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[GHC] #2358: Template Haskell's TupleT considers unary tuples as a valid types.

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	[GHC] #2358: Template Haskell's TupleT considers unary tuples as a valid types. by GHC-2 :: Rate this Message: Reply to Author \| View Threaded \| Show Only this Message #2358: Template Haskell's TupleT considers unary tuples as a valid types. ------------------------+--------------------------------------------------- Reporter: fons \| Owner: Type: bug \| Status: new Priority: normal \| Component: Template Haskell Version: 6.8.2 \| Severity: normal Keywords: \| Testcase: Architecture: Unknown \| Os: Unknown ------------------------+--------------------------------------------------- I don't know how tuples are internally implemented in GHC, but the Haskell report (3.8) specifically establishes two as their lower size bound. When provided a zero (or null list) arguments, all TupleT, TupP and TupE behave like the unit type (which is certainly reasonable). However, they handle argument 1 (or the singleton list) in different ways: * {{{TupleP [pat]}}} is equivalent to {{{pat}}} (which again, is perfectly reasonable) * {{{TupE [exp]}}} behaves as exp (again, it seems right) However: * {{{TupleT 1 `AppT` VarT ''Int}}} is a different type than {{{VarT ''Int}}} See the following two examples: 1. {{{tupE [exp]}}} behaves as expected: {{{ Prelude Language.Haskell.TH> $(sigE (tupE [[\|1\|]]) (conT ''Int)) 1 }}} 2. {{{tupleT 1}}} doesn't: {{{ Prelude Language.Haskell.TH> $(sigE [\|1\|] (tupleT 1 `appT` conT ''Int)) <interactive>:1:2: No instance for (Num (Int)) arising from the literal `1' at <interactive>:1:2-40 Possible fix: add an instance declaration for (Num (Int)) In the expression: $(sigE [\| 1 \|] (tupleT 1 `appT` conT 'Int)) In the definition of `it': it = $(sigE [\| 1 \|] (tupleT 1 `appT` conT 'Int)) }}} Probably, since unary tuples are not legal, the typechecker should simply raise an error when {{{TupleT}}} is found to have received {{{1}}} as argument. -- Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/2358> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler _______________________________________________ Glasgow-haskell-bugs mailing list Glasgow-haskell-bugs@... http://www.haskell.org/mailman/listinfo/glasgow-haskell-bugs
	Re: [GHC] #2358: Template Haskell's TupleT considers unary tuples as a valid types. by GHC-2 :: Rate this Message: Reply to Author \| View Threaded \| Show Only this Message #2358: Template Haskell's TupleT considers unary tuples as a valid types. ------------------------------+--------------------------------------------- Reporter: fons \| Owner: igloo Type: merge \| Status: new Priority: normal \| Milestone: Component: Template Haskell \| Version: 6.8.2 Severity: normal \| Resolution: Keywords: \| Difficulty: Unknown Testcase: TH_1tuple \| Architecture: Unknown Os: Unknown \| ------------------------------+--------------------------------------------- Changes (by simonpj): * testcase: => TH_1tuple * difficulty: => Unknown * type: bug => merge * owner: => igloo Comment: Fixed by {{{ Sat Jun 14 13:39:39 BST 2008 simonpj@... * Fix Trac #2358: 1-tuples in Template Haskell }}} Queue for merging to the branch, in the event of 6.8.4 Simon -- Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/2358#comment:1> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler _______________________________________________ Glasgow-haskell-bugs mailing list Glasgow-haskell-bugs@... http://www.haskell.org/mailman/listinfo/glasgow-haskell-bugs
	Re: [GHC] #2358: Template Haskell's TupleT considers unary tuples as a valid types. by GHC-2 :: Rate this Message: Reply to Author \| View Threaded \| Show Only this Message #2358: Template Haskell's TupleT considers unary tuples as a valid types. ------------------------------+--------------------------------------------- Reporter: fons \| Owner: igloo Type: merge \| Status: new Priority: normal \| Milestone: 6.8 branch Component: Template Haskell \| Version: 6.8.2 Severity: normal \| Resolution: Keywords: \| Difficulty: Unknown Testcase: TH_1tuple \| Architecture: Unknown Os: Unknown \| ------------------------------+--------------------------------------------- Changes (by igloo): * milestone: => 6.8 branch -- Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/2358#comment:2> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler _______________________________________________ Glasgow-haskell-bugs mailing list Glasgow-haskell-bugs@... http://www.haskell.org/mailman/listinfo/glasgow-haskell-bugs
	Re: [GHC] #2358: Template Haskell's TupleT considers unary tuples as a valid types. by GHC-2 :: Rate this Message: Reply to Author \| View Threaded \| Show Only this Message #2358: Template Haskell's TupleT considers unary tuples as a valid types. ------------------------------+--------------------------------------------- Reporter: fons \| Owner: Type: merge \| Status: new Priority: normal \| Milestone: 6.8 branch Component: Template Haskell \| Version: 6.8.2 Severity: normal \| Resolution: Keywords: \| Difficulty: Unknown Testcase: TH_1tuple \| Architecture: Unknown Os: Unknown \| ------------------------------+--------------------------------------------- Changes (by igloo): * owner: igloo => -- Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/2358#comment:3> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler _______________________________________________ Glasgow-haskell-bugs mailing list Glasgow-haskell-bugs@... http://www.haskell.org/mailman/listinfo/glasgow-haskell-bugs
	Re: [GHC] #2358: Template Haskell's TupleT considers unary tuples as a valid types. by GHC-2 :: Rate this Message: Reply to Author \| View Threaded \| Show Only this Message #2358: Template Haskell's TupleT considers unary tuples as a valid types. ------------------------------+--------------------------------------------- Reporter: fons \| Owner: Type: merge \| Status: closed Priority: normal \| Milestone: 6.8 branch Component: Template Haskell \| Version: 6.8.2 Severity: normal \| Resolution: fixed Keywords: \| Difficulty: Unknown Testcase: TH_1tuple \| Architecture: Unknown/Multiple Os: Unknown/Multiple \| ------------------------------+--------------------------------------------- Changes (by igloo): * status: new => closed * resolution: => fixed Comment: We won't be releasing 6.8.4. -- Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/2358#comment:6> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler _______________________________________________ Glasgow-haskell-bugs mailing list Glasgow-haskell-bugs@... http://www.haskell.org/mailman/listinfo/glasgow-haskell-bugs

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