#15389: -Wall-missed-specialisations warnings not fatal with -Werror -------------------------------------+------------------------------------- Reporter: ChaiTRex | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: 8.6.1 Component: Compiler | Version: 8.4.3 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- When compiling a program with GHC 8.4.3, vector 0.12.0.1 (with a dependency on primitive 0.6.4.0) and `-Wall-missed-specialisations -Werror`, warnings are produced, but they aren't fatal. `-Werror` should make them fatal but doesn't. A somewhat-minimal example: {{{#!hs {-# OPTIONS_GHC -Wall-missed-specialisations -Werror #-} {-# LANGUAGE MultiParamTypeClasses, TypeFamilies #-} module Warnings3 where import GHC.Base (liftM) import qualified Data.Vector.Generic.Base as G (Vector, basicUnsafeFreeze, basicUnsafeThaw, basicLength, basicUnsafeSlice, basicUnsafeIndexM, basicUnsafeCopy, elemseq) import qualified Data.Vector.Generic.Mutable.Base as GM (MVector, basicLength, basicUnsafeSlice, basicOverlaps, basicUnsafeNew, basicInitialize, basicUnsafeReplicate, basicUnsafeRead, basicUnsafeWrite, basicClear, basicSet, basicUnsafeCopy, basicUnsafeMove, basicUnsafeGrow) import qualified Data.Vector.Unboxed as U (Unbox, Vector) import qualified Data.Vector.Unboxed.Mutable as U (MVector) newtype T = T () deriving (Show, Eq, Ord) newtype C = C (U.Vector T) deriving (Show, Eq, Ord) instance U.Unbox T newtype instance U.MVector s T = MV_T (U.MVector s ()) instance GM.MVector U.MVector T where basicLength (MV_T mv) = GM.basicLength mv basicUnsafeSlice i l (MV_T mv) = MV_T (GM.basicUnsafeSlice i l mv) basicOverlaps (MV_T mv1) (MV_T mv2) = GM.basicOverlaps mv1 mv2 basicUnsafeNew l = MV_T `liftM` GM.basicUnsafeNew l basicInitialize (MV_T mv) = GM.basicInitialize mv basicUnsafeReplicate l _ = MV_T `liftM` GM.basicUnsafeReplicate l () basicUnsafeRead (MV_T mv) i = const (T ()) `liftM` GM.basicUnsafeRead mv i basicUnsafeWrite (MV_T mv) i _ = GM.basicUnsafeWrite mv i () basicClear (MV_T mv) = GM.basicClear mv basicSet (MV_T mv) x = GM.basicSet mv () basicUnsafeCopy (MV_T mv1) (MV_T mv2) = GM.basicUnsafeCopy mv1 mv2 basicUnsafeMove (MV_T mv1) (MV_T mv2) = GM.basicUnsafeMove mv1 mv2 basicUnsafeGrow (MV_T mv) l = MV_T `liftM` GM.basicUnsafeGrow mv l newtype instance U.Vector T = V_T (U.Vector ()) instance G.Vector U.Vector T where basicUnsafeFreeze (MV_T mv) = V_T `liftM` G.basicUnsafeFreeze mv basicUnsafeThaw (V_T v) = MV_T `liftM` G.basicUnsafeThaw v basicLength (V_T v) = G.basicLength v basicUnsafeSlice i l (V_T v) = V_T (G.basicUnsafeSlice i l v) basicUnsafeIndexM (V_T v) i = const (T ()) `liftM` G.basicUnsafeIndexM v i basicUnsafeCopy (MV_T mv) (V_T v) = G.basicUnsafeCopy mv v elemseq (V_T v) _ = G.elemseq v () }}} The warnings are: {{{ src/Warnings3.hs: warning: Could not specialise imported function ‘Data.Vector.Unboxed.$w$cshowsPrec’ when specialising ‘Data.Vector.Unboxed.$fShowVector_$cshowsPrec’ Probable fix: add INLINABLE pragma on ‘Data.Vector.Unboxed.$w$cshowsPrec’ src/Warnings3.hs: warning: Could not specialise imported function ‘Data.Vector.Unboxed.$fOrdVector_$cmin’ Probable fix: add INLINABLE pragma on ‘Data.Vector.Unboxed.$fOrdVector_$cmin’ src/Warnings3.hs: warning: Could not specialise imported function ‘Data.Vector.Unboxed.$fOrdVector_$cmax’ Probable fix: add INLINABLE pragma on ‘Data.Vector.Unboxed.$fOrdVector_$cmax’ }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/15389 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler