mirror of
https://github.com/rust-lang/rust-clippy
synced 2024-11-27 15:11:30 +00:00
118 lines
4 KiB
Rust
118 lines
4 KiB
Rust
#![warn(clippy::borrow_interior_mutable_const)]
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#![allow(clippy::declare_interior_mutable_const, clippy::ref_in_deref)]
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use std::borrow::Cow;
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use std::cell::{Cell, UnsafeCell};
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use std::fmt::Display;
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use std::sync::atomic::{AtomicUsize, Ordering};
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use std::sync::Once;
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const ATOMIC: AtomicUsize = AtomicUsize::new(5);
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const CELL: Cell<usize> = Cell::new(6);
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const ATOMIC_TUPLE: ([AtomicUsize; 1], Vec<AtomicUsize>, u8) = ([ATOMIC], Vec::new(), 7);
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const INTEGER: u8 = 8;
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const STRING: String = String::new();
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const STR: &str = "012345";
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const COW: Cow<str> = Cow::Borrowed("abcdef");
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const NO_ANN: &dyn Display = &70;
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static STATIC_TUPLE: (AtomicUsize, String) = (ATOMIC, STRING);
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const ONCE_INIT: Once = Once::new();
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trait Trait<T>: Copy {
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type NonCopyType;
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const ATOMIC: AtomicUsize;
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}
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impl Trait<u32> for u64 {
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type NonCopyType = u16;
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const ATOMIC: AtomicUsize = AtomicUsize::new(9);
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}
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// This is just a pointer that can be safely dereferended,
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// it's semantically the same as `&'static T`;
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// but it isn't allowed to make a static reference from an arbitrary integer value at the moment.
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// For more information, please see the issue #5918.
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pub struct StaticRef<T> {
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ptr: *const T,
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}
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impl<T> StaticRef<T> {
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/// Create a new `StaticRef` from a raw pointer
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///
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/// ## Safety
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///
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/// Callers must pass in a reference to statically allocated memory which
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/// does not overlap with other values.
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pub const unsafe fn new(ptr: *const T) -> StaticRef<T> {
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StaticRef { ptr }
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}
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}
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impl<T> std::ops::Deref for StaticRef<T> {
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type Target = T;
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fn deref(&self) -> &'static T {
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unsafe { &*self.ptr }
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}
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}
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// use a tuple to make sure referencing a field behind a pointer isn't linted.
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const CELL_REF: StaticRef<(UnsafeCell<u32>,)> = unsafe { StaticRef::new(std::ptr::null()) };
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fn main() {
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ATOMIC.store(1, Ordering::SeqCst); //~ ERROR interior mutability
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assert_eq!(ATOMIC.load(Ordering::SeqCst), 5); //~ ERROR interior mutability
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let _once = ONCE_INIT;
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let _once_ref = &ONCE_INIT; //~ ERROR interior mutability
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let _once_ref_2 = &&ONCE_INIT; //~ ERROR interior mutability
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let _once_ref_4 = &&&&ONCE_INIT; //~ ERROR interior mutability
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let _once_mut = &mut ONCE_INIT; //~ ERROR interior mutability
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let _atomic_into_inner = ATOMIC.into_inner();
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// these should be all fine.
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let _twice = (ONCE_INIT, ONCE_INIT);
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let _ref_twice = &(ONCE_INIT, ONCE_INIT);
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let _ref_once = &(ONCE_INIT, ONCE_INIT).0;
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let _array_twice = [ONCE_INIT, ONCE_INIT];
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let _ref_array_twice = &[ONCE_INIT, ONCE_INIT];
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let _ref_array_once = &[ONCE_INIT, ONCE_INIT][0];
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// referencing projection is still bad.
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let _ = &ATOMIC_TUPLE; //~ ERROR interior mutability
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let _ = &ATOMIC_TUPLE.0; //~ ERROR interior mutability
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let _ = &(&&&&ATOMIC_TUPLE).0; //~ ERROR interior mutability
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let _ = &ATOMIC_TUPLE.0[0]; //~ ERROR interior mutability
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let _ = ATOMIC_TUPLE.0[0].load(Ordering::SeqCst); //~ ERROR interior mutability
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let _ = &*ATOMIC_TUPLE.1; //~ ERROR interior mutability
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let _ = &ATOMIC_TUPLE.2;
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let _ = (&&&&ATOMIC_TUPLE).0;
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let _ = (&&&&ATOMIC_TUPLE).2;
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let _ = ATOMIC_TUPLE.0;
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let _ = ATOMIC_TUPLE.0[0]; //~ ERROR interior mutability
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let _ = ATOMIC_TUPLE.1.into_iter();
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let _ = ATOMIC_TUPLE.2;
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let _ = &{ ATOMIC_TUPLE };
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CELL.set(2); //~ ERROR interior mutability
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assert_eq!(CELL.get(), 6); //~ ERROR interior mutability
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assert_eq!(INTEGER, 8);
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assert!(STRING.is_empty());
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let a = ATOMIC;
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a.store(4, Ordering::SeqCst);
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assert_eq!(a.load(Ordering::SeqCst), 4);
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STATIC_TUPLE.0.store(3, Ordering::SeqCst);
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assert_eq!(STATIC_TUPLE.0.load(Ordering::SeqCst), 3);
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assert!(STATIC_TUPLE.1.is_empty());
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u64::ATOMIC.store(5, Ordering::SeqCst); //~ ERROR interior mutability
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assert_eq!(u64::ATOMIC.load(Ordering::SeqCst), 9); //~ ERROR interior mutability
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assert_eq!(NO_ANN.to_string(), "70"); // should never lint this.
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let _ = &CELL_REF.0;
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}
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