// Fake impl that's only really used for docs.
#[cfg(doc)]
#[stable(feature = "rust1", since = "1.0.0")]
-#[doc(tuple_variadic)]
+#[cfg_attr(not(bootstrap), doc(fake_variadic))]
/// This trait is implemented on arbitrary-length tuples.
impl<T: Clone> Clone for (T,) {
fn clone(&self) -> Self {
// Fake impl that's only really used for docs.
#[cfg(doc)]
#[stable(feature = "rust1", since = "1.0.0")]
-#[doc(tuple_variadic)]
+#[cfg_attr(not(bootstrap), doc(fake_variadic))]
/// This trait is implemented on arbitrary-length tuples.
impl<T: Copy> Copy for (T,) {
// empty
/// Note that all of this is not portable to platforms where function pointers and data pointers
/// have different sizes.
///
-/// ### Traits
+/// ### Trait implementations
///
-/// Function pointers implement the following traits:
+/// In this documentation the shorthand `fn (T₁, T₂, …, Tₙ)` is used to represent non-variadic
+/// function pointers of varying length. Note that this is a convenience notation to avoid
+/// repetitive documentation, not valid Rust syntax.
+///
+/// Due to a temporary restriction in Rust's type system, these traits are only implemented on
+/// functions that take 12 arguments or less, with the `"Rust"` and `"C"` ABIs. In the future, this
+/// may change:
///
-/// * [`Clone`]
/// * [`PartialEq`]
/// * [`Eq`]
/// * [`PartialOrd`]
/// * [`Pointer`]
/// * [`Debug`]
///
+/// The following traits are implemented for function pointers with any number of arguments and
+/// any ABI. These traits have implementations that are automatically generated by the compiler,
+/// so are not limited by missing language features:
+///
+/// * [`Clone`]
+/// * [`Copy`]
+/// * [`Send`]
+/// * [`Sync`]
+/// * [`Unpin`]
+/// * [`UnwindSafe`]
+/// * [`RefUnwindSafe`]
+///
/// [`Hash`]: hash::Hash
/// [`Pointer`]: fmt::Pointer
+/// [`UnwindSafe`]: panic::UnwindSafe
+/// [`RefUnwindSafe`]: panic::RefUnwindSafe
///
-/// Due to a temporary restriction in Rust's type system, these traits are only implemented on
-/// functions that take 12 arguments or less, with the `"Rust"` and `"C"` ABIs. In the future, this
-/// may change.
-///
-/// In addition, function pointers of *any* signature, ABI, or safety are [`Copy`], and all *safe*
-/// function pointers implement [`Fn`], [`FnMut`], and [`FnOnce`]. This works because these traits
-/// are specially known to the compiler.
+/// In addition, all *safe* function pointers implement [`Fn`], [`FnMut`], and [`FnOnce`], because
+/// these traits are specially known to the compiler.
#[stable(feature = "rust1", since = "1.0.0")]
mod prim_fn {}
+
+// Required to make auto trait impls render.
+// See src/librustdoc/passes/collect_trait_impls.rs:collect_trait_impls
+#[doc(hidden)]
+#[cfg(not(bootstrap))]
+impl<Ret, T> fn(T) -> Ret {}
+
+// Fake impl that's only really used for docs.
+#[cfg(doc)]
+#[stable(feature = "rust1", since = "1.0.0")]
+#[cfg_attr(not(bootstrap), doc(fake_variadic))]
+/// This trait is implemented on function pointers with any number of arguments.
+impl<Ret, T> Clone for fn(T) -> Ret {
+ fn clone(&self) -> Self {
+ loop {}
+ }
+}
+
+// Fake impl that's only really used for docs.
+#[cfg(doc)]
+#[stable(feature = "rust1", since = "1.0.0")]
+#[cfg_attr(not(bootstrap), doc(fake_variadic))]
+/// This trait is implemented on function pointers with any number of arguments.
+impl<Ret, T> Copy for fn(T) -> Ret {
+ // empty
+}