Auto merge of #3044 - rust-lang:rustup-2023-08-31, r=RalfJung

Automatic sync from rustc

3 files changed, 6 insertions, 4 deletions

diff --git a/compiler/rustc_codegen_cranelift/src/common.rs b/compiler/rustc_codegen_cranelift/src/common.rs
index 3081dcfa2b7..ec2da39398b 100644
--- a/compiler/rustc_codegen_cranelift/src/common.rs
+++ b/compiler/rustc_codegen_cranelift/src/common.rs
@@ -480,7 +480,7 @@ impl<'tcx> LayoutOfHelpers<'tcx> for RevealAllLayoutCx<'tcx> {
         if let LayoutError::SizeOverflow(_) | LayoutError::ReferencesError(_) = err {
             self.0.sess.span_fatal(span, err.to_string())
         } else {
-            span_bug!(span, "failed to get layout for `{}`: {}", ty, err)
+            self.0.sess.span_fatal(span, format!("failed to get layout for `{}`: {}", ty, err))
         }
     }
 }
diff --git a/compiler/rustc_codegen_cranelift/src/unsize.rs b/compiler/rustc_codegen_cranelift/src/unsize.rs
index 6aeba13f639..c6133f2b35c 100644
--- a/compiler/rustc_codegen_cranelift/src/unsize.rs
+++ b/compiler/rustc_codegen_cranelift/src/unsize.rs
@@ -88,7 +88,8 @@ fn unsize_ptr<'tcx>(
                 let src_f = src_layout.field(fx, i);
                 assert_eq!(src_layout.fields.offset(i).bytes(), 0);
                 assert_eq!(dst_layout.fields.offset(i).bytes(), 0);
-                if src_f.is_zst() {
+                if src_f.is_1zst() {
+                    // We are looking for the one non-1-ZST field; this is not it.
                     continue;
                 }
                 assert_eq!(src_layout.size, src_f.size);
@@ -151,6 +152,7 @@ pub(crate) fn coerce_unsized_into<'tcx>(
                 let dst_f = dst.place_field(fx, FieldIdx::new(i));
 
                 if dst_f.layout().is_zst() {
+                    // No data here, nothing to copy/coerce.
                     continue;
                 }
 
diff --git a/compiler/rustc_codegen_cranelift/src/vtable.rs b/compiler/rustc_codegen_cranelift/src/vtable.rs
index b309695c190..7598c6eee03 100644
--- a/compiler/rustc_codegen_cranelift/src/vtable.rs
+++ b/compiler/rustc_codegen_cranelift/src/vtable.rs
@@ -51,8 +51,8 @@ pub(crate) fn get_ptr_and_method_ref<'tcx>(
             '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_zst() {
-                        // we found the one non-zero-sized field that is allowed
+                    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;