[devit]

I think both "as" and using "transmute" for non-exceptional circumstances are mistakes in Rust.

There should instead be a bunch of type-specific cast operators that can check things like alignment and that what you intended to be a zero-extending integer cast is not in fact truncating to a smaller integer type, and so on.

It's not too late to deprecate "as" and discourage using "transmute" in favor of those.

[edflsafoiewq]

This isn't about transmute or having a specific operator that checks alignment. The point is that the alignment is part of the type is zig and, to a lesser degree, it's about having the comptime machinery for zig to decide, when you offset a &align(4) u8 by an expression, whether the result should have type &align(1) u8, &align(2) u8, or &align(4) u8.

[elcritch]

Exactly what I was thinking while reading the OP. It seems like it'd be possible to add alignment checks either manually via cast-operators or automatically via the compiler. Rust could at a minimum display a warning "possible alignment errors" when emitting that kind of LLVM IR.