Add `#[subdiagnostic]` field attribute to the diagnostic derive which
is applied to fields that have types which use the subdiagnostic derive.
Signed-off-by: David Wood <david.wood@huawei.com>
In the initial implementation of the `SessionSubdiagnostic`, the
`Applicability` of a suggestion can be set both as a field and as part
of the attribute, this commit adds the same support to the original
`SessionDiagnostic` derive.
Signed-off-by: David Wood <david.wood@huawei.com>
`SetOnce` trait was introduced in the subdiagnostic derive to simplify
the code a little bit, re-use it in the diagnostic derive too.
Signed-off-by: David Wood <david.wood@huawei.com>
Remove some duplicated code between both diagnostic derives by
introducing helper functions for reporting an error in case of a invalid
attribute.
Signed-off-by: David Wood <david.wood@huawei.com>
Split `SessionDiagnostic` and `SessionSubdiagnostic` derives and the
various helper functions into multiple modules.
Signed-off-by: David Wood <david.wood@huawei.com>
