How to use ghc-heap-view of ghc-8.6

Patrick Dougherty patrick.doc at
Sat Jul 7 04:05:18 UTC 2018

This effort mostly just brought the core of this [1] library into GHC. The main function you will want to try is `getClosureData`,which takes any value and returns the heap representation. There are some tricky aspects about evaluation, but I will refer you to the comments about `Box`s in [1].

As a shameless self-plug, I also wrote a bit about it. The first page is a brief intro to the heap, and the second is an example demonstrating how to track down a leaky accumulator. I also link to a few posts that sent me down this path.

This doesn't implement all of the functionality of [1], but it pulls in enough that hopefully it should be a little more stable between GHC versions. Also, you should be able to recreate many of the functions by looking at the source of [1] on hackage.


P.S. Sorry about using [1] so many times. Both libraries are called heap-view which makes it a little difficult to distinguish.

 On Friday, July 6, 2018 10:10 PM, Takenobu Tani <takenobu.hs at> wrote:

 Dear devs,

I'm interested in ghc-heap-view of ghc-8.6. [1]
Is there a document on how to use the ghc-heap-view of ghc-8.6?



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