Add OnceCell<T>: !Sync impl for diagnostics

Noratrieb · Noratrieb · commit e1f630f23de2 · 2023-01-19T20:14:21.000+01:00
diff --git a/library/core/src/cell/once.rs b/library/core/src/cell/once.rs
@@ -298,3 +298,7 @@ impl<T> const From<T> for OnceCell<T> {
         OnceCell { inner: UnsafeCell::new(Some(value)) }
     }
 }
+
+// Just like for `Cell<T>` this isn't needed, but results in nicer error messages.
+#[unstable(feature = "once_cell", issue = "74465")]
+impl<T> !Sync for OnceCell<T> {}

Original file line number	Diff line number	Diff line change
`@@ -298,3 +298,7 @@ impl<T> const From<T> for OnceCell<T> {`
`298`	`298`	`OnceCell { inner: UnsafeCell::new(Some(value)) }`
`299`	`299`	`}`
`300`	`300`	`}`
	`301`	`+`
	`302`	+// Just like for `Cell<T>` this isn't needed, but results in nicer error messages.
	`303`	`+#[unstable(feature = "once_cell", issue = "74465")]`
	`304`	`+impl<T> !Sync for OnceCell<T> {}`