[Bug #127119] 4.11 dies for certain RULES

[noreply@sourceforge.net]

Bug #127119, was updated on 2000-Dec-29 23:34
Here is a current snapshot of the bug.

Project: The Glasgow Haskell Compiler
Category: Compiler (Type checker)
Status: Closed
Resolution: Fixed
Bug Group: None
Priority: 5
Submitted by: chak
Assigned to : nobody
Summary: 4.11 dies for certain RULES

Details: Given

<code>
module Bug where

foo 1 = 2
bar 0 = 1

{-# RULES

  "foo/bar" foo bar = foobar

 #-}

foobar = 2
</code>

4.11 (couple of weeks old) dies with

  ghc-4.11: panic! (the `impossible' happened):
  	  basicTypes/Var.lhs:185: Non-exhaustive patterns in function
readMutTyVar

4.08.1 doesn't seem to have a problem with this code.


Follow-Ups:

Date: 2001-Jan-03 03:56
By: simonpj

Comment:
TcRules was quantifying over a bogus type variable
-------------------------------------------------------

For detailed info, follow this link:
http://sourceforge.net/bugs/?func=detailbug&bug_id=127119&group_id=8032