#2814: Compiler timeout
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Reporter: celes | Owner:
Type: bug | Status: closed
Priority: normal | Milestone:
Component: Compiler | Version: 6.10.1
Severity: normal | Resolution: wontfix
Keywords: | Difficulty: Unknown
Testcase: | Os: MacOS X
Architecture: x86 |
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Changes (by simonpj):
* status: new => closed
* difficulty: => Unknown
* resolution: => wontfix
Old description:
> Compiler times out and consumes 600+ MB of memory when compiling certain
> code. Previously reported this bug by email (was not registered). It was
> a more complicated version of this same thing and was in version 6.6. The
> first attached file is simplest I could make which still causes the
> problem. The second file is the original which when ran should reverse
> its input.
>
> % ghc --version
> The Glorious Glasgow Haskell Compilation System, version 6.10.1
> % ghc --make test2.hs
> [1 of 1] Compiling Main ( test2.hs, test2.o )
> <does not terminate>
New description:
Compiler times out and consumes 600+ MB of memory when compiling certain
code. Previously reported this bug by email (was not registered). It was a
more complicated version of this same thing and was in version 6.6. The
first attached file is simplest I could make which still causes the
problem. The second file is the original which when ran should reverse its
input.
{{{
% ghc --version
The Glorious Glasgow Haskell Compilation System, version 6.10.1
% ghc --make test2.hs
[1 of 1] Compiling Main ( test2.hs, test2.o )
<does not terminate>
}}}
Comment:
Ah! This is a known bug: it's even in the user manual:
[http://www.haskell.org/ghc/docs/latest/html/users_guide/bugs.html#bugs-
ghc]. It arises when you encode recursion using a data type:
{{{
data V = Fun (V -> V)
}}}
As the manual says, we've never fixed it because it's quite tricky and
awkward to do so, and it only ever shows up in non-contrived programs. I
guess if it happens in a "real" program we'll have to pay more attention.
For the moment I'll mark this "wont-fix" but yell if this programming
idiom is truly useful to you in real programs.
Simon
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/2814#comment:1>
GHC <http://www.haskell.org/ghc/>
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