Bug#868588: haskell-simple-templates FTBFS: Failed to load interface for Data.Aeson.Encoding.Internal

[Adrian Bunk]

Source: haskell-simple-templates
Version: 0.8.0.1-3
Severity: serious
Tags: buster sid

https://buildd.debian.org/status/package.php?p=haskell-simple-templates

...
[1 of 3] Compiling Web.Simple.Templates.ParserSpec ( test/Web/Simple/Templates/ParserSpec.hs, dist-ghc/build/test-simple-templates/test-simple-templates-tmp/Web/Simple/Templates/ParserSpec.o )
/usr/lib/haskell-packages/ghc/lib/x86_64-linux-ghc-8.0.2/aeson-1.0.2.1-CgbEAGwJWkq5wCUqDjmFHU/Data/Aeson/Types/ToJSON.hi
Declaration for $fToJSONKey[]_$ctoEncodingList:
  Failed to load interface for `Data.Aeson.Encoding.Internal'
  There are files missing in the `aeson-1.0.2.1' package,
  try running 'ghc-pkg check'.
  Use -v to see a list of the files searched for.
Cannot continue after interface file error
/usr/share/cdbs/1/class/hlibrary.mk:147: recipe for target 'build-ghc-stamp' failed
make: *** [build-ghc-stamp] Error 1