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98659a339d
This removes special-casing of boxes from `rustc_pattern_analysis`, as a first step in replacing `box_patterns` with `deref_patterns`. Incidentally, it fixes a bug caused by box patterns being represented as structs rather than pointers, where `exhaustive_patterns` could generate spurious `unreachable_patterns` lints on arms required for exhaustiveness; following the lint's advice would result in an error.
50 lines
1023 B
Rust
50 lines
1023 B
Rust
#![feature(exhaustive_patterns)]
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#![feature(box_patterns)]
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#![feature(never_type)]
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#![deny(unreachable_patterns)]
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mod foo {
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pub struct SecretlyEmpty {
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_priv: !,
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}
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}
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struct NotSoSecretlyEmpty {
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_priv: !,
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}
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fn foo() -> Option<NotSoSecretlyEmpty> {
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None
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}
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fn main() {
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let x: &[!] = &[];
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match x {
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&[] => (),
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&[..] => (),
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};
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let x: Result<Box<NotSoSecretlyEmpty>, &[Result<!, !>]> = Err(&[]);
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match x {
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Ok(box _) => (), // We'd get a non-exhaustiveness error if this arm was removed; don't lint.
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Err(&[]) => (),
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Err(&[..]) => (),
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}
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match x { //~ ERROR non-exhaustive patterns
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Err(&[]) => (),
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Err(&[..]) => (),
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}
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let x: Result<foo::SecretlyEmpty, Result<NotSoSecretlyEmpty, u32>> = Err(Err(123));
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match x {
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Ok(_y) => (),
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Err(Err(_y)) => (),
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Err(Ok(_y)) => (), //~ ERROR unreachable pattern
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}
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while let Some(_y) = foo() {
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//~^ ERROR unreachable pattern
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}
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}
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