Toplevel input, character 0:
> HB.structure Definition AbelianGrp := { A of IsAbelianGrp A }.
> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Warning:
pulling in dependencies: [err_miss_dep_IsAddComoid] 
Please list them or end the declaration with '&'
[HB.implicit-structure-dependency,HB,elpi,default]
The command has indeed failed with message:
HB: Unable to find mixin err_miss_dep_IsAddComoid on subject K
