Incorrect behaviour of GHC when driven by hie-bios compiled by haskell.nix

[expipiplus1]

If I compile hie-bios with haskell.nix, when it checks a file which runs reify 'id in a TH splice, the call to reify returns garbage results. A different, incorrect type for id every time (all alpha renamed forall a. b -> c).

Repro case here:

https://github.com/expipiplus1/hie-reload-example/tree/reify

Original issue here haskell/haskell-ide-engine#1744

[angerman]

This is indeed quite odd and the first thing I was thinking about was our reduced set of reinstallable libs, but as can be seen in the reproduction example, they have been set back to the stock set of ghc packages. Building ghc should be almost identical, though we do have some patches that upstream Nixpkgs does not have. I somehow doubt that just by building it via components this change would happen.

[expipiplus1]

Could it be that using the stock set is causing this?

Couple of notes:

• This doesn't seem to happen when just running GHC, I can only observe this when running through hie-bios (I haven't tried any other programs using the GHC API, I imagine that it would manifest there too and that this isn't actually hie-bios's fault)
• This isn't an abstract issue, it does affect code on Hackage, my specific broken library is autoapply however I guess that any TH which depends on type information will not work here.

[expipiplus1]

How possible would it be to compile ghc via haskell.nix without any of the extra patches? if only to run the repro case.

[angerman]

@expipiplus1 depends on the compiler you want but should be relatively straight forward.

The patches are defined here:

haskell.nix/overlays/bootstrap.nix

Lines 58 to 116 in 788e198

	ghc-patches = version: let
	# Returns true iff this derivation's version is strictly older than ver.
	versionLessThan = ver: builtins.compareVersions ver version == 1;
	# Returns true iff this derivation's verion is greater than or equal to ver.
	versionAtLeast = ver: !versionLessThan ver;
	from = start: final.lib.optional (versionAtLeast start);
	fromUntil = start: end: final.lib.optional (versionAtLeast start && versionLessThan end);
	until = end: final.lib.optional (versionLessThan end);
	always = final.lib.optional true;
	# Try to avoid reordering the patches unless a patch is added or changed that
	# will be applied to most versions of the GHC anyway (reordering the patches
	# results in rebuilds of GHC and reduces sharing in /nix/store).
	in fromUntil "8.4.4" "8.6" ./patches/ghc/ghc-8.4.4-reinstallable-lib-ghc.patch
	++ until "8.6" ./patches/ghc/iserv-move-8.4.1.patch # 6fbe5f274ba84181f5db50901639ae382ef68c4b -- merged; ghc-8.6.1
	++ until "8.6" ./patches/ghc/hsc2hs-8.4.2.patch
	++ until "8.6" ./patches/ghc/various-8.4.2.patch
	++ until "8.6" ./patches/ghc/lowercase-8.4.2.patch
	++ until "8.6" ./patches/ghc/cabal-exe-ext-8.4.2.patch
	++ until "8.6" ./patches/ghc/ghc-8.4.3-Cabal2201-SMP-test-fix.patch
	++ until "8.6" ./patches/ghc/outputtable-assert-8.4.patch
	++ fromUntil "8.6" "8.6.4" ./patches/ghc/MR148--T16104-GhcPlugins.patch
	++ until "8.6.4" ./patches/ghc/MR95--ghc-pkg-deadlock-fix.patch
	++ fromUntil "8.4" "8.6" ./patches/ghc/iserv-autoconf-8.4.1.patch # (same as below, but based on 8.4)
	++ fromUntil "8.6" "8.8" ./patches/ghc/iserv-autoconf-8.6.1.patch # 8f9f52d8e421ce544d5437a93117545d52d0eabd -- merged; ghc-8.8.1
	++ fromUntil "8.4" "8.6" ./patches/ghc/iserv-cleanup-8.8.1-prepare-8.4.1.patch # (prepare for below; see patch for details)
	++ until "8.10" ./patches/ghc/iserv-cleanup-8.8.1.patch # https://gitlab.haskell.org/ghc/ghc/merge_requests/250 -- merged; ghc-8.10.1
	++ fromUntil "8.4" "8.6" ./patches/ghc/iserv-cleanup-8.8.1-revert-8.4.1.patch # (revert prepare)
	++ fromUntil "8.2" "8.8" ./patches/ghc/MR545--ghc-pkg-databases.patch # https://gitlab.haskell.org/ghc/ghc/merge_requests/545 -- merged; ghc-8.8.1
	++ fromUntil "8.6" "8.8" ./patches/ghc/outputtable-assert-8.6.patch
	++ fromUntil "8.6.4" "8.8" ./patches/ghc/ghc-8.6.4-reenable-th-qq-in-stage1.patch
	++ until "8.8" ./patches/ghc/0001-Stop-the-linker-panic.patch # https://phabricator.haskell.org/D5012 -- merged; ghc-8.8.1
	++ until "8.8" ./patches/ghc/ghc-8.4.3-Cabal2201-allow-test-wrapper.patch # https://github.com/haskell/cabal/pulls/5995 -- merged; cabal-3.0.0 (ghc-8.8.1)
	++ until "8.8" ./patches/ghc/ghc-8.4.3-Cabal2201-response-file-support.patch # https://github.com/haskell/cabal/pulls/5996 -- merged; cabal-3.0.0 (ghc-8.8.1)
	++ until "8.8" ./patches/ghc/ghc-8.6-Cabal-fix-datadir.patch # https://github.com/haskell/cabal/issues/5862
	++ until "8.8" ./patches/ghc/MR196--ghc-pkg-shut-up.patch # https://gitlab.haskell.org/ghc/ghc/merge_requests/196 -- merged; ghc-8.8.1
	++ from "8.6" ./patches/ghc/mistuke-ghc-err_clean_up_error_handler-8ab1a89af89848f1713e6849f189de66c0ed7898.diff # this is part of Phyx- revamped io-manager.
	++ always ./patches/ghc/ghc-add-keepCAFs-to-rts.patch # https://gitlab.haskell.org/ghc/ghc/merge_requests/950 -- open
	++ always ./patches/ghc/lowercase-8.6.patch # https://gitlab.haskell.org/ghc/ghc/merge_requests/949 -- merged; ghc-8.8.1
	++ always ./patches/ghc/dll-loader-8.4.2.patch # https://gitlab.haskell.org/ghc/ghc/merge_requests/949 -- open
	++ always ./patches/ghc/ghc-8.4.3-Cabal2201-no-hackage-tests.patch # ?
	++ always ./patches/ghc/MR948--32bit-cross-th.patch # https://gitlab.haskell.org/ghc/ghc/merge_requests/948 -- open
	++ from "8.8" ./patches/ghc/cabal-host.patch # https://github.com/haskell/cabal/issues/5887
	++ fromUntil "8.6.4" "8.8" ./patches/ghc/ghc-8.6.4-prim-no-arm-atomics.patch
	++ fromUntil "8.6.4" "8.8" ./patches/ghc/global-offset-table.patch
	++ fromUntil "8.6.4" "8.8" ./patches/ghc/global-offset-table-2.patch
	++ always ./patches/ghc/respect-ar-path.patch
	++ until "8.12" ./patches/ghc/MR2537-use-one-shot-kqueue-on-macos.patch
	++ final.lib.optional (version == "8.6.3") ./patches/ghc/T16057--ghci-doa-on-windows.patch
	++ final.lib.optional (version == "8.6.3") ./patches/ghc/ghc-8.6.3-reinstallable-lib-ghc.patch
	++ final.lib.optional (version == "8.6.4") ./patches/ghc/ghc-8.6.4-reinstallable-lib-ghc.patch
	++ final.lib.optional (version == "8.6.5") ./patches/ghc/ghc-8.6.5-reinstallable-lib-ghc.patch
	++ final.lib.optional (version == "8.6.5") ./patches/ghc/ghc-8.6.5-atomic-arm-arch.patch
	++ final.lib.optional (version == "8.6.5") ./patches/ghc/MR3214-writable-rel-ro-data.patch
	++ final.lib.optional (version == "8.8.1") ./patches/ghc/ghc-8.8.1-reinstallable-lib-ghc.patch
	++ fromUntil "8.8.2" "8.9" ./patches/ghc/ghc-8.8.2-reinstallable-lib-ghc.patch
	++ final.lib.optional (version == "8.6.4") ./patches/ghc/ghc-8.6.4-better-plusSimplCountErrors.patch
	++ final.lib.optional (versionAtLeast "8.6.4" && final.stdenv.isDarwin) ./patches/ghc/ghc-macOS-loadArchive-fix.patch
	++ final.lib.optional (versionAtLeast "8.4.4" && final.stdenv.isDarwin) ./patches/ghc/ghc-darwin-gcc-version-fix.patch
	;

and below that you'll find the compilers. So you could just drop the ghc-patches attribute. For example here:

haskell.nix/overlays/bootstrap.nix

Lines 217 to 218 in 788e198

	ghc-patches = ghc-patches "8.6.5"
	++ [ D5123-patch haddock-900-patch ];

[michaelpj]

I suspect this is fairly stale, do reopen if it still happens.