fix detecting references to packed unsized fields

2023-09-05 22:29:51 +02:00
parent ab45885dec
commit 8b3435c10f
3 changed files with 37 additions and 12 deletions
--- a/compiler/rustc_const_eval/src/util/alignment.rs
+++ b/compiler/rustc_const_eval/src/util/alignment.rs
@@ -22,9 +22,11 @@ where

    let ty = place.ty(local_decls, tcx).ty;
    match tcx.layout_of(param_env.and(ty)) {
-        Ok(layout) if layout.align.abi <= pack => {
+        Ok(layout) if layout.align.abi <= pack && layout.is_sized() => {
            // If the packed alignment is greater or equal to the field alignment, the type won't be
            // further disaligned.
+            // However we need to ensure the field is sized; for unsized fields, `layout.align` is
+            // just an approximation.
            debug!(
                "is_disaligned({:?}) - align = {}, packed = {}; not disaligned",
                place,