1. 16 Feb, 2016 1 commit
  2. 15 Feb, 2016 1 commit
  3. 04 Feb, 2016 1 commit
    • Georgios Karachalias's avatar
      Overhaul the Overhauled Pattern Match Checker · 28f951ed
      Georgios Karachalias authored
      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 n...
      28f951ed
  4. 26 Jan, 2016 2 commits
    • Ryan Scott's avatar
      Split off -Wunused-type-variables from -Wunused-matches · 6817703b
      Ryan Scott authored
      Summary:
      Previously, `-Wunused-matches` would fire whenever it detected unused type
      variables in a type family or data family instance. This can be annoying for
      users who wish to use type variable names as documentation, as being
      `-Wall`-compliant would mean that they'd have to prefix many of their type
      variable names with underscores, making the documentation harder to read.
      
      To avoid this, a new warning `-Wunused-type-variables` was created that only
      encompasses unused variables in family instances. `-Wunused-matches` reverts
      back to its role of only warning on unused term-level pattern names. Unlike
      `-Wunused-matches`, `-Wunused-type-variables` is not implied by `-Wall`.
      
      Fixes #11451.
      
      Test Plan: ./validate
      
      Reviewers: goldfire, ekmett, austin, hvr, simonpj, bgamari
      
      Reviewed By: simonpj, bgamari
      
      Subscribers: thomie
      
      Differential Revision: https://phabricator.haskell.org/D1825
      
      GHC Trac Issues: #11451
      6817703b
    • Herbert Valerio Riedel's avatar
      5f5dc862
  5. 25 Jan, 2016 3 commits
  6. 24 Jan, 2016 1 commit
    • Herbert Valerio Riedel's avatar
      Implement `-Wnoncanonical-monadfail-instances` warning · fd6dd41c
      Herbert Valerio Riedel authored
      The MonadFail proposal implemented so far via #10751 only warns about
      missing `MonadFail` instances based on existence of failible pattern
      matches in `do`-blocks.
      
      However, based on the noncanonical Monad warnings implemented via #11150
      we can provide a different mechanism for detecting missing `MonadFail`
      instances quite cheaply. That is, by checking for canonical `fail` definitions.
      
      In the case of `Monad`/`MonadFail`, we define the canonical implementation of
      `fail` to be such that the soft-deprecated method shall (iff overridden) be
      defined in terms of the non-deprecated method. Consequently, in case of
      `MonadFail`, the `Monad(fail)` method shall be defined as alias of
      the `MonadFail(fail)` method.
      
      This allows us at some distant point in the future to remove `fail` from
      the `Monad` class, while having GHC ignore/tolerate such literal canonical
      method definitions.
      
      Reviewed By: bgamari, RyanGlScott
      
      Differential Revision: https://phabricator.haskell.org/D1838
      fd6dd41c
  7. 23 Jan, 2016 1 commit
  8. 09 Jan, 2016 2 commits
  9. 05 Jan, 2016 1 commit
  10. 27 Dec, 2015 1 commit
    • Georgios Karachalias's avatar
      Adding flags: -ffull-guard-reasoning and too-many-guards · bec5350d
      Georgios Karachalias authored
      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
      bec5350d
  11. 21 Dec, 2015 1 commit
    • msosn's avatar
      Warn about unused type variables in type families · eb7796f1
      msosn authored
      The warnings are enabled with the flag -fwarn-unused-matches, the same
      one that enables warnings on the term level.
      
      Identifiers starting with an underscore are now always parsed as type
      variables.  When the NamedWildCards extension is enabled, the renamer
      replaces those variables with named wildcards.
      
      An additional NameSet nwcs is added to LocalRdrEnv. It's used to keep
      names of the type variables that should be replaced with wildcards.
      
      While renaming HsForAllTy, when a name is explicitly bound it is removed
      from the nwcs NameSet. As a result, the renamer doesn't replace them in
      the quantifier body. (Trac #11098)
      
      Fixes #10982, #11098
      
      Reviewers: alanz, bgamari, hvr, austin, jstolarek
      
      Reviewed By: jstolarek
      
      Subscribers: goldfire, mpickering, RyanGlScott, thomie
      
      Differential Revision: https://phabricator.haskell.org/D1576
      
      GHC Trac Issues: #10982
      eb7796f1
  12. 16 Dec, 2015 1 commit
    • quchen's avatar
      Add `-W(no-)xxx` aliases for `-f(no-)warn-xxx` flags · 2206fa8c
      quchen authored
      This also updates the user's guide to refer to the `-W`-based warning
      flags by default.
      
      Quoting the release note entry:
      
      | Warnings can now be controlled with `-W(no-)...` flags in addition to
      | the old `-f(no-)warn...` ones. This was done as the first part of a
      | rewrite of the warning system to provide better control over warnings,
      | better warning messages, and more common syntax compared to other
      | compilers. The old `-fwarn...`-based warning flags will remain
      | functional for the forseeable future.
      
      This is part of
      https://ghc.haskell.org/wiki/Design/Warnings
      and addresses #11218
      
      Reviewed By: hvr, bgamari
      
      Differential Revision: https://phabricator.haskell.org/D1613
      2206fa8c
  13. 15 Dec, 2015 1 commit
  14. 12 Dec, 2015 1 commit
    • Matthew Pickering's avatar
      Implement -fwarn-missing-pat-syn-sigs · 1883afb2
      Matthew Pickering authored
      This adds a warning when a pattern synonym is not accompanied by a
      signature in the style of `-fwarn-missing-sigs`.
      
      It is turned on by -Wall.
      
      If the user specifies, `-fwarn-missing-exported-signatures` with
      `-fwarn-missing-pat-syn-sigs` then it will only warn when the pattern
      synonym is exported.
      
      Test Plan: ./validate
      
      Reviewers: hvr, austin, bgamari
      
      Reviewed By: bgamari
      
      Subscribers: thomie
      
      Differential Revision: https://phabricator.haskell.org/D1596
      
      GHC Trac Issues: #11053
      1883afb2
  15. 06 Dec, 2015 1 commit
    • Herbert Valerio Riedel's avatar
      Implement new `-fwarn-noncanonical-monoid-instances` · 986ceb16
      Herbert Valerio Riedel authored
      This is similiar to the `-fwarn-noncanonical-monad-instances` warning
      implemented via #11128, but applies to `Semigroup`/`Monoid` instead
      and the `(<>)`/`mappend` methods (of which `mappend` is planned to move
      out of `Monoid` at some point in the future being redundant and thus
      error-prone).
      
      This warning is contained in `-Wcompat` but not in `-Wall`.
      
      This addresses #11150
      
      Reviewed By: quchen
      
      Differential Revision: https://phabricator.haskell.org/D1553
      986ceb16
  16. 29 Nov, 2015 1 commit
    • quchen's avatar
      Implement warnings for Semigroups as parent of Monoid · 290def72
      quchen authored
      This patch is similar to the AMP patch (#8004), which offered two
      functions:
      
        1. Warn when an instance of a class has been given, but the type does
           not have a certain superclass instance
        2. Warn when top-level definitions conflict with future Prelude names
      
      These warnings are issued as part of the new `-Wcompat` warning group.
      
      Reviewers: hvr, ekmett, austin, bgamari
      
      Reviewed By: hvr, ekmett, bgamari
      
      Subscribers: ekmett, thomie
      
      Differential Revision: https://phabricator.haskell.org/D1539
      
      GHC Trac Issues: #11139
      290def72
  17. 25 Nov, 2015 1 commit
  18. 24 Nov, 2015 2 commits
    • quchen's avatar
      Add -Wcompat warning flag group · 6d147939
      quchen authored
      Reviewers: hvr, austin, thomie, bgamari
      
      Reviewed By: hvr, austin, thomie, bgamari
      
      Subscribers: thomie
      
      Differential Revision: https://phabricator.haskell.org/D1495
      
      GHC Trac Issues: #11000
      6d147939
    • Herbert Valerio Riedel's avatar
      Implement new `-fwarn-noncanonical-monad-instances` · f09f2470
      Herbert Valerio Riedel authored
      Warn about incoherent/non-canonical 'Applicative'/'Monad' instance
      declarations. Specifically the following invariants are checked:
      
      In 'Monad' instances declarations warn if the any of the following
      conditions does not hold:
      
       * If `return` is overridden it must be canonical (i.e. `return = pure`).
       * If `(>>)` is overridden it must be canonical (i.e. `(>>) = (*>)`).
      
      In 'Applicative' instance declarations:
      
       * Warn if 'pure' is defined backwards (i.e. `pure = return`).
       * Warn if '(*>)' is defined backwards (i.e. `(*>) = (>>)`).
      
      NB, this warning flag is not enabled via `-Wall` nor `-Wcompat`.
      
      This addresses #11128
      
      Reviewers: quchen, austin, bgamari
      
      Reviewed By: bgamari
      
      Differential Revision: https://phabricator.haskell.org/D1516
      f09f2470
  19. 18 Nov, 2015 1 commit
  20. 17 Nov, 2015 1 commit
    • quchen's avatar
      MonadFail proposal, phase 1 · 233d1312
      quchen authored
      This implements phase 1 of the MonadFail proposal (MFP, #10751).
      
      - MonadFail warnings are all issued as desired, tunable with two new flags
      - GHC was *not* made warning-free with `-fwarn-missing-monadfail-warnings`
        (but it's disabled by default right now)
      
      Credits/thanks to
      - Franz Thoma, whose help was crucial to implementing this
      - My employer TNG Technology Consulting GmbH for partially funding us
        for this work
      
      Reviewers: goldfire, austin, #core_libraries_committee, hvr, bgamari, fmthoma
      
      Reviewed By: hvr, bgamari, fmthoma
      
      Subscribers: thomie
      
      Projects: #ghc
      
      Differential Revision: https://phabricator.haskell.org/D1248
      
      GHC Trac Issues: #10751
      233d1312
  21. 08 Oct, 2015 1 commit
  22. 03 Oct, 2015 1 commit