Merge pull request #71928 from kavon/ncgenerics-fixes-1

NCGenerics: fix ExistentialAny handling

Author: kavon

lib/Sema/TypeCheckType.cpp

@@ -6079,12 +6079,23 @@ class ExistentialTypeSyntaxChecker : public ASTWalker {
       // If this is a type alias to a constraint type, the type
       // alias name must be prefixed with 'any' to be used as an
       // existential type.
-      if (type->isConstraintType()) {
+      if (type->isConstraintType() && !type->isAny() && !type->isAnyObject()) {
+        bool diagnose = false;
+
+        // Look for protocol members that require 'any'.
         auto layout = type->getExistentialLayout();
         for (auto *protoDecl : layout.getProtocols()) {
-          if (!protoDecl->existentialRequiresAny())
-            continue;
+          if (protoDecl->existentialRequiresAny()) {
+            diagnose = true;
+            break;
+          }
+        }
+
+        // If inverses are present, require 'any' too.
+        if (auto *PCT = type->getAs<ProtocolCompositionType>())
+          diagnose |= !PCT->getInverses().empty();
 
+        if (diagnose) {
           auto diag = Ctx.Diags.diagnose(
               T->getNameLoc(), diag::existential_requires_any,
               alias->getDeclaredInterfaceType(),

test/Generics/inverse_generics.swift

@@ -466,6 +466,14 @@ func checkExistentials() {
     let _: any Escapable & ~Escapable = 1 // expected-error {{composition cannot contain '~Escapable' when another member requires 'Escapable'}}
 }
 
+typealias NotCopyable = ~Copyable
+typealias EmptyComposition = ~Copyable & ~Escapable
+func test(_ t: borrowing NotCopyable) {} // expected-error {{use of 'NotCopyable' (aka '~Copyable') as a type must be written 'any NotCopyable'}}
+func test(_ t: borrowing EmptyComposition) {} // expected-error {{use of 'EmptyComposition' (aka '~Copyable & ~Escapable') as a type must be written 'any EmptyComposition' (aka 'any ~Copyable & ~Escapable')}}
+
+typealias Copy = Copyable
+func test(_ z1: Copy, _ z2: Copyable) {}
+
 // Conformances can be conditional on whether a generic parameter is Copyable
 protocol Arbitrary {}
 protocol AnotherOne {}

test/type/explicit_existential_swift6.swift

@@ -1,4 +1,5 @@
 // RUN: %target-typecheck-verify-swift -enable-upcoming-feature ExistentialAny
+// RUN: %target-typecheck-verify-swift -enable-upcoming-feature ExistentialAny -enable-experimental-feature NoncopyableGenerics
 
 protocol HasSelfRequirements {
   func foo(_ x: Self)
@@ -276,7 +277,7 @@ typealias Constraint = Input
 typealias ConstraintB = Input & InputB
 
 //expected-error@+2{{use of 'Constraint' (aka 'Input') as a type must be written 'any Constraint' (aka 'any Input')}}
-//expected-error@+1 2{{use of 'ConstraintB' (aka 'Input & InputB') as a type must be written 'any ConstraintB' (aka 'any Input & InputB')}}
+//expected-error@+1 {{use of 'ConstraintB' (aka 'Input & InputB') as a type must be written 'any ConstraintB' (aka 'any Input & InputB')}}
 func testConstraintAlias(x: Constraint, y: ConstraintB) {}
 
 typealias Existential = any Input
@@ -307,7 +308,7 @@ enum EE : Equatable, any Empty { // expected-error {{raw type 'any Empty' is not
 do {
   // expected-error@+1 {{use of protocol 'Decodable' as a type must be written 'any Decodable'}}
   let _: Decodable
-  // expected-error@+1 2 {{use of 'Codable' (aka 'Decodable & Encodable') as a type must be written 'any Codable' (aka 'any Decodable & Encodable')}}
+  // expected-error@+1 {{use of 'Codable' (aka 'Decodable & Encodable') as a type must be written 'any Codable' (aka 'any Decodable & Encodable')}}
   let _: Codable
 }
 
@@ -395,3 +396,14 @@ protocol PP {}
 struct A : PP {}
 let _: any PP = A() // Ok
 let _: any (any PP) = A() // expected-error{{redundant 'any' in type 'any (any PP)'}} {{8-12=}}
+
+// coverage for rdar://123332844
+let x: Any.Type = AnyObject.self
+let y: Any.Type = Any.self
+
+typealias Objectlike = AnyObject
+func f(_ x: Objectlike) {}
+
+typealias Copy = Copyable
+func h(_ z1: Copy, // expected-error {{use of 'Copy' (aka 'Copyable') as a type must be written 'any Copy' (aka 'any Copyable')}}
+       _ z2: Copyable) {} // expected-error {{use of protocol 'Copyable' as a type must be written 'any Copyable'}}