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