AST: Fix TypeBase::hasSimpleTypeRepr() for ProtocolCompositionType

Prior to the introduction of noncopyable generics, a ProtocolCompositionType
was 'simple' if it was exactly 'Any' or 'AnyObject'. Now, there is a new
simple case, where we have a single inverse requirement '~Copyable' or
'~Escapable', and the old logic was never updated to account for this
possibility. Instead, it would ignore inverses, so it would claim that
a composition like `P & ~Copyable` was simple when it shouldn't be.

Fixes rdar://139465298.

Author: slavapestov

lib/AST/Type.cpp

@@ -4561,11 +4561,28 @@ bool TypeBase::hasSimpleTypeRepr() const {
   }
 
   case TypeKind::ProtocolComposition: {
-    // 'Any', 'AnyObject' and single protocol compositions are simple
     auto composition = cast<const ProtocolCompositionType>(this);
+
+    // A protocol composition is simple if its syntactic representation does not
+    // involve `&`. This is true if we have 'Any', 'AnyObject', or a single
+    // inverse requirement like `~Copyable`.
+
+    // All other protocol compositions contain at least two `&`-separated terms.
+
+    // Add each logical member Foo.
     auto memberCount = composition->getMembers().size();
+
+    // And each inverse requirement ~Foo.
+    for (auto ip : composition->getInverses()) {
+      (void) ip;
+      ++memberCount;
+    }
+
+    // And finally, AnyObject.
     if (composition->hasExplicitAnyObject())
-      return memberCount == 0;
+      ++memberCount;
+
+    // Almost always, this will be > 1.
     return memberCount <= 1;
   }
 

test/ModuleInterface/existential-any.swift

@@ -46,3 +46,22 @@ public protocol ProtocolTypealias {
 
 // CHECK: public func dependentExistential<T>(value: (T) -> any main.P) where T : main.ProtocolTypealias
 public func dependentExistential<T: ProtocolTypealias>(value: (T) -> T.A) {}
+
+public protocol Yescopyable {}
+public protocol Noncopyable: ~Copyable {}
+
+// CHECK: public func existentialMetatype1(_: any (main.Noncopyable & ~Copyable).Type)
+// CHECK: public func existentialMetatype2(_: any (main.Noncopyable & main.Yescopyable).Type)
+// CHECK: public func existentialMetatype3(_: any ~Copyable.Type)
+
+public func existentialMetatype1(_: any (Noncopyable & ~Copyable).Type) {}
+public func existentialMetatype2(_: any (Yescopyable & Noncopyable).Type) {}
+public func existentialMetatype3(_: any ~Copyable.Type) {}
+
+// CHECK: public func metatypeExistential1(_: (any main.Noncopyable & ~Copyable).Type)
+// CHECK: public func metatypeExistential2(_: (any main.Noncopyable & main.Yescopyable).Type)
+// CHECK: public func metatypeExistential3(_: (any ~Copyable).Type)
+
+public func metatypeExistential1(_: (any Noncopyable & ~Copyable).Type) {}
+public func metatypeExistential2(_: (any Yescopyable & Noncopyable).Type) {}
+public func metatypeExistential3(_: (any ~Copyable).Type) {}