Offer a way to augment call stacks

Sometimes, I may want to capture some information that can be reported when an error occurs. Suppose I have

f x y = g x (h y)

g :: HasCallStack => ...
g x y = ..... (error "whoopsy") ....

I may want f to record information about y that will be reported if g throws an exception. As far as I can tell, the only currently supported way to do this is horrible and limited:

f x y = unsafeDupablePerformIO $
  catch (evaluate (g x (h y))) $ \e -> ....

I'd much rather have a function like

addMessage :: HasCallStack
           => String
           -> (HasCallStack => a)
           -> a

This would stick a string into the current call stack "frame" and call the argument. I imagine this can be implemented directly with the underlying implicit parameter, likely with a slight change to the CallStack representation.

Trac metadata

Trac field	Value
Version	8.4.1
Type	FeatureRequest
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Core Libraries
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