#15617: Unboxed tuples/sum error message on `a = show 5` in expression evaluation and interactive modes -------------------------------------+------------------------------------- Reporter: ChaiTRex | Owner: | JulianLeviston Type: bug | Status: new Priority: normal | Milestone: 8.6.1 Component: Compiler | Version: 8.6.1-beta1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Poor/confusing | Unknown/Multiple error message | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by osa1): As you say, `HscInterpreted` means modules are compiled to bytecode and then interpreted. Interpreter can interact with native code and with `-fobject-code` you tell GHCi to compile the loaded modules to native code rather than to bytecode (the default, or `-fbyte-code`). Either way the expressions you type in the GHCi prompt are compiled to bytecode and interpreted, so I think those options are only applied to the loaded modules. We need to avoid optimising those expressions. I think another (simpler) way for this might be to find the top-level function for compiling GHCi expressions to bytecode, and override relevant `DynFlag` fields there so that down the line the desugarer and simplifier do not optimise it. That means no new field to `DynFlags` so think it would be even better. If the top-level function to compile a GHCi expression/statement is also used for other purposes perhaps we can introduce a new top-level function for GHCi only, and override relevant `DynFlags` fields there. How does that sound? Sounds better to me as we don't add more to `DynFlags` (which is already huge). -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/15617#comment:11 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler