#1012: ghc panic with mutually recursive modules and template haskell
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Reporter: guest | Owner:
Type: bug | Status: reopened
Priority: normal | Milestone: 6.10 branch
Component: Template Haskell | Version: 6.8.2
Severity: normal | Resolution:
Keywords: | Difficulty: Unknown
Testcase: TH_import_loop | Architecture: Multiple
Os: Multiple |
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Changes (by simonpj):
* milestone: _|_ => 6.10 branch
Comment:
Fair enough. I have taken a little look at this, based on fons's
suggestion "``every module M that depends on a module C in a cycle, but is
not a member of that cycle, should have an implicit dependency on each of
the modules C1.. Cn in the cycle.``". Yes, I think that would not be too
hard to do. There are two places to think about:
* `ghc --make`: When deciding the up-sweep order, first do a SCC analysis
finding strongly connected components of modules, and top-sort those
components. Then linearise each component. That gives a linear order that
respects fons's suggestion.
* `ghc -M`: similar story, but less neat. We have to emit lots of extra
dependencies in the `makefile`, so that M depends on C1..Cn.
Not very hard, but more than an hours work. Let's do it for 6.10.
Simon
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/1012#comment:14>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler
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