On: Comparing k-NN in Rust

[pbsd]

Well Rust is checking for null pointers at the assembly level: http://goo.gl/eh2aqc (lines 22--27).

[pcwalton → pbsd]

Blech. I'm pretty sure LLVM, not the frontend, is inserting those null checks for some reason.

[kzrdude → pcwalton]

The slice iterator yields `Option<&T>`, the None variant is represented by a null pointer. That's probably the null check.

[dbaupp → pbsd]

This is https://github.com/mozilla/rust/issues/11751: LLVM doesn't understand (non)null pointers enough.