clippy::pointers_in_nomem_asm_block: passing pointers to nomem asm block

What you see

warning: passing pointers to nomem asm block
 --> main.rs:4:48
  |
4 |     unsafe { core::arch::asm!("mov [{p}], 42", p = in(reg) p, options(nomem, nostack)); }
  |                                                ^^^^^^^^^^^^^
  |
  = note: `nomem` means that no memory write or read happens inside the asm! block
  = note: if this is intentional and no pointers are read or written to, consider allowing the lint
  = help: for further information visit https://rust-lang.github.io/rust-clippy/stable/index.html#pointers_in_nomem_asm_block
  = note: `#[warn(clippy::pointers_in_nomem_asm_block)]` on by default

Real output of Clippy 0.1.99 (Rust 1.99) on the example below. Names and line numbers in yours will differ.

Does it matter?

nomem forbids any reads or writes to memory and passing a pointer suggests that either of those will happen.

Code that is most likely wrong or useless. Warns by default.

How to fix it

Clippy does not fix this one automatically. Change the code by hand:

Flagged

fn f(p: *mut u32) {
    unsafe { core::arch::asm!("mov [{p}], 42", p = in(reg) p, options(nomem, nostack)); }
}

Write this instead

fn f(p: *mut u32) {
    unsafe { core::arch::asm!("mov [{p}], 42", p = in(reg) p, options(nostack)); }
}

Turn it off, or on

Allow it where it does not fit your code, as narrowly as you can:

#[allow(clippy::pointers_in_nomem_asm_block)]
fn my_function() { /* ... */ }

[lints.clippy]
pointers_in_nomem_asm_block = "allow"

cargo clippy -- -A clippy::pointers-in-nomem-asm-block

The [lints] table needs Rust 1.74 or newer. In a workspace, put it under [workspace.lints.clippy] and add [lints] workspace = true to each member.