mirror of
https://github.com/rust-lang/rust.git
synced 2025-06-05 11:48:30 +00:00
8f42ac0043
Improve diagnostics for pointer arithmetic += and -= (fixes #137391) **Description**: This PR improves the diagnostic message for cases where a binary assignment operation like `ptr += offset` or `ptr -= offset` is attempted on `*mut T`. These operations are not allowed, and the compiler previously suggested calling `.add()` or `.wrapping_add()`, which is misleading if not assigned. This PR updates the diagnostics to suggest assigning the result of `.wrapping_add()` or `.wrapping_sub()` back to the pointer, e.g.: **Examples** For this code ```rust let mut arr = [0u8; 10]; let mut ptr = arr.as_mut_ptr(); ptr += 2; ``` it will say: ```rust 10 | ptr += 2; | ---^^^^^ | | | cannot use `+=` on type `*mut u8` | help: consider replacing `ptr += offset` with `ptr = ptr.wrapping_add(offset)` or `ptr.add(offset)` | 10 - ptr += 2; 10 + ptr = ptr.wrapping_add(2); ``` **Related issue**: #137391 cc `@nabijaczleweli` for context (issue author) |
||
|---|---|---|
| .. | ||
| assembly | ||
| auxiliary | ||
| codegen | ||
| codegen-units | ||
| coverage | ||
| coverage-run-rustdoc | ||
| crashes | ||
| debuginfo | ||
| incremental | ||
| mir-opt | ||
| pretty | ||
| run-make | ||
| rustdoc | ||
| rustdoc-gui | ||
| rustdoc-js | ||
| rustdoc-js-std | ||
| rustdoc-json | ||
| rustdoc-ui | ||
| ui | ||
| ui-fulldeps | ||
| COMPILER_TESTS.md | ||