has anyone seen this error before with the GHC JS backend?

Aborted('HEAP8' was not exported. add it to EXPORTED_RUNTIME_METHODS (see the Emscripten FAQ))

(nix run github:ncfavier/glam/ghcjs-backend#glam-js to reproduce; say yes at the prompts to avoid building GHC)

I have upstreamed a fix in ghc, which is not yet released and funnily I don’t think the fix works anyway. 😄 However there is a known to be working workaround:

Put this in the executable part of your .cabal file.

-- Workaround for a runtime error ("HEAP8 not found"). Only necessary until
-- https://gitlab.haskell.org/ghc/ghc/-/merge_requests/14362 is resolved.
ld-options: -sEXPORTED_RUNTIME_METHODS=HEAP8,HEAPU8

has anyone seen this error before with the GHC JS backend?

Aborted('HEAP8' was not exported. add it to EXPORTED_RUNTIME_METHODS (see the Emscripten FAQ))

Is this the blessed way to write an overlay that adds a package foo to all Haskell package sets, without undoing previous overlays? If so, should we add it to the manual?

final: prev: {
  haskell = prev.haskell // {
    packageOverrides = final.lib.composeExtensions prev.haskell.packageOverrides
      (hfinal: hprev: {
        foo = ...;
      });
  };
}

Is this the blessed way to write an overlay that adds a package foo to all Haskell package sets, without undoing previous overlays? If so, should we add it to the manual? If not, what is?

final: prev: {
  haskell = prev.haskell // {
    packageOverrides = final.lib.composeExtensions prev.haskell.packageOverrides
      (hfinal: hprev: {
        foo = ...;
      });
  };
}