See also https://pvp.haskell.org/faq

Version 1.5.0.0

• Add QuantifiedConstraints superclasses to Hashable1/2:

class (Eq1 t, forall a. Hashable a => Hashable (t a)) => Hashable1 t where
class (Eq2 t, forall a. Hashable a => Hashable1 (t a)) => Hashable2 t where

• Change contexts of Compose, Product and Sum instances. This and above is the similar change as CLC proposal #10

• The above changes require base-4.18.0.0, so we drop support for GHC prior GHC-9.6.5 (The hashable-1.4 branch will be maintained for time being for older GHC users).

• Make Arg a b instance behave as Hashable a instance.

Version 1.4.7.0

• Make arch-native disabled by default.

Version 1.4.6.0

• Use GND&DerivingVia to derive newtype intances (Data.Semigroup, Data.Monoid, Identity etc).

Version 1.4.5.0

• Drop support for GHCs prior 8.6.5
• Use xxhash for hashing bytestrings and bytearrays. Note: when compiling binaries for distribution, you may need to disable arch-native flag.

Version 1.4.4.0

• Depend on os-string-2 for GHC-9.2+
• Support filepath-1.5

Version 1.4.3.0

• Export defaultHashWithSalt and defaultHash.
• Fix issue of tuples with 0 first component causing all-zero state.
• Change hashInt to mix bits more.

Version 1.4.2.0

• Fix the foreign signature of getThreadId https://github.com/haskell-unordered-containers/hashable/pull/263
• Drop support for GHCs prior GHC-8.2 The recent unordered-containers releases support only GHC-8.2+
• Add instance for OsString, PosixString, WindowsString from filepath-1.4.100.1
• Add Hashable ByteArray instance using data-array-byte compat package

Version 1.4.1.0

• Add instance for Data.Array.Byte.ByteArray.

Version 1.4.0.2

• Restore older GHC support
• Support GHC-9.0.2

Version 1.4.0.1

• text-2.0 compatibility

Version 1.4.0.0

• Eq is now a superclass of Hashable. Also Eq1 is a superclass of Hashable1 and Eq2 is a superclass of Hashable2 when exists.

• Remove Hashable1 Fixed instance

• Remove Hashable1 Semi.Min/Max/... instances as they don’t have Eq1 instance.

Version 1.3.5.0

• Add Solo instance (base-4.15+, GHC-9+)

Version 1.3.4.1

• Fix compilation on 32 bit platforms
• Fix Tree instance

Version 1.3.4.0

• Text and ByteString hashes include length. This fixes a variant of https://github.com/haskell-unordered-containers/hashable/issues/74 for texts and bytestrings. https://github.com/haskell-unordered-containers/hashable/pull/223
• Use correct prime in combine. This should improve the hash quality of compound structures on 64bit systems. https://github.com/haskell-unordered-containers/hashable/pull/224
• Add instance for types in containers package https://github.com/haskell-unordered-containers/hashable/pull/226
• Change Int, Int64 and Word64 hashWithSalt slightly. https://github.com/haskell-unordered-containers/hashable/pull/227

Version 1.3.3.0

• Text hashing uses 64-bit FNV prime
• Don’t truncate Text hashvalues on 64bit Windows: https://github.com/haskell-unordered-containers/hashable/pull/211

Version 1.3.2.0

• Add Hashable (Fixed a) for base <4.7 versions.
• Add documentation:
  • hashable is not a stable hash
  • hashWithSalt may return negative values
  • there is time-compat with Hashable instances for time types.
• Add random-initial-seed flag causing the initial seed to be randomized on each start of an executable using hashable.

Version 1.3.1.0

• Add Hashable1 instances to semigroups types.

• Use ghc-bignum with GHC-9.0

• Use FNV-1 constants.

• Make hashable-examples a test-suite

Version 1.3.0.0

• Semantic change of Hashable Arg instance to not hash the second argument of Arg in order to be consistent with Eq Arg (#171)

• Semantic change of Hashable Float and Hashable Double instances to hash -0.0 and 0.0 to the same value (#173)

• Add Hashable instance for Fingerprint (#156)

• Add new Data.Hashable.Generic module providing the default implementations genericHashWithSalt and genericLiftHashWithSalt together with other Generics support helpers (#148, #178)

• Bump minimum version requirement of base to base-4.5 (i.e. GHC >= 7.4)

---

Version 1.2.7.0

• Add Hashable and Hashable1 instances for Complex

• Fix undefined behavior in hashable_fn_hash() implementation due to signed integer overflow (#152)

• Mark Data.Hashable.Lifted as Trustworthy (re SafeHaskell)

• Support GHC 8.4

Version 1.2.6.1

• Use typeRepFingerprint from Type.Reflection.Unsafe

• Bump minimum version of base to 4.4.

Version 1.2.6.0

• Add support for type-indexed Typeable.

• Rework the Generic hashable for sums.

Version 1.2.5.0

• Add Hashable1 and Hashable2

• Add instances for: Eq1, Ord1, Show1, Ptr, FunPtr, IntPtr, WordPtr

• Add Hashed type for caching the hash function result.

Version 1.2.4.0

• Add instances for: Unique, Version, Fixed, NonEmpty, Min, Max, Arg, First, Last, WrappedMonoid, Option

• Support GHC 8.0

Version 1.2.3.3

• Support integer-simple.

Version 1.2.3.2

• Add support for GHC 7.10 typeRepFingerprint

Version 1.2.3.1

• Added support for random 1.1.*.

Version 1.2.3.0

• Silence integer literal overflow warning

• Add support for GHC 7.10 integer-gmp2 & Natural

• Add instance for Data.Void

• Make the SSE .cabal flags manual

• Add an upper bound on bytestring

Version 1.2.2.0

• Add instances for Data.ByteString.Short

• Use a 32-bit default salt on 32-bit archs.

Version 1.2.1.0

• Revert instances to their 1.1 implementations to regain the performance we had then.

• Remove use of random salt altogether. Without using SipHash the benefit is unclear (i.e. collision attacks still work) and the complexity is no longer worth it.

• Documentation improvements.

Version 1.2.0.10

• Fix for GHC 7.0.

Version 1.2.0.9

• Stop using SipHash. The current implementation still has segfault causing bugs that we won’t be able to fix soon.

• Stop using Wang hash. It degrades performance of fixed-size integer hashing too much.

Version 1.2.0.8

• Fix linking issue when SSE was disabled.

• Hash small signed Integers correctly.

Version 1.2.0.7

• Add flags to control usage of SSE.

Version 1.2.0.6

• Fix another segfault caused by SSE2 code.

Version 1.2.0.5

• More portability fixes.

• Force stack alignment to 16 bytes everywhere. Fixes a segfault.

• Fix bug where code relied on rewrite rules firing for correctness.

Version 1.2.0.4

• Update docs to match code.

• Work around bug in GHCi runtime linker, which never call static initializers.

Version 1.2.0.3

• Make building of SSE 4.1 code conditional, as it doesn’t work on all platforms.

• Use a fixed salt, but allow random salting. Random salting by default broke people’s code.

Version 1.2.0.2

• Work around ghci linker bug on Windows.

Version 1.2.0.1

• Fix performance bug in SSE implementation of SipHash.

• Fix segfault due to incorrect stack alignment on Windows.

Version 1.2.0.0

• Switch string hashing from FNV-1 to SipHash, in an effort to prevent collision attacks.

• Switch fixed-size integer hashing to Wang hash.

• The default salt now switched on every program run, in an effort to prevent collision attacks.

• Move hash method out of Hashable type class.

• Add support for generic instance deriving.

• Add instance for Ordering.

---

Version 1.1.2.5

• Bug fix for bytestring < 0.10.0.

Version 1.1.2.4

• Switch string hashing from Bernstein to FNV-1

• Faster instance for Integer.

• Update dependency on base, ghc-prim

• Now works with GHC 7.6.

Version 1.1.2.3

• Add instance for TypeRep.

• Update dependency on test-framework.

Version 1.1.2.2

• Bug fix for GHC 7.4

Version 1.1.2.1

• Update dependency on test-framework.

• Improve documentation of combine.

Version 1.1.2.0

• Fix hash collision issues for lists and tuples when using a user-specified salt.

• Add instances for Integer, Ratio, Float, Double, and StableName.

• Improved instances for tuples and lists.

Version 1.1.1.0

• Add hashWithSalt, which allows the user to create different hash values for the same input by providing different seeds. This is useful for application like Cuckoo hashing which need a family of hash functions.

• Fix a bug in the Hashable instance for Int64/Word64 on 32-bit platforms.

• Improved resilience to leading zero in the input being hashed.

Version 1.1.0.0

• Add instance for: strict and lazy Texts, ThreadId

• Add hashPtrWithSalt and hashByteArrayWithSalt.

• Faster ByteArray# hashing.

• Fix a signedness bug that affected ByteString.

• Fix ByteString hashing to work correctly on both 32 and 64-bit platforms.

Version 1.0.1.1

• Fix bug in Hashable instance for lazy ByteStrings where differences in the internal structure of the ByteString could cause different hash values for ByteStrings that are equal according to ==.

Version 1.0.1.0

• Add two helpers for creating Hashable instances: hashPtr and hashByteArray.

---

Version 1.0.0

• Separate Hashable class to its own package from hashmap 1.0.0.3.