
Bundled with GHC 8.6.1

The STM invariantchecking mechanism (always
and alwaysSucceeds
), which
was deprecated in GHC 8.4, has been removed (as proposed in
https://github.com/ghcproposals/ghcproposals/blob/master/proposals/0011deprecatestminvariants.rst).
This is a bit earlier than proposed in the deprecation pragma included in
GHC 8.4, but due to community feedback we decided to move ahead with the
early removal.
Existing users are encouraged to encapsulate their STM operations in safe
abstractions which can perform the invariant checking without help from the
runtime system.

Add a new module GHC.ResponseFile
(previously defined in the haddock
package). (#13896)

Move the module Data.Functor.Contravariant
from the
contravariant
package to base
.

($!)
is now representationpolymorphic like ($)
.

Add Applicative
(for K1
), Semigroup
and Monoid
instances in
GHC.Generics
. (#14849)

asinh
for Float
and Double
is now numerically stable in the face of
nonsmall negative arguments and enormous arguments of either sign. (#14927)

Numeric.showEFloat (Just 0)
now respects the user’s requested precision.
(#15115)

Data.Monoid.Alt
now has Foldable
and Traversable
instances. (#15099)

Data.Monoid.Ap
has been introduced

Control.Exception.throw
is now levity polymorphic. (#15180)

Data.Ord.Down
now has a number of new instances. These include:
MonadFix
, MonadZip
, Data
, Foldable
, Traversable
, Eq1
, Ord1
,
Read1
, Show1
, Generic
, Generic1
. (#15098)

Bundled with GHC 8.4.1

System.IO.openTempFile
is now threadsafe on Windows.

Deprecated GHC.Stats.GCStats
interface has been removed.

Add showHFloat
to Numeric

Add Div
, Mod
, and Log2
functions on typelevel naturals
in GHC.TypeLits
.

Add Alternative
instance for ZipList
(#13520)

Add instances Num
, Functor
, Applicative
, Monad
, Semigroup
and Monoid
for Data.Ord.Down
(#13097).

Add Semigroup
instance for EventLifetime
.

Make Semigroup
a superclass of Monoid
;
export Semigroup((<>))
from Prelude
; remove Monoid
reexport
from Data.Semigroup
(#14191).

Generalise instance Monoid a => Monoid (Maybe a)
to
instance Semigroup a => Monoid (Maybe a)
.

Add infixl 9 !!
declaration for Data.List.NonEmpty.!!

Add <&>
operator to Data.Functor
(#14029)

Remove the deprecated Typeable{1..7}
type synonyms (#14047)

Make Data.Type.Equality.==
a closed type family. It now works for all
kinds out of the box. Any modules that previously declared instances of this
family will need to remove them. Whereas the previous definition was somewhat
ad hoc, the behavior is now completely uniform. As a result, some applications
that used to reduce no longer do, and conversely. Most notably, (==)
no
longer treats the *
, j > k
, or ()
kinds specially; equality is
tested structurally in all cases.

Add instances Semigroup
and Monoid
for Control.Monad.ST
(#14107).

The Read
instances for Proxy
, Coercion
, (:~:)
, (:~~:)
, and U1
now ignore the parsing precedence. The effect of this is that read
will
be able to successfully parse more strings containing "Proxy"
et al.
without surrounding parentheses (e.g., "Thing Proxy"
) (#12874).

Add iterate'
, a strict version of iterate
, to Data.List
and Data.OldList
(#3474)

Add Data
instances for IntPtr
and WordPtr
(#13115)

Add missing MonadFail
instance for Control.Monad.Strict.ST.ST

Make zipWith
and zipWith3
inlinable (#14224)

Type.Reflection.App
now matches on function types (fixes #14236)

Type.Reflection.withTypeable
is now polymorphic in the RuntimeRep
of
its result.

Add installSEHHandlers
to MiscFlags
in GHC.RTS.Flags
to determine if
exception handling is enabled.

The deprecated functions isEmptyChan
and unGetChan
in
Control.Concurrent.Chan
have been removed (#13561).

Add generateCrashDumpFile
to MiscFlags
in GHC.RTS.Flags
to determine
if a core dump will be generated on crashes.

Add generateStackTrace
to MiscFlags
in GHC.RTS.Flags
to determine if
stack traces will be generated on unhandled exceptions by the RTS.

getExecutablePath
now resolves symlinks on Windows (#14483)

Deprecated STM invariant checking primitives (checkInv
, always
, and
alwaysSucceeds
) in GHC.Conc.Sync
(#14324).

Add a FixIOException
data type to Control.Exception.Base
, and change
fixIO
to throw that instead of a BlockedIndefinitelyOnMVar
exception
(#14356).

Bundled with GHC 8.2.1

Data.Type.Bool.Not
given a type family dependency (#12057).

Foreign.Ptr
now exports the constructors for IntPtr
and WordPtr
(#11983)

Generic1
, as well as the associated datatypes and typeclasses in
GHC.Generics
, are now polykinded (#10604)

New modules
Data.Bifoldableand
Data.Bitraversable(previously defined in the
bifunctors` package) (#10448)

Data.Either
now provides fromLeft
and fromRight
(#12402)

Data.Type.Coercion
now provides gcoerceWith
(#12493)

New methods liftReadList(2)
and liftReadListPrec(2)
in the
Read1
/Read2
classes that are defined in terms of ReadPrec
instead of
ReadS
, as well as related combinators, have been added to
Data.Functor.Classes
(#12358)

Add Semigroup
instance for IO
, as well as for Event
and Lifetime
from GHC.Event
(#12464)

Add Data
instance for Const
(#12438)

Added Eq1
, Ord1
, Read1
and Show1
instances for NonEmpty
.

Add wrappers for blksize_t
, blkcnt_t
, clockid_t
, fsblkcnt_t
,
fsfilcnt_t
, id_t
, key_t
, and timer_t
to System.Posix.Types (#12795)

Add CBool
, a wrapper around C’s bool
type, to Foreign.C.Types
(#13136)

Raw buffer operations in GHC.IO.FD
are now strict in the buffer, offset, and length operations (#9696)

Add plusForeignPtr
to Foreign.ForeignPtr
.

Add type family AppendSymbol (m :: Symbol) (n :: Symbol) :: Symbol
to GHC.TypeLits
(#12162)

Add GHC.TypeNats
module with Natural
based KnownNat
. The Nat
operations in GHC.TypeLits
are a thin compatibility layer on top.
Note: the KnownNat
evidence is changed from an Integer
to a Natural
.

The type of asProxyTypeOf
in Data.Proxy
has been generalized (#12805)

liftA2
is now a method of the Applicative
class. liftA2
and
<*>
each have a default implementation based on the other. Various
library functions have been updated to use liftA2
where it might offer
some benefit. liftA2
is not yet in the Prelude
, and must currently be
imported from Control.Applicative
. It is likely to be added to the
Prelude
in the future. (#13191)

A new module, Type.Reflection
, exposing GHC’s new typeindexed type
representation mechanism is now provided.

Data.Dynamic
now exports the Dyn
data constructor, enabled by the new
typeindexed type representation mechanism.

Data.Type.Equality
now provides a kind heterogeneous type equality
evidence type, (:~~:)
.

The CostCentresXML
constructor of GHC.RTS.Flags.DoCostCentres
has been
replaced by CostCentresJSON
due to the new JSON export format supported by
the cost centre profiler.

The ErrorCall
pattern synonym has been given a COMPLETE
pragma so that
functions which solely match again ErrorCall
do not produce
nonexhaustive patternmatch warnings (#8779)

Change the implementations of maximumBy
and minimumBy
from
Data.Foldable
to use foldl1
instead of foldr1
. This makes them run
in constant space when applied to lists. (#10830)

mkFunTy
, mkAppTy
, and mkTyConApp
from Data.Typeable
no longer exist.
This functionality is superceded by the interfaces provided by
Type.Reflection
.

mkTyCon3
is no longer exported by Data.Typeable
. This function is
replaced by Type.Reflection.Unsafe.mkTyCon
.

Data.List.NonEmpty.unfold
has been deprecated in favor of unfoldr
,
which is functionally equivalent.

Bundled with GHC 8.0

error
and undefined
now print a partial stacktrace alongside the error message.

New errorWithoutStackTrace
function throws an error without printing the stack trace.

The restore operation provided by mask
and uninterruptibleMask
now
restores the previous masking state whatever the current masking state is.

New GHC.Generics.packageName
operation

Redesigned GHC.Stack.CallStack
data type. As a result, CallStack
’s
Show
instance produces different output, and CallStack
no longer has an
Eq
instance.

New GHC.Generics.packageName
operation

New GHC.Stack.Types
module now contains the definition of
CallStack
and SrcLoc

New GHC.Stack.Types.emptyCallStack
function builds an empty CallStack

New GHC.Stack.Types.freezeCallStack
function freezes a CallStack
preventing future pushCallStack
operations from having any effect

New GHC.Stack.Types.pushCallStack
function pushes a callsite onto a CallStack

New GHC.Stack.Types.fromCallSiteList
function creates a CallStack
from
a list of callsites (i.e., [(String, SrcLoc)]
)

GHC.SrcLoc
has been removed

GHC.Stack.showCallStack
and GHC.SrcLoc.showSrcLoc
are now called
GHC.Stack.prettyCallStack
and GHC.Stack.prettySrcLoc
respectively

add Data.List.NonEmpty
and Data.Semigroup
(to become
superclass of Monoid
in the future). These modules were
provided by the semigroups
package previously. (#10365)

Add selSourceUnpackedness
, selSourceStrictness
, and
selDecidedStrictness
, three functions which look up strictness
information of a field in a data constructor, to the Selector
type class
in GHC.Generics
(#10716)

Add URec
, UAddr
, UChar
, UDouble
, UFloat
, UInt
, and UWord
to
GHC.Generics
as part of making GHC generics capable of handling
unlifted types (#10868)

The Eq
, Ord
, Read
, and Show
instances for U1
now use lazier
patternmatching

Keep shift{L,R}
on Integer
with negative shiftarguments from
segfaulting (#10571)

Add forkOSWithUnmask
to Control.Concurrent
, which is like
forkIOWithUnmask
, but the child is run in a bound thread.

The MINIMAL
definition of Arrow
is now arr AND (first OR (***))
.

The MINIMAL
definition of ArrowChoice
is now left OR (+++)
.

Exported GiveGCStats
, DoCostCentres
, DoHeapProfile
, DoTrace
,
RtsTime
, and RtsNat
from GHC.RTS.Flags

New function GHC.IO.interruptible
used to correctly implement
Control.Exception.allowInterrupt
(#9516)

Made PatternMatchFail
, RecSelError
, RecConError
, RecUpdError
,
NoMethodError
, and AssertionFailed
newtypes (#10738)

New module Control.Monad.IO.Class
(previously provided by transformers
package). (#10773)

New modules Data.Functor.Classes
, Data.Functor.Compose
,
Data.Functor.Product
, and Data.Functor.Sum
(previously provided by
transformers
package). (#11135)

New instances for Proxy
: Eq1
, Ord1
, Show1
, Read1
. All
of the classes are from Data.Functor.Classes
(#11756).

New module Control.Monad.Fail
providing new MonadFail(fail)
class (#10751)

Add GHC.TypeLits.TypeError
and ErrorMessage
to allow users
to define custom compiletime error messages.

Redesign GHC.Generics
to use typelevel literals to represent the
metadata of generic representation types (#9766)

The IsString
instance for [Char]
has been modified to eliminate
ambiguity arising from overloaded strings and functions like (++)
.

Move Const
from Control.Applicative
to its own module in
Data.Functor.Const
. (#11135)

Reexport Const
from Control.Applicative
for backwards compatibility.

Expand Floating
class to include operations that allow for better
precision: log1p
, expm1
, log1pexp
and log1mexp
. These are not
available from Prelude
, but the full class is exported from Numeric
.

New Control.Exception.TypeError
datatype, which is thrown when an
expression fails to typecheck when run using fdefertypeerrors
(#10284)

The bitSize
method of Data.Bits.Bits
now has a (partial!)
default implementation based on bitSizeMaybe
. (#12970)

Alt
, Dual
, First
, Last
, Product
, and Sum
now have Data
,
MonadZip
, and MonadFix
instances

The datatypes in GHC.Generics
now have Enum
, Bounded
, Ix
,
Functor
, Applicative
, Monad
, MonadFix
, MonadPlus
, MonadZip
,
Foldable
, Foldable
, Traversable
, Generic1
, and Data
instances
as appropriate.

Maybe
now has a MonadZip
instance

All
and Any
now have Data
instances

Dual
, First
, Last
, Product
, and Sum
now have Foldable
and
Traversable
instances

Dual
, Product
, and Sum
now have Functor
, Applicative
, and
Monad
instances

(,) a
now has a Monad
instance

ZipList
now has Foldable
and Traversable
instances

Identity
now has Semigroup
and Monoid
instances

Identity
and Const
now have Bits
, Bounded
, Enum
, FiniteBits
,
Floating
, Fractional
, Integral
, IsString
, Ix
, Num
, Real
,
RealFloat
, RealFrac
and Storable
instances. (#11210, #11790)

()
now has a Storable
instance

Complex
now has Generic
, Generic1
, Functor
, Foldable
, Traversable
,
Applicative
, and Monad
instances

System.Exit.ExitCode
now has a Generic
instance

Data.Version.Version
now has a Generic
instance

IO
now has a Monoid
instance

Add MonadPlus IO
and Alternative IO
instances
(previously orphans in transformers
) (#10755)

CallStack
now has an IsList
instance

The field spInfoName
of GHC.StaticPtr.StaticPtrInfo
has been removed.
The value is no longer available when constructing the StaticPtr
.

VecElem
and VecCount
now have Enum
and Bounded
instances.

Bundled with GHC 7.10.1

Make Applicative
a superclass of Monad

Add reverse application operator Data.Function.(&)

Add Data.List.sortOn
sorting function

Add System.Exit.die

Deprecate versionTags
field of Data.Version.Version
.
Add makeVersion :: [Int] > Version
constructor function to aid
migration to a future versionTags
less Version
.

Add IsList Version
instance

Weaken RealFloat constraints on some Data.Complex
functions

Add Control.Monad.(<$!>)
as a strict version of (<$>)

The Data.Monoid
module now has the PolyKinds
extension
enabled, so that the Monoid
instance for Proxy
are polykinded
like Proxy
itself is.

Make abs
and signum
handle (0.0) correctly per IEEE754.

Reexport Data.Word.Word
from Prelude

Add countLeadingZeros
and countTrailingZeros
methods to
Data.Bits.FiniteBits
class

Add Data.List.uncons
list destructor (#9550)

Export Monoid(..)
from Prelude

Export Foldable(..)
from Prelude
(hiding fold
, foldl'
, foldr'
, and toList
)

Export Traversable(..)
from Prelude

Set fixity for Data.Foldable.{elem,notElem}
to match the
conventional one set for Data.List.{elem,notElem}
(#9610)

Turn toList
, elem
, sum
, product
, maximum
, and minimum
into Foldable
methods (#9621)

Replace the Data.List
exported functions
all, and, any, concat, concatMap, elem, find, product, sum,
mapAccumL, mapAccumR
by reexports of their generalised Data.Foldable
/Data.Traversable
counterparts. In other words, unqualified imports of Data.List
and Data.Foldable
/Data.Traversable
no longer lead to conflicting
definitions. (#9586)

New (unofficial) module GHC.OldList
containing only listspecialised
versions of the functions from Data.List
(in other words, GHC.OldList
corresponds to base4.7.0.2
’s Data.List
)

Replace the Control.Monad
exported functions
sequence_, msum, mapM_, forM_,
forM, mapM, sequence
by reexports of their generalised Data.Foldable
/Data.Traversable
counterparts. In other words, unqualified imports of Control.Monad
and Data.Foldable
/Data.Traversable
no longer lead to conflicting
definitions. (#9586)

Generalise Control.Monad.{when,unless,guard}
from Monad
to
Applicative
and from MonadPlus
to Alternative
respectively.

Generalise Control.Monad.{foldM,foldM_}
to Foldable

scanr
, mapAccumL
and filterM
now take part in list fusion (#9355,
#9502, #9546)

Remove deprecated Data.OldTypeable
(#9639)

New module Data.Bifunctor
providing the Bifunctor(bimap,first,second)
class (previously defined in bifunctors
package) (#9682)

New module Data.Void
providing the canonical uninhabited type Void
(previously defined in void
package) (#9814)

Update Unicode class definitions to Unicode version 7.0

Add Alt
, an Alternative
wrapper, to Data.Monoid
. (#9759)

Add isSubsequenceOf
to Data.List
(#9767)

The arguments to ==
and eq
in Data.List.nub
and Data.List.nubBy
are swapped, such that Data.List.nubBy (<) [1,2]
now returns [1]
instead of [1,2]
(#2528, #3280, #7913)

New module Data.Functor.Identity
(previously provided by transformers
package). (#9664)

Add scanl'
, a strictly accumulating version of scanl
, to Data.List
and Data.OldList
. (#9368)

Add fillBytes
to Foreign.Marshal.Utils
.

Add new displayException
method to Exception
typeclass. (#9822)

Add Data.Bits.toIntegralSized
, a sizechecked version of
fromIntegral
. (#9816)

New module Numeric.Natural
providing new Natural
type
representing nonnegative arbitraryprecision integers. The GHC.Natural
module exposes additional GHCspecific primitives. (#9818)

Add (Storable a, Integeral a) => Storable (Ratio a)
instance (#9826)

Add Storable a => Storable (Complex a)
instance (#9826)

New module GHC.RTS.Flags
that provides accessors to runtime flags.

Expose functions for perthread allocation counters and limits in GHC.Conc
disableAllocationLimit :: IO ()
enableAllocationLimit :: IO ()
getAllocationCounter :: IO Int64
setAllocationCounter :: Int64 > IO ()
together with a new exception AllocationLimitExceeded
.

Make read . show = id
for Data.Fixed
(#9240)

Add calloc
and callocBytes
to Foreign.Marshal.Alloc
. (#9859)

Add callocArray
and callocArray0
to Foreign.Marshal.Array
. (#9859)

Restore invariant in Data (Ratio a)
instance (#10011)

Add/expose rnfTypeRep
, rnfTyCon
, typeRepFingerprint
, and
tyConFingerprint
helpers to Data.Typeable
.

Define proper MINIMAL
pragma for class Ix
. (#10142)

Bundled with GHC 7.8.1

Add /Since: 4.[4567].0.0/
Haddock annotations to entities
denoting the package version, when the given entity was introduced
(or its type signature changed in a noncompatible way)

The Control.Category
module now has the PolyKinds
extension
enabled, meaning that instances of Category
no longer need be of
kind * > * > *
.

There are now Foldable
and Traversable
instances for Either a
,
Const r
, and (,) a
.

There are now Show
, Read
, Eq
, Ord
, Monoid
, Generic
, and
Generic1
instances for Const
.

There is now a Data
instance for Data.Version
.

A new Data.Bits.FiniteBits
class has been added to represent
types with fixed bitcount. The existing Bits
class is extended
with a bitSizeMaybe
method to replace the now obsolete
bitsize
method.

Data.Bits.Bits
gained a new zeroBits
method which completes the
Bits
API with a direct way to introduce a value with all bits cleared.

There are now Bits
and FiniteBits
instances for Bool
.

There are now Eq
, Ord
, Show
, Read
, Generic
. and Generic1
instances for ZipList
.

There are now Eq
, Ord
, Show
and Read
instances for Down
.

There are now Eq
, Ord
, Show
, Read
and Generic
instances
for types in GHC.Generics (U1
, Par1
, Rec1
, K1
, M1
,
(:+:)
, (:*:)
, (:.:)
).

Data.Monoid
: There are now Generic
instances for Dual
, Endo
,
All
, Any
, Sum
, Product
, First
, and Last
; as well as
Generic1
instances for Dual
, Sum
, Product
, First
, and Last
.

The Data.Monoid.{Product,Sum}
newtype wrappers now have Num
instances.

There are now Functor
instances for System.Console.GetOpt
’s
ArgOrder
, OptDescr
, and ArgDescr
.

A zerowidth unboxed polykinded Proxy#
was added to
GHC.Prim
. It can be used to make it so that there is no the
operational overhead for passing around proxy arguments to model
type application.

New Data.Proxy
module providing a concrete, polykinded proxy type.

New Data.Coerce
module which exports the new Coercible
class
together with the coerce
primitive which provide safe coercion
(wrt role checking) between types with same representation.

Control.Concurrent.MVar
has a new implementation of readMVar
,
which fixes a longstanding bug where readMVar
is only atomic if
there are no other threads running putMVar
. readMVar
now is
atomic, and is guaranteed to return the value from the first
putMVar
. There is also a new tryReadMVar
which is a
nonblocking version.

New Control.Concurrent.MVar.withMVarMasked
which executes
IO
action with asynchronous exceptions masked in the same style
as the existing modifyMVarMasked
and modifyMVarMasked_
.

New threadWait{Read,Write}STM :: Fd > IO (STM (), IO ())
functions added to Control.Concurrent
for waiting on FD
readiness with STM actions.

Expose Data.Fixed.Fixed
’s constructor.

There are now byte endianswapping primitives
byteSwap{16,32,64}
available in Data.Word
, which use
optimized machine instructions when available.

Data.Bool
now exports bool :: a > a > Bool > a
, analogously
to maybe
and either
in their respective modules.

Data.Either
now exports isLeft, isRight :: Either a b > Bool
.

Debug.Trace
now exports traceId
, traceShowId
, traceM
,
and traceShowM
.

Data.Functor
now exports ($>)
and void
.

Rewrote portions of Text.Printf
, and made changes to Numeric
(added Numeric.showFFloatAlt
and Numeric.showGFloatAlt
) and
GHC.Float
(added formatRealFloatAlt
) to support it. The
rewritten version is extensible to user types, adds a “generic”
format specifier “%v
”, extends the printf
spec to support much
of C’s printf(3)
functionality, and fixes the spurious warnings
about using Text.Printf.printf
at (IO a)
while ignoring the
return value. These changes were contributed by Bart Massey.

The minimal complete definitions for all typeclasses with cyclic
default implementations have been explicitly annotated with the
new {# MINIMAL #}
pragma.

Control.Applicative.WrappedMonad
, which can be used to convert a
Monad
to an Applicative
, has now a
Monad m => Monad (WrappedMonad m)
instance.

There is now a Generic
and a Generic1
instance for WrappedMonad
and WrappedArrow
.

Handle ExitFailure (sig)
on Unix by killing process with signal sig
.

New module Data.Type.Bool
providing operations on typelevel booleans.

Expose System.Mem.performMinorGC
for triggering minor GCs.

New System.Environment.{set,unset}Env
for manipulating
environment variables.

Add Typeable
instance for (>)
and RealWorld
.

Declare CPP header <Typeable.h>
officially obsolete as GHC 7.8+
does not support handwritten Typeable
instances anymore.

Remove (unmaintained) Hugs98 and NHC98 specific code.

Optimize System.Timeout.timeout
for the threaded RTS.

Remove deprecated functions unsafeInterleaveST
, unsafeIOToST
,
and unsafeSTToIO
from Control.Monad.ST
.

Add a new superclass SomeAsyncException
for all asynchronous exceptions
and makes the existing AsyncException
and Timeout
exception children
of SomeAsyncException
in the hierarchy.

Remove deprecated functions blocked
, unblock
, and block
from
Control.Exception
.

Remove deprecated function forkIOUnmasked
from Control.Concurrent
.

Remove deprecated function unsafePerformIO
export from Foreign
(still available via System.IO.Unsafe.unsafePerformIO
).

Various fixes and other improvements (see Git history for full details).