[Agda] a strange "unsolved" report

[James Wood]

Hi Sergei,

Quick questions first: is `_∷_` overloaded at all in this context?
That'd be my guess for why Agda has no clue what the type is supposed to be.

Regards,
James

On 04/10/2020 18:19, mechvel at scico.botik.ru wrote:
> Dear Agda developers,
> 
> There is a question about the following code fragment:
> 
> -----------------------------------------------------
> +ms-assoc-aux {monᶜ a e ∷ mons} {monᶜ b e' ∷ mons'} {monᶜ c e'' ∷
> mons''} ... =
> 
>     aux (<-cmp e e') (<-cmp e' e'') (<-cmp e e'')
>     where
>     m = monᶜ a e;  m' = monᶜ b e';   m'' = monᶜ c e''
> 
>     mmons = m ∷ mons                 -- *
> 
>     -- m'mons' : List Mon            -- (I-s)
>     m'mons' = m' ∷ mons'             -- (I)
> 
>     m''mons'' = m'' ∷ mons''
>     ...
> -----------------------------------------------------
> 
> Agda 2.6.1 reports
> "
> Sort _1156  [ at ...Over-abelianGroup.agda:414,5-12 ]
> _1157 : _1156  [ at ...Over-abelianGroup.agda:414,5-12 ]
> _1159 : _1157  [ at ...Over-abelianGroup.agda:414,15-25 ]
> "
> 
> I guess this is the kind of "unsolved metas".
> And the first "unsolved" is about the line marked (I).
> 
> The previous line (marked *) is solved - while it is not any more clear
> than (I).
> 
> Then, after adding the signature (I-s), everything is type-checked.
> 1) This necessity to add signature in the middle of an array of short
> assignments of the same
>    type looks strange.
> 2) There are many similar fragments in the program, and I never observed
> such an effect.
> 
> What might this mean?
> 
> -- 
> SM
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