extern functions can't be declared unsafe

[jdm]

unsafe extern fn foo() {}

/Users/jdm/src/servo/src/servo/dom/bindings/document.rs:124:7: 124:13 error: expecting fn, found extern

extern unsafe fn foo() {}

/Users/jdm/src/servo/src/servo/dom/bindings/document.rs:124:7: 124:13 error: expecting mod, found unsafe

extern fn unsafe foo() {}

/Users/jdm/src/servo/src/servo/dom/bindings/document.rs:124:10: 124:16 error: found unsafe in restricted position

[bblum]

I don't think this is a problem - making a function unsafe means what whoever calls it must surround it with an unsafe block or be unsafe themself, but extern functions are never called, only passed.

Try extern fn foo { unsafe { } }

[jdm]

I use the unsafe marker as a way to reduce the visual complexity of a function in which there are a number of unsafe blocks, or the whole body of the function belongs in an unsafe block.

[bblum]

You can also write extern fn foo() unsafe { ... }.

[jdm]

Curses, the one permutation I did not try.

[bblum]

It's equivalent to the one I said above, just with fewer braces.