nix-build fails due to incomplete definition of unpack

[kjekac]

macOS 10.13.4 nix 2.1.3

Output:

➜  typedefs git:(master) nix-build default.nix -A typedefs
these derivations will be built:
  /nix/store/chwyrvnnh59ib11crq31d0nfr6qiqmkn-idris-typedefs-dev.drv
building '/nix/store/chwyrvnnh59ib11crq31d0nfr6qiqmkn-idris-typedefs-dev.drv'...
unpacking sources
unpacking source archive /nix/store/pqwi1h8976g6l8nab0hjnklywinl24w3-typedefs
source root is typedefs
patching sources
configuring
no configure script, doing nothing
building
Entering directory `./src'
Leaving directory `./src'
running tests
Entering directory `./src'
Type checking /private/tmp/nix-build-idris-typedefs-dev.drv-0/idris27013-0.idr
.idris-wrapped_: Erasure/getArity: definition not found for with block in Prelude.Strings.unpack
CallStack (from HasCallStack):
  error, called at src/Idris/Erasure.hs:602:20 in idris-1.3.0-HQONzYd57BmLbdAngG1p5r:Idris.Erasure
builder for '/nix/store/chwyrvnnh59ib11crq31d0nfr6qiqmkn-idris-typedefs-dev.drv' failed with exit code 1
error: build of '/nix/store/chwyrvnnh59ib11crq31d0nfr6qiqmkn-idris-typedefs-dev.drv' failed

[danawoodman]

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