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* Documentation: use https linksKrzysztof Gogolewski2021-09-081-4/+4
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* Implement proposal 403: Lexer cleanupOleg Grenrus2021-04-051-0/+21
| | | | | This allows Other Numbers to be used in identifiers, and also documents other, already existing lexer divergence from Haskell Report
* Introduce GHC2021 languageJoachim Breitner2021-03-101-19/+8
| | | | | | This adds support for -XGHC2021, as described in Proposal 0380 [1]. [1] https://github.com/ghc-proposals/ghc-proposals/blob/master/proposals/0380-ghc2021.rst
* Documentation fixesKrzysztof Gogolewski2021-01-301-7/+9
| | | | | | | | | | | | | | | - Add missing :since: for NondecreasingIndentation and OverlappingInstances - Remove duplicated descriptions for Safe Haskell flags and UndecidableInstances. Instead, the sections contain a link. - compare-flags: Also check for options supported by ghci. This uncovered two more that are not documented. The flag -smp was removed. - Formatting fixes - Remove the warning about -XNoImplicitPrelude - it was written in 1996, the extension is no longer dangerous. - Fix misspelled :reverse: flags Fixes #18958.
* Add a section about failable patterns in the GHC user's guideHécate2021-01-271-0/+31
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* Remove "Operator sections" from docs/users_guide/bugs.rstVladislav Zavialov2020-10-141-25/+0
| | | | | The issue described in that section was fixed by 2b89ca5b850b4097447cc4908cbb0631011ce979
* Add missing Ix instances for tuples of size 6 through 15 (#16643)Joshua Price2020-06-301-3/+2
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* Improve parser error messages for TypeApplicationsVladislav Zavialov2020-06-011-4/+11
| | | | | | | | | | | | | | With this patch, we always parse f @t as a type application, thereby producing better error messages. This steals two syntactic forms: * Prefix form of the @-operator in expressions. Since the @-operator is a divergence from the Haskell Report anyway, this is not a major loss. * Prefix form of @-patterns. Since we are stealing loose infix form anyway, might as well sacrifice the prefix form for the sake of much better error messages.
* Whitespace-sensitive bang patterns (#1087, #17162)wip/whitespace-and-lookaheadVladislav Zavialov2019-11-271-0/+39
| | | | | | | | | | | | | | | | | | This patch implements a part of GHC Proposal #229 that covers five operators: * the bang operator (!) * the tilde operator (~) * the at operator (@) * the dollar operator ($) * the double dollar operator ($$) Based on surrounding whitespace, these operators are disambiguated into bang patterns, lazy patterns, strictness annotations, type applications, splices, and typed splices. This patch doesn't cover the (-) operator or the -Woperator-whitespace warning, which are left as future work.
* users-guide: Document NondecreasingIndentationBen Gamari2019-10-081-1/+8
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* users-guide: Refer to language extension flags via :extension:Ben Gamari2019-10-081-4/+4
| | | | Previously several were referred to via :ghc-flag:`-X...`.
* users-guide: Fix a variety of broken links and syntaxBen Gamari2019-06-191-2/+2
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* Minor spelling fixes to users guide.P.C. Shyamshankar2019-05-291-1/+1
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* Correct the large tuples section in user's guideJoshua Price2019-05-271-8/+8
| | | | Fixes #16644.
* Update Trac ticket URLs to point to GitLabRyan Scott2019-03-151-1/+1
| | | | | This moves all URL references to Trac tickets to their corresponding GitLab counterparts.
* User's Guide: forall is a keyword nowadaysVladislav Zavialov2019-02-231-0/+7
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* Fix trac #15702, as a followon to fix for #13704.Chris Smith2018-11-171-11/+27
| | | | | | | | | | | | | | | | | | Summary: The effect of this change is that -main-is changes the default export list for the main module, but does not apply the same change to non-main modules. This fixes some cases where -main-is was used to wrap a module that expected that default behavior (exporting `main`, even when that wasn't the main entry point name). Reviewers: mpickering, monoidal, bgamari Subscribers: rwbarton, carter GHC Trac Issues: #13704, #15702 Differential Revision: https://phabricator.haskell.org/D5322
* resolve T13704chessai2018-10-021-0/+28
| | | | | | | | | | | | | | | | | Summary: allow -main-is to change export list for default module header, allowing one to change the entry point to one's program. Test Plan: ./validate Reviewers: bgamari, nomeata, mpickering Reviewed By: mpickering Subscribers: mpickering, rwbarton, carter GHC Trac Issues: #13704 Differential Revision: https://phabricator.haskell.org/D5189
* Fix minor formatting issue in users_guide/bugs.rstJosh Price2018-07-301-0/+2
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* Implement BlockArguments (#10843)Takano Akio2018-01-311-6/+0
| | | | | | | | | | | | | | | | | | | | | | | | This patch implements the BlockArguments extension, as proposed at https://github.com/ghc-proposals/ghc-proposals/pull/90. It also fixes #10855 as a side-effect. This patch adds a large number of shift-reduce conflicts to the parser. All of them concern the ambiguity as to where constructs like `if` and `let` end. Fortunately they are resolved correctly by preferring shift. The patch is based on @gibiansky's ArgumentDo implementation (D1219). Test Plan: ./validate Reviewers: goldfire, bgamari, alanz, mpickering Reviewed By: bgamari, mpickering Subscribers: Wizek, dfeuer, gibiansky, rwbarton, thomie, mpickering, carter GHC Trac Issues: #10843, #10855 Differential Revision: https://phabricator.haskell.org/D4260
* Remove broken citeseer citation linksChris Martin2017-09-011-1/+1
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* Sections with undefined operators have non-standard behaviorDavid Luposchainsky2017-08-171-0/+23
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* A few documentation fixesDavid Feuer2017-05-201-1/+1
| | | | | | | | | | | | | | `MIN_VERSION_pkg` was documented backwards. An important caveat about initializing the Haskell runtime was buried in a footnote. The documentation of `-dynamic` was (even more) confusing. Reviewers: austin, bgamari Reviewed By: bgamari Subscribers: rwbarton, thomie Differential Revision: https://phabricator.haskell.org/D3582
* Document AMP as a Report deviationDavid Feuer2017-02-241-2/+7
| | | | | | | | | | | | | | | | `Applicative` as a superclass of `Monad` is non-standard. Fixes #13196. [skip ci] Reviewers: austin, bgamari Reviewed By: bgamari Subscribers: thomie Differential Revision: https://phabricator.haskell.org/D3185
* Typos in manual and comments [ci skip]Gabor Greif2017-01-171-2/+2
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* Use latin1 code page on Windows for response files.Tamar Christina2017-01-151-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Summary: D2917 added a change that will make paths on Windows response files use DOS 8.3 shortnames to get around the fact that `libiberty` assumes a one byte per character encoding. This is actually not the problem, the actual problem is that GCC on Windows doesn't seem to support Unicode at all. This comes down to how unicode characters are handled between POSIX and Windows. On Windows, Unicode is only supported using a multibyte character encoding such as `wchar_t` with calls to the appropriate wide version of APIs (name post-fixed with the `W` character). On Posix I believe the standard `char` is used and based on the value it is decoded to the correct string. GCC doesn't seem to make calls to the Wide version of the Windows APIs, and even if it did, it's character representation would be wrong. So I believe GCC just does not support utf-8 paths on Windows. So the hack in D2917 is the only way to get Unicode support. The problem is however that `GCC` is not the only tool with this issue and we don't use response files for every invocation of the tools. Most of the tools probably don't support it. Furthermore, DOS 8.1 shortnames only exist when the path or file physically exists on disk. We pass lots of paths to GCC that don't exist yet, like the output file. D2917 works around this by splitting the path from the file and try shortening that. But this may not always work. In short, even if we do Unicode correctly (which we don't atm, the GCC driver we build uses `char` instead of `wchar_t`) we won't be able to compile using unicode paths that need to be passed to `GCC`. So not sure about the point of D2917. What we can do is support the most common non-ascii characters by writing the response files out using the `latin1` code page. Test Plan: compile + make test TEST=T12971 Reviewers: austin, bgamari, erikd Reviewed By: bgamari Subscribers: thomie, #ghc_windows_task_force Differential Revision: https://phabricator.haskell.org/D2942 GHC Trac Issues: #12971
* Remove references to -XRelaxedPolyRecBen Gamari2016-09-081-0/+51
| | | | | | | | | | | | Test Plan: Read it Reviewers: dfeuer, austin Subscribers: thomie Differential Revision: https://phabricator.haskell.org/D2515 GHC Trac Issues: #11691
* Add Read1/Read2 methods defined in terms of ReadPrecRyan Scott2016-08-311-1/+11
| | | | | | | | | | | | | | | | | This adds new methods `liftReadList(2)` and `liftReadListPrec(2)` to the `Read1`/`Read2` classes which are defined in terms of `ReadPrec` instead of `ReadS`. This also adds related combinators and changes existing `Read1` and `Read2` instances to be defined in terms of the new methods. Reviewers: hvr, austin, bgamari Reviewed By: bgamari Subscribers: thomie Differential Revision: https://phabricator.haskell.org/D2379 GHC Trac Issues: #12358
* Trac #11554 fix loopy GADTsAlexander Vieth2016-06-301-7/+0
| | | | | | | | | | | | | | Summary: Fixes T11554 Reviewers: goldfire, thomie, simonpj, austin, bgamari Reviewed By: thomie, simonpj, bgamari Subscribers: simonpj, goldfire, thomie Differential Revision: https://phabricator.haskell.org/D2283 GHC Trac Issues: #11554
* Fix comments about scavenging WEAK objectsTakano Akio2016-05-121-5/+0
| | | | | | | | | | | | | | | | | | This is a follow-up of D2189. If fixes some comments, deletes a section in the User's Guide about the bug, and updates .mailmap as suggested on the WorkinConventions wiki page. Test Plan: It compiles. Reviewers: austin, simonmar, bgamari Reviewed By: bgamari Subscribers: thomie Differential Revision: https://phabricator.haskell.org/D2202 GHC Trac Issues: #11108
* users-guide: Add references to various issues in bugs sectionBen Gamari2016-03-291-0/+37
| | | | | | | | | | | | | | Test Plan: Read it Reviewers: austin Reviewed By: austin Subscribers: thomie Differential Revision: https://phabricator.haskell.org/D2052 GHC Trac Issues: #7411, #11197, #11554, #11715
* Show: Restore redundant parentheses around recordsBen Gamari2016-03-241-0/+15
| | | | | | | | | | | | | | | | | | | | As discussed in #2530 we are going to continue to produce parentheses here in order to preserve compatibility with previous GHC releases. It was found that dropped parentheses would break some testsuites which compared against output from Show. This has been documented in the users guide. This reverts commit 5692643c9d17e746327588cd6157a923642b7975. Test Plan: Validate Reviewers: hvr, austin Subscribers: thomie Differential Revision: https://phabricator.haskell.org/D2027 GHC Trac Issues: #2350
* Overhaul the Overhauled Pattern Match CheckerGeorge Karachalias2016-02-041-10/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Overhaul the Overhauled Pattern Match Checker * Changed the representation of Value Set Abstractions. Instead of using a prefix tree, we now use a list of Value Vector Abstractions. The set of constraints Delta for every Value Vector Abstraction is the oracle state so that we solve everything only once. * Instead of doing everything lazily, we prune at once (and in general everything is much stricter). Hence, an example written with pattern guards is checked in almost the same time as the equivalent with pattern matching. * Do not store the covered and the divergent sets at all. Since what we only need is a yes/no (does this clause cover anything? Does it force any thunk?) We just keep a boolean for each. * Removed flags `-Wtoo-many-guards` and `-ffull-guard-reasoning`. Replaced with `fmax-pmcheck-iterations=n`. Still debatable what should the default `n` be. * When a guard is for sure not going to contribute anything, we treat it as such: The oracle is not called and cases `CGuard`, `UGuard` and `DGuard` from the paper are not happening at all (the generation of a fresh variable, the unfolding of the pattern list etc.). his combined with the above seems to be enough to drop the memory increase for test T783 down to 18.7%. * Do not export function `dsPmWarn` (it is now called directly from within `checkSingle` and `checkMatches`). * Make `PmExprVar` hold a `Name` instead of an `Id`. The term oracle does not handle type information so using `Id` was a waste of time/space. * Added testcases T11195, T11303b (data families) and T11374 The patch addresses at least the following: Trac #11195, #11276, #11303, #11374, #11162 Test Plan: validate Reviewers: goldfire, bgamari, hvr, austin Subscribers: simonpj, thomie Differential Revision: https://phabricator.haskell.org/D1795
* users_guide: Use semantic directive/role for command line optionsBen Gamari2016-01-091-53/+30
| | | | | | And GHCi commands. This makes cross-referencing much easier. Also normalize markup a bit and add some missing flags.
* Adding flags: -ffull-guard-reasoning and too-many-guardsGeorge Karachalias2015-12-271-5/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Introduction of two new flags, for more precise control over the new pattern match checker's behaviour when reasoning about guards. This is supposed to address #11195 (and maybe more performance bugs related to the NP-Hardness of coverage checking). Expected behaviour: * When `-ffull-guard-reasoning` is on, run the new pattern match checker in its full power * When `-ffull-guard-reasoning` is off (the default), for every match, check a metric to see whether pattern match checking for it has high probability of being non performant (at the the moment we check whether the number of guards is over 20 but I would like to use a more precise measure in the future). If the probability is high: - Oversimplify the guards (less expressive but more performant) and run the checker, and - Issue a warning about the simplification that happened. A new flag `-Wtoo-many-guards/-Wno-too-many-guards` suppresses the warning about the simplification (useful when combined with -Werror). Test Plan: validate Reviewers: goldfire, austin, hvr, bgamari Reviewed By: bgamari Subscribers: mpickering, thomie Differential Revision: https://phabricator.haskell.org/D1676 GHC Trac Issues: #11195
* Note #11108 in the bugs section of users guideBen Gamari2015-11-261-0/+5
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* Note STM's vulnerability to non-allocating loopsBen Gamari2015-11-261-4/+6
| | | | | | | | | | | | | | Test Plan: Read it Reviewers: austin, fryguybob Reviewed By: austin Subscribers: thomie, fryguybob Differential Revision: https://phabricator.haskell.org/D1523 GHC Trac Issues: #10639, #367
* Move user's guide to ReStructuredTextBen Gamari2015-10-031-0/+492
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