[NCGenerics] Sendable doesn't require Copyable

Author: kavon

stdlib/public/core/Sendable.swift

@@ -129,7 +129,13 @@
 /// ### Sendable Metatypes
 ///
 /// Metatypes such as `Int.Type` implicitly conform to the `Sendable` protocol.
+#if $NoncopyableGenerics && $NonescapableTypes
+@_marker public protocol Sendable: ~Copyable, ~Escapable { }
+#elseif $NoncopyableGenerics
+@_marker public protocol Sendable: ~Copyable { }
+#else
 @_marker public protocol Sendable { }
+#endif
 ///
 /// A type whose values can safely be passed across concurrency domains by copying,
 /// but which disables some safety checking at the conformance site.

test/Generics/inverse_generics.swift

@@ -101,6 +101,8 @@ protocol Test: ~Copyable {
   init?() // expected-error {{noncopyable types cannot have failable initializers yet}}
 }
 
+struct NoncopyableAndSendable: ~Copyable, Sendable {}
+
 /// ---------------
 
 // expected-note@+2 {{consider adding '~Copyable' to generic enum 'Maybe'}}