#8537: confusing error message for specialize pragma -------------------------------------+------------------------------------ Reporter: carter | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.6.3 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Unknown/Multiple Type of failure: None/Unknown | Difficulty: Unknown Test Case: | Blocked By: Blocking: | Related Tickets: -------------------------------------+------------------------------------ Old description:

I get the following confusing error/warning about SPECIALIZE {{{

SPECIALISE pragma for non-overloaded function `$cfmap'

}}}

with the following example module

{{{

{-# LANGUAGE PolyKinds #-} {-# LANGUAGE BangPatterns #-} {-# LANGUAGE DataKinds #-} {-# LANGUAGE TypeFamilies #-} {-# LANGUAGE GADTs #-} {-# LANGUAGE DeriveDataTypeable #-} {-# LANGUAGE TypeOperators #-} {-# LANGUAGE FlexibleInstances #-} {-# LANGUAGE FlexibleContexts #-} {-# LANGUAGE FunctionalDependencies #-} {-# LANGUAGE UndecidableInstances #-} {-# LANGUAGE ScopedTypeVariables #-} {-# LANGUAGE StandaloneDeriving #-} {-# LANGUAGE CPP #-} {-# LANGUAGE TemplateHaskell #-} {-# LANGUAGE NoImplicitPrelude #-}

module Numerical.Types.Shape where

import Control.Applicative import Data.Foldable import Data.Monoid import Data.Functor import Prelude (seq, ($!),($),Show(..),Eq(),Int)

data Nat = S !Nat | Z --deriving (Eq,Show,Read)

{- not doing the HLIST style shape because I don't want to have any pattern matchings going on.

Also would play hell with locality quality in the address translation hackery, because there'd be an extra load to get those ints! -} infixr 3 :*

{- the concern basically boils down to "will it specialize / inline well"

-} data Shape (rank :: Nat) a where Nil :: Shape Z a (:*) :: !(a) -> !(Shape r a ) -> Shape (S r) a

--deriving instance (Show (Shape rank a))

-- deriving instance Eq (Shape rank a)

-- #if defined( __GLASGOW_HASKELL__ ) && ( __GLASGOW_HASKELL__ >= 707) --deriving instance Typeable (Shape rank a) -- #endif

instance Functor (Shape Z) where

fmap = \ f Nil -> Nil {-# INLINABLE fmap #-}

{-# SPECIALIZE fmap :: (Int ->Int )-> (Shape Z Int)-> (Shape Z Int) #-}

}}}

New description: I get the following confusing error/warning about SPECIALIZE {{{ SPECIALISE pragma for non-overloaded function `$cfmap' }}} with the following example module {{{ {-# LANGUAGE PolyKinds #-} {-# LANGUAGE BangPatterns #-} {-# LANGUAGE DataKinds #-} {-# LANGUAGE TypeFamilies #-} {-# LANGUAGE GADTs #-} {-# LANGUAGE DeriveDataTypeable #-} {-# LANGUAGE TypeOperators #-} {-# LANGUAGE FlexibleInstances #-} {-# LANGUAGE FlexibleContexts #-} {-# LANGUAGE FunctionalDependencies #-} {-# LANGUAGE UndecidableInstances #-} {-# LANGUAGE ScopedTypeVariables #-} {-# LANGUAGE StandaloneDeriving #-} {-# LANGUAGE CPP #-} {-# LANGUAGE TemplateHaskell #-} {-# LANGUAGE NoImplicitPrelude #-} module Numerical.Types.Shape where import Control.Applicative import Data.Foldable import Data.Monoid import Data.Functor import Prelude (seq, ($!),($),Show(..),Eq(),Int) data Nat = S !Nat | Z infixr 3 :* data Shape (rank :: Nat) a where Nil :: Shape Z a (:*) :: !(a) -> !(Shape r a ) -> Shape (S r) a instance Functor (Shape Z) where fmap = \ f Nil -> Nil {-# INLINABLE fmap #-} {-# SPECIALIZE fmap :: (Int ->Int )-> (Shape Z Int)-> (Shape Z Int) #-} }}} -- Comment (by simonpj): The `$cfmap` part is not very clever, but the actual message is fine isn't it? There isn't any useful specialisation we can do on `fmap` at type `(Shape Z)` is there? I suppose you might say that the pattern match is exhaustive so we could omit the test for `Nil` vs `(:*)`, but that's all. Simon -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/8537#comment:1 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler

#8537: confusing error message for specialize pragma -------------------------------------+------------------------------------ Reporter: carter | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.6.3 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Unknown/Multiple Type of failure: None/Unknown | Difficulty: Unknown Test Case: | Blocked By: Blocking: | Related Tickets: -------------------------------------+------------------------------------ Comment (by Simon Peyton Jones ): In [changeset:"2a88f8fbe24f3a9e832f3bc76ac3b877e79cf978/testsuite"]: {{{ #!CommitTicketReference repository="testsuite" revision="2a88f8fbe24f3a9e832f3bc76ac3b877e79cf978" Test Trac #8537 }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/8537#comment:3 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler

#8537: confusing error message for specialize pragma -------------------------------------------------+------------------------- Reporter: carter | Owner: Type: bug | Status: Priority: normal | closed Component: Compiler | Milestone: Resolution: fixed | Version: 7.6.3 Operating System: Unknown/Multiple | Keywords: Type of failure: None/Unknown | Architecture: Test Case: | Unknown/Multiple simplCore/should_compile/T8537 | Difficulty: Blocking: | Unknown | Blocked By: | Related Tickets: -------------------------------------------------+------------------------- Comment (by carter): great! -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/8537#comment:5 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler