59 lines
1.8 KiB
Rust
59 lines
1.8 KiB
Rust
// Copyright 2014-2018 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution.
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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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#[warn(clippy::eval_order_dependence)]
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#[allow(unused_assignments, unused_variables, clippy::many_single_char_names, clippy::no_effect, dead_code, clippy::blacklisted_name)]
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fn main() {
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let mut x = 0;
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let a = { x = 1; 1 } + x;
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// Example from iss#277
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x += { x = 20; 2 };
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// Does it work in weird places?
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// ...in the base for a struct expression?
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struct Foo { a: i32, b: i32 };
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let base = Foo { a: 4, b: 5 };
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let foo = Foo { a: x, .. { x = 6; base } };
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// ...inside a closure?
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let closure = || {
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let mut x = 0;
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x += { x = 20; 2 };
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};
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// ...not across a closure?
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let mut y = 0;
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let b = (y, || { y = 1 });
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// && and || evaluate left-to-right.
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let a = { x = 1; true } && (x == 3);
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let a = { x = 1; true } || (x == 3);
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// Make sure we don't get confused by alpha conversion.
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let a = { let mut x = 1; x = 2; 1 } + x;
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// No warning if we don't read the variable...
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x = { x = 20; 2 };
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// ...if the assignment is in a closure...
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let b = { || { x = 1; }; 1 } + x;
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// ... or the access is under an address.
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let b = ({ let p = &x; 1 }, { x = 1; x });
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// Limitation: l-values other than simple variables don't trigger
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// the warning.
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let mut tup = (0, 0);
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let c = { tup.0 = 1; 1 } + tup.0;
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// Limitation: you can get away with a read under address-of.
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let mut z = 0;
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let b = (&{ z = x; x }, { x = 3; x });
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}
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