newStdGen leaks memory when result is not used
When newStdGen is invoked repeatedly without making any use of the resulting StdGen values, it leaks memory, as in the following:
-- Leaks memory
main = forever newStdGen
When a random number produced by the result is evaluated, no leak occurs:
-- Does not leak memory
main = forever $ do
r <- newStdGen
evaluate $ fst $ next r
However, evaluating the result itself is not sufficient to eliminate the leak:
-- Leaks memory
main = forever $ do
r <- newStdGen
evaluate r
After sufficient iterations of newStdGen, subsequent use will cause a stack overflow:
-- Causes stack overflow
main = do
replicateM 1000000 newStdGen
r <- newStdGen
evaluate $ fst $ next r
Trac metadata
Trac field | Value |
---|---|
Version | 7.6.3 |
Type | Bug |
TypeOfFailure | OtherFailure |
Priority | normal |
Resolution | Unresolved |
Component | libraries/random |
Test case | |
Differential revisions | |
BlockedBy | |
Related | |
Blocking | |
CC | |
Operating system | |
Architecture |