mikros/rust
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Rollup merge of #115798 - RalfJung:non_1zst_field, r=wesleywiser

Browse Source 
add helper method for finding the one non-1-ZST field
This commit is contained in:
Matthias Krüger 2023-09-13 18:37:42 +02:00 committed by GitHub
commit 1956fb84f3
1 changed files with 6 additions and 13 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

19
src/vtable.rs
View File

@ -48,19 +48,12 @@ pub(crate) fn get_ptr_and_method_ref<'tcx>(
) -> (Pointer, Value) {
let (ptr, vtable) = 'block: {
if let Abi::Scalar(_) = arg.layout().abi {
'descend_newtypes: while !arg.layout().ty.is_unsafe_ptr() && !arg.layout().ty.is_ref() {
for i in 0..arg.layout().fields.count() {
let field = arg.value_field(fx, FieldIdx::new(i));
if !field.layout().is_1zst() {
// we found the one non-1-ZST field that is allowed
// now find *its* non-zero-sized field, or stop if it's a
// pointer
arg = field;
continue 'descend_newtypes;
}
}
bug!("receiver has no non-zero-sized fields {:?}", arg);
while !arg.layout().ty.is_unsafe_ptr() && !arg.layout().ty.is_ref() {
let (idx, _) = arg
.layout()
.non_1zst_field(fx)
.expect("not exactly one non-1-ZST field in a `DispatchFromDyn` type");
arg = arg.value_field(fx, FieldIdx::new(idx));
}
}