FStarLang / FStarLang/FStar

Effect definitions cannot be given directly (but must be defined previously...)

Open
#877 0 comments 0 reactions 0 assignees View on GitHub
component/dm4free kind/enhancement
Dominant language
F*
Stars
3.1k
Forks
266
Avg merge
21h 1m
Merged PRs (30d)
54

Description

The following code where the definition of the effect combinators are inlined fails badly :
```total reifiable reflectable new_effect_for_free {
STATE_h (s:Type0) : a:Type -> Effect
with repr = (fun (a:Type) -> s -> M (a * s))
; bind = (fun (a:Type) (b:Type) (f:st s a) (g:a -> st s b) ->
fun (s0:s) -> let (x,s) = f s0 in g x s)
; return = (fun (a:Type) (x:a) -> fun s0 -> x, s0)
}
```

```
Error: Computation for [(fun a b f g s0 -> let uu___#2217 : (tuple2 a@4 s) = (f@2 s0@0) in
(match uu___@0 with
| (Mktuple2 #.uu___#2229 #.uu___#2230 x#2223 s#2224) -> ((g@4 x@1) s@0)))] is not total : PURE (a:Type -> b:Type -> f:(st s a@1) -> g:(uu___:a@2 -> Tot (st s b@2)) -> s0:s -> Tot ((fun s a b f g s0 uu___ -> ((fun s a b f g s0 -> (tuple2 b@3 s@5)) s@6 a@5 b@4 f@3 g@2 s0@1)) s a@4 b@3 f@2 g@1 s0@0 (f@2 s0@0))) !
```

Contributor guide

Open the contributing guide

Research direction

Start with the inline effect-combinator definition and reproduce the reported totality error. Investigate why the inlined definition is rejected despite the shown effect operations, and consider the issue resolved when this example is accepted or produces an appropriate diagnostic.

Written by the indexing model from the issue text.

Assessment

Domain
compilers
Issue type
Bug
Difficulty
5/5
Estimated time
Over a week
Activity status
Stale
Clarity
Needs clarification
Newbie friendliness
20/100

Get new issues in your inbox

A short digest of beginner-friendly GitHub issues.