Clippy · Correctness

Transmuting null into a function pointer

clippy::transmute_null_to_fn

Use Option<fn()> and None instead of transmuting a null pointer into a function pointer.

Not a defect when

There is no such case: a null function pointer is undefined behavior the moment it exists, so the code always needs Option<fn> and None instead.

Clippy, with the compiler behind it. The only pass that compiles.

Serious: worth interrupting other work for.

The tier bounds how severe a rule may be; its category bounds the tier.

The changed line itself.

What --scope contextual looks at to decide whether a change caused the finding.

Turn it off, or make it blocking, without touching the code it flags:

rust-doctor --rule clippy::transmute_null_to_fn=off .
rust-doctor --rule clippy::transmute_null_to_fn=error .