Rollup merge of #107446 - clubby789:rustc-parse-diag-migrate, r=compiler-errors

[rust.git] / compiler / rustc_builtin_macros / src / deriving / debug.rs

diff --git a/compiler/rustc_builtin_macros/src/deriving/debug.rs b/compiler/rustc_builtin_macros/src/deriving/debug.rs
index 897048f64211e37d509d31457f1d71cf4d7edf3f..e8a353b1c8fcc61474ad64cb001971ede5a5b67a 100644 (file)
--- a/compiler/rustc_builtin_macros/src/deriving/debug.rs
+++ b/compiler/rustc_builtin_macros/src/deriving/debug.rs
@@ -76,6 +76,21 @@ fn show_substructure(cx: &mut ExtCtxt<'_>, span: Span, substr: &Substructure<'_>
     // The number of fields that can be handled without an array.
     const CUTOFF: usize = 5;
 
+    fn expr_for_field(
+        cx: &ExtCtxt<'_>,
+        field: &FieldInfo,
+        index: usize,
+        len: usize,
+    ) -> ast::ptr::P<ast::Expr> {
+        if index < len - 1 {
+            field.self_expr.clone()
+        } else {
+            // Unsized types need an extra indirection, but only the last field
+            // may be unsized.
+            cx.expr_addr_of(field.span, field.self_expr.clone())
+        }
+    }
+
     if fields.is_empty() {
         // Special case for no fields.
         let fn_path_write_str = cx.std_path(&[sym::fmt, sym::Formatter, sym::write_str]);
@@ -98,8 +113,8 @@ fn show_substructure(cx: &mut ExtCtxt<'_>, span: Span, substr: &Substructure<'_>
                 let name = cx.expr_str(field.span, field.name.unwrap().name);
                 args.push(name);
             }
-            // Use an extra indirection to make sure this works for unsized types.
-            let field = cx.expr_addr_of(field.span, field.self_expr.clone());
+
+            let field = expr_for_field(cx, field, i, fields.len());
             args.push(field);
         }
         let expr = cx.expr_call_global(span, fn_path_debug, args);
@@ -109,13 +124,13 @@ fn show_substructure(cx: &mut ExtCtxt<'_>, span: Span, substr: &Substructure<'_>
         let mut name_exprs = Vec::with_capacity(fields.len());
         let mut value_exprs = Vec::with_capacity(fields.len());
 
-        for field in fields {
+        for i in 0..fields.len() {
+            let field = &fields[i];
             if is_struct {
                 name_exprs.push(cx.expr_str(field.span, field.name.unwrap().name));
             }
 
-            // Use an extra indirection to make sure this works for unsized types.
-            let field = cx.expr_addr_of(field.span, field.self_expr.clone());
+            let field = expr_for_field(cx, field, i, fields.len());
             value_exprs.push(field);
         }
 
@@ -138,7 +153,10 @@ fn show_substructure(cx: &mut ExtCtxt<'_>, span: Span, substr: &Substructure<'_>
         let path_debug = cx.path_global(span, cx.std_path(&[sym::fmt, sym::Debug]));
         let ty_dyn_debug = cx.ty(
             span,
-            ast::TyKind::TraitObject(vec![cx.trait_bound(path_debug)], ast::TraitObjectSyntax::Dyn),
+            ast::TyKind::TraitObject(
+                vec![cx.trait_bound(path_debug, false)],
+                ast::TraitObjectSyntax::Dyn,
+            ),
         );
         let ty_slice = cx.ty(
             span,