#12622: Unboxed static pointers lead to missing SPT entries -------------------------------------+------------------------------------- Reporter: mboes | Owner: | facundo.dominguez Type: bug | Status: patch Priority: normal | Milestone: Component: Compiler | Version: 8.1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Phab:D2709 Wiki Page: | -------------------------------------+------------------------------------- Comment (by facundo.dominguez): Preventing StaticPtrs from being unpacked is not necessary. Turns out that there is a bug in the code that floats out static pointers. The identifier of the following binding is not exported and it should. {{{ lvl_sG5 :: forall a_aEy. StaticPtr (a_aEy -> Bool) lvl_sG5 = \ (@ a_aEy) -> GHC.StaticPtr.StaticPtr @ (a_aEy -> Bool) 13520098690657238824## 6110703080284699228## lvl_sG4 (g @ a_aEy) }}} Having the id as exported, prevents the simplifier from removing it, which is what we want. However, our minimal example still fails linting. The problem is this line in `Main.hs`: {{{ let T s = sg :: T (Bool -> Bool) }}} Which gets translated to {{{ s :: StaticPtr (Bool -> Bool) s = case sg of T dt_d2bM dt_d2bN dt_d2bO dt_d2bP -> GHC.StaticPtr.StaticPtr dt_d2bM dt_d2bN dt_d2bO dt_d2bP }}} which the linter rejects because it contains an occurrence of the StaticPtr data constructor which cannot be floated. Note that this occurrence is harmless, since it is not created by a `static` form and does not correspond to an entry in the Static Pointer Table. Nonetheless, the linter is confused, and I don't know yet how to help it. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/12622#comment:5 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler