as-pointer-underscore suggests *const fn() -> u32 {foo} #15281
Description
Using the following flags
--force-warn clippy::as-pointer-underscore
this code:
fn foo() -> u32 {
42
}
fn main() {
let _ = &foo as *const _;
}caused the following diagnostics:
Checking _a v0.1.0 (/tmp/icemaker_global_tempdir.rRt3FW0YoNlv/icemaker_clippyfix_tempdir.1JeGlSZeKs9N/_a)
warning: using inferred pointer cast
--> src/main.rs:6:21
|
6 | let _ = &foo as *const _;
| ^^^^^^^^ help: use explicit type: `*const fn() -> u32 {foo}`
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#as_pointer_underscore
= note: requested on the command line with `--force-warn clippy::as-pointer-underscore`
warning: `_a` (bin "_a") generated 1 warning (run `cargo clippy --fix --bin "_a"` to apply 1 suggestion)
Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.36s
However after applying these diagnostics, the resulting code:
fn foo() -> u32 {
42
}
fn main() {
let _ = &foo as *const fn() -> u32 {foo};
}no longer compiled:
Checking _a v0.1.0 (/tmp/icemaker_global_tempdir.rRt3FW0YoNlv/icemaker_clippyfix_tempdir.1JeGlSZeKs9N/_a)
error: expected one of `!`, `(`, `.`, `::`, `;`, `<`, `?`, or `else`, found `{`
--> src/main.rs:6:40
|
6 | let _ = &foo as *const fn() -> u32 {foo};
| ^ expected one of 8 possible tokens
error: could not compile `_a` (bin "_a" test) due to 1 previous error
warning: build failed, waiting for other jobs to finish...
error: could not compile `_a` (bin "_a") due to 1 previous error
Version:
rustc 1.90.0-nightly (3014e79f9 2025-07-15)
binary: rustc
commit-hash: 3014e79f9c8d5510ea7b3a3b70d171d0948b1e96
commit-date: 2025-07-15
host: x86_64-unknown-linux-gnu
release: 1.90.0-nightly
LLVM version: 20.1.8