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matthiaskrgr opened this issue Nov 19, 2022 · 0 comments · Fixed by #10948
Closed

FP borrow_as_ptr #9884

matthiaskrgr opened this issue Nov 19, 2022 · 0 comments · Fixed by #10948
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C-bug Category: Clippy is not doing the correct thing I-false-positive Issue: The lint was triggered on code it shouldn't have I-suggestion-causes-error Issue: The suggestions provided by this Lint cause an ICE/error when applied

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Summary

.

Lint Name

borrow_as_ptr

Reproducer

I tried this code:

enum Foo {}
impl Drop for Foo {
    fn drop(&mut self) {}
}

fn main() {
    unsafe { std::ptr::read(&1u8 as *const u8 as *const Foo) };
}

I saw this happen:
cargo clippy --fix -- -Wclippy::borrow_as_ptr

warning: failed to automatically apply fixes suggested by rustc to crate `a`

after fixes were automatically applied the compiler reported errors within these files:

  * src/main.rs

This likely indicates a bug in either rustc or cargo itself,
and we would appreciate a bug report! You're likely to see
a number of compiler warnings after this message which cargo
attempted to fix but failed. If you could open an issue at
https://github.com/rust-lang/rust/issues
quoting the full output of this command we'd be very appreciative!
Note that you may be able to make some more progress in the near-term
fixing code with the `--broken-code` flag

The following errors were reported:
error[E0745]: cannot take address of a temporary
 --> src/main.rs:7:48
  |
7 |     unsafe { std::ptr::read(std::ptr::addr_of!(1u8) as *const Foo) };
  |                                                ^^^ temporary value

error: aborting due to previous error

For more information about this error, try `rustc --explain E0745`.
Original diagnostics will follow.

warning: borrow as raw pointer
 --> src/main.rs:7:29
  |
7 |     unsafe { std::ptr::read(&1u8 as *const u8 as *const Foo) };
  |                             ^^^^^^^^^^^^^^^^^ help: try: `std::ptr::addr_of!(1u8)`
  |
  = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#borrow_as_ptr
  = note: requested on the command line with `-W clippy::borrow-as-ptr`

warning: `a` (bin "a") generated 1 warning (run `cargo fix --bin "a"` to apply 1 suggestion)
warning: `a` (bin "a" test) generated 1 warning (1 duplicate)

Version

rustc 1.67.0-nightly (b833ad56f 2022-11-18)
binary: rustc
commit-hash: b833ad56f46a0bbe0e8729512812a161e7dae28a
commit-date: 2022-11-18
host: x86_64-unknown-linux-gnu
release: 1.67.0-nightly
LLVM version: 15.0.4

Additional Labels

No response

@matthiaskrgr matthiaskrgr added C-bug Category: Clippy is not doing the correct thing I-suggestion-causes-error Issue: The suggestions provided by this Lint cause an ICE/error when applied I-false-positive Issue: The lint was triggered on code it shouldn't have labels Nov 19, 2022
@bors bors closed this as completed in b3fd7b8 Jun 21, 2023
bors added a commit that referenced this issue Feb 4, 2024
Add new lint: `ref_as_ptr`

Fixes #10130

Added new lint `ref_as_ptr` that checks for conversions from references to pointers and suggests using `std::ptr::from_{ref, mut}` instead.

The name is different than suggested in the issue (`as_ptr_cast`) since there were some other lints with similar names (`ptr_as_ptr`, `borrow_as_ptr`) and I wanted to follow the convention.

Note that this lint conflicts with the `borrow_as_ptr` lint in the sense that it recommends changing `&foo as *const _` to `std::ptr::from_ref(&foo)` instead of `std::ptr::addr_of!(foo)`. Personally, I think the former is more readable and, in contrast to `addr_of` macro, can be also applied to temporaries (cf. #9884).

---

changelog: New lint: [`ref_as_ptr`]
[#12087](#12087)
bors added a commit that referenced this issue Feb 4, 2024
Add new lint: `ref_as_ptr`

Fixes #10130

Added new lint `ref_as_ptr` that checks for conversions from references to pointers and suggests using `std::ptr::from_{ref, mut}` instead.

The name is different than suggested in the issue (`as_ptr_cast`) since there were some other lints with similar names (`ptr_as_ptr`, `borrow_as_ptr`) and I wanted to follow the convention.

Note that this lint conflicts with the `borrow_as_ptr` lint in the sense that it recommends changing `&foo as *const _` to `std::ptr::from_ref(&foo)` instead of `std::ptr::addr_of!(foo)`. Personally, I think the former is more readable and, in contrast to `addr_of` macro, can be also applied to temporaries (cf. #9884).

---

changelog: New lint: [`ref_as_ptr`]
[#12087](#12087)
bors added a commit that referenced this issue Feb 4, 2024
Add new lint: `ref_as_ptr`

Fixes #10130

Added new lint `ref_as_ptr` that checks for conversions from references to pointers and suggests using `std::ptr::from_{ref, mut}` instead.

The name is different than suggested in the issue (`as_ptr_cast`) since there were some other lints with similar names (`ptr_as_ptr`, `borrow_as_ptr`) and I wanted to follow the convention.

Note that this lint conflicts with the `borrow_as_ptr` lint in the sense that it recommends changing `&foo as *const _` to `std::ptr::from_ref(&foo)` instead of `std::ptr::addr_of!(foo)`. Personally, I think the former is more readable and, in contrast to `addr_of` macro, can be also applied to temporaries (cf. #9884).

---

changelog: New lint: [`ref_as_ptr`]
[#12087](#12087)
bors added a commit that referenced this issue Feb 4, 2024
Add new lint: `ref_as_ptr`

Fixes #10130

Added new lint `ref_as_ptr` that checks for conversions from references to pointers and suggests using `std::ptr::from_{ref, mut}` instead.

The name is different than suggested in the issue (`as_ptr_cast`) since there were some other lints with similar names (`ptr_as_ptr`, `borrow_as_ptr`) and I wanted to follow the convention.

Note that this lint conflicts with the `borrow_as_ptr` lint in the sense that it recommends changing `&foo as *const _` to `std::ptr::from_ref(&foo)` instead of `std::ptr::addr_of!(foo)`. Personally, I think the former is more readable and, in contrast to `addr_of` macro, can be also applied to temporaries (cf. #9884).

---

changelog: New lint: [`ref_as_ptr`]
[#12087](#12087)
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Labels
C-bug Category: Clippy is not doing the correct thing I-false-positive Issue: The lint was triggered on code it shouldn't have I-suggestion-causes-error Issue: The suggestions provided by this Lint cause an ICE/error when applied
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