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8a8717e971
According to https://discourse.llvm.org/t/rfc-volatile-access-to-non-dereferenceable-memory-may-be-well-defined/86303/4, LLVM allows volatile operations on null and handles it correctly. This should be allowed in Rust as well, because I/O memory may be hard-coded to address 0 in some cases, like the AVR chip ATtiny1626. A test case that ensured a failure when passing null to volatile was removed, since it's now valid. Due to the addition of `maybe_is_aligned` to `ub_checks`, `maybe_is_aligned_and_not_null` was refactored to use it. docs: revise restrictions on volatile operations A distinction between usage on Rust memory vs. non-Rust memory was introduced. Documentation was reworded to explain what that means, and make explicit that: - No trapping can occur from volatile operations; - On Rust memory, all safety rules must be respected; - On Rust memory, the primary difference from regular access is that volatile always involves a memory dereference; - On Rust memory, the only data affected by an operation is the one pointed to in the argument(s) of the function; - On Rust memory, provenance follows the same rules as non-volatile access; - On non-Rust memory, any address known to not contain Rust memory is valid (including 0 and usize::MAX); - On non-Rust memory, no Rust memory may be affected (it is implicit that any other non-Rust memory may be affected, though, even if not referenced by the pointer). This should be relevant when, for example, reading register A causes a flag to change in register B, or writing to A causes B to change in some way. Everything affected mustn't be inside an allocation. - On non-Rust memory, provenance is irrelevant and a pointer with none can be used in a valid way. fix: don't lint null as UB for volatile Also remove a now-unneeded `allow` line. fix: additional wording nits
301 lines
16 KiB
Plaintext
301 lines
16 KiB
Plaintext
error: calling this function with a null pointer is undefined behavior, even if the result of the function is unused
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--> $DIR/invalid_null_args.rs:8:5
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LL | / ptr::write(
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LL | |
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LL | | ptr::null_mut() as *mut u32,
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| | --------------- null pointer originates from here
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LL | | mem::transmute::<[u8; 4], _>([0, 0, 0, 255]),
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LL | | );
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| |_____^
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= help: for more information, visit <https://doc.rust-lang.org/std/ptr/index.html> and <https://doc.rust-lang.org/reference/behavior-considered-undefined.html>
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= note: `#[deny(invalid_null_arguments)]` on by default
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error: calling this function with a null pointer is undefined behavior, even if the result of the function is unused
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--> $DIR/invalid_null_args.rs:15:5
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LL | / ptr::write(
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LL | |
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LL | | null_ptr as *mut u32,
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LL | | mem::transmute::<[u8; 4], _>([0, 0, 0, 255]),
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LL | | );
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| |_____^
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= help: for more information, visit <https://doc.rust-lang.org/std/ptr/index.html> and <https://doc.rust-lang.org/reference/behavior-considered-undefined.html>
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note: null pointer originates from here
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--> $DIR/invalid_null_args.rs:14:20
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LL | let null_ptr = ptr::null_mut();
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| ^^^^^^^^^^^^^^^
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error: calling this function with a null pointer is undefined behavior, even if the result of the function is unused
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--> $DIR/invalid_null_args.rs:21:23
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LL | let _: &[usize] = std::slice::from_raw_parts(ptr::null(), 0);
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^^-----------^^^^
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| null pointer originates from here
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= help: for more information, visit <https://doc.rust-lang.org/std/ptr/index.html> and <https://doc.rust-lang.org/reference/behavior-considered-undefined.html>
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error: calling this function with a null pointer is undefined behavior, even if the result of the function is unused
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--> $DIR/invalid_null_args.rs:23:23
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LL | let _: &[usize] = std::slice::from_raw_parts(ptr::null_mut(), 0);
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^^---------------^^^^
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| null pointer originates from here
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= help: for more information, visit <https://doc.rust-lang.org/std/ptr/index.html> and <https://doc.rust-lang.org/reference/behavior-considered-undefined.html>
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error: calling this function with a null pointer is undefined behavior, even if the result of the function is unused
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--> $DIR/invalid_null_args.rs:25:23
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LL | let _: &[usize] = std::slice::from_raw_parts(0 as *mut _, 0);
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^^-^^^^^^^^^^^^^^
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| null pointer originates from here
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= help: for more information, visit <https://doc.rust-lang.org/std/ptr/index.html> and <https://doc.rust-lang.org/reference/behavior-considered-undefined.html>
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error: calling this function with a null pointer is undefined behavior, even if the result of the function is unused
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--> $DIR/invalid_null_args.rs:27:23
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LL | let _: &[usize] = std::slice::from_raw_parts(mem::transmute(0usize), 0);
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^------^^^^^
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| null pointer originates from here
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= help: for more information, visit <https://doc.rust-lang.org/std/ptr/index.html> and <https://doc.rust-lang.org/reference/behavior-considered-undefined.html>
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error: calling this function with a null pointer is undefined behavior, even if the result of the function is unused
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--> $DIR/invalid_null_args.rs:30:23
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LL | let _: &[usize] = std::slice::from_raw_parts_mut(ptr::null_mut(), 0);
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^---------------^^^^
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| null pointer originates from here
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= help: for more information, visit <https://doc.rust-lang.org/std/ptr/index.html> and <https://doc.rust-lang.org/reference/behavior-considered-undefined.html>
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error: calling this function with a null pointer is undefined behavior, even if the result of the function is unused
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--> $DIR/invalid_null_args.rs:33:5
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LL | ptr::copy::<usize>(ptr::null(), ptr::NonNull::dangling().as_ptr(), 0);
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| ^^^^^^^^^^^^^^^^^^^-----------^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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| null pointer originates from here
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= help: for more information, visit <https://doc.rust-lang.org/std/ptr/index.html> and <https://doc.rust-lang.org/reference/behavior-considered-undefined.html>
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error: calling this function with a null pointer is undefined behavior, even if the result of the function is unused
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--> $DIR/invalid_null_args.rs:35:5
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LL | ptr::copy::<usize>(ptr::NonNull::dangling().as_ptr(), ptr::null_mut(), 0);
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^---------------^^^^
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| null pointer originates from here
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= help: for more information, visit <https://doc.rust-lang.org/std/ptr/index.html> and <https://doc.rust-lang.org/reference/behavior-considered-undefined.html>
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error: calling this function with a null pointer is undefined behavior, even if the result of the function is unused
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--> $DIR/invalid_null_args.rs:38:5
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LL | ptr::copy_nonoverlapping::<usize>(ptr::null(), ptr::NonNull::dangling().as_ptr(), 0);
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^-----------^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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| null pointer originates from here
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= help: for more information, visit <https://doc.rust-lang.org/std/ptr/index.html> and <https://doc.rust-lang.org/reference/behavior-considered-undefined.html>
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error: calling this function with a null pointer is undefined behavior, even if the result of the function is unused
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--> $DIR/invalid_null_args.rs:40:5
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LL | / ptr::copy_nonoverlapping::<usize>(
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LL | |
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LL | | ptr::NonNull::dangling().as_ptr(),
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LL | | ptr::null_mut(),
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| | --------------- null pointer originates from here
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LL | | 0,
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LL | | );
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| |_____^
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= help: for more information, visit <https://doc.rust-lang.org/std/ptr/index.html> and <https://doc.rust-lang.org/reference/behavior-considered-undefined.html>
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error: calling this function with a null pointer is undefined behavior, even if the result of the function is unused
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--> $DIR/invalid_null_args.rs:51:17
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LL | let _a: A = ptr::read(ptr::null());
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| ^^^^^^^^^^-----------^
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| null pointer originates from here
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= help: for more information, visit <https://doc.rust-lang.org/std/ptr/index.html> and <https://doc.rust-lang.org/reference/behavior-considered-undefined.html>
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error: calling this function with a null pointer is undefined behavior, even if the result of the function is unused
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--> $DIR/invalid_null_args.rs:53:17
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LL | let _a: A = ptr::read(ptr::null_mut());
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| ^^^^^^^^^^---------------^
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| null pointer originates from here
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= help: for more information, visit <https://doc.rust-lang.org/std/ptr/index.html> and <https://doc.rust-lang.org/reference/behavior-considered-undefined.html>
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error: calling this function with a null pointer is undefined behavior, even if the result of the function is unused
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--> $DIR/invalid_null_args.rs:56:17
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LL | let _a: A = ptr::read_unaligned(ptr::null());
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| ^^^^^^^^^^^^^^^^^^^^-----------^
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| null pointer originates from here
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= help: for more information, visit <https://doc.rust-lang.org/std/ptr/index.html> and <https://doc.rust-lang.org/reference/behavior-considered-undefined.html>
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error: calling this function with a null pointer is undefined behavior, even if the result of the function is unused
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--> $DIR/invalid_null_args.rs:58:17
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LL | let _a: A = ptr::read_unaligned(ptr::null_mut());
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| ^^^^^^^^^^^^^^^^^^^^---------------^
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| null pointer originates from here
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= help: for more information, visit <https://doc.rust-lang.org/std/ptr/index.html> and <https://doc.rust-lang.org/reference/behavior-considered-undefined.html>
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error: calling this function with a null pointer is undefined behavior, even if the result of the function is unused
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--> $DIR/invalid_null_args.rs:65:17
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LL | let _a: A = ptr::replace(ptr::null_mut(), v);
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| ^^^^^^^^^^^^^---------------^^^^
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| null pointer originates from here
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= help: for more information, visit <https://doc.rust-lang.org/std/ptr/index.html> and <https://doc.rust-lang.org/reference/behavior-considered-undefined.html>
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error: calling this function with a null pointer is undefined behavior, even if the result of the function is unused
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--> $DIR/invalid_null_args.rs:68:5
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LL | ptr::swap::<A>(ptr::null_mut(), &mut v);
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| ^^^^^^^^^^^^^^^---------------^^^^^^^^^
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| null pointer originates from here
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= help: for more information, visit <https://doc.rust-lang.org/std/ptr/index.html> and <https://doc.rust-lang.org/reference/behavior-considered-undefined.html>
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error: calling this function with a null pointer is undefined behavior, even if the result of the function is unused
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--> $DIR/invalid_null_args.rs:70:5
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LL | ptr::swap::<A>(&mut v, ptr::null_mut());
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| ^^^^^^^^^^^^^^^^^^^^^^^---------------^
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| null pointer originates from here
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= help: for more information, visit <https://doc.rust-lang.org/std/ptr/index.html> and <https://doc.rust-lang.org/reference/behavior-considered-undefined.html>
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error: calling this function with a null pointer is undefined behavior, even if the result of the function is unused
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--> $DIR/invalid_null_args.rs:73:5
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LL | ptr::swap_nonoverlapping::<A>(ptr::null_mut(), &mut v, 0);
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^---------------^^^^^^^^^^^^
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| null pointer originates from here
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= help: for more information, visit <https://doc.rust-lang.org/std/ptr/index.html> and <https://doc.rust-lang.org/reference/behavior-considered-undefined.html>
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error: calling this function with a null pointer is undefined behavior, even if the result of the function is unused
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--> $DIR/invalid_null_args.rs:75:5
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LL | ptr::swap_nonoverlapping::<A>(&mut v, ptr::null_mut(), 0);
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^---------------^^^^
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| null pointer originates from here
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= help: for more information, visit <https://doc.rust-lang.org/std/ptr/index.html> and <https://doc.rust-lang.org/reference/behavior-considered-undefined.html>
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error: calling this function with a null pointer is undefined behavior, even if the result of the function is unused
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--> $DIR/invalid_null_args.rs:78:5
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LL | ptr::write(ptr::null_mut(), v);
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| ^^^^^^^^^^^---------------^^^^
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| null pointer originates from here
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= help: for more information, visit <https://doc.rust-lang.org/std/ptr/index.html> and <https://doc.rust-lang.org/reference/behavior-considered-undefined.html>
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error: calling this function with a null pointer is undefined behavior, even if the result of the function is unused
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--> $DIR/invalid_null_args.rs:81:5
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LL | ptr::write_unaligned(ptr::null_mut(), v);
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| ^^^^^^^^^^^^^^^^^^^^^---------------^^^^
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| null pointer originates from here
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= help: for more information, visit <https://doc.rust-lang.org/std/ptr/index.html> and <https://doc.rust-lang.org/reference/behavior-considered-undefined.html>
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error: calling this function with a null pointer is undefined behavior, even if the result of the function is unused
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--> $DIR/invalid_null_args.rs:87:5
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LL | ptr::write_bytes::<usize>(ptr::null_mut(), 42, 0);
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^---------------^^^^^^^^
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| null pointer originates from here
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= help: for more information, visit <https://doc.rust-lang.org/std/ptr/index.html> and <https://doc.rust-lang.org/reference/behavior-considered-undefined.html>
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error: calling this function with a null pointer is undefined behavior, even if the result of the function is unused
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--> $DIR/invalid_null_args.rs:92:18
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LL | let _a: u8 = ptr::read(const_ptr);
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| ^^^^^^^^^^^^^^^^^^^^
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= help: for more information, visit <https://doc.rust-lang.org/std/ptr/index.html> and <https://doc.rust-lang.org/reference/behavior-considered-undefined.html>
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note: null pointer originates from here
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--> $DIR/invalid_null_args.rs:14:20
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LL | let null_ptr = ptr::null_mut();
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| ^^^^^^^^^^^^^^^
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error: calling this function with a null pointer is undefined behavior, even if the result of the function is unused
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--> $DIR/invalid_null_args.rs:99:5
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LL | std::slice::from_raw_parts::<()>(ptr::null(), 0);
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^-----------^^^^
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| null pointer originates from here
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= help: for more information, visit <https://doc.rust-lang.org/std/ptr/index.html> and <https://doc.rust-lang.org/reference/behavior-considered-undefined.html>
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error: calling this function with a null pointer is undefined behavior, even if the result of the function is unused
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--> $DIR/invalid_null_args.rs:101:5
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LL | std::slice::from_raw_parts::<Zst>(ptr::null(), 0);
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^-----------^^^^
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| null pointer originates from here
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= help: for more information, visit <https://doc.rust-lang.org/std/ptr/index.html> and <https://doc.rust-lang.org/reference/behavior-considered-undefined.html>
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error: calling this function with a null pointer is undefined behavior, even if the result of the function is unused
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--> $DIR/invalid_null_args.rs:103:5
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LL | std::slice::from_raw_parts_mut::<()>(ptr::null_mut(), 0);
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^---------------^^^^
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| null pointer originates from here
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= help: for more information, visit <https://doc.rust-lang.org/std/ptr/index.html> and <https://doc.rust-lang.org/reference/behavior-considered-undefined.html>
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error: calling this function with a null pointer is undefined behavior, even if the result of the function is unused
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--> $DIR/invalid_null_args.rs:105:5
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LL | std::slice::from_raw_parts_mut::<Zst>(ptr::null_mut(), 0);
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^---------------^^^^
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| null pointer originates from here
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= help: for more information, visit <https://doc.rust-lang.org/std/ptr/index.html> and <https://doc.rust-lang.org/reference/behavior-considered-undefined.html>
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error: aborting due to 28 previous errors
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