# Objective
#19421 implemented `Ord` for `EntityGeneration` along the lines of [the
impl from
slotmap](https://docs.rs/slotmap/latest/src/slotmap/util.rs.html#8):
```rs
/// Returns if a is an older version than b, taking into account wrapping of
/// versions.
pub fn is_older_version(a: u32, b: u32) -> bool {
let diff = a.wrapping_sub(b);
diff >= (1 << 31)
}
```
But that PR and the slotmap impl are different:
**slotmap impl**
- if `(1u32 << 31)` is greater than `a.wrapping_sub(b)`, then `a` is
older than `b`
- if `(1u32 << 31)` is equal to `a.wrapping_sub(b)`, then `a` is older
than `b`
- if `(1u32 << 31)` is less than `a.wrapping_sub(b)`, then `a` is equal
or newer than `b`
**previous PR impl**
- if `(1u32 << 31)` is greater than `a.wrapping_sub(b)`, then `a` is
older than `b`
- if `(1u32 << 31)` is equal to `a.wrapping_sub(b)`, then `a` is equal
to `b` ⚠️
- if `(1u32 << 31)` is less than `a.wrapping_sub(b)`, then `a` is newer
than `b` ⚠️
This ordering is also not transitive, therefore it should not implement
`PartialOrd`.
## Solution
Fix the impl in a standalone method, remove the `Partialord`/`Ord`
implementation.
## Testing
Given the first impl was wrong and got past reviews, I think a new unit
test is justified.
76b8310da5