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[GHC] #14812: Dot-Notation for Function Application
by GHC 19 Feb '18

19 Feb '18

#14812: Dot-Notation for Function Application -------------------------------------+------------------------------------- Reporter: tepan | Owner: (none) Type: feature | Status: new request | Priority: normal | Milestone: Component: Compiler | 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: -------------------------------------+------------------------------------- Please allow to put a dot `.` (without spaces) between two things for ''flipped'' function application. This could make for code in pseudo-OOP style: {{{#!hs encrypt(str) = do { str.map(succ); } }}} Currently, as a workaround, this can be achieved by defining `(.) = flip ($)` (making `.` for function composition unavailable, though): {{{#!hs encrypt(str) = do { str.map(succ); } where (.) = flip ($) }}} (For a remotely similar look-and-feel, one could use `Data.Function.((&))` instead of `(.)`.) Please note that `.` without spaces is already an OOP-like notational convenience in order to denote Modules and their elements. {{{#!hs x = do { Prelude.length("Hello World!"); } }}} This means, that a distinction between ` . ` (with spaces) and `.` (without spaces) is already been made, which is why `Just . Just $ 42` compiles, wheras `Just.Just $ 42` doesn't. Analogously, with this Feature Request implemented, `"Hello".map(succ)` would compile whereas `"Hello" . map(succ)"` wouldn't. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14812> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #5889: -fno-prof-count-entries leads to linking errors
by GHC 19 Feb '18

19 Feb '18

#5889: -fno-prof-count-entries leads to linking errors -------------------------------------+------------------------------------- Reporter: akio | Owner: bgamari Type: bug | Status: closed Priority: highest | Milestone: 8.4.1 Component: Compiler | Version: 8.3 Resolution: fixed | Keywords: Operating System: Linux | Architecture: x86_64 | (amd64) Type of failure: GHC rejects | Test Case: valid program | profiling/should_compile/T5889 Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Phab:D4325 Wiki Page: | -------------------------------------+------------------------------------- Changes (by bgamari): * status: merge => closed * resolution: => fixed Comment: Merged with 583e392a83c17e8baf45bc6ee5b998afae190a44. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/5889#comment:33> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #14820: MultiFunctionalDependencies
by GHC 19 Feb '18

19 Feb '18

#14820: MultiFunctionalDependencies -------------------------------------+------------------------------------- Reporter: zaoqi | Owner: (none) Type: feature | Status: new request | Priority: normal | Milestone: Component: Compiler | 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: -------------------------------------+------------------------------------- -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14820> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #4102: Bit manipulation built-ins
by GHC 19 Feb '18

19 Feb '18

#4102: Bit manipulation built-ins -------------------------------------+------------------------------------- Reporter: uzytkownik | Owner: (none) Type: feature request | Status: closed Priority: normal | Milestone: 8.0.2 Component: Core Libraries | Version: 6.12.2 Resolution: fixed | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: #14819 | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Changes (by bgamari): * related: => #14819 -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/4102#comment:25> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #14818: Provide highestOneBit function in Data.Bits module
by GHC 19 Feb '18

19 Feb '18

#14818: Provide highestOneBit function in Data.Bits module -------------------------------------+------------------------------------- Reporter: kostmo | Owner: (none) Type: feature | Status: new request | Priority: normal | Milestone: Component: | Version: 8.2.2 libraries/base | 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: -------------------------------------+------------------------------------- This function yields the [https://stackoverflow.com/a/17379704/105137 largest power of 2 less than or equal to the given number]. Relative to the Java standard library, which [https://docs.oracle.com/javase/7/docs/api/java/lang/Integer.html#highestOne… provides this function], there is a gap in the Haskell library, even though the Haskell docs [https://hackage.haskell.org/package/base-4.10.1.0/docs/Data- Bits.html#v:countLeadingZeros describe a method to calculate logBase2 via the `countLeadingZeros` function]. From the Java documentation: > The implementations of the "bit twiddling" methods (such as `highestOneBit` and `numberOfTrailingZeros`) are based on material from Henry S. Warren, Jr.'s ''Hacker's Delight'', (Addison Wesley, 2002). -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14818> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #14811: Unary unboxed tuple field causes panic
by GHC 18 Feb '18

18 Feb '18

#14811: Unary unboxed tuple field causes panic -------------------------------------+------------------------------------- Reporter: dfeuer | Owner: (none) Type: bug | Status: new Priority: high | Milestone: 8.6.1 Component: Compiler | Version: 8.2.2 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: Compile-time Unknown/Multiple | crash or panic Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- Compiling this code under 8.2 or HEAD (but not 8.0), I get an error. {{{#!hs {-# language UnboxedTuples #-} module Reccy where data Foo a = Foo (# a #) }}} {{{ Reccy.hs:1:1: error: Can't find interface-file declaration for variable GHC.Types.$tcUnit# Probable cause: bug in .hi-boot file, or inconsistent .hi file Use -ddump-if-trace to get an idea of which file caused the error | 1 | -- {-# language GADTs, TypeOperators #-} | ^ }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14811> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #13994: STG lint failure on master
by GHC 18 Feb '18

18 Feb '18

#13994: STG lint failure on master -------------------------------------+------------------------------------- Reporter: bgamari | Owner: (none) Type: bug | Status: new Priority: high | Milestone: 8.4.1 Component: Compiler | Version: 8.3 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: -------------------------------------+------------------------------------- As of 4700baaf8f9bf3c44a53a595d840c7c14cfd6f98 building with this `build.mk` results in an STG lint failure, {{{ BuildFlavour = devel2 include mk/flavours/$(BuildFlavour).mk GhcLibHcOpts += -g3 -ddump-to-file -ddump-stg -dcore-lint -dstg-lint -dcmm-lint GhcRtsHcOpts += -g3 GhcStage2HcOpts += -g3 -ddump-to-file -ddump-stg -dcore-lint -dstg-lint -dcmm-lint }}} The failures occurs while building `libraries/integer-gmp/dist- install/build/GHC/Integer/Type.o` and are of the form, {{{ *** Stg Lint ErrMsgs: in Stg2Stg *** <no location info>: warning: [in body of lambda with binders m0_scBi :: State# s_a2Ej -> State# s_a2Ej, s1_scBj :: State# s_a2Ej] s'_scBk is out of scope <no location info>: warning: [RHS of $j1_sdij :: (# BigNat, GmpLimb# #)] Let(rec) binder ‘$j1_sdij’ has unlifted type ‘(# BigNat, GmpLimb# #)’ RHS: (elided for brevity) <no location info>: warning: [RHS of $j4_sdQ1 :: (# BigNat, BigNat #)] Let(rec) binder ‘$j4_sdQ1’ has unlifted type ‘(# BigNat, BigNat #)’ RHS: (elided) }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13994> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #13185: haskell-relational-query: ghc: panic! (the 'impossible' happened)
by GHC 18 Feb '18

18 Feb '18

#13185: haskell-relational-query: ghc: panic! (the 'impossible' happened) -------------------------------------+------------------------------------- Reporter: LocutusOfBorg | Owner: Type: bug | Status: new Priority: high | Milestone: Component: Compiler | Version: 8.0.2 Keywords: | Operating System: Linux Architecture: | Type of failure: Compile-time Unknown/Multiple | crash or panic Test Case: build | Blocked By: relational-query with ghc 8.0.2 | Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- Hello, this seems a regression of ghc 8.0.2 since 8.0.1 was building it fine: https://launchpadlibrarian.net/303858976/buildlog_ubuntu-zesty-amd64 .haskell-relational-query_0.8.3.2-2build1_BUILDING.txt.gz as you can see in the build log: Preprocessing test suite 'sqls' for relational-query-0.8.3.2... [1 of 3] Compiling Model ( test/Model.hs, dist-ghc/build/sqls /sqls-tmp/Model.o ) [2 of 3] Compiling Lex ( test/Lex.hs, dist-ghc/build/sqls /sqls-tmp/Lex.o ) [3 of 3] Compiling Main ( test/sqlsEq.hs, dist-ghc/build/sqls /sqls-tmp/Main.o ) ghc: panic! (the 'impossible' happened) (GHC version 8.0.2 for x86_64-unknown-linux): Simplifier ticks exhausted When trying UnfoldingDone runReaderT To increase the limit, use -fsimpl-tick-factor=N (default 100) If you need to do this, let GHC HQ know, and what factor you needed To see detailed counts use -ddump-simpl-stats Total ticks: 405365 Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug /usr/share/cdbs/1/class/hlibrary.mk:147: recipe for target 'build-ghc- stamp' failed make: *** [build-ghc-stamp] Error 1 dpkg-buildpackage: error: debian/rules build gave error exit status 2 thanks, Gianfranco -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13185> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #9429: Alternative to type family Any
by GHC 18 Feb '18

18 Feb '18

#9429: Alternative to type family Any -------------------------------------+------------------------------------- Reporter: mboes | Owner: Type: feature request | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.9 Keywords: | Operating System: Architecture: Unknown/Multiple | Unknown/Multiple Difficulty: Unknown | Type of failure: Blocked By: | None/Unknown Related Tickets: 9097, 9380 | Test Case: | Blocking: | Differential Revisions: -------------------------------------+------------------------------------- In GHC HEAD, `Any` is no longer a datatype. There are good reasons for this change, one of which was explained in #9097, the original ticket, and another in #9380. Unfortunately, a casualty of this change is that it is no longer easy to generalize the [https://hackage.haskell.org/package/rank1dynamic|rank1dynamic package] to rank-1 types with type variables of arbitrary kind (not just `*`). We submitted a way to do so [here], that exploits the fact that `Any` has the very magical property of inhabiting *all* kinds, including closed ones. This works for GHC 7.8, but won't work in HEAD, because we require that there exists a `Typeable` instance for `Any`, just as there are `Typeable` instances for any other type one wishes to have instances for. The reason is that now that `Any` is a type family, `Any` is no longer a legal instance head. There are several possible solutions that I see: * while it's clearly dangerous for the compiler to be inserting the old `Any` during typechecking from the moment that we have computation in types over closed kinds, we may still want the old `Any`, say under a different name, as a backdoor. It wouldn't be used by the compiler during type checking - only by packages such as rank1dynamic. I believe that furthermore, if we restrict the old `Any` to not inhabit closed kinds, then none of the problems cited in the above tickets arise. * Instead of making the new `Any` a type family, keep it a datatype, but ban it from inhabiting closed kinds. I don't know if such an `Any` would be sufficient for the purposes of GHC, however. * Hardwire a `Typeable` instance for the `Any` type family (not sure if this makes sense). -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9429> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #7259: Eta expansion of products in System FC
by GHC 18 Feb '18

18 Feb '18

#7259: Eta expansion of products in System FC -------------------------------------+------------------------------------- Reporter: simonpj | Owner: simonpj Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.6.1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Changes (by kcsongor): * cc: kcsongor (added) -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/7259#comment:23> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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