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Core lint error on unlifted implicit parameter

Summary

Unlifted implicit parameters cannot (AFAICT) be used, but they can be bound.

This results in a core lint error.

Steps to reproduce

ghci> :set -dcore-lint -XMagicHash -XImplicitParams
ghci> let ?foo = 4# in 4
*** Core Lint errors : in result of desugar expression ***
<interactive>:4:1: warning:
    Bad axiom application (check_ki1 N:IP[0] <"foo">_N <Int#>_N
                                     TYPE 'IntRep
                                     a_aOq
                                     *)
      N:IP[0] <"foo">_N <Int#>_N
[...]
*** End of Offense ***

<no location info>: error:
Compilation had errors

Expected Behavior

This should throw a type error.

Environment

  • GHC version used: GHC 9.8.1, HEAD

Optional:

  • Operating System: Arch Linux on WSL2 on Windows 11
  • System Architecture: x86_64
Edited by Jakob Brünker
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