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