rust/tests/ui/cast_slice_different_sizes.rs

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#![allow(clippy::let_unit_value)]
fn main() {
let x: [i32; 3] = [1_i32, 2, 3];
let r_x = &x;
// Check casting through multiple bindings
// Because it's separate, it does not check the cast back to something of the same size
let a = r_x as *const [i32];
let b = a as *const [u8];
let c = b as *const [u32];
// loses data
let loss = r_x as *const [i32] as *const [u8];
// Cast back to same size but different type loses no data, just type conversion
// This is weird code but there's no reason for this lint specifically to fire *twice* on it
let restore = r_x as *const [i32] as *const [u8] as *const [u32];
// Check casting through blocks is detected
let loss_block_1 = { r_x as *const [i32] } as *const [u8];
let loss_block_2 = {
let _ = ();
r_x as *const [i32]
} as *const [u8];
// Check that resores of the same size are detected through blocks
let restore_block_1 = { r_x as *const [i32] } as *const [u8] as *const [u32];
let restore_block_2 = { ({ r_x as *const [i32] }) as *const [u8] } as *const [u32];
let restore_block_3 = {
let _ = ();
({
let _ = ();
r_x as *const [i32]
}) as *const [u8]
} as *const [u32];
// Check that the result of a long chain of casts is detected
let long_chain_loss = r_x as *const [i32] as *const [u32] as *const [u16] as *const [i8] as *const [u8];
let long_chain_restore =
r_x as *const [i32] as *const [u32] as *const [u16] as *const [i8] as *const [u8] as *const [u32];
}
// foo and foo2 should not fire, they're the same size
fn foo(x: *mut [u8]) -> *mut [u8] {
x as *mut [u8]
}
fn foo2(x: *mut [u8]) -> *mut [u8] {
x as *mut _
}
// Test that casts as part of function returns work
fn bar(x: *mut [u16]) -> *mut [u8] {
x as *mut [u8]
}
fn uwu(x: *mut [u16]) -> *mut [u8] {
x as *mut _
}
fn bar2(x: *mut [u16]) -> *mut [u8] {
x as _
}
// constify
fn bar3(x: *mut [u16]) -> *const [u8] {
x as _
}
// unconstify
fn bar4(x: *const [u16]) -> *mut [u8] {
x as _
}
// function returns plus blocks
fn blocks(x: *mut [u16]) -> *mut [u8] {
({ x }) as _
}
fn more_blocks(x: *mut [u16]) -> *mut [u8] {
{ ({ x }) as _ }
}