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Update range pattern refutability #489

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Merged
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Dec 28, 2018
Merged

Update range pattern refutability #489

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9 changes: 6 additions & 3 deletions src/patterns.md
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Expand Up @@ -418,9 +418,12 @@ println!("{}", match 0xfacade {
});
```

Range patterns are always refutable, even when they cover the complete set
of possible values of a type. For example, `0u8..=255u8` is refutable even though
it covers all possible values of `u8`.
Range patterns for (non-`usize` and -`isize`) integer and `char` types are irrefutable
when they span the entire set of possible values of a type. For example, `0u8..=255u8`
is irrefutable. The range of values for an integer type is the closed range from its
minimum to maximum value. The range of values for a `char` type are precisely those
ranges containing all Unicode Scalar Values: `'\u{0000}'..='\u{D7FF}'` and
`'\u{E000}'..='\u{10FFFF}'`.

## Reference patterns

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