54 lines
1.7 KiB
Rust
54 lines
1.7 KiB
Rust
// Copyright 2013 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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// Constants (static variables) can be used to match in patterns, but mutable
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// statics cannot. This ensures that there's some form of error if this is
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// attempted.
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static mut a: isize = 3;
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fn main() {
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// If they can't be matched against, then it's possible to capture the same
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// name as a variable, hence this should be an unreachable pattern situation
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// instead of spitting out a custom error about some identifier collisions
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// (we should allow shadowing)
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match 4 {
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a => {} //~ ERROR match bindings cannot shadow statics
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_ => {}
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}
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}
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struct NewBool(bool);
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enum Direction {
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North,
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East,
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South,
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West
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}
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const NEW_FALSE: NewBool = NewBool(false);
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struct Foo {
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bar: Option<Direction>,
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baz: NewBool
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}
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static mut STATIC_MUT_FOO: Foo = Foo { bar: Some(Direction::West), baz: NEW_FALSE };
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fn mutable_statics() {
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match (Foo { bar: Some(Direction::North), baz: NewBool(true) }) {
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Foo { bar: None, baz: NewBool(true) } => (),
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STATIC_MUT_FOO => (),
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//~^ ERROR match bindings cannot shadow statics
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Foo { bar: Some(Direction::South), .. } => (),
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Foo { bar: Some(EAST), .. } => (),
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Foo { bar: Some(Direction::North), baz: NewBool(true) } => (),
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Foo { bar: Some(EAST), baz: NewBool(false) } => ()
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}
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}
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