GHC 7.0.1 (or very strange dimensional-0.8.0.1) bug

[Bjorn Buckwalter]

Thanks for the report Pavel! Indeed strange. I don't have GHC 7.0.1
installed but definitely don't see this with 6.12.3. Did you put in a
GHC bug report at http://hackage.haskell.org/trac/ghc/wiki/ReportABug?
If not I'll do it tomorrow.

As a work-around you could try providing an explicit type signature (I
suspect the type inferencer is looping), but maybe you've figured out
something workable for you already.

Thanks,
Bjorn

(Sorry for the re-repost, Pavel, my incompetence is matched only by my
perseverance.)


On Tue, Jan 25, 2011 at 22:02, Pavel Perikov <perikov at gmail.com> wrote:
> in ghci:
> Prelude> import Numeric.Units.Dimensional.Prelude as D
> Prelude Numeric.Units.Dimensional.Prelude> D.sqrt $ let s = 9 *~ (meter D.*
> meter) in s
> 3.0 m
> Prelude Numeric.Units.Dimensional.Prelude> D.sqrt $ 9 *~ (meter D.* meter)
> ghci hangs.
> complied and optimized code detects <<loop>> and let-trick from the above
> does not help.
> Here's the complete ghci -v session which contains all package versions
>
> ghci -v
> GHCi, version 7.0.1: http://www.haskell.org/ghc/  :? for help
> Glasgow Haskell Compiler, Version 7.0.1, for Haskell 98, stage 2 booted by
> GHC version 6.12.3
> Using binary package database:
> /Library/Frameworks/GHC.framework/Versions/7.0.1-i386/usr/lib/ghc-7.0.1/package.conf.d/package.cache
> Using binary package database:
> /Users/pavel/.ghc/i386-darwin-7.0.1/package.conf.d/package.cache
> hiding package containers-0.3.0.0 to avoid conflict with later version
> containers-0.4.0.0
> hiding package QuickCheck-2.3.0.2 to avoid conflict with later version
> QuickCheck-2.4.0.1
> wired-in package ghc-prim mapped to
> ghc-prim-0.2.0.0-0713122c5f9038c6f0355a37e294e054
> wired-in package integer-gmp mapped to
> integer-gmp-0.2.0.2-bfb191b8468e4d812a2bb92622cb246e
> wired-in package base mapped to
> base-4.3.0.0-1ea085b64a078bd9d5eaa9d8d525e35e
> wired-in package rts mapped to builtin_rts
> wired-in package template-haskell mapped to
> template-haskell-2.5.0.0-f262af1f92a427f5cf4133bff041044f
> wired-in package dph-seq not found.
> wired-in package dph-par not found.
> Hsc static flags: -static
> Loading package ghc-prim ... linking ... done.
> Loading package integer-gmp ... linking ... done.
> Loading package base ... linking ... done.
> Loading package ffi-1.0 ... linking ... done.
> Prelude> import Numeric.Units.Dimensional.Prelude as D
> hiding package containers-0.3.0.0 to avoid conflict with later version
> containers-0.4.0.0
> hiding package QuickCheck-2.3.0.2 to avoid conflict with later version
> QuickCheck-2.4.0.1
> wired-in package ghc-prim mapped to
> ghc-prim-0.2.0.0-0713122c5f9038c6f0355a37e294e054
> wired-in package integer-gmp mapped to
> integer-gmp-0.2.0.2-bfb191b8468e4d812a2bb92622cb246e
> wired-in package base mapped to
> base-4.3.0.0-1ea085b64a078bd9d5eaa9d8d525e35e
> wired-in package rts mapped to builtin_rts
> wired-in package template-haskell mapped to
> template-haskell-2.5.0.0-f262af1f92a427f5cf4133bff041044f
> wired-in package dph-seq not found.
> wired-in package dph-par not found.
> *** Parser:
> hiding package containers-0.3.0.0 to avoid conflict with later version
> containers-0.4.0.0
> hiding package QuickCheck-2.3.0.2 to avoid conflict with later version
> QuickCheck-2.4.0.1
> wired-in package ghc-prim mapped to
> ghc-prim-0.2.0.0-0713122c5f9038c6f0355a37e294e054
> wired-in package integer-gmp mapped to
> integer-gmp-0.2.0.2-bfb191b8468e4d812a2bb92622cb246e
> wired-in package base mapped to
> base-4.3.0.0-1ea085b64a078bd9d5eaa9d8d525e35e
> wired-in package rts mapped to builtin_rts
> wired-in package template-haskell mapped to
> template-haskell-2.5.0.0-f262af1f92a427f5cf4133bff041044f
> wired-in package dph-seq not found.
> wired-in package dph-par not found.
> Prelude Numeric.Units.Dimensional.Prelude> D.sqrt $ let s = 9 *~ (meter D.*
> meter) in s
> hiding package containers-0.3.0.0 to avoid conflict with later version
> containers-0.4.0.0
> hiding package QuickCheck-2.3.0.2 to avoid conflict with later version
> QuickCheck-2.4.0.1
> wired-in package ghc-prim mapped to
> ghc-prim-0.2.0.0-0713122c5f9038c6f0355a37e294e054
> wired-in package integer-gmp mapped to
> integer-gmp-0.2.0.2-bfb191b8468e4d812a2bb92622cb246e
> wired-in package base mapped to
> base-4.3.0.0-1ea085b64a078bd9d5eaa9d8d525e35e
> wired-in package rts mapped to builtin_rts
> wired-in package template-haskell mapped to
> template-haskell-2.5.0.0-f262af1f92a427f5cf4133bff041044f
> wired-in package dph-seq not found.
> wired-in package dph-par not found.
> *** Parser:
> *** Desugar:
> *** Simplify:
> *** CorePrep:
> *** ByteCodeGen:
> Loading package old-locale-1.0.0.2 ... linking ... done.
> Loading package time-1.2.0.3 ... linking ... done.
> Loading package numtype-1.0 ... linking ... done.
> Loading package dimensional-0.8.0.1 ... linking ... done.
> 3.0 m
> hiding package containers-0.3.0.0 to avoid conflict with later version
> containers-0.4.0.0
> hiding package QuickCheck-2.3.0.2 to avoid conflict with later version
> QuickCheck-2.4.0.1
> wired-in package ghc-prim mapped to
> ghc-prim-0.2.0.0-0713122c5f9038c6f0355a37e294e054
> wired-in package integer-gmp mapped to
> integer-gmp-0.2.0.2-bfb191b8468e4d812a2bb92622cb246e
> wired-in package base mapped to
> base-4.3.0.0-1ea085b64a078bd9d5eaa9d8d525e35e
> wired-in package rts mapped to builtin_rts
> wired-in package template-haskell mapped to
> template-haskell-2.5.0.0-f262af1f92a427f5cf4133bff041044f
> wired-in package dph-seq not found.
> wired-in package dph-par not found.
> Prelude Numeric.Units.Dimensional.Prelude> D.sqrt $ 9 *~ (meter D.* meter)
> hiding package containers-0.3.0.0 to avoid conflict with later version
> containers-0.4.0.0
> hiding package QuickCheck-2.3.0.2 to avoid conflict with later version
> QuickCheck-2.4.0.1
> wired-in package ghc-prim mapped to
> ghc-prim-0.2.0.0-0713122c5f9038c6f0355a37e294e054
> wired-in package integer-gmp mapped to
> integer-gmp-0.2.0.2-bfb191b8468e4d812a2bb92622cb246e
> wired-in package base mapped to
> base-4.3.0.0-1ea085b64a078bd9d5eaa9d8d525e35e
> wired-in package rts mapped to builtin_rts
> wired-in package template-haskell mapped to
> template-haskell-2.5.0.0-f262af1f92a427f5cf4133bff041044f
> wired-in package dph-seq not found.
> wired-in package dph-par not found.
> *** Parser:
> *** Desugar:
> *** Simplify:
> *** CorePrep:
> *** ByteCodeGen:
> HANG!
>
>