#6096: tc126(optasm) is failing with a core lint error
---------------------------------+------------------------------------------
Reporter: igloo | Owner:
Type: bug | Status: new
Priority: high | Milestone: 7.6.1
Component: Compiler | Version: 7.5
Keywords: | Os: Unknown/Multiple
Architecture: Unknown/Multiple | Failure: GHC rejects valid program
Difficulty: Unknown | Testcase: tc126
Blockedby: | Blocking:
Related: |
---------------------------------+------------------------------------------
`tc126(optasm)` is failing with a core lint error.
The code:
{{{
{-# LANGUAGE MultiParamTypeClasses, FunctionalDependencies,
FlexibleInstances, FlexibleContexts, UndecidableInstances #-}
-- UndecidableInstances now needed because the Coverage Condition fails
-- !!! Functional dependency test. Hugs [Apr 2001] fails to typecheck this
-- Rather bizarre example submitted by Jonathon Bell
module ShouldCompile where
-- module Foo where
class Bug f a r | f a -> r where
bug::f->a->r
instance Bug (Int->r) Int r
instance (Bug f a r) => Bug f (c a) (c r)
f:: Bug(Int->Int) a r => a->r
f = bug (id::Int->Int)
g1 = f (f [0::Int])
-- Inner f gives result type
-- f [0::Int] :: Bug (Int->Int) [Int] r => r
-- Which matches the second instance declaration, giving r = [r']
-- f [0::Int] :: Bug (Int->Int) Int r' => r'
-- Wwich matches the first instance decl giving r' = Int
-- f [0::Int] :: Int
-- The outer f now has constraint
-- Bug (Int->Int) Int r
-- which makes r=Int
-- So g1::Int
g2 = f (f (f [0::Int]))
-- The outer f repeats the exercise, so g2::Int
-- This is the definition that Hugs rejects
}}}
The failure:
{{{
=====> tc126(optasm) 120 of 326 [0, 0, 0]
cd . && '/home/ian/ghc/git/ghc/inplace/bin/ghc-stage2' -fforce-recomp
-dcore-lint -dcmm-lint -dno-debug-output -no-user-package-conf -rtsopts
-fno-ghci-history -c tc126.hs -O -fasm -fno-warn-incomplete-patterns
>tc126.comp.stderr 2>&1
Compile failed (status 256) errors were:
tc126.hs:15:25: Warning:
No explicit method or default declaration for `bug'
In the instance declaration for `Bug (Int -> r) Int r'
tc126.hs:16:10: Warning:
No explicit method or default declaration for `bug'
In the instance declaration for `Bug f (c a) (c r)'
*** Core Lint errors : in result of Common sub-expression ***
{-# LINE 33 "tc126.hs #-}: Warning:
[RHS of ShouldCompile.g2 :: [GHC.Types.Int]]
The type of this binder doesn't match the type of its RHS:
ShouldCompile.g2
Binder's type: [GHC.Types.Int]
Rhs type: [GHC.Types.Int] -> [GHC.Types.Int]
*** Offending Program ***
lvl_sbL
:: forall f_aal (c_aam :: * -> *) a_aan r_aao.
f_aal -> c_aam a_aan -> c_aam r_aao
[LclId, Str=DmdType b]
lvl_sbL =
\ (@ f_aal) (@ (c_aam :: * -> *)) (@ a_aan) (@ r_aao) ->
Control.Exception.Base.noMethodBindingError
@ (f_aal -> c_aam a_aan -> c_aam r_aao)
"tc126.hs:16:10-51|ShouldCompile.bug"
$cbug_abl
:: forall f_aal (c_aam :: * -> *) a_aan r_aao.
ShouldCompile.Bug f_aal a_aan r_aao =>
f_aal -> c_aam a_aan -> c_aam r_aao
[LclId,
Arity=1,
Str=DmdType Ab,
Unf=Unf{Src=InlineStable, TopLvl=True, Arity=1, Value=True,
ConLike=True, WorkFree=True, Expandable=True,
Guidance=ALWAYS_IF(unsat_ok=True,boring_ok=True)
Tmpl= \ (@ f_aal) (@ (c_aam :: * -> *)) (@ a_aan) (@ r_aao) _ ->
lvl_sbL @ f_aal @ c_aam @ a_aan @ r_aao}]
$cbug_abl =
\ (@ f_aal) (@ (c_aam :: * -> *)) (@ a_aan) (@ r_aao) _ ->
lvl_sbL @ f_aal @ c_aam @ a_aan @ r_aao
ShouldCompile.$fBugfcc [InlPrag=INLINE (sat-args=0)]
:: forall f_aal (c_aam :: * -> *) a_aan r_aao.
ShouldCompile.Bug f_aal a_aan r_aao =>
ShouldCompile.Bug f_aal (c_aam a_aan) (c_aam r_aao)
[LclIdX[DFunId(nt)],
Arity=1,
Str=DmdType Ab,
Unf=Unf{Src=InlineStable, TopLvl=True, Arity=1, Value=True,
ConLike=True, WorkFree=True, Expandable=True,
Guidance=ALWAYS_IF(unsat_ok=False,boring_ok=True)
Tmpl= $cbug_abl
`cast` (forall f_aal (c_aam :: * -> *) a_aan r_aao.
<ShouldCompile.Bug f_aal a_aan r_aao>
-> Sym
<(ShouldCompile.NTCo:Bug <f_aal> <c_aam a_aan>
<c_aam r_aao>)>
:: (forall f_aal (c_aam :: * -> *) a_aan r_aao.
ShouldCompile.Bug f_aal a_aan r_aao =>
f_aal -> c_aam a_aan -> c_aam r_aao)
~#
(forall f_aal (c_aam :: * -> *) a_aan r_aao.
ShouldCompile.Bug f_aal a_aan r_aao =>
ShouldCompile.Bug f_aal (c_aam a_aan) (c_aam
r_aao)))}]
ShouldCompile.$fBugfcc =
(\ (@ f_aal)
(@ (c_aam :: * -> *))
(@ a_aan)
(@ r_aao)
(eta_B1 :: ShouldCompile.Bug f_aal a_aan r_aao) ->
$cbug_abl @ f_aal @ c_aam @ a_aan @ r_aao eta_B1)
`cast` (forall f_aal (c_aam :: * -> *) a_aan r_aao.
<ShouldCompile.Bug f_aal a_aan r_aao>
-> Sym
<(ShouldCompile.NTCo:Bug <f_aal> <c_aam a_aan> <c_aam
r_aao>)>
:: (forall f_aal (c_aam :: * -> *) a_aan r_aao.
ShouldCompile.Bug f_aal a_aan r_aao =>
f_aal -> c_aam a_aan -> c_aam r_aao)
~#
(forall f_aal (c_aam :: * -> *) a_aan r_aao.
ShouldCompile.Bug f_aal a_aan r_aao =>
ShouldCompile.Bug f_aal (c_aam a_aan) (c_aam r_aao)))
$cbug_abh
:: forall r_aap. (GHC.Types.Int -> r_aap) -> GHC.Types.Int -> r_aap
[LclId, Str=DmdType b]
$cbug_abh =
\ (@ r_aap) ->
Control.Exception.Base.noMethodBindingError
@ ((GHC.Types.Int -> r_aap) -> GHC.Types.Int -> r_aap)
"tc126.hs:15:25-47|ShouldCompile.bug"
ShouldCompile.$fBug(->)Intr [InlPrag=INLINE (sat-args=0)]
:: forall r_aap.
ShouldCompile.Bug (GHC.Types.Int -> r_aap) GHC.Types.Int r_aap
[LclIdX[DFunId(nt)],
Str=DmdType b,
Unf=Unf{Src=InlineStable, TopLvl=True, Arity=0, Value=False,
ConLike=False, WorkFree=True, Expandable=True,
Guidance=ALWAYS_IF(unsat_ok=False,boring_ok=True)
Tmpl= $cbug_abh
`cast` (forall r_aap.
Sym
<(ShouldCompile.NTCo:Bug
<GHC.Types.Int -> r_aap> <GHC.Types.Int>
<r_aap>)>
:: (forall r_aap.
(GHC.Types.Int -> r_aap) -> GHC.Types.Int ->
r_aap)
~#
(forall r_aap.
ShouldCompile.Bug (GHC.Types.Int -> r_aap)
GHC.Types.Int r_aap))}]
ShouldCompile.$fBug(->)Intr =
$cbug_abh
`cast` (forall r_aap.
Sym
<(ShouldCompile.NTCo:Bug
<GHC.Types.Int -> r_aap> <GHC.Types.Int> <r_aap>)>
:: (forall r_aap.
(GHC.Types.Int -> r_aap) -> GHC.Types.Int -> r_aap)
~#
(forall r_aap.
ShouldCompile.Bug (GHC.Types.Int -> r_aap) GHC.Types.Int
r_aap))
$sf_sbw :: [GHC.Types.Int] -> [GHC.Types.Int]
[LclId, Str=DmdType b]
$sf_sbw = case lvl_sbL of wild_00 { }
ShouldCompile.f
:: forall a_aaf r_aag.
ShouldCompile.Bug (GHC.Types.Int -> GHC.Types.Int) a_aaf r_aag =>
a_aaf -> r_aag
[LclIdX,
Arity=1,
Str=DmdType C(S),
RULES: "SPEC ShouldCompile.f [[GHC.Types.Int], [GHC.Types.Int]]" [ALWAYS]
forall ($dBug_XbY
:: ShouldCompile.Bug
(GHC.Types.Int -> GHC.Types.Int)
[GHC.Types.Int] [GHC.Types.Int]).
ShouldCompile.f @ [GHC.Types.Int] @ [GHC.Types.Int]
$dBug_XbY
= $sf_sbw]
ShouldCompile.f =
\ (@ a_a)
(@ r_b)
($dBug_aaQ
:: ShouldCompile.Bug (GHC.Types.Int -> GHC.Types.Int) a_a r_b) ->
($dBug_aaQ
`cast` (<ShouldCompile.NTCo:Bug
<GHC.Types.Int -> GHC.Types.Int> <a_a> <r_b>>
:: ShouldCompile.Bug (GHC.Types.Int -> GHC.Types.Int) a_a r_b
~#
((GHC.Types.Int -> GHC.Types.Int) -> a_a -> r_b)))
(GHC.Base.id @ GHC.Types.Int)
ShouldCompile.g2 :: [GHC.Types.Int]
[LclIdX, Str=DmdType b]
ShouldCompile.g2 = $sf_sbw
ShouldCompile.g1 :: [GHC.Types.Int]
[LclIdX, Str=DmdType b]
ShouldCompile.g1 = $sf_sbw
*** End of Offense ***
<no location info>:
Compilation had errors
*** unexpected failure for tc126(optasm)
}}}
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/6096>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler
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