There is no instance for HasLink

[benz0li]

This error occurs when trying to build pandoc 2.19.2 with GHC 9.4.2.

Steps to reproduce

1. Clone repository:

   git clone https://github.com/jgm/pandoc.git

2. Checkout 2.19.2:

   cd pandoc

   git checkout 2.19.2

3. Update codebase:

   diff --git a/Makefile b/Makefile
   index f5beb0a44..587b0f764 100644
   --- a/Makefile
   +++ b/Makefile
   @@ -3,7 +3,7 @@ pandoc=$(shell find dist -name pandoc -type f -exec ls -t {} \; | head -1)
    SOURCEFILES?=$(shell git ls-tree -r master --name-only | grep "\.hs$$")
    BRANCH?=master
    ARCH=$(shell uname -m)
   -DOCKERIMAGE=registry.gitlab.b-data.ch/ghc/ghc4pandoc:9.2.3
   +DOCKERIMAGE=registry.gitlab.b-data.ch/ghc/ghc4pandoc:9.4.2
    COMMIT=$(shell git rev-parse --short HEAD)
    TIMESTAMP=$(shell date "+%Y%m%d_%H%M")
    LATESTBENCH=$(word 1,$(shell ls -t bench_*.csv 2>/dev/null))
   diff --git a/linux/make_artifacts.sh b/linux/make_artifacts.sh
   index 4653a0c19..c30440976 100644
   --- a/linux/make_artifacts.sh
   +++ b/linux/make_artifacts.sh
   @@ -27,7 +27,8 @@ ghc --version
    
    cabal update
    cabal clean
   -cabal configure -f-export-dynamic -fembed_data_files --enable-executable-static --ghc-options '-j4 +RTS -A256m -RTS -split-sections -optc-Os -optl=-pthread' pandoc
   +cabal configure -f-export-dynamic -fembed_data_files --allow-newer --enable-executable-static --ghc-options '-j4 +RTS -A256m -RTS -split-sections -optc-Os 
   +-optl=-pthread' pandoc
    cabal build -j4
    for f in $(find dist-newstyle -name 'pandoc' -type f -perm /400); do cp $f $ARTIFACTS/; done
    

4. Make Debian package:

   make debpkg

Log file: docker-log.txt

[Taneb]

Extracting the error from the linked logs, for others' convenience:

[31 of 33] Compiling Servant.Links    ( src/Servant/Links.hs, dist/build/Servant/Links.o, dist/build/Servant/Links.dyn_o )

src/Servant/Links.hs:650:10: error:
    • There is no instance for HasLink (arr :> ...)
      arr expects 1
                  GHC.TypeNats.+ Servant.API.TypeErrors.Arity' b more arguments
    • In the ambiguity check for an instance declaration
      In the instance declaration for ‘HasLink ((arr :: a -> b) :> sub)’
    |
650 | instance TypeError (PartialApplication HasLink arr) => HasLink ((arr :: a -> b) :> sub)
    |          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

src/Servant/Links.hs:656:31: error:
    • There is no instance for HasLink (ty :> ...)
    • In the ambiguity check for an instance declaration
      In the instance declaration for ‘HasLink (ty :> sub)’
    |
656 | instance {-# OVERLAPPABLE #-} TypeError (NoInstanceForSub HasLink ty) => HasLink (ty :> sub)
    |                               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

[benz0li]

Resolved by #1592