diff options
Diffstat (limited to 'compiler/rustc_const_eval/src/util')
| -rw-r--r-- | compiler/rustc_const_eval/src/util/alignment.rs | 10 |
1 files changed, 8 insertions, 2 deletions
diff --git a/compiler/rustc_const_eval/src/util/alignment.rs b/compiler/rustc_const_eval/src/util/alignment.rs index bdb08a9828e..8642dfccd78 100644 --- a/compiler/rustc_const_eval/src/util/alignment.rs +++ b/compiler/rustc_const_eval/src/util/alignment.rs @@ -21,12 +21,18 @@ where }; let ty = place.ty(local_decls, tcx).ty; + let unsized_tail = || tcx.struct_tail_with_normalize(ty, |ty| ty, || {}); match tcx.layout_of(param_env.and(ty)) { - Ok(layout) if layout.align.abi <= pack && layout.is_sized() => { + Ok(layout) + if layout.align.abi <= pack + && (layout.is_sized() + || matches!(unsized_tail().kind(), ty::Slice(..) | ty::Str)) => + { // 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. + // just an approximation -- except when the unsized tail is a slice, where the alignment + // is fully determined by the type. debug!( "is_disaligned({:?}) - align = {}, packed = {}; not disaligned", place, |