Vendor dependencies for 0.3.0 release

vendor/variadics_please/examples/demonstrations/all_tuples.rs

@@ -0,0 +1,32 @@
+use variadics_please::all_tuples;
+
+fn main() {}
+
+pub trait Foo {
+    const FOO_HARDER: bool;
+    fn foo() -> bool;
+}
+
+macro_rules! impl_tuple_foo {
+    ($(#[$meta:meta])* $($name: ident),*) => {
+        #[allow(unused_variables)]
+        #[allow(non_snake_case)]
+        #[allow(clippy::unused_unit)]
+        $(#[$meta])*
+        impl<$($name: Foo),*> Foo for ($($name,)*) {
+            const FOO_HARDER: bool = true $(&& $name::FOO_HARDER)*;
+
+            fn foo() -> bool {
+                true
+            }
+        }
+    };
+}
+
+all_tuples!(
+    #[doc(fake_variadic)]
+    impl_tuple_foo,
+    0,
+    15,
+    F
+);