Finite list becomes infinite after maping fractional function for high numbers
Tested with version 8.2.2 and 8.0.2 (stack lts-11.5, lts-9.21, nightly-2018-04-14) with GHC and GHCi on archlinux amd64.
- *Code that produces wrong results**
map (/2) [9007199254740990..9007199254740991]- *Expected behaviour**
same as with low values:
map (/2) [5..6]resulting in:
[2.5,3.0]- *Actual behaviour**
resulting in an infinite list:
[4.503599627370495e15,4.5035996273704955e15,4.503599627370496e15..]- *Similar code that produces expected results**
multiplication works:
map (*2) [9007199254740990..9007199254740991]slightly smaller number work:
map (/2) [9007199254740989..9007199254740990]using a comma to produce the same list works:
map (/2) [9007199254740990,9007199254740991]- *Similar code that also produces unexpected results**
more elements in the list:
map (/2) [9007199254740990..9007199254740999]
map (/2) [9007199254740990..9007199354740999]substituting the number and doing calculations:
map (/2) [9007199254740990..9007199254740990+1]
let a = 9007199254740990
map (/2) [a..a+1]using scan and fold:
foldl1 (/) [9007199254740990..9007199254740991]
scanl1 (/) [9007199254740990..9007199254740991]- *Notes**
This somehow only happens with high numbers when using fractional operations and using .. to construct the list.
Trac metadata
| Trac field | Value |
|---|---|
| Version | 8.2.2 |
| Type | Bug |
| TypeOfFailure | OtherFailure |
| Priority | normal |
| Resolution | Unresolved |
| Component | Compiler |
| Test case | |
| Differential revisions | |
| BlockedBy | |
| Related | |
| Blocking | |
| CC | |
| Operating system | |
| Architecture |