May 2018 - ghc-devs - Haskell.org

8.6.1 status
by Ben Gamari 23 May '18

23 May '18

Hi everyone, As noted a few weeks ago, the 8.6.1 fork is quickly approaching. Currently the plan is to cut the branch on Friday, 1 May 2018. After the branch there will likely be a few days of bug fixing and clean-up, followed by the alpha 1 release. Let me know if you have a patch which you would like to see included that hasn't yet been submitted for review. Cheers, - Ben

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Quantified constraints
by Simon Peyton Jones 23 May '18

23 May '18

Friends Now that the Quantified Constraints proposal<https://github.com/Gertjan423/ghc-proposals/blob/quantified-constraints/pro…> is accepted, I want to commit it to GHC before the 8.6 release. It's up on https://phabricator.haskell.org/D4724 for your review. It's rebased on master, and validates clean. There's also a useful wiki page<https://ghc.haskell.org/trac/ghc/wiki/QuantifiedConstraints>. Thanks! Simon

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Build Failure
by Ningning Xie 23 May '18

23 May '18

Hi everyone, I pulled from the head this morning and would like to rebase my local changes on it. Even before I do rebase, I got a build error. Everything is fine last time I built (almost one week ago). Then I tried to glone a new repo and the build gives me the same error message. After a little bit searching, the error message seems to be specific to MacOS (mine is Sierra 10.12.6). Platform info (Let me know if you need more information): *--- repo/ghc * *»* which ghc ghc: aliased to stack ghc *--- repo/ghc * *»* stack exec -- ghc --version The Glorious Glasgow Haskell Compilation System, version 7.10.3 *--- repo/ghc * *»* gcc --version Configured with: --prefix=/Library/Developer/CommandLineTools/usr --with-gxx-include-dir=/usr/include/c++/4.2.1 Apple LLVM version 9.0.0 (clang-900.0.39.2) Target: x86_64-apple-darwin16.7.0 Thread model: posix InstalledDir: /Library/Developer/CommandLineTools/usr/bin Has anyone encountered the same problem and any clue on how to solve it? Thanks, Ningning "inplace/bin/ghc-stage1" -hisuf p_hi -osuf p_o -hcsuf p_hc -static -prof -eventlog -H32m -O -Wall -this-unit-id integer-gmp-1.0.2.0 -hide-all-packages -i -ilibraries/integer-gmp/src/ -ilibraries/integer-gmp/dist-install/build -Ilibraries/integer-gmp/dist-install/build -ilibraries/integer-gmp/dist-install/build/./autogen -Ilibraries/integer-gmp/dist-install/build/./autogen -Ilibraries/integer-gmp/include -Ilibraries/integer-gmp/dist-install/build/include -optP-include -optPlibraries/integer-gmp/dist-install/build/./autogen/cabal_macros.h -package-id ghc-prim-0.5.3 -this-unit-id integer-gmp -Wall -XHaskell2010 -O2 -no-user-package-db -rtsopts -Wno-deprecated-flags -Wnoncanonical-monad-instances -odir libraries/integer-gmp/dist-install/build -hidir libraries/integer-gmp/dist-install/build -stubdir libraries/integer-gmp/dist-install/build -c libraries/integer-gmp/src//GHC/Integer/Logarithms.hs -o libraries/integer-gmp/dist-install/build/GHC/Integer/Logarithms.p_o -dyno libraries/integer-gmp/dist-install/build/GHC/Integer/Logarithms.dyn_o */var/folders/zq/tn9b58wn37b0yby0vm8_7_cr0000gn/T/ghc47691_0/ghc_3.s:221:8: **error:* * error: unsupported relocation with subtraction expression, symbol '_integerzmgmp_GHCziIntegerziType_quotInteger_closure' can not be undefined in a subtraction expression* * .long _integerzmgmp_GHCziIntegerziType_quotInteger_closure-(_sMi_info)+0* * ^* * |* *221 |* .long _integerzmgmp_GHCziIntegerziType_quotInteger_closure-(_sMi_info)+0 * |** ^* */var/folders/zq/tn9b58wn37b0yby0vm8_7_cr0000gn/T/ghc47691_0/ghc_3.s:318:8: **error:* * error: unsupported relocation with subtraction expression, symbol '_integerzmgmp_GHCziIntegerziType_quotInteger_closure' can not be undefined in a subtraction expression* * .long _integerzmgmp_GHCziIntegerziType_quotInteger_closure-(_cPd_info)+0* * ^* * |* *318 |* .long _integerzmgmp_GHCziIntegerziType_quotInteger_closure-(_cPd_info)+0 * |** ^* */var/folders/zq/tn9b58wn37b0yby0vm8_7_cr0000gn/T/ghc47691_0/ghc_3.s:390:8: **error:* * error: unsupported relocation with subtraction expression, symbol '_integerzmgmp_GHCziIntegerziType_quotInteger_closure' can not be undefined in a subtraction expression* * .long _integerzmgmp_GHCziIntegerziType_quotInteger_closure-(_cP8_info)+0* * ^* * |* *390 |* .long _integerzmgmp_GHCziIntegerziType_quotInteger_closure-(_cP8_info)+0 * |** ^* `gcc' failed in phase `Assembler'. (Exit code: 1) make[1]: *** [libraries/integer-gmp/dist-install/build/GHC/Integer/Logarithms.p_o] Error 1

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Cannot compute type fingerprint in plugin, kinds/types are mixed
by alice 23 May '18

23 May '18

Hello again. I’m trying to make a function in a type-checking plugin that takes TyCoRep#Type and makes its fingerprint that matches `typeRepFingerprint (typeRep :: TypeRep (type))`. As I understood the type’s fingerprint is made in DsBinds#dsEvTypeable by generating a code that makes the fingerprint, so I can’t reuse functions which are already written. My goal is to write a function that makes fingerprints of types which are not type variables such as Int, Maybe Int, ‘[Int] etc. So I tried to follow `mkTrCon` and `mkTrApp` style, and I think I managed to process simple types like Int, Maybe Int — right now I’m processing TyConApp only. But when I tried to make promoted data fingerprint like ‘[Int] I faced some problems. For example, for making `’Just Int` fingerprint first I have to compute 'Just fingerprint by computing 'Just tyCon’s and * fingerprints, then combining them into one fingerprint. Then I have to apply ‘Just to Int. But when I try to do something like that while type checking I cannot separate two cases that match runtime’s`TypeRep (a b)` (a representation for a type application) and `TypeRep a` (a representation for a type constructor) because they are represented by TyConApp. Also I can’t separate tyCon kinds and types for type application because they are merged into one list which is stored in `TyConApp _ [KindOrType]`. [KindOrType] list for `’Just Int` is `[*, Int]`. Is there any way to separate this two cases and kinds/types? Probably there is an easier way to make this function? If not, does type fingerprint function seem possible to make? Any help would be appreciated, Alice.

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abi-depends field
by Simon Peyton Jones 22 May '18

22 May '18

I'm seeing lots of these errors. What's this "ignoring (possibly broken) abi-depends field" stuff? Or have I failed to update sufficiently vigorously somwhow? Simon =====> T13350(normal) 1 of 1 [0, 0, 0] cd "./should_compile/T13350/T13350.run" && $MAKE -s --no-print-directory T13350 Actual stdout output differs from expected: diff -uw "/dev/null" "./should_compile/T13350/T13350.run/T13350.run.stdout.normalised" --- /dev/null 2018-04-26 12:34:15.027999213 +0100 +++ ./should_compile/T13350/T13350.run/T13350.run.stdout.normalised 2018-05-21 10:33:05.181794031 +0100 @@ -0,0 +1 @@ +ignoring (possibly broken) abi-depends field for packages *** unexpected failure for T13350(normal) Unexpected results from: TEST="T13350" SUMMARY for test run started at Mon May 21 10:32:53 2018 BST 0:00:12 spent to go through 1 total tests, which gave rise to 1 test cases, of which 0 were skipped 0 had missing libraries 0 expected passes 0 expected failures 0 caused framework failures 0 caused framework warnings 0 unexpected passes 1 unexpected failures 0 unexpected stat failures Unexpected failures: should_compile/T13350/T13350.run T13350 [bad stdout] (normal)

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505 Error on https://www.haskell.org/ghc/license.html
by Joachim Breitner 22 May '18

22 May '18

Hi, on https://www.haskell.org/ghc/license.html I see 500 Internal Server Error nginx before and after the text. I don’t expect many people to look there, but still ugly. Cheers, Joachim -- Joachim Breitner mail(a)joachim-breitner.de http://www.joachim-breitner.de/

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Potential improvements for CSE, strictness analyzer, let-floating
by Peter Podlovics 21 May '18

21 May '18

Hi all, During the summer, as a university project, I would like to make some contributions to GHC. There are three topics in particular that piqued my interest: common subexpression elimination, strictness analysis, and let-floating. I would like to ask you whether there is any room for improvement in these parts of the compiler. Could you give me some pointers? Thanks in advance, Peter

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Built-in type family with one input argument
by alice 21 May '18

21 May '18

Hello, I’ve made a built-in function that takes a list and returns a list: `type family MySet [k] -> [k]`. I think I did something wrong because right now I’m getting an exception like that: ``` Extracted [Int, Bool, Char] — input list 1 List_ty '[Bool, Char, Int] — sorted list 1 Extracted [Int, Bool, Char] — input list 2 (?) List_ty '[Bool, Char, Int] — sorted list 2 (?) ghc: panic! (the 'impossible' happened) (GHC version 8.4.2 for x86_64-apple-darwin): ASSERT failed! Bad coercion hole co_a2QJ: MySet '[Bool, Char, Int] nominal (MySet '[Int, Bool, Char] :: [*]) ~# ('[Bool, Char, Int] :: [*]) Call stack: CallStack (from HasCallStack): callStackDoc, called at compiler/utils/Outputable.hs:1208:22 in ghc:Outputable assertPprPanic, called at compiler/typecheck/TcMType.hs:306:25 in ghc:TcMType Call stack: CallStack (from HasCallStack): callStackDoc, called at compiler/utils/Outputable.hs:1150:37 in ghc:Outputable pprPanic, called at compiler/utils/Outputable.hs:1206:5 in ghc:Outputable assertPprPanic, called at compiler/typecheck/TcMType.hs:306:25 in ghc:TcMType Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug ``` when I’m trying to check the ~ relation: ``` test :: Proxy (GHC.TypeLits.MySet '[Int, Bool, Char]) -> Proxy (GHC.TypeLits.MySet '[Int, Bool, Char]) test = id ``` But when I do something like that: ``` test :: (GHC.TypeLits.MySet '[Int, Bool, Char] ~ as, GHC.TypeLits.MySet '[Int, Bool, Char] ~ bs) => Proxy as -> Proxy bs test = id ``` everything is fine. I think the problem is that I tried to follow TcTypeNats#typeSymbolCmpTyCon etc style but all the functions there have two inputs and one output with built-in kind (I tried to do [k] kind by myself), so probably I understood something wrong. Could someone give me a hint what I did wrong, please? I can show my code if needed. Thank you for your time, Alice.

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Re: Add HeapView functionality (ec22f7d)
by Joachim Breitner 20 May '18

20 May '18

Hi, Am Sonntag, den 20.05.2018, 15:43 +0000 schrieb git(a)git.haskell.org: > commit ec22f7ddc81b40a9dbcf140e5cf44730cb776d00 > Author: Patrick Dougherty <patrick.doc(a)ameritech.net> > Date: Wed May 16 16:50:13 2018 -0400 > > Add HeapView functionality > > This pulls parts of Joachim Breitner's ghc-heap-view library inside GHC. > The bits added are the C hooks into the RTS and a basic Haskell wrapper > to these C hooks. The main reason for these to be added to GHC proper > is that the code needs to be kept in sync with the closure types > defined by the RTS. It is expected that the version of HeapView shipped > with GHC will always work with that version of GHC and that extra > functionality can be layered on top with a library like ghc-heap-view > distributed via Hackage. whoohoo, this is great! I did not not expect that the horrifying (but maybe not horrible) hack that I wrote so many years ago becomes an official feature :-) I’ll be curious in what ways our community will use (or abuse) this feature… Patrick, you mention that a library like ghc-heap-view will still be required. Are you interested in updating it to use the new interfaces, or even take it over completely? Compatibility with ghc-vis (http://felsin9.de/nnis/ghc-vis/) is probably the most important goal here. I’m CC’ing the author of ghc- vis, Dennis. Or maybe ghc-vis should use the GHC-provided wrappers directly? Dennis, are you still invested in maintaining ghc-vis? Cheers, Joachim -- Joachim Breitner mail(a)joachim-breitner.de http://www.joachim-breitner.de/

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TTG hsSyn for Batch and Interactive Parsing
by Alan & Kim Zimmerman 18 May '18

18 May '18

I want to be able to run the GHC parser in one of two modes, batch which functions as now, and interactive which will (eventually) be incremental. In addition, the hsSyn AST for each will have different TTG[1] annotations, so that it can better support IDE usage. I think this can be done by changing the types in HsExtension to introduce a 'Process' type as follows data Pass = Parsed Process | Renamed | Typechecked deriving (Data) data Process = Batch | Interactive deriving (Show, Data) We then rename the pass synonyms so that batch is the default type GhcPs = GhcPass ('Parsed 'Batch) type GhcPsI = GhcPass ('Parsed 'Interactive) I have attached a simple proof of concept file, which emulates parsing and renaming. Is this an appropriate approach to take? Alan [1] Trees That Grow https://ghc.haskell.org/trac/ghc/wiki/ ImplementingTreesThatGrow

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