#13360: Add a flag to enable inferring HasCallStack constraints -------------------------------------+------------------------------------- Reporter: gridaphobe | Owner: (none) Type: feature request | Status: new Priority: normal | Milestone: 8.4.1 Component: Compiler | Version: 8.0.1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by gridaphobe): The underlying data structure is a slight twist on a linked list. https://hackage.haskell.org/package/base-4.10.0.0/docs/src/GHC.Stack.Types.h... The `FreezeCallStack` constructor is an experimental addition to let library authors avoid exposing implementation details in `CallStack`s. You're right that the cost of adding a `CallStack` should be roughly equivalent to passing another argument around, plus the cost of allocating each source location in the stack. It would make sense for the cost to be linear in the depth of the stack, each addition needs to allocate a new `PushCallStack` constructor, but maybe the constant factors can be improved. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13360#comment:10 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler