[Haskell-cafe] Linker troubles with cabal sandbox

Hello folks, I'm getting some linker trouble in the form of: "Undefined symbols for architecture x86_64: ... ld: symbol(s) not found for architecture x86_64" When trying to compile a simple hashtables example https://hackage.haskell.org/package/hashtables-1.2.0.0 I came across a previous thread with a solution https://www.haskell.org/pipermail/haskell-cafe/2014-October/116469.html but it's not working for me. Here are the steps I'm taking and the verbose errors: https://gist.github.com/zmoazeni/b68c66f5e15654948946 Can someone give me a hand? Thanks! Zach