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Description
I tried this code:
fn main() {
let mut tmp: usize = 3;
let immut_addr = &tmp as *const _;
let addr = immut_addr.cast_mut();
}
I expected to see this happen: the code compiles successfully (but with unused warnings)
Instead, this happened: The compiler fails to infer the type of addr
because it doesn't recognize that the type it inferred for immut_addr is always the same as the one cast_mut produces
On stable the compiler suggests to add : *const _
to immut_addr as a type annotation, but after adding this, it errors the same way it did before.
Meta
rustc --version --verbose
:
This happens both on stable (1.78) and on the latest nightly
rustc 1.80.0-nightly (1fffb2a35 2024-04-28)
binary: rustc
commit-hash: 1fffb2a355dfee65bf6aa5a9db35f33d3ee93aec
commit-date: 2024-04-28
host: x86_64-unknown-linux-gnu
release: 1.80.0-nightly
LLVM version: 18.1.4
Output
error[E0699]: cannot call a method on a raw pointer with an unknown pointee type
--> src/main.rs:6:27
|
6 | let addr = immut_addr.cast_mut();
|