The -e and --interactive flags setup HscInterpreted as the language in
#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): Here's another way to say what I mean. When in GHCi we do two kinds of compilation: - We compile loaded modules (if necessary) - We compile expressions typed in the GHCi prompt The target only makes sense for (1). In (2) we only compile to bytecode. So really `HscInterpreted` and flags like `-O` etc. are only applicable to (1). But currently we also apply some of those flags/settings to (e.g. `-O`) to (2) which is what's causing this bug. One of my suggestions in comment:11 was to separate these two compilations so that when we do (2) we never try to optimise the code. This can be done by implementing a new (or modifying the existing one if one already exists) top-level function for compiling GHCi expressions and updating `DynFlags` there to fix the compilation settings (e.g. by resetting optimisation level) for GHCi. Is this any more clear than my previous comment? main'
in Main.hs. DynFlags can be used to override this target (ie with -fbytecode or -fobjectcode). It seems like a mistake to be able to override it when it's already set to the HscInterpreted target, though I don't really understand if that's actually wanted.
So the lang/target doesn't matter when compiling GHCi expressions, as you _have to_ compile those to bytecode regardless of the lang/target. I meant overriding optimisation settings, not the lang/target. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/15617#comment:14 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler