mirror of https://github.com/rust-lang/rust
93 lines
2.5 KiB
Rust
93 lines
2.5 KiB
Rust
//@ edition:2021
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//@ check-pass
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#![allow(unreachable_code)]
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#![warn(unused)]
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#![allow(dead_code)]
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#[derive(Debug)]
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struct Point {
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x: i32,
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y: i32,
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}
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pub fn f() {
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let mut a = 1;
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let mut c = Point{ x:1, y:0 };
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// Captured by value, but variable is dead on entry.
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(move || {
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// This will not trigger a warning for unused variable as
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// c.x will be treated as a Non-tracked place
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c.x = 1;
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println!("{}", c.x);
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a = 1; //~ WARN value captured by `a` is never read
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println!("{}", a);
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})();
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// Read and written to, but never actually used.
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(move || {
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// This will not trigger a warning for unused variable as
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// c.x will be treated as a Non-tracked place
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c.x += 1;
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a += 1; //~ WARN unused variable: `a`
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})();
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(move || {
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println!("{}", c.x);
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// Value is read by closure itself on later invocations.
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// This will not trigger a warning for unused variable as
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// c.x will be treated as a Non-tracked place
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c.x += 1;
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println!("{}", a);
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a += 1;
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})();
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let b = Box::new(42);
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(move || {
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println!("{}", c.x);
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// Never read because this is FnOnce closure.
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// This will not trigger a warning for unused variable as
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// c.x will be treated as a Non-tracked place
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c.x += 1;
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println!("{}", a);
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a += 1; //~ WARN value assigned to `a` is never read
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drop(b);
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})();
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}
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#[derive(Debug)]
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struct MyStruct<'a> {
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x: Option<& 'a str>,
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y: i32,
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}
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pub fn nested() {
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let mut a : Option<& str>;
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a = None;
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let mut b : Option<& str>;
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b = None;
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let mut d = MyStruct{ x: None, y: 1};
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let mut e = MyStruct{ x: None, y: 1};
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(|| {
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(|| {
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// This will not trigger a warning for unused variable as
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// d.x will be treated as a Non-tracked place
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d.x = Some("d1");
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d.x = Some("d2");
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a = Some("d1"); //~ WARN value assigned to `a` is never read
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a = Some("d2");
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})();
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(move || {
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// This will not trigger a warning for unused variable as
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//e.x will be treated as a Non-tracked place
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e.x = Some("e1");
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e.x = Some("e2");
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b = Some("e1"); //~ WARN value assigned to `b` is never read
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//~| WARN unused variable: `b`
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b = Some("e2"); //~ WARN value assigned to `b` is never read
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})();
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})();
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}
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fn main() {}
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