51 lines
1.3 KiB
Rust
51 lines
1.3 KiB
Rust
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// Test that dead code warnings are issued for superfluous assignments of
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// fields or variables to themselves (issue #75356).
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// check-pass
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#![allow(unused_assignments)]
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#![warn(dead_code)]
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fn main() {
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let mut x = 0;
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x = x;
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//~^ WARNING: useless assignment of variable of type `i32` to itself
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x = (x);
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//~^ WARNING: useless assignment of variable of type `i32` to itself
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x = {x};
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// block expressions don't count as self-assignments
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struct S<'a> { f: &'a str }
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let mut s = S { f: "abc" };
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s = s;
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//~^ WARNING: useless assignment of variable of type `S` to itself
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s.f = s.f;
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//~^ WARNING: useless assignment of field of type `&str` to itself
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struct N0 { x: Box<i32> }
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struct N1 { n: N0 }
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struct N2(N1);
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struct N3 { n: N2 };
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let mut n3 = N3 { n: N2(N1 { n: N0 { x: Box::new(42) } }) };
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n3.n.0.n.x = n3.n.0.n.x;
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//~^ WARNING: useless assignment of field of type `Box<i32>` to itself
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let mut t = (1, ((2, 3, (4, 5)),));
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t.1.0.2.1 = t.1.0.2.1;
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//~^ WARNING: useless assignment of field of type `i32` to itself
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let mut y = 0;
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macro_rules! assign_to_y {
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($cur:expr) => {{
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y = $cur;
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}};
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}
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assign_to_y!(y);
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// self-assignments in macro expansions are not reported either
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}
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