whoCreated produces an uninformative stack trace when an exception is raised in a CAF

Consider the following program:

{-# LANGUAGE ScopedTypeVariables #-}
module Main where

import Control.Exception
import GHC.Stack

{-# NOINLINE caf #-}
caf :: [Int]
caf = [1..500]

{-# NOINLINE caf_exc #-}
caf_exc :: Int
caf_exc = caf !! 1000

{-# NOINLINE foo #-}
foo :: Int -> Int
foo 0 = caf_exc
foo n = foo $ n - 1

{-# NOINLINE bar #-}
bar :: Int -> Int
bar n = bar' n
  where
    bar' 0 = foo n
    bar' m = bar' $ m - 1

main :: IO ()
main = print (bar 10) `catch`
       \(e :: SomeException) -> do stacktrace <- whoCreated e
                                   print stacktrace

By default, when built with profiling, whoCreated in the example above produces a quite uninformative stack trace:

$ ./caf-nostack
["GHC.List.CAF (<entire-module>)"]

However, if you run the program with +RTS -xc, you'll see that it prints a stack trace with much more context:

$ ./caf-nostack +RTS -xc
*** Exception (reporting due to +RTS -xc): (THUNK_2_0), stack trace: 
  GHC.List.CAF
  --> evaluated by: Main.caf_exc,
  called from Main.CAF
  --> evaluated by: Main.foo,
  called from Main.bar.bar',
  called from Main.bar,
  called from Main.main,
  called from Main.CAF
  --> evaluated by: Main.main
["GHC.List.CAF (<entire-module>)"]

It'd be nice if whoCreated produced something closer to the +RTS -xc output in this case.

Cabalised test project: https://github.com/23Skidoo/caf-nostack

Trac metadata

Trac field	Value
Version	8.0.1
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Compiler
Test case
Differential revisions
BlockedBy
Related
Blocking
CC
Operating system
Architecture

evaluated by: Main.caf_exc,\r\n called from Main.CAF\r\n --> evaluated by: Main.foo,\r\n called from Main.bar.bar',\r\n called from Main.bar,\r\n called from Main.main,\r\n called from Main.CAF\r\n --> evaluated by: Main.main\r\n[\"GHC.List.CAF ()\"]\r\n}}}\r\n\r\nIt'd be nice if `whoCreated` produced something closer to the `+RTS -xc` output in this case.\r\n\r\nCabalised test project: https://github.com/23Skidoo/caf-nostack","type_of_failure":"OtherFailure","blocking":[]} -->