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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.
19 lines
678 B
Rust
19 lines
678 B
Rust
#![feature(const_mut_refs)]
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use std::ptr;
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// This code should remain unsafe because of the two unsafe operations here,
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// even if in a hypothetical future we deem all &raw (const|mut) *ptr exprs safe.
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static mut BYTE: u8 = 0;
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static mut BYTE_PTR: *mut u8 = ptr::addr_of_mut!(BYTE);
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// An unsafe static's ident is a place expression in its own right, so despite the above being safe
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// (it's fine to create raw refs to places!) the following derefs the ptr before creating its ref!
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static mut DEREF_BYTE_PTR: *mut u8 = ptr::addr_of_mut!(*BYTE_PTR);
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//~^ ERROR: use of mutable static
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//~| ERROR: dereference of raw pointer
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fn main() {
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let _ = unsafe { DEREF_BYTE_PTR };
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}
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