TypeCheckType: Fix existential 'any' migration diagnostics for extra-modular protocols

AnthonyLatsis · AnthonyLatsis · commit 1939ca06a9fd · 2023-04-12T22:56:01.000+03:00
diff --git a/include/swift/AST/Decl.h b/include/swift/AST/Decl.h
@@ -4874,8 +4874,14 @@ class ProtocolDecl final : public NominalTypeDecl {
   bool requiresSelfConformanceWitnessTable() const;
 
   /// Determine whether an existential type must be explicitly prefixed
-  /// with \c any. \c any is required if any of the members contain
-  /// an associated type, or if \c Self appears in non-covariant position.
+  /// with \c any. \c any is required if one of the following conditions is met
+  /// for this protocol or an inherited protocol:
+  /// - The protocol has an associated type requirement.
+  /// - `Self` appears in non-covariant position in the type signature of a
+  ///   value requirement.
+  ///
+  /// @Note This method does not take the state of language features into
+  /// account.
   bool existentialRequiresAny() const;
 
   /// Returns a list of protocol requirements that must be assessed to
diff --git a/lib/Sema/TypeCheckDecl.cpp b/lib/Sema/TypeCheckDecl.cpp
@@ -714,10 +714,6 @@ ExistentialConformsToSelfRequest::evaluate(Evaluator &evaluator,
 bool
 ExistentialRequiresAnyRequest::evaluate(Evaluator &evaluator,
                                         ProtocolDecl *decl) const {
-  auto &ctx = decl->getASTContext();
-  if (ctx.LangOpts.hasFeature(Feature::ExistentialAny))
-    return true;
-
   // ObjC protocols do not require `any`.
   if (decl->isObjC())
     return false;
diff --git a/lib/Sema/TypeCheckType.cpp b/lib/Sema/TypeCheckType.cpp
@@ -5127,6 +5127,10 @@ class ExistentialTypeVisitor
     if (T->isInvalid())
       return;
 
+    if (Ctx.LangOpts.hasFeature(Feature::ImplicitSome)) {
+      return;
+    }
+
     // Compute the type repr to attach 'any' to.
     TypeRepr *replaceRepr = T;
     // Insert parens in expression context for '(any P).self'
@@ -5159,7 +5163,8 @@ class ExistentialTypeVisitor
       OS << ")";
 
     if (auto *proto = dyn_cast_or_null<ProtocolDecl>(T->getBoundDecl())) {
-      if (proto->existentialRequiresAny() && !Ctx.LangOpts.hasFeature(Feature::ImplicitSome)) {
+      if (Ctx.LangOpts.hasFeature(Feature::ExistentialAny) ||
+          proto->existentialRequiresAny()) {
         Ctx.Diags.diagnose(T->getNameLoc(),
                            diag::existential_requires_any,
                            proto->getDeclaredInterfaceType(),
@@ -5177,7 +5182,8 @@ class ExistentialTypeVisitor
       if (type->isConstraintType()) {
         auto layout = type->getExistentialLayout();
         for (auto *protoDecl : layout.getProtocols()) {
-          if (!protoDecl->existentialRequiresAny() || Ctx.LangOpts.hasFeature(Feature::ImplicitSome))
+          if (!Ctx.LangOpts.hasFeature(Feature::ExistentialAny) &&
+              !protoDecl->existentialRequiresAny())
             continue;
 
           Ctx.Diags.diagnose(T->getNameLoc(),
diff --git a/test/type/explicit_existential.swift b/test/type/explicit_existential.swift
@@ -207,17 +207,9 @@ extension MyError {
   }
 }
 
-struct Wrapper {
-  typealias E = Error
-}
-
-func typealiasMemberReferences(metatype: Wrapper.Type) {
-  let _: Wrapper.E.Protocol = metatype.E.self
-  let _: (any Wrapper.E).Type = metatype.E.self
-}
-
 func testAnyTypeExpr() {
   let _: (any P).Type = (any P).self
+  let _: (any P1 & P2).Type = (any P1 & P2).self
 
   func test(_: (any P).Type) {}
   test((any P).self)
@@ -281,6 +273,12 @@ enum EE : Equatable, any Empty { // expected-error {{raw type 'any Empty' is not
   case hack
 }
 
+// Protocols from a serialized module (the standard library).
+do {
+  let _: Decodable
+  let _: Codable
+}
+
 func testAnyFixIt() {
   struct ConformingType : HasAssoc {
     typealias Assoc = Int
@@ -302,6 +300,19 @@ func testAnyFixIt() {
   // expected-error@+2 {{use of protocol 'HasAssoc' as a type must be written 'any HasAssoc'}}{{10-18=(any HasAssoc)}}
   // expected-error@+1 {{use of protocol 'HasAssoc' as a type must be written 'any HasAssoc'}}{{30-38=(any HasAssoc)}}
   let _: HasAssoc.Protocol = HasAssoc.self
+  do {
+    struct Wrapper {
+      typealias HasAssocAlias = HasAssoc
+    }
+    let wrapperMeta: Wrapper.Type
+    // FIXME: Both of these fix-its are wrong.
+    // 1. 'any' is attached to 'HasAssocAlias' instead of 'Wrapper.HasAssocAlias'
+    // 2. What is the correct fix-it for the initializer?
+    //
+    // expected-error@+2:20 {{use of 'Wrapper.HasAssocAlias' (aka 'HasAssoc') as a type must be written 'any Wrapper.HasAssocAlias' (aka 'any HasAssoc')}}{{20-33=(any HasAssocAlias)}}
+    // expected-error@+1:57 {{use of 'Wrapper.HasAssocAlias' (aka 'HasAssoc') as a type must be written 'any Wrapper.HasAssocAlias' (aka 'any HasAssoc')}}{{57-70=(any HasAssocAlias)}}
+    let _: Wrapper.HasAssocAlias.Protocol = wrapperMeta.HasAssocAlias.self
+  }
   // expected-error@+1 {{use of protocol 'HasAssoc' as a type must be written 'any HasAssoc'}}{{11-19=any HasAssoc}}
   let _: (HasAssoc).Protocol = (any HasAssoc).self
   // expected-error@+1 {{use of protocol 'HasAssoc' as a type must be written 'any HasAssoc'}}{{10-18=(any HasAssoc)}}
diff --git a/test/type/explicit_existential_multimodule1.swift b/test/type/explicit_existential_multimodule1.swift
@@ -0,0 +1,15 @@
+// RUN: %empty-directory(%t)
+// RUN: %target-swift-frontend %s         -swift-version 5 -emit-module -DM -module-name M -emit-module-path %t/M.swiftmodule -enable-upcoming-feature ExistentialAny
+// RUN: %target-swift-frontend %s -verify -swift-version 5 -typecheck -I %t
+
+// Test that the feature state used to compile a module is not reflected in
+// the module file. The feature must not be enforced on protocols originating in
+// a different module just because that module was compiled with the feature
+// enabled.
+
+#if M
+public protocol P {}
+#else
+import M
+func test(_: P) {}
+#endif
diff --git a/test/type/explicit_existential_multimodule2.swift b/test/type/explicit_existential_multimodule2.swift
@@ -0,0 +1,15 @@
+// RUN: %empty-directory(%t)
+// RUN: %target-swift-frontend %s         -swift-version 5 -emit-module -DM -module-name M -emit-module-path %t/M.swiftmodule
+// RUN: %target-swift-frontend %s -verify -swift-version 5 -typecheck -I %t -enable-upcoming-feature ExistentialAny
+
+// Test that a protocol that requires 'any' *only* when the feature is enabled
+// is diagnosed as expected when said protocol originates in a different module.
+// In other words, test that deserialization does not affect 'any' migration
+// diagnostics.
+
+#if M
+public protocol P {}
+#else
+import M
+func test(_: P) {} // expected-error {{use of protocol 'P' as a type must be written 'any P'}}
+#endif
diff --git a/test/type/explicit_existential_swift6.swift b/test/type/explicit_existential_swift6.swift
@@ -229,17 +229,9 @@ extension MyError {
   }
 }
 
-struct Wrapper {
-  typealias E = Error
-}
-
-func typealiasMemberReferences(metatype: Wrapper.Type) {
-  let _: Wrapper.E.Protocol = metatype.E.self
-  let _: (any Wrapper.E).Type = metatype.E.self
-}
-
 func testAnyTypeExpr() {
   let _: (any P).Type = (any P).self
+  let _: (any P1 & P2).Type = (any P1 & P2).self
 
   func test(_: (any P).Type) {}
   test((any P).self)
@@ -311,6 +303,13 @@ enum EE : Equatable, any Empty { // expected-error {{raw type 'any Empty' is not
   case hack
 }
 
+// Protocols from a serialized module (the standard library).
+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')}}
+  let _: Codable
+}
 
 func testAnyFixIt() {
   struct ConformingType : HasAssoc {
@@ -333,6 +332,19 @@ func testAnyFixIt() {
   // expected-error@+2 {{use of protocol 'HasAssoc' as a type must be written 'any HasAssoc'}}{{10-18=(any HasAssoc)}}
   // expected-error@+1 {{use of protocol 'HasAssoc' as a type must be written 'any HasAssoc'}}{{30-38=(any HasAssoc)}}
   let _: HasAssoc.Protocol = HasAssoc.self
+  do {
+    struct Wrapper {
+      typealias HasAssocAlias = HasAssoc
+    }
+    let wrapperMeta: Wrapper.Type
+    // FIXME: Both of these fix-its are wrong.
+    // 1. 'any' is attached to 'HasAssocAlias' instead of 'Wrapper.HasAssocAlias'
+    // 2. What is the correct fix-it for the initializer?
+    //
+    // expected-error@+2:20 {{use of 'Wrapper.HasAssocAlias' (aka 'HasAssoc') as a type must be written 'any Wrapper.HasAssocAlias' (aka 'any HasAssoc')}}{{20-33=(any HasAssocAlias)}}
+    // expected-error@+1:57 {{use of 'Wrapper.HasAssocAlias' (aka 'HasAssoc') as a type must be written 'any Wrapper.HasAssocAlias' (aka 'any HasAssoc')}}{{57-70=(any HasAssocAlias)}}
+    let _: Wrapper.HasAssocAlias.Protocol = wrapperMeta.HasAssocAlias.self
+  }
   // expected-error@+1 {{use of protocol 'HasAssoc' as a type must be written 'any HasAssoc'}}{{11-19=any HasAssoc}}
   let _: (HasAssoc).Protocol = (any HasAssoc).self
   // expected-error@+1 {{use of protocol 'HasAssoc' as a type must be written 'any HasAssoc'}}{{10-18=(any HasAssoc)}}
