Opened 7 years ago

Closed 7 years ago

Last modified 6 years ago

#1194 closed bug (fixed)

tcrun032 regressed

Reported by: igloo Owned by:
Priority: normal Milestone: 6.6.1
Component: Compiler Version: 6.6
Keywords: Cc:
Operating System: Unknown/Multiple Architecture: Unknown/Multiple
Type of failure: Difficulty: Unknown
Test Case: tcrun032 Blocked By:
Blocking: Related Tickets:

Description

The tcrun032 test:

{-# OPTIONS -fglasgow-exts -fallow-undecidable-instances #-}

-- This tests the recursive-dictionary stuff.
--
-- The derived instance needs 

module Main where

data Fix f = In (f (Fix f))  deriving( Show, Eq )
data L x = Nil | Cons Int x  deriving (Show, Eq)

main = do { print (In Nil);
        print (In Nil == In Nil) }

now fails with:

tcrun032.hs:9:5:
    No instance for (Show (f (Fix f)))
      arising from the 'deriving' clause of a data type declaration
      at tcrun032.hs:9:5
    Possible fix: add an instance declaration for (Show (f (Fix f)))
    When deriving the instance for `Show (Fix f)'

tcrun032.hs:9:5:
    No instance for (Eq (f (Fix f)))
      arising from the 'deriving' clause of a data type declaration
      at tcrun032.hs:9:5
    Possible fix: add an instance declaration for (Eq (f (Fix f)))
    When deriving the instance for `Eq (Fix f)'

in the 6.6 branch. Both 6.6 and the HEAD work.

Change History (3)

comment:1 Changed 7 years ago by simonpj

  • Resolution set to fixed
  • Status changed from new to closed

Fixed.

comment:2 Changed 6 years ago by simonmar

  • Architecture changed from Unknown to Unknown/Multiple

comment:3 Changed 6 years ago by simonmar

  • Operating System changed from Unknown to Unknown/Multiple
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