Inferred CallStacks expose implicit parameter
It was noticed (in a thread on ghc-devs) that introducing a CallStack-carrying term into the RHS of a let binding in GHCi produces a type which itself carries a callstack.
I could be wrong but as far as I know this is a bug: the solver should never introduce a constraint that the user didn't write; it should merely provide an empty callstack in the event that a callstack constraint can't be solved.
Prelude> let myList = [1, 2, 3 :: Integer]
Prelude> let myList' = myList ++ undefined
Prelude> :t myList
myList :: [Integer]
Prelude> :t myList'
myList' :: (?callStack::GHC.Stack.Types.CallStack) => [Integer]
Trac metadata
Trac field | Value |
---|---|
Version | 8.0.1-rc2 |
Type | Bug |
TypeOfFailure | OtherFailure |
Priority | high |
Resolution | Unresolved |
Component | Compiler (Type checker) |
Test case | |
Differential revisions | |
BlockedBy | |
Related | |
Blocking | |
CC | gridaphobe |
Operating system | |
Architecture |