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Miri engine is too permissive with type-changing MIR assignments #70405
Description
rust/src/librustc_mir/interpret/place.rs
Line 856 in 02046a5
&mut T to a &T variable. We should instead employ a function like
fn mir_assign_valid_types(dst: Ty<'tcx>, src: Ty<'tcx>) {
dst == src || match (&dst.kind, &src.kind) {
(ty::Ref(_, _, dst_pointee), ty::Ref(_, _, src_pointee)) => dst_pointee == src_pointee,
_ => false,
}
}(source #69700 (comment))
be sure to also add appropriate mutability checks to the patterns (mutable for the source, immutable for the dest)
Activity
[-]Miri engine is too permissive with MIR assignments[/-][+]Miri engine is too permissive with type-changing MIR assignments[/+]Rollup merge of rust-lang#70532 - RalfJung:miri-assign, r=eddyb
RalfJung commentedon Apr 3, 2020
@eddyb do we want to keep this open, as you have some future plans for checking subtyping or some such thing?
eddyb commentedon Apr 3, 2020
I'm not sure, I think we should experiment with deeper lifetime erasure but I likely won't have the time to get involved myself any time soon. Maybe that should have its own issue though.