temporary_as_ptr: also fire on Cell & MaybeUninit

Author: GrigorenkoPV

compiler/rustc_lint/src/methods.rs

@@ -136,7 +136,7 @@ fn is_temporary_rvalue(expr: &Expr<'_>) -> bool {
 
 // None => not a container
 // Some(true) => CString
-// Some(false) => String, Vec, box, array
+// Some(false) => String, Vec, box, array, MaybeUninit, Cell
 fn as_container(cx: &LateContext<'_>, ty: Ty<'_>) -> Option<bool> {
     if ty.is_array() {
         Some(false)
@@ -154,10 +154,14 @@ fn as_container(cx: &LateContext<'_>, ty: Ty<'_>) -> Option<bool> {
             None
         }
     } else if let Some(def) = ty.ty_adt_def() {
+        for lang_item in [LangItem::String, LangItem::MaybeUninit] {
+            if cx.tcx.is_lang_item(def.did(), lang_item) {
+                return Some(false);
+            }
+        }
         match cx.tcx.get_diagnostic_name(def.did()) {
             Some(sym::cstring_type) => Some(true),
-            Some(sym::Vec) => Some(false),
-            _ if cx.tcx.is_lang_item(def.did(), LangItem::String) => Some(false),
+            Some(sym::Vec | sym::Cell) => Some(false),
             _ => None,
         }
     } else {

compiler/rustc_span/src/symbol.rs

@@ -170,6 +170,7 @@ symbols! {
         CallOnceFuture,
         CallRefFuture,
         Capture,
+        Cell,
         Center,
         Cleanup,
         Clone,

library/core/src/cell.rs

@@ -304,6 +304,7 @@ pub use once::OnceCell;
 /// ```
 ///
 /// See the [module-level documentation](self) for more.
+#[cfg_attr(not(test), rustc_diagnostic_item = "Cell")]
 #[stable(feature = "rust1", since = "1.0.0")]
 #[repr(transparent)]
 pub struct Cell<T: ?Sized> {