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Null fn lints by Niki4tap · Pull Request #10099 · rust-lang/rust-clippy · GitHub

 1 year ago
source link: https://github.com/rust-lang/rust-clippy/pull/10099
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@Niki4tap Niki4tap commented Dec 18, 2022 •

edited by xFrednet

Adds lints to check for code, that assumes nullable fn().

Lint examples:

transmute_null_to_fn:

error: transmuting a known null pointer into a function pointer
  --> $DIR/transmute_null_to_fn.rs:9:23
   |
LL |         let _: fn() = std::mem::transmute(std::ptr::null::<()>());
   |                       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ this transmute results in undefined behavior
   |
   = help: try wrapping your function pointer type in `Option<T>` instead, and using `None` as a null pointer value

fn_null_check:

error: function pointer assumed to be nullable, even though it isn't
  --> $DIR/fn_null_check.rs:13:8
   |
LL |     if (fn_ptr as *mut ()).is_null() {}
   |        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = help: try wrapping your function pointer type in `Option<T>` instead, and using `is_none` to check for null pointer value

Closes #1644

changelog: Improvement: [transmuting_null]: Now detects const pointers to all types
#10099
changelog: New lint: [transmute_null_to_fn]
#10099
changelog: New lint: [fn_null_check]
#10099


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