[ruby-core:101574] [Ruby master Bug#17409] Endless range of dates stuck on include? when miss

Issue #17409 has been updated by zverok (Victor Shepelev).


@duerst

> What's the reason there is no redefinition for Date?

First, I don't think there is a reason for _any_ redefinition, actually, it just muddies the semantical difference of `include?` vs `cover?`. Redefinition for numerics is a legacy from when `===` was implemented via `include?`, so it was necessary for this "intuitively right" code to work:
```ruby
case 1.5
when 1...2
```
...but since `===` switched to `cover?` (#14575), any redefinition is unnecessary (I don't know why @jeremyevans0 [did it this way](https://github.com/ruby/ruby/commit/6954ff1dcb538ee6c042872088b64464a1ef6089) for String, but probably there were good reasons).

In addition, behavior for `Date` can't be redefined to core code because `Date` is not a core class, and ruby-core developers are actively fighting any attempts to make it a general-purpose useful class (which is a separate funny topic).

OTOH, the generic `(x1..x2).include?(y)` probably **might** be fixed for cases when `y` obviously `< x1`, so there's no need for iteration... Though, I'd say that any use of `include?` for semi-open ranges should be discouraged (because the user most probably had `cover?` in mind).

----------------------------------------
Bug #17409: Endless range of dates stuck on include? when miss
https://bugs.ruby-lang.org/issues/17409#change-89359

* Author: gsmetal (Sergey G)
* Status: Rejected
* Priority: Normal
* ruby -v: ruby 2.7.1p83 (2020-03-31 revision a0c7c23c9c) [x86_64-linux]
* Backport: 2.5: UNKNOWN, 2.6: UNKNOWN, 2.7: UNKNOWN
----------------------------------------
This code stucks (on latest ruby 2.7.1):
```ruby
require 'date'

(Date.today..).include?(Date.today - 1)
```

But it works well with `cover?`:
```ruby
2.7.1 :001 > require 'date'
 => true 
2.7.1 :002 > (Date.today..).cover?(Date.today - 1)
 => false 
```



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