#14779: Compiling with -g fails -lint-core checks -------------------------------------+------------------------------------- Reporter: niteria | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: (Debugging) | Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Compile-time | Unknown/Multiple crash or panic | Test Case: Blocked By: | Blocking: Related Tickets: #14122, #14123, | Differential Rev(s): #8472, #14406 | Wiki Page: | -------------------------------------+------------------------------------- Comment (by niteria):
That is bad, and we should not allow it. In which case whichever code is generating it needs to be fixed.
https://phabricator.haskell.org/D3925 suggests that this is the way we want to proceed. It refers to this note: {{{ Note [CoreSyn top-level string literals] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ As an exception to the usual rule that top-level binders must be lifted, we allow binding primitive string literals (of type Addr#) of type Addr# at the top level. This allows us to share string literals earlier in the pipeline and crucially allows other optimizations in the Core2Core pipeline to fire. Consider, f n = let a::Addr# = "foo"# in \x -> blah In order to be able to inline `f`, we would like to float `a` to the top. Another option would be to inline `a`, but that would lead to duplicating string literals, which we want to avoid. See Trac #8472. The solution is simply to allow top-level unlifted binders. We can't allow arbitrary unlifted expression at the top-level though, unlifted binders cannot be thunks, so we just allow string literals. It is important to note that top-level primitive string literals cannot be wrapped in Ticks, as is otherwise done with lifted bindings. CoreToStg expects to see just a plain (Lit (MachStr ...)) expression on the RHS of primitive string bindings; anything else and things break. CoreLint checks this invariant. Also see Note [Compilation plan for top-level string literals]. }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/14779#comment:2 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler