:set +r doesn't work for interpreted modules

I expect

a = trace "a" 1 

and then evaluating a repeatedly to show: "a" 1

as a result. ghci seems to do this, but with larger programs this doesn't appear to happen.

I guess it's an implementation detail in that expressions don't "need" to be evaluated twice, but for debugging purposes it's vital that it does.

I want that the first run of an algorithm produces the same trace as any subsequent one. Especially when one uses the 6.7 debugger this is an issue. Essentially, I need to load another module first and then the module I am interested in and then set the breakpoints again. This is a UI nightmare.

The option +r "revert top-level expressions after each evaluation" seems to indicate that should do what I want, but it doesn't.

Trac metadata

Trac field	Value
Version	6.7
Type	Bug
TypeOfFailure	OtherFailure
Priority	high
Resolution	Unresolved
Component	Compiler
Test case
Differential revisions
BlockedBy
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Blocking
CC
Operating system	Unknown
Architecture	Unknown