(\d+)" -> "DefId(..:.."
//@ normalize-stderr: "\[[A-Fa-f0-9]{4}\]" -> "[....]"

#![feature(rustc_attrs)]

#[rustc_dump_generics]
struct Struct<'lifetime, const CONST: usize, GENERIC> {
    stuff: &'lifetime [GENERIC; CONST],
}

produces:

error: rustc_dump_generics: DefId(..:.. ~ rustc_dump_generics[....]::Struct)
--> $DIR/rustc_dump_generics.rs:9:1
 |
9 | struct Struct<'lifetime, const CONST: usize, GENERIC> {
 | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 |
note: Generics {
         parent: None,
         parent_count: 0,
         own_params: [
             GenericParamDef {
                 name: "'lifetime",
                 def_id: DefId(..:.. ~ rustc_dump_generics[....]::Struct::'lifetime),
                 index: 0,
                 pure_wrt_drop: false,
                 kind: Lifetime,
             },
             GenericParamDef {
                 name: "CONST",
                 def_id: DefId(..:.. ~ rustc_dump_generics[....]::Struct::CONST),
                 index: 1,
                 pure_wrt_drop: false,
                 kind: Const {
                     has_default: false,
                 },
             },
             GenericParamDef {
                 name: "GENERIC",
                 def_id: DefId(..:.. ~ rustc_dump_generics[....]::Struct::GENERIC),
                 index: 2,
                 pure_wrt_drop: false,
                 kind: Type {
                     has_default: false,
                     synthetic: false,
                 },
             },
         ],
         param_def_id_to_index: [
             (
                 DefId(..:.. ~ rustc_dump_generics[....]::Struct::'lifetime),
                 0,
             ),
             (
                 DefId(..:.. ~ rustc_dump_generics[....]::Struct::CONST),
                 1,
             ),
             (
                 DefId(..:.. ~ rustc_dump_generics[....]::Struct::GENERIC),
                 2,
             ),
         ],
         has_self: false,
         has_late_bound_regions: None,
     }
--> $DIR/rustc_dump_generics.rs:9:1
 |
9 | struct Struct<'lifetime, const CONST: usize, GENERIC> {
 | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

error: aborting due to 1 previous error