3fdd8d5ef3
The implied deref to statics introduced by HIR->THIR lowering is only
used to create place expressions, it lacks unsafe semantics.
It is also confusing, as there is no visible `*ident` in the source.
For both classes of "unsafe static" (extern static and static mut)
allow this operation.
We lack a clear story around `thread_local! { static mut }`, which
is actually its own category of item that reuses the static syntax but
has its own rules. It's possible they should be similarly included, but
in the absence of a good reason one way or another, we do not bless it.
27 lines
980 B
Rust
27 lines
980 B
Rust
//@ check-pass
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#![feature(raw_ref_op)]
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use std::ptr;
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// see https://github.com/rust-lang/rust/issues/125833
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// notionally, taking the address of an extern static is a safe operation,
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// as we only point at it instead of generating a true reference to it
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// it may potentially induce linker errors, but the safety of that is not about taking addresses!
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// any safety obligation of the extern static's correctness in declaration is on the extern itself,
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// see RFC 3484 for more on that: https://rust-lang.github.io/rfcs/3484-unsafe-extern-blocks.html
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extern "C" {
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static THERE: u8;
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static mut SOMEWHERE: u8;
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}
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fn main() {
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let ptr2there = ptr::addr_of!(THERE);
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let ptr2somewhere = ptr::addr_of!(SOMEWHERE);
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let ptr2somewhere = ptr::addr_of_mut!(SOMEWHERE);
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// testing both addr_of and the expression it directly expands to
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let raw2there = &raw const THERE;
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let raw2somewhere = &raw const SOMEWHERE;
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let raw2somewhere = &raw mut SOMEWHERE;
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}
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