rust/tests/ui/borrow_deref_ref.rs

75 lines
1.3 KiB
Rust

//@run-rustfix
//@aux-build: proc_macros.rs
#![allow(dead_code, unused_variables)]
extern crate proc_macros;
use proc_macros::with_span;
fn main() {}
mod should_lint {
fn one_help() {
let a = &12;
let b = &*a;
let b = &mut &*bar(&12);
}
fn bar(x: &u32) -> &u32 {
x
}
}
// this mod explains why we should not lint `&mut &* (&T)`
mod should_not_lint1 {
fn foo(x: &mut &u32) {
*x = &1;
}
fn main() {
let mut x = &0;
foo(&mut &*x); // should not lint
assert_eq!(*x, 0);
foo(&mut x);
assert_eq!(*x, 1);
}
}
// similar to should_not_lint1
mod should_not_lint2 {
struct S<'a> {
a: &'a u32,
b: u32,
}
fn main() {
let s = S { a: &1, b: 1 };
let x = &mut &*s.a;
*x = &2;
}
}
with_span!(
span
fn just_returning(x: &u32) -> &u32 {
x
}
fn dont_lint_proc_macro() {
let a = &mut &*just_returning(&12);
}
);
// this mod explains why we should not lint `& &* (&T)`
mod false_negative {
fn foo() {
let x = &12;
let addr_x = &x as *const _ as usize;
let addr_y = &&*x as *const _ as usize; // assert ok
// let addr_y = &x as *const _ as usize; // assert fail
assert_ne!(addr_x, addr_y);
}
}