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| author | Ben Gamari <bgamari.foss@gmail.com> | 2018-06-16 23:44:03 -0400 |
|---|---|---|
| committer | Ben Gamari <ben@smart-cactus.org> | 2018-06-16 23:44:04 -0400 |
| commit | 4cd552184cbc5bed33da21497537df4e400a1a2f (patch) | |
| tree | 2ee01f16e0b16f2f0273e47cb3d3e6d40b753455 /libraries/base | |
| parent | d55035f5fe1312f81a7d3af397d117820e85ad57 (diff) | |
| download | haskell-4cd552184cbc5bed33da21497537df4e400a1a2f.tar.gz | |
base: Add default implementation for Data.Bits.bitSize
Fixes #12970 and will provide a reasonable migration path for the
eventual remove of this function.
Test Plan: Validate
Reviewers: ekmett, hvr
Subscribers: rwbarton, thomie, carter
GHC Trac Issues: #12970
Differential Revision: https://phabricator.haskell.org/D4857
Diffstat (limited to 'libraries/base')
| -rw-r--r-- | libraries/base/Data/Bits.hs | 4 | ||||
| -rw-r--r-- | libraries/base/changelog.md | 3 |
2 files changed, 7 insertions, 0 deletions
diff --git a/libraries/base/Data/Bits.hs b/libraries/base/Data/Bits.hs index 60edf78dea..18110b55a8 100644 --- a/libraries/base/Data/Bits.hs +++ b/libraries/base/Data/Bits.hs @@ -190,8 +190,12 @@ class Eq a => Bits a where {-| Return the number of bits in the type of the argument. The actual value of the argument is ignored. The function 'bitSize' is undefined for types that do not have a fixed bitsize, like 'Integer'. + + Default implementation based upon 'bitSizeMaybe' provided since + 4.12.0.0. -} bitSize :: a -> Int + bitSize b = fromMaybe (error "bitSize is undefined") (bitSizeMaybe b) {-| Return 'True' if the argument is a signed type. The actual value of the argument is ignored -} diff --git a/libraries/base/changelog.md b/libraries/base/changelog.md index 5188fa9331..9e896d3671 100644 --- a/libraries/base/changelog.md +++ b/libraries/base/changelog.md @@ -325,6 +325,9 @@ * New `Control.Exception.TypeError` datatype, which is thrown when an expression fails to typecheck when run using `-fdefer-type-errors` (#10284) + * The `bitSize` method of `Data.Bits.Bits` now has a (partial!) + default implementation based on `bitSizeMaybe`. (#12970) + ### New instances * `Alt`, `Dual`, `First`, `Last`, `Product`, and `Sum` now have `Data`, |