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34877da01c
This is the case of `a < T` for some structured T. By relaxing, we are actually allowing `a` to be a _supertype_ of T as far as abilities go, which is not correct. Seems like it was just erroneously mirrored from the opposite case.
1.6 KiB
1.6 KiB
Checks for some bad type checking behavior. Some ability subtyping was too lenient when higher-order functions were involved.
foreach : (a ->{g} ()) -> [a] ->{g} ()
foreach f = cases
[] -> ()
x +: xs ->
f x
foreach f xs
forkIt : '{IO} () ->{IO} ()
forkIt e =
_ = IO.forkComp e
()
thunk : '{IO,Exception} ()
thunk = do
raise (Failure (typeLink MiscFailure) "thunk" (Any ()))
go = do
foreach forkIt [thunk]
Loading changes detected in scratch.u.
I found an ability mismatch when checking the application
18 | foreach forkIt [thunk]
When trying to match [Unit ->{𝕖75, IO, Exception} Unit] with
[Unit ->{IO} Unit] the left hand side contained extra
abilities: {𝕖75, Exception}
This comes from issue #3513
(<<) : (b ->{e} c) -> (a ->{e} b) -> a ->{e} c
(<<) f g x = f (g x)
catchAll.impl : '{IO, Exception} a ->{IO} Either Failure a
catchAll.impl thunk =
handle tryEval do catch thunk
with
cases
{ x } -> x
{Exception.raise f -> _} -> Left f
fancyTryEval : '{g, IO, Exception} a ->{g, IO, Exception} a
fancyTryEval = reraise << catchAll.impl
Loading changes detected in scratch.u.
The expression in red
needs the abilities: {g76}
but was assumed to only require: {IO, Exception}
This is likely a result of using an un-annotated function as an argument with concrete abilities. Try adding an annotation to the function definition whose body is red.
13 | fancyTryEval = reraise << catchAll.impl