make Cell & SyncUnsafeCell lang items instead of diagnostic items

Author: GrigorenkoPV

compiler/rustc_hir/src/lang_items.rs

@@ -225,7 +225,10 @@ language_item_table! {
     Index,                   sym::index,               index_trait,                Target::Trait,          GenericRequirement::Exact(1);
     IndexMut,                sym::index_mut,           index_mut_trait,            Target::Trait,          GenericRequirement::Exact(1);
 
+
+    Cell,                    sym::cell,                cell_type,                  Target::Struct,         GenericRequirement::None;
     UnsafeCell,              sym::unsafe_cell,         unsafe_cell_type,           Target::Struct,         GenericRequirement::None;
+    SyncUnsafeCell,          sym::sync_unsafe_cell,    sync_unsafe_cell_type,      Target::Struct,         GenericRequirement::None;
     VaList,                  sym::va_list,             va_list,                    Target::Struct,         GenericRequirement::None;
 
     Deref,                   sym::deref,               deref_trait,                Target::Trait,          GenericRequirement::Exact(0);

compiler/rustc_hir_analysis/src/check/check.rs

@@ -1261,10 +1261,13 @@ pub(super) fn check_transparent<'tcx>(tcx: TyCtxt<'tcx>, adt: ty::AdtDef<'tcx>)
                 ty::Adt(def, args) => {
                     if matches!(
                         tcx.as_lang_item(def.did()),
-                        Some(LangItem::UnsafeCell | LangItem::ManuallyDrop | LangItem::MaybeUninit)
-                    ) || matches!(
-                        tcx.get_diagnostic_name(def.did()),
-                        Some(sym::Cell | sym::SyncUnsafeCell)
+                        Some(
+                            LangItem::Cell
+                                | LangItem::UnsafeCell
+                                | LangItem::SyncUnsafeCell
+                                | LangItem::ManuallyDrop
+                                | LangItem::MaybeUninit
+                        )
                     ) {
                         // These are the types from `std` that guarantee that
                         // they have the same layout as `T`.

compiler/rustc_span/src/symbol.rs

@@ -170,7 +170,6 @@ symbols! {
         CallOnceFuture,
         CallRefFuture,
         Capture,
-        Cell,
         Center,
         Cleanup,
         Clone,
@@ -322,7 +321,6 @@ symbols! {
         SubdiagMessage,
         Subdiagnostic,
         Sync,
-        SyncUnsafeCell,
         T,
         Target,
         ToOwned,
@@ -531,6 +529,7 @@ symbols! {
         ceilf16,
         ceilf32,
         ceilf64,
+        cell,
         cfg,
         cfg_accessible,
         cfg_attr,
@@ -1861,6 +1860,7 @@ symbols! {
         surface_async_drop_in_place,
         sym,
         sync,
+        sync_unsafe_cell,
         synthetic,
         t32,
         target,

library/core/src/cell.rs

@@ -304,7 +304,7 @@ pub use once::OnceCell;
 /// ```
 ///
 /// See the [module-level documentation](self) for more.
-#[cfg_attr(not(test), rustc_diagnostic_item = "Cell")]
+#[cfg_attr(not(bootstrap), lang = "cell")]
 #[stable(feature = "rust1", since = "1.0.0")]
 #[repr(transparent)]
 pub struct Cell<T: ?Sized> {
@@ -2296,7 +2296,7 @@ impl<T> UnsafeCell<*mut T> {
 /// making this type just as unsafe to use.
 ///
 /// See [`UnsafeCell`] for details.
-#[cfg_attr(not(test), rustc_diagnostic_item = "SyncUnsafeCell")]
+#[cfg_attr(not(bootstrap), lang = "sync_unsafe_cell")]
 #[unstable(feature = "sync_unsafe_cell", issue = "95439")]
 #[repr(transparent)]
 pub struct SyncUnsafeCell<T: ?Sized> {