Bad hpc hash function
In the hpc module Trace.Hpc.Util there is the following code:
instance (HpcHash a,HpcHash b) => HpcHash (a,b) where
toHash (a,b) = toHash a * 33 `hxor` toHash b
This is bad and I can only presume that what was actually intended was
instance (HpcHash a,HpcHash b) => HpcHash (a,b) where
toHash (a,b) = (toHash a * 33) `hxor` toHash b
Otherwise a hash of 0 for a will result in a total hash of 0.
Trac metadata
Trac field | Value |
---|---|
Version | 7.2.2 |
Type | Bug |
TypeOfFailure | OtherFailure |
Priority | normal |
Resolution | Unresolved |
Component | Code Coverage |
Test case | |
Differential revisions | |
BlockedBy | |
Related | |
Blocking | |
CC | |
Operating system | |
Architecture |