mirror of https://github.com/rust-lang/rust
105 lines
3.1 KiB
Rust
105 lines
3.1 KiB
Rust
//@ run-pass
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//@ edition:2021
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// This is a test of several uses of rustc_ast::util::classify::expr_requires_semi_to_be_stmt
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// by the Rust parser, which relates to the insertion of statement boundaries
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// after certain kinds of expressions if they appear at the head of a statement.
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#![allow(unused_braces, unused_unsafe)]
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macro_rules! unit {
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() => {
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{ () }
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};
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}
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#[derive(Copy, Clone)]
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struct X;
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fn main() {
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let x = X;
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// There is a statement boundary before `|x| x`, so it's a closure.
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let _: fn(X) -> X = { if true {} |x| x };
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let _: fn(X) -> X = { if true {} else {} |x| x };
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let _: fn(X) -> X = { match () { () => {} } |x| x };
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let _: fn(X) -> X = { { () } |x| x };
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let _: fn(X) -> X = { unsafe {} |x| x };
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let _: fn(X) -> X = { while false {} |x| x };
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let _: fn(X) -> X = { loop { break; } |x| x };
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let _: fn(X) -> X = { for _ in 0..0 {} |x| x };
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let _: fn(X) -> X = { const {} |x| x };
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let _: fn(X) -> X = { unit! {} |x| x };
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// No statement boundary, so `|x| x` is 2× BitOr operation.
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() = { "" |x| x };
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() = { ("") |x| x };
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() = { [""] |x| x };
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() = { unit!() |x| x };
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() = { unit![] |x| x };
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// All the same cases, but as a match arm.
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() = match x {
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// Statement boundary before `| X`, which becomes a new arm with leading vert.
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X if false => if true {} | X if false => {}
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X if false => if true {} else {} | X if false => {}
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X if false => match () { () => {} } | X if false => {}
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X if false => { () } | X if false => {}
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X if false => unsafe {} | X if false => {}
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X if false => while false {} | X if false => {}
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X if false => loop { break; } | X if false => {}
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X if false => for _ in 0..0 {} | X if false => {}
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X if false => const {} | X if false => {}
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// No statement boundary, so `| X` is BitOr.
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X if false => "" | X,
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X if false => ("") | X,
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X if false => [""] | X,
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X if false => unit! {} | X, // !! inconsistent with braced mac call in statement position
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X if false => unit!() | X,
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X if false => unit![] | X,
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X => {}
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};
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// Test how the statement boundary logic interacts with macro metavariables /
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// "invisible delimiters".
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macro_rules! assert_statement_boundary {
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($expr:expr) => {
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let _: fn(X) -> X = { $expr |x| x };
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() = match X {
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X if false => $expr | X if false => {}
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X => {}
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};
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};
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}
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macro_rules! assert_no_statement_boundary {
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($expr:expr) => {
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() = { $expr |x| x };
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() = match x {
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X if false => $expr | X,
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X => {}
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};
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};
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}
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assert_statement_boundary!(if true {});
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assert_no_statement_boundary!("");
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}
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impl std::ops::BitOr<X> for () {
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type Output = ();
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fn bitor(self, _: X) {}
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}
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impl std::ops::BitOr<X> for &str {
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type Output = ();
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fn bitor(self, _: X) {}
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}
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impl<T, const N: usize> std::ops::BitOr<X> for [T; N] {
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type Output = ();
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fn bitor(self, _: X) {}
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}
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