Rollup merge of #129829 - compiler-errors:decode-non-optional, r=lcnr
Make decoding non-optional `LazyArray` panic if not set
Tables may be [defined](https://github.com/rust-lang/rust/blob/9649706eada1b2c68cf6504356efb058f68ad739/compiler/rustc_metadata/src/rmeta/mod.rs#L377) as `optional:` or `defaulted:`. If optional, if we try to read a value from a key that was never encoded, we should panic. This has high value in ensuring correctness over a defaulted table, so the tradeoff is worth considering, since it signals the compiler has a buggy encode impl, rather than just defaulting to a value.
HOWEVER, `optional:` arrays were side-stepping this. So this PR fixes that, and makes `optional:` tables of `LazyArray` act like `LazyValue`, and panic if it's not assigned a value during encoding.
During this PR, I found that `deduced_param_attrs` has buggy (?? i think??) implementation where it will refuse to encode cross-crate `deduced_param_attrs` unless we're codegening, we're optimizing the library, and incremental is disabled. This seems incredibly wrong, but I don't want to fix it in this PR.
https://github.com/rust-lang/rust/blob/9649706eada1b2c68cf6504356efb058f68ad739/compiler/rustc_metadata/src/rmeta/encoder.rs#L1733-L1747
diff --git a/compiler/rustc_metadata/src/rmeta/decoder/cstore_impl.rs b/compiler/rustc_metadata/src/rmeta/decoder/cstore_impl.rs
index 0f46cac..1264510 100644
--- a/compiler/rustc_metadata/src/rmeta/decoder/cstore_impl.rs
+++ b/compiler/rustc_metadata/src/rmeta/decoder/cstore_impl.rs
@@ -71,8 +71,8 @@ impl<'a, 'tcx, T: Copy + Decodable<DecodeContext<'a, 'tcx>>> ProcessQueryValue<'
for Option<DecodeIterator<'a, 'tcx, T>>
{
#[inline(always)]
- fn process_decoded(self, tcx: TyCtxt<'tcx>, _err: impl Fn() -> !) -> &'tcx [T] {
- if let Some(iter) = self { tcx.arena.alloc_from_iter(iter) } else { &[] }
+ fn process_decoded(self, tcx: TyCtxt<'tcx>, err: impl Fn() -> !) -> &'tcx [T] {
+ if let Some(iter) = self { tcx.arena.alloc_from_iter(iter) } else { err() }
}
}
@@ -84,12 +84,12 @@ impl<'a, 'tcx, T: Copy + Decodable<DecodeContext<'a, 'tcx>>>
fn process_decoded(
self,
tcx: TyCtxt<'tcx>,
- _err: impl Fn() -> !,
+ err: impl Fn() -> !,
) -> ty::EarlyBinder<'tcx, &'tcx [T]> {
ty::EarlyBinder::bind(if let Some(iter) = self {
tcx.arena.alloc_from_iter(iter)
} else {
- &[]
+ err()
})
}
}
@@ -300,7 +300,20 @@ fn into_args(self) -> (DefId, SimplifiedType) {
.unwrap_or_else(|| panic!("{def_id:?} does not have eval_static_initializer")))
}
trait_def => { table }
- deduced_param_attrs => { table }
+ deduced_param_attrs => {
+ // FIXME: `deduced_param_attrs` has some sketchy encoding settings,
+ // where we don't encode unless we're optimizing, doing codegen,
+ // and not incremental (see `encoder.rs`). I don't think this is right!
+ cdata
+ .root
+ .tables
+ .deduced_param_attrs
+ .get(cdata, def_id.index)
+ .map(|lazy| {
+ &*tcx.arena.alloc_from_iter(lazy.decode((cdata, tcx)))
+ })
+ .unwrap_or_default()
+ }
is_type_alias_impl_trait => {
debug_assert_eq!(tcx.def_kind(def_id), DefKind::OpaqueTy);
cdata.root.tables.is_type_alias_impl_trait.get(cdata, def_id.index)
