Function generic_defaults_with_diagnostics 

pub(crate) fn generic_defaults_with_diagnostics<'db>(
    db: &'db dyn HirDatabase,
    def: GenericDefId,
) -> &'db TyLoweringResult<'db, GenericDefaults>

Resolve the default type params from generics.

Diagnostics are only returned for this GenericDefId (returned defaults include parents).