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

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.