March 2018 - ghc-tickets

[GHC] #14711: Machine readable output of coverage
by GHC 14 Sep '18

14 Sep '18

#14711: Machine readable output of coverage -------------------------------------+------------------------------------- Reporter: Koterpillar | Owner: (none) Type: feature | Status: new request | Priority: normal | Milestone: Component: Code Coverage | Version: 8.2.2 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- When integrating with a CI system, it might be useful to fail the build, alert or take other actions based on coverage percentage. To do that, hpc needs to output a summary coverage report in a machine readable format. For example, the current output: {{{ 38% expressions used (1779/4624) 57% boolean coverage (16/28) 56% guards (9/16), 6 always True, 1 always False 58% 'if' conditions (7/12), 2 always False, 3 unevaluated 100% qualifiers (0/0) 7% alternatives used (103/1410) 75% local declarations used (102/136) 40% top-level declarations used (185/457) }}} can be represented as: {{{ { expressions: { total: 4624, used: 1779, percentage: 0.38 }, boolean: { total: 28, used: 16, percentage: 0.57 }, <...> } }}} This output can be then parsed to decide whether to fail the build, produce a coverage graph over time, etc. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14711> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #14099: Document fundeps
by GHC 14 Sep '18

14 Sep '18

#14099: Document fundeps -------------------------------------+------------------------------------- Reporter: bgamari | Owner: (none) Type: task | Status: new Priority: normal | Milestone: Component: Documentation | Version: 8.2.1 Keywords: newcomers | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- Currently the documentation for functional dependencies in the GHC user's guide is quite poor. Fix this. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14099> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #11143: Feature request: Add index/read/write primops with byte offset for ByteArray#
by GHC 14 Sep '18

14 Sep '18

#11143: Feature request: Add index/read/write primops with byte offset for ByteArray# -------------------------------------+------------------------------------- Reporter: vagarenko | Owner: Type: feature | Status: new request | Priority: normal | Milestone: 8.2.1 Component: Compiler | Version: 7.10.2 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- Currently, primops for indexing `ByteArray#` and reading/writing `MutableByteArray#` have the following form: {{{#!hs indexTYPEArray# :: ByteArray# -> Int# -> TYPE# readTYPEArray# :: MutableByteArray# s -> Int# -> State# s -> (#State# s, TYPE##) writeTYPEArray# :: MutableByteArray# s -> Int# -> TYPE# -> State# s -> State# s }}} where second argument of type `Int#` is an offset measured in terms of the size of `TYPE#`. This is inconvinient if I want to store values of different types inside `ByteArray#`: I have to read values of type `Int8` and then glue them together with some bitwise operations. I suggest adding number of primops, similar to existing ones, which would accept offset in bytes from the start of the `ByteArray#`: {{{#!hs -- | Read 8-bit integer; offset in bytes. indexByteInt8Array# :: ByteArray# -> Int# -> Int# -- | Read 16-bit integer; offset in bytes. indexByteInt16Array# :: ByteArray# -> Int# -> Int# -- | Read 32-bit integer; offset in bytes. indexByteInt32Array# :: ByteArray# -> Int# -> Int# -- | Read 8-bit integer; offset in bytes. readInt8Array# :: MutableByteArray# s -> Int# -> State# s -> (#State# s, Int##) -- | Read 16-bit integer; offset in bytes. readInt16Array# :: MutableByteArray# s -> Int# -> State# s -> (#State# s, Int##) -- | Read 32-bit integer; offset in bytes. readInt32Array# :: MutableByteArray# s -> Int# -> State# s -> (#State# s, Int##) }}} and so on... -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11143> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #10700: include/stg/Prim.h isn't C++ compatible
by GHC 14 Sep '18

14 Sep '18

#10700: include/stg/Prim.h isn't C++ compatible -------------------------------------+------------------------------------- Reporter: Fabian | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Build | Version: 7.10.1 System | Keywords: FFI | Operating System: Unknown/Multiple Architecture: | Type of failure: Other Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Revisions: | -------------------------------------+------------------------------------- StgWord hs_cmpxchg8(volatile StgWord8 *x, StgWord old, StgWord new); and a few other declarations in Prim.h causes problems as they use ''new'' as a variable name. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10700> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #10833: Use injective type families when dealing with givens
by GHC 14 Sep '18

14 Sep '18

#10833: Use injective type families when dealing with givens -------------------------------------+------------------------------------- Reporter: jstolarek | Owner: jstolarek Type: feature | Status: new request | Priority: normal | Milestone: Component: Compiler | Version: 7.10.2 (Type checker) | Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: #6018 Differential Revisions: | -------------------------------------+------------------------------------- Consider this code: {{{#!hs type family Id a = r | r -> a id :: (Id a ~ Id b) => a -> b id x = x }}} GHC currently rejects it because it does not use type family injectivity information when dealing with the given constraints. Implementing this requires changing Core. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10833> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #14902: GHC HEAD cannot be booted GHC 8.4.1
by GHC 13 Sep '18

13 Sep '18

#14902: GHC HEAD cannot be booted GHC 8.4.1 -------------------------------------+------------------------------------- Reporter: osa1 | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.5 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- I get this when I try to boot GHC HEAD with GHC 8.4.1 (using official binaries): {{{ $ make ===--- building phase 0 make --no-print-directory -f ghc.mk phase=0 phase_0_builds utils/genprimopcode/ghc.mk:19: utils/genprimopcode/dist/package-data.mk: No such file or directory utils/deriveConstants/ghc.mk:19: utils/deriveConstants/dist/package- data.mk: No such file or directory utils/genapply/ghc.mk:23: utils/genapply/dist/package-data.mk: No such file or directory libraries/hpc/ghc.mk:3: libraries/hpc/dist-boot/package-data.mk: No such file or directory libraries/binary/ghc.mk:3: libraries/binary/dist-boot/package-data.mk: No such file or directory libraries/text/ghc.mk:3: libraries/text/dist-boot/package-data.mk: No such file or directory libraries/transformers/ghc.mk:3: libraries/transformers/dist-boot/package- data.mk: No such file or directory libraries/mtl/ghc.mk:3: libraries/mtl/dist-boot/package-data.mk: No such file or directory libraries/parsec/ghc.mk:3: libraries/parsec/dist-boot/package-data.mk: No such file or directory libraries/Cabal/Cabal/ghc.mk:3: libraries/Cabal/Cabal/dist-boot/package- data.mk: No such file or directory libraries/ghc-boot-th/ghc.mk:3: libraries/ghc-boot-th/dist-boot/package- data.mk: No such file or directory libraries/ghc-boot/ghc.mk:3: libraries/ghc-boot/dist-boot/package-data.mk: No such file or directory libraries/template-haskell/ghc.mk:3: libraries/template-haskell/dist-boot /package-data.mk: No such file or directory libraries/terminfo/ghc.mk:3: libraries/terminfo/dist-boot/package-data.mk: No such file or directory libraries/ghci/ghc.mk:3: libraries/ghci/dist-boot/package-data.mk: No such file or directory compiler/ghc.mk:446: compiler/stage1/package-data.mk: No such file or directory utils/hsc2hs/ghc.mk:21: utils/hsc2hs/dist/package-data.mk: No such file or directory utils/ghc-pkg/ghc.mk:70: utils/ghc-pkg/dist/package-data.mk: No such file or directory ghc/ghc.mk:111: ghc/stage1/package-data.mk: No such file or directory "inplace/bin/ghc-cabal" configure libraries/binary dist-boot --with- ghc="/home/omer/ghc_bins/ghc-8.4.1-bin/bin/ghc" --with-ghc- pkg="/home/omer/ghc_bins/ghc-8.4.1-bin/bin/ghc-pkg" --package- db=/home/omer/haskell/ghc/libraries/bootstrapping.conf --disable-library- for-ghci --enable-library-vanilla --enable-library-for-ghci --disable- library-profiling --disable-shared --configure-option=CFLAGS="-Wall -fno- stack-protector -Werror=unused-but-set-variable -Wno-error=inline" --configure- option=LDFLAGS=" " --configure-option=CPPFLAGS=" " --gcc-options="-Wall -fno-stack-protector -Werror=unused-but-set-variable -Wno-error=inline " --constraint "binary == 0.8.5.1" --constraint "text == 1.2.3.0" --constraint "transformers == 0.5.5.0" --constraint "mtl == 2.2.2" --constraint "parsec == 3.1.13.0" --constraint "Cabal == 2.2.0.0" --constraint "hpc == 0.6.0.3" --constraint "ghc-boot-th == 8.5" --constraint "ghc-boot == 8.5" --constraint "template-haskell == 2.13.0.0" --constraint "ghci == 8.5" --constraint "terminfo == 0.4.1.1" --with-gcc="gcc" --with-ld="ld.gold" --with-ar="ar" --with- alex="/home/omer/.local/bin/alex" --with- happy="/home/omer/.local/bin/happy" Warning: binary.cabal:19:24: unexpected unknown build-type: 'Simple' Simple ghc-cabal: dieVerbatim: user error (ghc-cabal: Failed parsing "./binary.cabal". ) libraries/binary/ghc.mk:3: recipe for target 'libraries/binary/dist-boot /package-data.mk' failed make[1]: *** [libraries/binary/dist-boot/package-data.mk] Error 1 Makefile:122: recipe for target 'all' failed make: *** [all] Error 2 }}} Switching to 8.2.1 works fine. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14902> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #12420: Users guide link for hsc2hs has bitrotten
by GHC 13 Sep '18

13 Sep '18

#12420: Users guide link for hsc2hs has bitrotten -------------------------------------+------------------------------------- Reporter: ezyang | Owner: Type: task | Status: new Priority: normal | Milestone: Component: hsc2hs | Version: 8.0.1 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- https://hackage.haskell.org/package/hsc2hs links to http://www.haskell.org/ghc/docs/latest/html/users_guide/hsc2hs.html which is dead. I think https://downloads.haskell.org/~ghc/latest/docs/html/users_guide/utils.html #writing-haskell-interfaces-to-c-code-hsc2hs is what is desired. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12420> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #14896: QuantifiedConstraints: GHC does doesn't discharge constraints if they are quantified
by GHC 13 Sep '18

13 Sep '18

#14896: QuantifiedConstraints: GHC does doesn't discharge constraints if they are quantified -------------------------------------+------------------------------------- Reporter: Iceland_jack | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.5 Keywords: | Operating System: Unknown/Multiple QuantifiedConstraints, wipT2893 | Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- This came up on a [https://www.reddit.com/r/haskell/comments/8257mz/how_quantifiedconstraints_… reddit thread], {{{#!hs {-# Language QuantifiedConstraints #-} class (forall aa. Functor (bi aa)) => Bifunctor bi where first :: (a -> a') -> (bi a b -> bi a' b) bimap :: Bifunctor bi => (a -> a') -> (b -> b') -> (bi a b -> bi a' b') bimap f g = first f . fmap g }}} This is the type we want for `bimap` even if we mix & match `Bifunctor` and `Functor`. We already know that we can `fmap @(bi xx)` for any `xx` but this is not the inferred type. Instead GHC infers a type (tidied up) with a superfluous `Functor` constraint {{{#!hs bimap :: (Bifunctor bi, Functor (bi a)) => (a -> a') -> (b -> b') -> (bi a b -> bi a' b') }}} Indeed post-composing with a superfluous `fmap @(bi a')` incurs yet another `Functor` constraint {{{#!hs bimap :: (Bifunctor bi, Functor (bi a), Functor (bi a')) => (a -> a') -> (b -> b') -> (bi a b -> bi a' b') bimap f g = fmap id . first f . fmap g }}} A terminology question, I'm not sure how to phrase what GHC isn't doing to the `Functor` constraints: ‘discharge’? -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14896> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #14025: Object file is put in wrong directory when any source has absolute path
by GHC 13 Sep '18

13 Sep '18

#14025: Object file is put in wrong directory when any source has absolute path -------------------------------------+------------------------------------- Reporter: literon | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.1 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- Files: `/tmp/e/A.hs`, `/tmp/e/dep.c`. Current dir: `/tmp/e`. `ghc -odir /tmp/xyzzy A.hs dep.c`: works as expected, puts `dep.o` in `/tmp/xyzzy`. But try to prefix either `A.hs` or `dep.c` (or both) with `/tmp/e/`, and suddenly `dep.o` is put in `/tmp/e`, not in `/tmp/xyzzy`. Couldn't check with 8.2.1 yet. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14025> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #11197: Overeager deferred type errors
by GHC 11 Sep '18

11 Sep '18

#11197: Overeager deferred type errors -------------------------------------+------------------------------------- Reporter: goldfire | Owner: goldfire Type: bug | Status: new Priority: normal | Milestone: 8.0.1 Component: Compiler | Version: 7.11 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- With `TypeInType`, the solver now works in terms of unlifted equality. The only place this matters is in deferred type errors, which now are more eager than they were before. For example: {{{ {-# OPTIONS_GHC -fdefer-type-errors #-} module Main where main = do putStrLn "Hi there." putStrLn True }}} This used to print {{{ Hi there. Defer: Defer.hs:7:12: error: ... }}} Now it prints {{{ Defer: Defer.hs:7:12: error: ... }}} No more `Hi there.`. Thinking about Core, this change should be expected. GHC puts all evidence bindings for `main` at the top, and with unlifted equality in the solver, these bindings now contain `case typeError ... of ...`, which forces the type error eagerly. Previously, there was a lazy binding for a lifted equality witness, unpacked only at the last moment by magic in the desugarer, thus the lazier warning. Simon has proposed customizing the !FloatIn pass to deal with this scenario. I do believe this would work nicely, but I have not yet implemented it. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11197> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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