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Alice ✨

@welltypedwit.ch

2.5K followers 330 following 4.6K posts

When the limestone of imperative programming has worn away, the granite of functional programming will be revealed underneath -Simon Peyton Jones

https://welltypedwit.ch

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Alice ✨

@welltypedwit.ch

see you in 3 hours

GoodTimesWithScar hermitcraft 11 episode 1: 50:52

Grian and GeminiTay Hermitcraft 11 Episode 1: 1:01:41 and 1:17:35

November 8, 2025 at 3:07 PM

Alice ✨

@welltypedwit.ch

this is a very american quiz though huh ^^

We must reform our elections by expanding ballot access. Citizens should be automatically registered and sent a ballot

October 24, 2025 at 10:07 PM

Alice ✨

@welltypedwit.ch

wow, that's surprisingly accurate

government: 100% unitary democracy
economy: 53.5% social democracy 48.5%: socialism
society: 71.4% social justice 28.6% freedom
relgiion: 88.2% atheist 11.8% apathy
security: 100% humanist
foreign policy: 59.1% internationalist 40.9% open borders

October 24, 2025 at 10:07 PM

Alice ✨

@welltypedwit.ch

1.5 hours later i finally got this minimized omg

this only happens if one module defines a type like this with RequiredTypeArguments, that is used in another module where RequiredTypeArguments is turned *off*, but ApplicativeDo is turned *on* **and** the bound type variable is used at least twice

$A.hs: {-# LANGUAGE RequiredTypeArguments #-} module A where import Data.Kind (Type) higherRankRTA :: (forall s -> a) -> a higherRankRTA _ = undefined B.hs: {-# LANGUAGE GHC2021 #-} {-# LANGUAGE ApplicativeDo #-} {-# LANGUAGE NoRequiredTypeArguments #-} module B where import A (higherRankRTA) import Data.Functor.Identity (Identity) import Data.Proxy (Proxy) danger :: Identity () danger = higherRankRTA $ \s -> do _ :: Proxy s <- undefined _ :: Proxy s <- undefined pure ()$

October 22, 2025 at 9:26 PM

Alice ✨

@welltypedwit.ch

oops

$/home/prophet/Code/vega-graph/src/Vega/SCC.hs:33:28: error: [GHC-76329] • GHC internal error: ‘s’ is not in scope during type checking, but it passed the renamer tcl_env of environment: [a6x5 :-> Type variable ‘node’ = node :: *, a6x6 :-> Type variable ‘es’ = es :: [Effect], a6xG :-> Identifier[outEdgesOrPrecomputedSCC::node -> Eff es (Maybe [node]), NotLetBound], a6xH :-> Identifier[node::node, NotLetBound], a6xR :-> Type variable ‘s’ = s :: k0, r5cb :-> Identifier[computeSCC::forall node (es :: [Effect]). (Show node, Hashable node, Trace :> es) => (node -> Eff es (Maybe [node])) -> node -> Eff es (HashMap node SCCId), TopLevelLet {} True], r6x4 :-> Identifier[newSCCId::forall (es :: [Effect]). (IOE :> es) => Eff es SCCId, TopLevelLet]]$

October 22, 2025 at 7:48 PM

Alice ✨

@welltypedwit.ch

i hate sccs (no, they're actually really cool but this is like the fifth time i got this panic omg)

ERROR: PANIC (the 'impossible' happened): SCC map for declaration MkDeclarationName {moduleName = MkModuleName {package = MkPackageName "knucklebones", subModules = fromList ["Main"]}, name = "TurnResult"} is missing its own binding.
SCCs: fromList []
CallStack (from HasCallStack):
error, called at src/Relude/Debug.hs:283:11 in relude-1.2.2.2-49XUvkEaanJEVa9xYTIMnb:Relude.Debug
error, called at src/Vega/Effect/GraphPersistence/InMemory.hs:365:28 in vega-0.1.0.0-9MZYQnIf4mmoTzMmugakT:Vega.Effect.GraphPersistence.InMemory

October 22, 2025 at 7:18 PM

Alice ✨

@welltypedwit.ch

welp

[compile/types/existential-dependent.vega]: FAILED
Expected error message:
Actual error message: ERROR: PANIC (the 'impossible' happened): type variable not found in type checker: MkLocalName {parent = MkDeclarationName {moduleName = MkModuleName {package = MkPackageName "existential-dependent", subModules = fromList ["Main"]}, name = "f"}, name = "r", count = 0}
CallStack (from HasCallStack):
error, called at src/Relude/Debug.hs:283:11 in relude-1.2.2.2-49XUvkEaanJEVa9xYTIMnb:Relude.Debug
error, called at src/Vega/TypeCheck.hs:69:20 in vega-0.1.0.0-9MZYQnIf4mmoTzMmugakT:Vega.TypeCheck
typeVariableKind, called at src/Vega/TypeCheck.hs:802:28 in vega-0.1.0.0-9MZYQnIf4mmoTzMmugakT:Vega.TypeCheck

October 21, 2025 at 12:24 PM

Alice ✨

@welltypedwit.ch

omg i hate error recovery. this is so subtle

-- TODO: If the program is well-typed, this is definitely okay since the body kind cannot mention any of the variables
-- bound by the existential anyway (they're parametric). If it isn't, this might cause panics about unresolved type variables
-- later on though.

October 21, 2025 at 12:17 PM

Alice ✨

@welltypedwit.ch

what did she mean by this

[compile/types/existential.vega]: FAILED
/home/prophet/Code/vega-graph/test/run/./Main.vega:2:13: ERROR:
Expected: identifier
Actual: )
┃
2 ┃ f : forall () -> exists (a : Type(IntRep)). (Int -> a, a -> String);
┃ ▔

October 21, 2025 at 11:34 AM

Alice ✨

@welltypedwit.ch

oh that works! this seems wrong though? the point of ! is that it can be coerced to any type (including ones that satisfy Drop) so I would have expected an ambiguity error?

same code but with drop(panic!()) called in main

error[E0277]: the trait bound `!: !Drop` is not satisfied
--> src/main.rs:11:10
|
11 | drop(panic!());
| ---- ^^^^^^^^ the trait bound `!: !Drop` is not satisfied
| |
| required by a bound introduced by this call
|
note: required by a bound in `drop`
--> src/main.rs:6:8
|
4 | fn drop<T>(_t: T)
| ---- required by a bound in this function
5 | where
6 | T: !Drop,
| ^^^^^ required by this bound in `drop`

October 20, 2025 at 11:27 PM

Alice ✨

@welltypedwit.ch

i tried a boxed iterator as well and this took a whole 1.2ms so i'm not sure that's it? boxing is obviously going to be slower than in haskell and ocaml but not by a factor of 100 right?

$fn repeated_cons(n: u64) -> u64 { let mut iterator: Box<dyn Iterator<Item = u64>> = Box::new((0..=0).into_iter()); for i in 1..n { iterator = Box::new((std::iter::once(i)).chain(iterator)) } iterator.sum::<u64>() }$

October 20, 2025 at 2:51 PM

Alice ✨

@welltypedwit.ch

oh noo ^^ mine is just this

(the black_box calls are there to prevent it from cheating and constant folding the iterator away but it did compile without them)

$repeated_direct_cons() -> u64 { let iter = std::iter::once(1000).chain(black_box(std::iter::once(999).chain(black_box(std::iter::once(998).chain... iter.sum::<u64>() }$

October 20, 2025 at 12:42 AM

Alice ✨

@welltypedwit.ch

A4 Noah (farmer): There are more innocents among witches than any other profession

October 18, 2025 at 12:07 AM

Alice ✨

@welltypedwit.ch

{- NOTE: Ord instances
-----------------------------------------------------
Nearly all derived `Ord` instances in this module are entirely meaningless.
We only need to derive them because megaparsec stores its custom parse errors
in a `Set` and we sometimes need to store AST nodes to improve our error messages
(e.g. InvalidExistentialBinders contains the ForallBinderS values the user actually wrote)
-}

October 17, 2025 at 2:36 PM

Alice ✨

@welltypedwit.ch

achievement unlocked

[27 of 36] Compiling Vega.TypeCheck [Source file changed]
<no location info>: error:
panic! (the 'impossible' happened)
GHC version 9.10.2:
lookupConstructorInfo: not a ConLike
name: GenericInstantiation
Call stack:
CallStack (from HasCallStack):
callStackDoc, called at compiler/GHC/Utils/Panic.hs:190:37 in ghc-9.10.2-d434:GHC.Utils.Panic
pprPanic, called at compiler/GHC/Rename/Env.hs:439:18 in ghc-9.10.2-d434:GHC.Rename.Env
CallStack (from HasCallStack):
panic, called at compiler/GHC/Utils/Error.hs:507:29 in ghc-9.10.2-d434:GHC.Utils.Error

Please report this as a GHC bug: https://www.haskell.org/ghc/reportabug

October 17, 2025 at 1:46 PM

Alice ✨

@welltypedwit.ch

omg i found it. so what happened is that the precedence for --> here is wrong and *also* the pretty printer for types has a bug that makes it print this incorrectly: this is actually
`((Int, ?a) -> Array)(?a)` (which is ill-kinded obviously)

$builtinTypes :: HashMap GlobalName Type builtinTypes = [ (internalName "replicateArray", forall_ "a" \a -> [intType, a] --> arrayType @@ [a])$

October 16, 2025 at 3:29 PM

Alice ✨

@welltypedwit.ch

uh oh

/home/prophet/Code/vega-graph/teeest/src/Main.vega:5:17: ERROR:
Type mismatch
Unable to unify
expected type (internal:Internal:Int, internal:Internal:String) -{?e}> internal:Internal:Array(?w)
actual type (internal:Internal:Int, ?a) -> internal:Internal:Array(?a)
┃
5 ┃ let array = replicateArray(5, "a");
┃ ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔

October 16, 2025 at 3:07 PM

Alice ✨

@welltypedwit.ch

C2 Hilda, pilot: There are more criminals among cops than any other profession

October 16, 2025 at 1:13 PM

Alice ✨

@welltypedwit.ch

i wasn't expecting south african either lol

(fwiw i think you sound quite british ^^)

german: 42%, south african: 35%, albanian: 10%, accent sterngth: 71%

October 15, 2025 at 3:39 PM

Alice ✨

@welltypedwit.ch

i'm so confused by what their politics are? like, misandry, environmentalism, anti-semitisim and anti-antifa are an... interesting combination lol

clearsky post from this person:

Decades ago when I worked with Citizen Action and Greenpeace many Americans mocked progressives. Same as this era. Thanks to those who took us in. Soros or antifas were never with us.

October 14, 2025 at 1:19 PM

Alice ✨

@welltypedwit.ch

OH WAIT NEVERMIND
i did not read this correctly lol. it's 54% *of the 15% that said they were already part of a marginalized group*. so the real answer is just 8.1%, which is *lower* than haskell, wow