July 2014 - ghc-tickets

[GHC] #9246: GHC generates poor code for repeated uses of min/max
by GHC 03 Nov '14

03 Nov '14

#9246: GHC generates poor code for repeated uses of min/max ------------------------------+-------------------------------------------- Reporter: arotenberg | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.8.2 Keywords: | Operating System: Windows Architecture: x86_64 | Type of failure: Runtime performance bug (amd64) | Test Case: Difficulty: Unknown | Blocking: Blocked By: | Related Tickets: #6135 | ------------------------------+-------------------------------------------- Consider the following module, which intends to implement a [http://tavianator.com/2011/05/fast-branchless-raybounding-box- intersections/ branchless ray-AABB intersection test]: {{{ module SimpleGeom where data Vec3 = Vec3 {-# UNPACK #-} !Double {-# UNPACK #-} !Double {-# UNPACK #-} !Double data Ray = Ray !Vec3 !Vec3 !Vec3 data AABB = AABB !Vec3 !Vec3 testRayAABBIntersection :: Ray -> AABB -> Bool testRayAABBIntersection (Ray (Vec3 ox oy oz) _ (Vec3 invDx invDy invDz)) (AABB (Vec3 minX minY minZ) (Vec3 maxX maxY maxZ)) = let tx1 = (minX - ox) * invDx tx2 = (maxX - ox) * invDx ty1 = (minY - oy) * invDy ty2 = (maxY - oy) * invDy tz1 = (minZ - oz) * invDz tz2 = (maxZ - oz) * invDz tmin = min tx1 tx2 `max` min ty1 ty2 `max` min tz1 tz2 tmax = max tx1 tx2 `min` max ty1 ty2 `min` max tz1 tz2 in tmax >= max 0 tmin }}} Everything is strict primitive operations, so GHC should generate very simple, fast code, right? But upon compiling with {{{ghc -O -ddump-simpl -ddump-to-file SimpleGeom}}}, I found a mess of nested local lambdas and similar performance-killing expression forms. (See the attached output file.) There are two possible issues I can see here. 1. GHC is trying to expand out all of the branches recursively (I would presume via case-of-cases transformation), which is a bad idea in this instance compared to just performing the cases sequentially and storing their results. 1. GHC is generating branches for floating-point min/max. Instruction sets like SSE2 include non-branching floating-point min/max instructions, which is exactly what this algorithm was designed to exploit, but GHC does not generate code that could take advantage of these instructions. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9246> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #8261: Windows Testsuite stuck at configuring timeout
by GHC 03 Nov '14

03 Nov '14

#8261: Windows Testsuite stuck at configuring timeout ------------------------------+--------------------------------- Reporter: leroux | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Test Suite | Version: 7.6.3 Keywords: | Operating System: Windows Architecture: x86 | Type of failure: None/Unknown Difficulty: Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | ------------------------------+--------------------------------- When running the testsuite, it gets stuck at {{{Configuring timeout-1...}}}. I tried adding a verbosity flag to the ENV vars, but they didn't make any affect on the {{{./Setup}}} args. Relating to my development setup...I've followed the instructions from http://ghc.haskell.org/trac/ghc/wiki/Building/Preparation/Windows (using MinGW). I was rather surprised when I was building GHC, it threw an error saying that "libmpfr-3.dll" was missing, so I fetched that from a cygwin mirror and threw it in {{{msys/bin}}}, but even after doing that, I got errors saying that it could find certain cygwin libraries ({{{cyg*.dll}}}). So I just installed the entirety of cygwin and it started working fine. The only ticket I found that is related to this is #1599, but I'm not sure. ---- System details: {{{ # Windows 7 x86 (32-bit) $ uname -a MINGW32_NT-6.1 LEROUX-WINBUILD 1.0.18(0.48/3/2) 2012-11-21 22:34 i686 Msys $ echo $PATH /c/MinGW/bin:.:/usr/local/bin:/mingw/bin:/bin:/c/Program Files/Haskell/bin:/c/Program Files/Haskell Platform/2013.2.0.0/lib/extralibs/bin:/c/ Program Files/Haskell Platform/2013.2.0.0/bin:/c/Windows/system32:/c/Windows:/c/Windows/System32/Wbem:/c/Windows/System32/WindowsPowerShell/v 1.0/:/c/Program Files/Haskell Platform/2013.2.0.0/mingw/bin:/c/Program Files/Git/cmd:/c/Users/leroux/AppData/Roaming/cabal/bin:/mingw/bin:/us r/bin:/c/cygwin/bin }}} ---- Here's the testsuite run: {{{ $ make test WAY=normal make -C testsuite/tests CLEANUP=1 OUTPUT_SUMMARY=../../testsuite_summary.txt fast make[1]: Entering directory `/home/leroux/devel/ghc- validate/testsuite/tests' make fast=YES make[2]: Entering directory `/home/leroux/devel/ghc- validate/testsuite/tests' Looks like you don't have timeout, building it first... make -C ../timeout all make[3]: Entering directory `/home/leroux/devel/ghc- validate/testsuite/timeout' rm -rf install-inplace 'C:/MinGW/msys/1.0/home/leroux/devel/ghc-validate/inplace/bin/ghc- stage2.exe' --make Setup ./Setup configure --with-compiler='C:/MinGW/msys/1.0/home/leroux/devel /ghc-validate/inplace/bin/ghc-stage2.exe' \ --with-hc- pkg='C:/MinGW/msys/1.0/home/leroux/devel/ghc-validate/inplace/bin/ghc- pkg.exe' \ --with- hsc2hs='C:/MinGW/msys/1.0/home/leroux/devel/ghc- validate/inplace/bin/hsc2hs.exe' \ \ --ghc-option=-threaded --prefix='C:/MinGW/msys/1.0/home/leroux/devel/ghc- validate/testsuite/timeout/install-inplace ' Configuring timeout-1... }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8261> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #8295: T4850 deadlocks when run with -Ds on Windows (also it's failing)
by GHC 03 Nov '14

03 Nov '14

#8295: T4850 deadlocks when run with -Ds on Windows (also it's failing) --------------------------+------------------------------------------------ Reporter: ezyang | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: | Version: 7.7 Runtime System | Operating System: Windows Keywords: | Type of failure: Incorrect result at runtime Architecture: x86_64 | Test Case: T4850 (amd64) | Blocking: Difficulty: | Unknown | Blocked By: | Related Tickets: | --------------------------+------------------------------------------------ T4850 has been failing recently, reporting too *few* OS threads allocated. That's pretty odd. What is also odd (and much less good) is that T4850 is deadlocking when you run it with `-Ds`. Uh oh! {{{ bash.exe-3.1$ ./T4850 +RTS -Ds 7eb0: created capset 0 of type 2 7eb0: created capset 1 of type 3 7eb0: cap 0: initialised 7eb0: assigned cap 0 to capset 0 7eb0: assigned cap 0 to capset 1 7eb0: allocated 1 more capabilities 7eb0: new task (taskCount: 1) 7eb0: returning; I want capability 0 7eb0: resuming capability 0 7eb0: cap 0: created thread 1 7eb0: new bound thread (1) 7eb0: cap 0: schedule() 7eb0: cap 0: running thread 1 (ThreadRunGHC) 7eb0: cap 0: created thread 2 7eb0: cap 0: thread 1 stopped (finished) 7eb0: bound thread (1) finished 7eb0: starting new worker on capability 0 7eb0: new worker task (taskCount: 2) 7eb0: task exiting 7eb0: new task (taskCount: 2) 7eb0: returning; I want capability 0 7fc0: cap 0: schedule() 7fc0: giving up capability 0 7fc0: passing capability 0 to worker 0x7eb0 7eb0: resuming capability 0 7eb0: cap 0: created thread 3 7eb0: new bound thread (3) 7eb0: cap 0: schedule() 7eb0: giving up capability 0 7eb0: passing capability 0 to worker 0x7fc0 7fc0: woken up on capability 0 7fc0: resuming capability 0 7fc0: cap 0: running thread 2 (ThreadRunGHC) 7fc0: cap 0: thread 2 stopped (suspended while making a foreign call) 7fc0: passing capability 0 to bound task 0x7eb0 7eb0: woken up on capability 0 7eb0: resuming capability 0 7eb0: cap 0: running thread 3 (ThreadRunGHC) 7eb0: cap 0: thread 3 stopped (suspended while making a foreign call) 7eb0: starting new worker on capability 0 7eb0: new worker task (taskCount: 3) 7eb0: returning; I want capability 0 7b50: cap 0: schedule() 7b50: giving up capability 0 7b50: passing capability 0 to bound task 0x7eb0 7eb0: resuming capability 0 7eb0: cap 0: running thread 3 (ThreadRunGHC) 7eb0: cap 0: created thread 4 7eb0: cap 0: thread 3 stopped (blocked on an MVar) thread 3 @ 00e03bbc is blocked on an MVar @ 00e021e4 (TSO_DIRTY) 7eb0: giving up capability 0 7eb0: passing capability 0 to worker 0x7b50 7b50: woken up on capability 0 7b50: resuming capability 0 7b50: cap 0: running thread 4 (ThreadRunGHC) 7b50: cap 0: thread 4 stopped (suspended while making a foreign call) 7b50: starting new worker on capability 0 7b50: new worker task (taskCount: 4) 7b50: new task (taskCount: 4) 7b50: returning; I want capability 0 7de4: cap 0: schedule() 7de4: giving up capability 0 7de4: passing capability 0 to worker 0x7b50 7b50: resuming capability 0 7b50: cap 0: created thread 5 7b50: new bound thread (5) 7b50: cap 0: schedule() 7b50: cap 0: running thread 5 (ThreadRunGHC) 7b50: cap 0: thread 5 stopped (finished) 7b50: bound thread (5) finished 7b50: freeing capability 0 7b50: task exiting 7b50: returning; I want capability 0 7b50: resuming capability 0 7b50: cap 0: running thread 4 (ThreadRunGHC) 7b50: cap 0: waking up thread 3 on cap 0 7b50: cap 0: thread 4 stopped (finished) 7b50: giving up capability 0 7b50: passing capability 0 to bound task 0x7eb0 7eb0: woken up on capability 0 7eb0: resuming capability 0 7eb0: cap 0: running thread 3 (ThreadRunGHC) 7eb0: cap 0: thread 3 stopped (suspended while making a foreign call) 7eb0: freeing capability 0 7eb0: returning; I want capability 0 7eb0: resuming capability 0 7eb0: cap 0: running thread 3 (ThreadRunGHC) 7eb0: cap 0: thread 3 stopped (suspended while making a foreign call) 7eb0: freeing capability 0 4 7eb0: returning; I want capability 0 7eb0: resuming capability 0 7eb0: cap 0: running thread 3 (ThreadRunGHC) 7eb0: cap 0: created thread 6 7eb0: cap 0: thread 3 stopped (blocked on an MVar) thread 3 @ 00e03bbc is blocked on an MVar @ 00e021e4 (TSO_DIRTY) 7eb0: giving up capability 0 7eb0: passing capability 0 to worker 0x7b50 7b50: woken up on capability 0 7b50: resuming capability 0 7b50: cap 0: running thread 6 (ThreadRunGHC) 7b50: cap 0: thread 6 stopped (suspended while making a foreign call) 7b50: freeing capability 0 7b50: new task (taskCount: 4) 7b50: returning; I want capability 0 7b50: resuming capability 0 7b50: cap 0: created thread 7 7b50: new bound thread (7) 7b50: cap 0: schedule() 7b50: cap 0: running thread 7 (ThreadRunGHC) 7b50: cap 0: thread 7 stopped (finished) 7b50: bound thread (7) finished 7b50: freeing capability 0 7b50: task exiting 7b50: returning; I want capability 0 7b50: resuming capability 0 7b50: cap 0: running thread 6 (ThreadRunGHC) 7b50: cap 0: waking up thread 3 on cap 0 7b50: cap 0: thread 6 stopped (finished) 7b50: giving up capability 0 7b50: passing capability 0 to bound task 0x7eb0 7eb0: woken up on capability 0 7eb0: resuming capability 0 7eb0: cap 0: running thread 3 (ThreadRunGHC) 7eb0: cap 0: thread 3 stopped (suspended while making a foreign call) 7eb0: freeing capability 0 7eb0: returning; I want capability 0 7eb0: resuming capability 0 7eb0: cap 0: running thread 3 (ThreadRunGHC) 7eb0: cap 0: thread 3 stopped (suspended while making a foreign call) 7eb0: freeing capability 0 4 7eb0: returning; I want capability 0 7eb0: resuming capability 0 7eb0: cap 0: running thread 3 (ThreadRunGHC) 7eb0: cap 0: thread 3 stopped (yielding) 7eb0: cap 0: running thread 3 (ThreadRunGHC) 7eb0: cap 0: thread 3 stopped (finished) 7eb0: bound thread (3) finished 7eb0: freeing capability 0 7eb0: task exiting 7eb0: new task (taskCount: 4) 7eb0: returning; I want capability 0 7eb0: resuming capability 0 7eb0: cap 0: created thread 8 7eb0: new bound thread (8) 7eb0: cap 0: schedule() 7eb0: cap 0: running thread 8 (ThreadRunGHC) 7eb0: cap 0: thread 8 stopped (finished) 7eb0: bound thread (8) finished 7eb0: freeing capability 0 7eb0: task exiting 7eb0: new task (taskCount: 4) 7fc0: returning; I want capability 0 7fc0: resuming capability 0 7fc0: cap 0: running thread 2 (ThreadRunGHC) 7eb0: returning; I want capability 0 7fc0: cap 0: thread 2 stopped (suspended while making a foreign call) 7fc0: passing capability 0 to worker 0x7eb0 7fc0: returning; I want capability 0 7fc0: resuming capability 0 7fc0: cap 0: running thread 2 (ThreadRunGHC) 7fc0: cap 0: thread 2 stopped (suspended while making a foreign call) 7fc0: passing capability 0 to worker 0x7eb0 7fc0: returning; I want capability 0 7fc0: resuming capability 0 7fc0: cap 0: running thread 2 (ThreadRunGHC) 7fc0: cap 0: thread 2 stopped (suspended while making a foreign call) 7fc0: passing capability 0 to worker 0x7eb0 7fc0: returning; I want capability 0 7fc0: resuming capability 0 7fc0: cap 0: running thread 2 (ThreadRunGHC) 7fc0: cap 0: thread 2 stopped (suspended while making a foreign call) 7fc0: passing capability 0 to worker 0x7eb0 7fc0: returning; I want capability 0 7fc0: resuming capability 0 7fc0: cap 0: running thread 2 (ThreadRunGHC) 7fc0: cap 0: thread 2 stopped (suspended while making a foreign call) 7fc0: passing capability 0 to worker 0x7eb0 7fc0: returning; I want capability 0 7fc0: resuming capability 0 7fc0: cap 0: running thread 2 (ThreadRunGHC) 7fc0: cap 0: thread 2 stopped (suspended while making a foreign call) 7fc0: passing capability 0 to worker 0x7eb0 7fc0: returning; I want capability 0 7fc0: resuming capability 0 7fc0: cap 0: running thread 2 (ThreadRunGHC) 7fc0: cap 0: thread 2 stopped (suspended while making a foreign call) 7fc0: passing capability 0 to worker 0x7eb0 7fc0: returning; I want capability 0 7fc0: resuming capability 0 7fc0: cap 0: running thread 2 (ThreadRunGHC) 7fc0: cap 0: thread 2 stopped (suspended while making a foreign call) 7fc0: passing capability 0 to worker 0x7eb0 7fc0: returning; I want capability 0 7fc0: resuming capability 0 7fc0: cap 0: running thread 2 (ThreadRunGHC) 7fc0: cap 0: thread 2 stopped (suspended while making a foreign call) 7fc0: passing capability 0 to worker 0x7eb0 7fc0: returning; I want capability 0 7fc0: resuming capability 0 7fc0: cap 0: running thread 2 (ThreadRunGHC) 7fc0: cap 0: thread 2 stopped (suspended while making a foreign call) 7fc0: passing capability 0 to worker 0x7eb0 7fc0: returning; I want capability 0 7fc0: resuming capability 0 7fc0: cap 0: running thread 2 (ThreadRunGHC) 7fc0: cap 0: thread 2 stopped (suspended while making a foreign call) 7fc0: passing capability 0 to worker 0x7eb0 7fc0: returning; I want capability 0 7fc0: resuming capability 0 7fc0: cap 0: running thread 2 (ThreadRunGHC) 7fc0: cap 0: thread 2 stopped (suspended while making a foreign call) 7fc0: passing capability 0 to worker 0x7eb0 7fc0: returning; I want capability 0 7fc0: resuming capability 0 7fc0: cap 0: running thread 2 (ThreadRunGHC) 7fc0: cap 0: thread 2 stopped (suspended while making a foreign call) 7fc0: passing capability 0 to worker 0x7eb0 7fc0: returning; I want capability 0 7fc0: resuming capability 0 7fc0: cap 0: running thread 2 (ThreadRunGHC) 7fc0: cap 0: thread 2 stopped (suspended while making a foreign call) 7fc0: passing capability 0 to worker 0x7eb0 7fc0: returning; I want capability 0 7fc0: resuming capability 0 7fc0: cap 0: running thread 2 (ThreadRunGHC) 7fc0: cap 0: thread 2 stopped (suspended while making a foreign call) 7fc0: passing capability 0 to worker 0x7eb0 7fc0: returning; I want capability 0 7fc0: resuming capability 0 7fc0: cap 0: running thread 2 (ThreadRunGHC) 7fc0: cap 0: thread 2 stopped (suspended while making a foreign call) 7fc0: passing capability 0 to worker 0x7eb0 7fc0: returning; I want capability 0 7fc0: resuming capability 0 7fc0: cap 0: running thread 2 (ThreadRunGHC) 7fc0: cap 0: thread 2 stopped (suspended while making a foreign call) 7fc0: passing capability 0 to worker 0x7eb0 7fc0: returning; I want capability 0 7fc0: resuming capability 0 7fc0: cap 0: running thread 2 (ThreadRunGHC) 7fc0: cap 0: thread 2 stopped (suspended while making a foreign call) 7fc0: passing capability 0 to worker 0x7eb0 7fc0: returning; I want capability 0 7fc0: resuming capability 0 7fc0: cap 0: running thread 2 (ThreadRunGHC) 7fc0: cap 0: thread 2 stopped (suspended while making a foreign call) 7fc0: passing capability 0 to worker 0x7eb0 7fc0: returning; I want capability 0 7fc0: resuming capability 0 7fc0: cap 0: running thread 2 (ThreadRunGHC) 7fc0: cap 0: thread 2 stopped (suspended while making a foreign call) 7fc0: passing capability 0 to worker 0x7eb0 7fc0: returning; I want capability 0 7fc0: resuming capability 0 7fc0: cap 0: running thread 2 (ThreadRunGHC) 7fc0: cap 0: thread 2 stopped (suspended while making a foreign call) 7fc0: passing capability 0 to worker 0x7eb0 7fc0: returning; I want capability 0 7fc0: resuming capability 0 7fc0: cap 0: running thread 2 (ThreadRunGHC) 7fc0: cap 0: thread 2 stopped (suspended while making a foreign call) 7fc0: passing capability 0 to worker 0x7eb0 7fc0: returning; I want capability 0 7fc0: resuming capability 0 7fc0: cap 0: running thread 2 (ThreadRunGHC) 7fc0: cap 0: thread 2 stopped (suspended while making a foreign call) 7fc0: passing capability 0 to worker 0x7eb0 7fc0: returning; I want capability 0 7fc0: resuming capability 0 7fc0: cap 0: running thread 2 (ThreadRunGHC) 7fc0: cap 0: thread 2 stopped (suspended while making a foreign call) 7fc0: passing capability 0 to worker 0x7eb0 7fc0: returning; I want capability 0 7fc0: resuming capability 0 7fc0: cap 0: running thread 2 (ThreadRunGHC) 7fc0: cap 0: thread 2 stopped (suspended while making a foreign call) 7fc0: passing capability 0 to worker 0x7eb0 7fc0: returning; I want capability 0 7fc0: resuming capability 0 7fc0: cap 0: running thread 2 (ThreadRunGHC) 7fc0: cap 0: thread 2 stopped (suspended while making a foreign call) 7fc0: passing capability 0 to worker 0x7eb0 7fc0: returning; I want capability 0 7fc0: resuming capability 0 7fc0: cap 0: running thread 2 (ThreadRunGHC) 7fc0: cap 0: thread 2 stopped (suspended while making a foreign call) 7fc0: passing capability 0 to worker 0x7eb0 7fc0: returning; I want capability 0 7fc0: resuming capability 0 7fc0: cap 0: running thread 2 (ThreadRunGHC) 7fc0: cap 0: thread 2 stopped (suspended while making a foreign call) 7fc0: passing capability 0 to worker 0x7eb0 7fc0: returning; I want capability 0 7fc0: resuming capability 0 7fc0: cap 0: running thread 2 (ThreadRunGHC) 7fc0: cap 0: thread 2 stopped (suspended while making a foreign call) 7fc0: passing capability 0 to worker 0x7eb0 7fc0: returning; I want capability 0 7fc0: resuming capability 0 7fc0: cap 0: running thread 2 (ThreadRunGHC) 7fc0: cap 0: thread 2 stopped (yielding) 7fc0: SCHED_INTERRUPTING 7fc0: cap 0: requesting sequential GC 7fc0: grabbing all the capabilies (0/1) all threads: threads on capability 0: thread 2 @ 00e037bc is not blocked (TSO_DIRTY) other threads: 7fc0: deleting all threads 7fc0: cap 0: raising exception in thread 2. 7fc0: cap 0: starting GC 7fc0: cap 0: GC working 7fc0: cap 0: GC idle 7fc0: cap 0: GC done 7fc0: cap 0: GC idle 7fc0: cap 0: GC done 7fc0: cap 0: GC idle 7fc0: cap 0: GC done 7fc0: cap 0: all caps stopped for GC 7fc0: cap 0: finished GC 7fc0: SCHED_SHUTTING_DOWN 7fc0: giving up capability 0 7fc0: passing capability 0 to worker 0x7eb0 7eb0: resuming capability 0 7eb0: passing capability 0 to worker 0x7fc0 7eb0: shutting down capability 0, attempt 0 7fc0: woken up on capability 0 7eb0: runnable threads or workers still alive, yielding 7eb0: passing capability 0 to worker 0x7fc0 7eb0: shutting down capability 0, attempt 1 7eb0: not owner, yielding 7eb0: shutting down capability 0, attempt 2 7eb0: not owner, yielding 7eb0: shutting down capability 0, attempt 3 7eb0: not owner, yielding 7eb0: shutting down capability 0, attempt 4 7eb0: not owner, yielding 7eb0: shutting down capability 0, attempt 5 7eb0: not owner, yielding 7eb0: shutting down capability 0, attempt 6 7eb0: not owner, yielding 7eb0: shutting down capability 0, attempt 7 7eb0: not owner, yielding 7eb0: shutting down capability 0, attempt 8 7eb0: not owner, yielding 7eb0: shutting down capability 0, attempt 9 7eb0: not owner, yielding 7eb0: shutting down capability 0, attempt 10 7eb0: not owner, yielding 7eb0: shutting down capability 0, attempt 11 7eb0: not owner, yielding 7eb0: shutting down capability 0, attempt 12 7eb0: not owner, yielding 7eb0: shutting down capability 0, attempt 13 7eb0: not owner, yielding 7eb0: shutting down capability 0, attempt 14 7eb0: not owner, yielding 7eb0: shutting down capability 0, attempt 15 7eb0: not owner, yielding 7eb0: shutting down capability 0, attempt 16 7eb0: not owner, yielding 7eb0: shutting down capability 0, attempt 17 7eb0: not owner, yielding 7eb0: shutting down capability 0, attempt 18 7eb0: not owner, yielding ... }}} ad infinitum. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8295> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #8571: Validation fails
by GHC 02 Nov '14

02 Nov '14

#8571: Validation fails ----------------------------------+--------------------------------- Reporter: khyperia | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Test Suite | Version: 7.6.3 Keywords: | Operating System: Windows Architecture: x86_64 (amd64) | Type of failure: None/Unknown Difficulty: Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | ----------------------------------+--------------------------------- {{{ =====> T5267(normal) 50 of 3812 [0, 0, 0] cd ./arrows/should_compile && 'c:/Users/Evan/Documents/ghc/bindisttest/install dir/bin/ghc.exe' -fforce-recomp -dcore-lint -dcmm-lint -dno-debug-output -no-us er-package-db -rtsopts -fno-ghci-history -c T5267.hs >T5267.comp.stderr 2>&1 Compile failed (status 256) errors were: T5267.hs:11:15: tee: standard output: Permission denied }}} followed by an infinite hang. If I comment out that specific test, another test fails a few tests later. If I comment out that one, another one fails a few later. If I comment out *that* one... you get the picture. Running as administrator does not solve the permission denied issue. I am on Windows 8.1, if that matters. I think, I am not sure, that any test with expect_broken in them hangs without moving on. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8571> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #8967: Add syntax for creating finite maps and sets
by GHC 02 Nov '14

02 Nov '14

#8967: Add syntax for creating finite maps and sets ------------------------------------+------------------------------------- Reporter: tibbe | Owner: Type: feature request | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.6.3 Keywords: | Operating System: Unknown/Multiple Architecture: Unknown/Multiple | Type of failure: None/Unknown Difficulty: Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | ------------------------------------+------------------------------------- Many languages have syntax for creating maps. Commonly used syntax is either {{{ {key1: value1, key2: value2, ...} }}} or {{{ {key1 => value1, key2 => value2, ...} }}} Since few Haskellers (with the notable exception of SPJ) use the curly bracket Haskell syntax for layout, I thought we could co-opt it and instead use it for map (and set literals.) The feature would of course be protected by a language pragma as to not break old code. Strawman proposal: `{key1: value1, key2: value2, ...}` desugars to `fromList [(key1, value1), (key2, value2), ...]`, using a new type class: {{{#!haskell class IsMap m where type Key m type Value m fromList :: [(Key m, Value m)] -> m }}} `{:}` is the literal for empty maps. Analogously, `{value1, value2, ...}` desugars to `fromList [value1, value2, ...]`, using a new type class: {{{#!haskell class IsSet m where type Item m fromList :: [Item m] -> m }}} `{}` is the literal for empty sets. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8967> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #9084: Template Haskell should warn when it encounters an unencodable pragma
by GHC 02 Nov '14

02 Nov '14

#9084: Template Haskell should warn when it encounters an unencodable pragma ------------------------------------+------------------------------------- Reporter: goldfire | Owner: goldfire Type: bug | Status: new Priority: normal | Milestone: Component: Template Haskell | Version: 7.8.2 Keywords: | Operating System: Unknown/Multiple Architecture: Unknown/Multiple | Type of failure: None/Unknown Difficulty: Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | ------------------------------------+------------------------------------- When I say this {{{ {-# LANGUAGE TemplateHaskell #-} {-# OPTIONS_GHC -Wall #-} module Bug where $([d| class C a where meth :: a -> a meth = undefined -- give a (silly) default {-# MINIMAL meth #-} |]) instance C Int }}} I get no warnings. I'm not surprised that TH doesn't handle every pragma that GHC knows about, but it should issue a (suppressable) warning when it discards one. I can fix this one. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9084> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #9262: Allow free variables in reifyInstances
by GHC 02 Nov '14

02 Nov '14

#9262: Allow free variables in reifyInstances ------------------------------------+------------------------------------- Reporter: goldfire | Owner: goldfire Type: feature request | Status: new Priority: normal | Milestone: Component: Template Haskell | Version: 7.8.2 Keywords: | Operating System: Unknown/Multiple Architecture: Unknown/Multiple | Type of failure: None/Unknown Difficulty: Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | ------------------------------------+------------------------------------- When I say {{{ {-# LANGUAGE TemplateHaskell #-} module Bug where import Language.Haskell.TH $( do insts <- reifyInstances ''Eq [ListT `AppT` VarT (mkName "a")] runIO $ putStrLn $ pprint insts return [] ) }}} I get {{{ Bug.hs:7:4: Not in scope: type variable ‘a’ In the argument of reifyInstances: GHC.Classes.Eq [a] }}} But, I wanted the declaration for `instance Eq a => Eq [a]`. The error message isn't wrong, exactly -- `a` really isn't in scope -- but I think we can do better by just treating variables as fresh. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9262> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #9236: hGetContents leads to late/silent failures
by GHC 31 Oct '14

31 Oct '14

#9236: hGetContents leads to late/silent failures ------------------------------------+------------------------------------- Reporter: dfeuer | Owner: Type: feature request | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.6.3 Keywords: | Operating System: Unknown/Multiple Architecture: Unknown/Multiple | Type of failure: None/Unknown Difficulty: Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | ------------------------------------+------------------------------------- A common newbie error: {{{ #!haskell withFile "file" ReadMode hGetContents >>= putStr }}} The problem, of course, is that the result of `withFile "file" ReadMode hGetContents` isn't forced until `putStr` is executed, at which point the file has already been closed. The Haskell report doesn't specify what it will find, and, at least in 7.6.3, it finds the string empty. The behavior that seems most correct to me would be to guarantee that if a file has not been completely read (or read up to an I/O error) when it is closed, then its contents should be reported as something like `"Four score and seven years ag"++error "Forcing a suspended computation led to an attempted read from a handle that was already closed."` Since the current system apparently puts an `[]` as a temporary marker while waiting to see what the rest of the list will be, I imagine that the fix is as simple as putting the error thunk there instead. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9236> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #9242: Implement {-# OVERLAPPABLE #-} and {-# INCOHERENT #-} pragmas
by GHC 31 Oct '14

31 Oct '14

#9242: Implement {-# OVERLAPPABLE #-} and {-# INCOHERENT #-} pragmas ------------------------------------+------------------------------------- Reporter: simonpj | Owner: Type: feature request | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.8.2 Keywords: | Operating System: Unknown/Multiple Architecture: Unknown/Multiple | Type of failure: None/Unknown Difficulty: Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | ------------------------------------+------------------------------------- The language extensions `-XIncoherentInstances` and `-XOverlappingInstances` (described in [http://www.haskell.org/ghc/docs/latest/html/users_guide/type-class- extensions.html#instance-overlap the user manual]) apply to every instance declaration in the module. Internally, however, GHC records this information on a per-instance-declaration basis. It would be much better for the programmer to be able to control these matters on a per-instance-declaration basis. Thus: {{{ instance Show a => Show [a] where {-# OVERLAPPABLE #-} ... instance Show [Char] where ... }}} We came across the need for this when discussing the `Typeable` instances. We have a generic instance like this: {{{ instance (Typeable f, Typeable a) => Typeable (f a) where .... }}} but also want {{{ instance KnownNat n => Typeable (n :: Nat) where ... }}} If we seek `(Typeable (x::Nat))`, we should pick the second instance even though in principle you might imagine that `x` might be instantiated to `(f a)`, for some `f` and `a`. But we know that there are no type constructors `f` of kind `blah -> Nat`, so this can never happen and it's safe to pick the second instance. So a local `{-# INCOHERENT #-}` pragma for this particular instance declaration would be very useful to express this fact. {{{ instance KnownNat n => Typeable (n :: Nat) where {-# INCOHERENT #-} ... }}} Quite apart from this special case, it's plain better to have per-instance control * Rather than a remote per-module flag, the pragma draws attention that ''this particular instance'' is incoherent, overlappable or whatever. * The current situation almost certainly means that more instances are marked overlapping than are really necessary. I have some design questions. * Where should the pragma appear, syntactically? {{{ instance {-# OVERLAPPABLE #-} Show a => Show [a] where ... or instance Show a => Show [a] {-# OVERLAPPABLE #-} where ... or instance Show a => Show [a] where {-# OVERLAPPABLE #-} }}} Remember that `SPECIALISE INSTANCE` pragmas appear in the third of the above positions, so I mildly favour that. * The user manual (link above) allows overlap if ''either'' instance is compiled with `-XOverlappingInstances` (see the rules towards the end of [http://www.haskell.org/ghc/docs/latest/html/users_guide/type-class- extensions.html#instance-overlap 7.6.3.5). It would be more explicit to have two pragmas, one to say "I can be overlapped" and one to say "I can overlap something else". The rule would then be that "either IX is marked `{-# OVERLAPPABLE #-}` or IY is marked `{-# OVERLAPPING #-}`. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9242> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #9367: :list does not underline expression correctly in WinGHCi for files with Windows-style newlines
by GHC 30 Oct '14

30 Oct '14

#9367: :list does not underline expression correctly in WinGHCi for files with Windows-style newlines ----------------------------------+--------------------------------------- Reporter: kraai | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: GHCi | Version: 7.6.3 Keywords: | Operating System: Windows Architecture: x86_64 (amd64) | Type of failure: None/Unknown Difficulty: Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Revisions: ----------------------------------+--------------------------------------- When I load a file that uses Windows-style newlines in WinGHCi, set a breakpoint, run to that breakpoint, and execute ":list", the carets that should underline the breakpoint expression are instead appended to the line. I'll attach a screenshot and the file I loaded. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9367> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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