- ghc-tickets - Haskell.org

[GHC] #12103: Typed Template Haskell missing many utilities provided by untyped variant
by GHC 11 Jan '19

11 Jan '19

#12103: Typed Template Haskell missing many utilities provided by untyped variant -------------------------------------+------------------------------------- Reporter: bgamari | Owner: Type: bug | Status: new Priority: normal | Milestone: 8.2.1 Component: Template | Version: 8.0.1 Haskell | 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 typed TH feels a bit second-class as it lacks a number of handy utilities which are provided in the untyped case. In my brief look at this I encountered the following, {{{#!hs type TExpQ a = Q (TExp a) stringT :: String -> TExpQ String trueT, false :: TExpQ Bool }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12103> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

1 5

[GHC] #10945: Typed Template Haskell splices broken in HEAD (7.11)
by GHC 11 Jan '19

11 Jan '19

#10945: Typed Template Haskell splices broken in HEAD (7.11) -------------------------------------+------------------------------------- Reporter: jstolarek | Owner: Type: bug | Status: new Priority: high | Milestone: 8.0.1 Component: Template | Version: 7.11 Haskell | Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | -------------------------------------+------------------------------------- In the latest HEAD (e2b579e8d77357e8b36f57d15daead101586ac8e) when I say: {{{#!hs $$(return [ SigD (mkName "m") (ForallT [PlainTV (mkName "a")] [] (AppT (AppT ArrowT (VarT (mkName "a"))) (VarT (mkName "a")))) , FunD (mkName "m") [Clause [VarP (mkName "x")] (NormalB (VarE (mkName "x"))) []] ]) }}} I get: {{{ ghc-stage2: panic! (the 'impossible' happened) (GHC version 7.11.20151007 for x86_64-unknown-linux): runRnSplice $$(return [SigD (mkName "m") (ForallT [PlainTV (mkName "a")] [] (AppT (AppT ArrowT (VarT (mkName "a"))) (VarT (mkName "a")))), FunD (mkName "m") [Clause [VarP (mkName "x")] (NormalB (VarE (mkName "x"))) []]]) }}} This code compiles correctly in GHC 7.10.1. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10945> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

1 13

[GHC] #11452: Typed Template Haskell sneakily allows impredicativity
by GHC 11 Jan '19

11 Jan '19

#11452: Typed Template Haskell sneakily allows impredicativity -------------------------------------+------------------------------------- Reporter: goldfire | Owner: goldfire Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.1 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: -------------------------------------+------------------------------------- The following module is accepted: {{{#!hs {-# LANGUAGE ExplicitForAll, TemplateHaskell #-} module Bug where impred :: forall a. a -> a impred = $$( [|| \x -> x ||] ) }}} But that requires an intermediate `TExp (forall a. a -> a)`. Will fix in ongoing work. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11452> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

1 6

[GHC] #10949: Document typed Template Haskell
by GHC 11 Jan '19

11 Jan '19

#10949: Document typed Template Haskell -------------------------------------+------------------------------------- Reporter: goldfire | Owner: Type: bug | Status: new Priority: high | Milestone: 8.0.1 Component: Template | Version: 7.10.2 Haskell | Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: Documentation Unknown/Multiple | bug Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | -------------------------------------+------------------------------------- As far as I can tell, typed Template Haskell is completely missing from the manual. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10949> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

1 3

[GHC] #14838: missing "incomplete-patterns" warning for TH-generated functions
by GHC 11 Jan '19

11 Jan '19

#14838: missing "incomplete-patterns" warning for TH-generated functions -------------------------------------+------------------------------------- Reporter: gelisam | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Template | Version: 8.2.2 Haskell | Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: Incorrect Unknown/Multiple | error/warning at compile-time Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- "incomplete-patterns" warnings are generated for TH-generated case expressions, but not for TH-generated functions, so the behaviour is inconsistent. For example: {{{#!hs {-# LANGUAGE TemplateHaskell #-} module Lib where import Language.Haskell.TH qIncompleteCase :: Q [Dec] qIncompleteCase = [d| incompleteCase :: Bool -> () incompleteCase b = case b of True -> () |] qIncompleteFunction :: Q [Dec] qIncompleteFunction =[d| incompleteFunction :: Bool -> () incompleteFunction True = () |] }}} {{{#!hs {-# LANGUAGE TemplateHaskell #-} module Bug where import Lib $qIncompleteCase $qIncompleteFunction incompleteCase' :: Bool -> () incompleteCase' b = case b of True -> () incompleteFunction' :: Bool -> () incompleteFunction' True = () }}} When compiling the above two files with `-Wall`, GHC 8.2.2 produces an "incomplete-patterns" warning for `qIncompleteCase`, `incompleteCase'`, and `incompleteFunction'`, but not for `qIncompleteFunction`. I would prefer to get a warning for `qIncompleteFunction` as well. My use case is the [https://hackage.haskell.org/package/surjective surjective] package, in which I intentionally generate code which produces warnings in order to warn the user about corresponding issues in their code. I could generate [https://github.com/gelisam/surjective/blob/master/src/Surjective.hs#L158-L1… better error messages] if GHC generated warnings for TH-generated functions as well. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14838> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

1 13

[GHC] #16169: Unused variable warning affects compositionality when generating code
by GHC 11 Jan '19

11 Jan '19

#16169: Unused variable warning affects compositionality when generating code -------------------------------------+------------------------------------- Reporter: mpickering | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.6.3 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: -------------------------------------+------------------------------------- If I'm generating a program using template haskell, I might define a combinator to help me generate lambdas. {{{ type Code a = Q (TExp a) _lam :: (Code a -> Code b) -> Code (a -> b) _lam f = [|| \a -> $$(f [|| a ||]) ||] }}} However, if I now pass a constant function into `_lam`, the generated code contains an unused variable `a` that I can do nothing about and desire not to do anything about. {{{ c5 :: Code (a -> Int) c5 = _lam (const [|| 5 ||]) }}} However, GHC decides that it's wise to warn me about this when I splice it in. {{{ > $$c5 F2.hs:6:5: warning: [-Wunused-matches] Defined but not used: ‘a’ | 6 | q = $$c5 | ^^^ }}} As Ryan will tell you, I'm against emitting warnings from generated code as it breaks the abstraction. The code that is generated is guaranteed to be type and scope correct but any aesthetic warning is irrelevant to the consumer. I see it in precisely the same way as warning if we use a function that contains an unused variable in a library. Once the definition is exported from the library, its definition is opaque. The same principle should be applied to code generated by template haskell. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/16169> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

1 3

[GHC] #16167: -ddump-json output empty with runghc
by GHC 11 Jan '19

11 Jan '19

#16167: -ddump-json output empty with runghc -------------------------------------+------------------------------------- Reporter: shmish111 | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.4.3 Keywords: | Operating System: MacOS X Architecture: x86_64 | Type of failure: Incorrect (amd64) | error/warning at compile-time Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- If I create a haskell file called, for example, Main.hs which does not compile and run `ghc -ddump-json Main.hs` I will get a json formatted output after the error messages. This is a list of the errors, as expected. However if I run `runghc -ddump-json Main.hs` I get an empty list at the end `[]` -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/16167> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

1 5

[GHC] #15399: Build failure on PowerPC 64-bit big endian
by GHC 11 Jan '19

11 Jan '19

#15399: Build failure on PowerPC 64-bit big endian ---------------------------------+---------------------------------------- Reporter: trommler | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.5 Keywords: | Operating System: Linux Architecture: powerpc64 | Type of failure: Building GHC failed Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: ---------------------------------+---------------------------------------- Building GHC 8.6.1 alpha 2 fails with these errors on Powerpc 64-bit big endian Linux: {{{ [ 5076s] utils/check-ppr/Main.hs:44:18: error: [ 5076s] * GHC internal error: `astFile' is not in scope during type checking, but it passed the renamer [ 5076s] tcl_env of environment: [agVj :-> Identifier[libdir::FilePath, NotLetBound], [ 5076s] agVk :-> Identifier[fileName::String, NotLetBound], [ 5076s] agVl :-> Identifier[p::a, NotLetBound], [ 5076s] agVo :-> Identifier[anns::ApiAnns, TopLevelLet [agVl :-> p] False], [ 5076s] agVp :-> Identifier[pragmas::String, TopLevelLet [agVo :-> anns] False], [ 5076s] agVq :-> Identifier[newFile::FilePath, TopLevelLet [agVk :-> fileName] False], [ 5076s] rfRp :-> Identifier[usage::String, TopLevelLet [] True], [ 5076s] rfU1 :-> Identifier[main::IO (), TopLevelLet [] True], [ 5076s] rfU2 :-> Identifier[testOneFile::FilePath [ 5076s] -> String [ 5076s] -> IO (), TopLevelLet [] True], [ 5076s] rfU3 :-> Identifier[parseOneFile::FilePath [ 5076s] -> FilePath [ 5076s] -> IO [ 5076s] ParsedModule, TopLevelLet [] True], [ 5076s] rfU4 :-> Identifier[getPragmas::ApiAnns -> String, TopLevelLet], [ 5076s] rfU5 :-> Identifier[pp::forall a. [ 5076s] Outputable a => [ 5076s] a -> String, TopLevelLet [] True]] [ 5076s] * In the first argument of `writeFile', namely `astFile' [ 5076s] In a stmt of a 'do' block: writeFile astFile origAst [ 5076s] In the expression: [ 5076s] do p <- parseOneFile libdir fileName [ 5076s] let pped = pragmas ++ "\n" ++ pp (pm_parsed_source p) [ 5076s] anns = pm_annotations p [ 5076s] .... [ 5076s] writeFile astFile origAst [ 5076s] writeFile newFile pped [ 5076s] .... [ 5076s] | [ 5076s] 44 | writeFile astFile origAst [ 5076s] | ^^^^^^^ [ 5076s] utils/check-ppr/ghc.mk:18: recipe for target 'utils/check-ppr /dist-install/build/Main.o' failed [ 5076s] make[1]: *** [utils/check-ppr/dist-install/build/Main.o] Error 1 [ 5076s] make[1]: *** Waiting for unfinished jobs.... [ 5077s] [ 5077s] utils/check-api-annotations/Main.hs:116:32: error: [ 5077s] * GHC internal error: `GenericQ' is not in scope during type checking, but it passed the renamer [ 5077s] tcl_env of environment: [agZx :-> Type variable `r' = r :: k0] [ 5077s] * In the type signature: [ 5077s] everything :: (r -> r -> r) -> GenericQ r -> GenericQ r [ 5077s] | [ 5077s] 116 | everything :: (r -> r -> r) -> GenericQ r -> GenericQ r [ 5077s] | ^^^^^^^^ [ 5077s] utils/check-api-annotations/ghc.mk:18: recipe for target 'utils /check-api-annotations/dist-install/build/Main.o' failed [ 5077s] make[1]: *** [utils/check-api-annotations/dist- install/build/Main.o] Error 1 [ 5077s] [ 5077s] utils/ghctags/Main.hs:61:36: error: [ 5077s] * GHC internal error: `FoundThing' is not in scope during type checking, but it passed the renamer [ 5077s] tcl_env of environment: [rCTr :-> ATcTyCon FileData :: *, [ 5077s] rCTs :-> APromotionErr RecDataConPE, [ 5077s] rCTw :-> ATcTyCon FileName :: *] [ 5077s] * In the type `[FoundThing]' [ 5077s] In the definition of data constructor `FileData' [ 5077s] In the data declaration for `FileData' [ 5077s] | [ 5077s] 61 | data FileData = FileData FileName [FoundThing] (Map Int String) [ 5077s] | ^^^^^^^^^^ [ 5077s] utils/ghctags/ghc.mk:18: recipe for target 'utils/ghctags/dist- install/build/Main.o' failed }}} Alpha 2 builds fine on PowerPC 64-bit little endian Linux. I am setting version to 8.5 as there is no tag for 8.6.1 alpha 2 yet. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15399> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

1 11

[GHC] #15948: Hadrian cannot build on Windows
by GHC 10 Jan '19

10 Jan '19

#15948: Hadrian cannot build on Windows -------------------------------------+------------------------------------- Reporter: bgamari | Owner: (none) Type: bug | Status: new Priority: highest | Milestone: 8.8.1 Component: Build System | Version: 8.7 (Hadrian) | 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: -------------------------------------+------------------------------------- The Hadrian build on Windows currently fails with {{{ 'C:/msys64/home/ben/ghc/builds/0/project-0/_build/stage0/bin/ghc.exe' exited ghc.exe: could not detect mingw toolchain }}} when trying to build the RTS. I strongly suspect that the problem is that the stage1 toolchain built by Hadrian lives in `_build/stage0/bin/ghc` whereas the mingw tarballs were extracted to `inplace/mingw`. It's quite unclear to me how this ever worked. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15948> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

1 5

[GHC] #16118: SYB link in Data.Data is dead
by GHC 10 Jan '19

10 Jan '19

#16118: SYB link in Data.Data is dead -------------------------------------+------------------------------------- Reporter: ocramz | Owner: (none) Type: bug | Status: new Priority: lowest | Milestone: Component: | Version: 8.6.3 libraries/base | Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: Documentation Unknown/Multiple | bug Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- The link to the SYB blog given in the Data.Data haddocks (http://foswiki.cs.uu.nl/foswiki/bin/view/GenericProgramming/SYB) is dead. Is there a backup copy somewhere? -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/16118> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

1 2