Limit ConcurrentValue inference to non-public, non-frozen structs and enums

Author: DougGregor

lib/Sema/TypeCheckConcurrency.cpp

@@ -2504,10 +2504,21 @@ bool swift::checkConcurrentValueConformance(
 
 NormalProtocolConformance *GetImplicitConcurrentValueRequest::evaluate(
     Evaluator &evaluator, NominalTypeDecl *nominal) const {
-  // Only structs and enums get implicit ConcurrentValue conformances.
+  // Only structs and enums can get implicit ConcurrentValue conformances.
   if (!isa<StructDecl>(nominal) && !isa<EnumDecl>(nominal))
     return nullptr;
 
+  // Public, non-frozen structs and enums defined in Swift don't get implicit
+  // ConcurrentValue conformances.
+  if (nominal->getFormalAccessScope(
+          /*useDC=*/nullptr,
+          /*treatUsableFromInlineAsPublic=*/true).isPublic() &&
+      !(nominal->hasClangNode() ||
+        nominal->getAttrs().hasAttribute<FixedLayoutAttr>() ||
+        nominal->getAttrs().hasAttribute<FrozenAttr>())) {
+    return nullptr;
+  }
+
   // Check the context in which the conformance occurs.
   if (auto *file = dyn_cast<FileUnit>(nominal->getModuleScopeContext())) {
     switch (file->getKind()) {

test/ClangImporter/objc_async.swift

@@ -93,3 +93,9 @@ actor MySubclassCheckingSwiftAttributes : ProtocolWithSwiftAttributes {
 
   func uiActorMethod() { }
 }
+
+// ConcurrentValue conformance inference for imported types.
+func acceptCV<T: ConcurrentValue>(_: T) { }
+func testCV(r: NSRange) {
+  acceptCV(r)
+}

test/Concurrency/concurrent_value_inference.swift

@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift
+// RUN: %target-typecheck-verify-swift -enable-library-evolution
 
 class C1 { }
 final class C2: ConcurrentValue { }
@@ -26,7 +26,7 @@ struct GS2<T> {
 }
 
 func acceptCV<T: ConcurrentValue>(_: T) { }
-// expected-note@-1 4{{where 'T' =}}
+// expected-note@-1 6{{where 'T' =}}
 
 // Example that was triggering circular dependencies.
 struct Signature { }
@@ -62,10 +62,28 @@ enum BitcodeElement {
   case record(Record)
 }
 
+// Public structs and enums do not get implicit ConcurrentValue unless they
+// are frozen.
+public struct PublicStruct {
+  var i: Int
+}
+
+public enum PublicEnum {
+  case some
+}
+
+@frozen public struct FrozenPublicStruct {
+  var i: Int
+}
+
+@frozen public enum FrozenPublicEnum {
+  case some
+}
 
 func testCV(
   c1: C1, c2: C2, s1: S1, e1: E1, e2: E2, gs1: GS1<Int>, gs2: GS2<Int>,
-  bc: Bitcode
+  bc: Bitcode, ps: PublicStruct, pe: PublicEnum,
+  fps: FrozenPublicStruct, fpe: FrozenPublicEnum
 ) {
   acceptCV(c1) // expected-error{{'C1' conform to 'ConcurrentValue'}}
   acceptCV(c2)
@@ -75,6 +93,14 @@ func testCV(
   acceptCV(gs1)
   acceptCV(gs2) // expected-error{{'GS2<Int>' conform to 'ConcurrentValue'}}
 
-  // Note available due to recursive conformance dependencies.
+  // Not available due to recursive conformance dependencies.
   acceptCV(bc) // expected-error{{global function 'acceptCV' requires that 'Bitcode' conform to 'ConcurrentValue'}}
+
+  // Not available due to "public".
+  acceptCV(ps) // expected-error{{global function 'acceptCV' requires that 'PublicStruct' conform to 'ConcurrentValue'}}
+  acceptCV(pe) // expected-error{{global function 'acceptCV' requires that 'PublicEnum' conform to 'ConcurrentValue'}}
+
+  // Public is okay when also @frozen.
+  acceptCV(fps)
+  acceptCV(fpe)
 }

test/Incremental/Verifier/multi-file-private/Inputs/Inner.swift

@@ -12,4 +12,3 @@ public func blah(foo: Foo) {}
 public var defaultFoo: Foo = {
   return Inner()
 }
-// expected-superclass{{main.Inner}}

test/Serialization/multi-file-type-eraser.swift

@@ -8,7 +8,7 @@
 // Ensure we don't crash during merge-modules - no matter the order of inputs.
 
 // CHECK: Statistics
-// CHECK: 3 Serialization - # of normal protocol conformances completed
+// CHECK: 2 Serialization - # of normal protocol conformances completed
 
 public struct AnyWindows : Vista {
   public init<V: Vista>(erasing vista: V) {

test/SymbolGraph/Relationships/ConformsTo/Basic.swift

@@ -11,6 +11,6 @@ public struct S: P {
   public var x: Int
 }
 
-// CHECK-DAG: "kind": "conformsTo"
-// CHECK-DAG: "source": "s:5Basic1SV"
-// CHECK-DAG: "target": "s:5Basic1PP"
+// CHECK: "kind": "conformsTo"
+// CHECK-NEXT: "source": "s:5Basic1SV"
+// CHECK-NEXT: "target": "s:5Basic1PP"

test/SymbolGraph/Relationships/TargetFallback.swift

@@ -10,12 +10,7 @@ public struct S: CustomStringConvertible {
   }
 }
 
-// CHECK-DAG:      "kind": "conformsTo",
-// CHECK-DAG: "source": "s:14TargetFallback1SV",
-// CHECK-DAG: "target": "s:s15ConcurrentValueP",
-// CHECK-DAG: "targetFallback": "Swift.ConcurrentValue"
-
-// CHECK-DAG:      "kind": "conformsTo",
-// CHECK-DAG: "source": "s:14TargetFallback1SV",
-// CHECK-DAG: "target": "s:s23CustomStringConvertibleP",
-// CHECK-DAG: "targetFallback": "Swift.CustomStringConvertible"
+// CHECK:      "kind": "conformsTo",
+// CHECK-NEXT: "source": "s:14TargetFallback1SV",
+// CHECK-NEXT: "target": "s:s23CustomStringConvertibleP",
+// CHECK-NEXT: "targetFallback": "Swift.CustomStringConvertible"

test/SymbolGraph/Something/Something.swift

@@ -10,10 +10,6 @@ public struct MyStruct: P {
   public func foo() {}
 }
 
-// CHECK-DAG: "kind": "conformsTo",
-// CHECK-DAG: "source": "s:9Something8MyStructV",
-// CHECK-DAG: "target": "s:s15ConcurrentValueP",
-
-// CHECK-DAG: "kind": "conformsTo",
-// CHECK-DAG: "source": "s:9Something8MyStructV",
-// CHECK-DAG: "target": "s:12SomeProtocol1PP",
+// CHECK: "kind": "conformsTo",
+// CHECK-NEXT: "source": "s:9Something8MyStructV",
+// CHECK-NEXT: "target": "s:12SomeProtocol1PP",

test/SymbolGraph/Symbols/SkipsPublicUnderscore.swift

@@ -60,7 +60,4 @@ extension _ShouldntAppear.InnerShouldntAppear {
 
 extension _ShouldntAppear.InnerShouldntAppear: Equatable {}
 
-// CHECK: "relationships": [
-// CHECK: "kind": "conformsTo",
-// CHECK: "source": "s:21SkipsPublicUnderscore0B5OuterV",
-// CHECK-NEXT: "target": "s:s15ConcurrentValueP",
+// CHECK: "relationships": []

test/api-digester/Outputs/Cake-abi.txt

@@ -90,6 +90,7 @@ cake: Var fixedLayoutStruct2.NoLongerWithFixedBinaryOrder is no longer a stored
 /* Protocol Conformance Change */
 cake: Class C7 has added a conformance to an existing protocol P1
 cake: Class SuperClassChange has added a conformance to an existing protocol P1
+cake: Enum IceKind has removed conformance to ConcurrentValue
 cake: Protocol P3 has added inherited protocol P4
 cake: Protocol P3 has removed inherited protocol P2
 cake: Struct fixedLayoutStruct has added a conformance to an existing protocol P2

test/api-digester/Outputs/Cake.txt

@@ -48,6 +48,7 @@ cake: Var C1.CIIns2 changes from strong to weak
 cake: EnumElement FrozenKind.AddedCase has been added as a new enum case
 
 /* Conformance changes */
+cake: Enum IceKind has removed conformance to ConcurrentValue
 cake: Func ObjCProtocol.removeOptional() is no longer an optional requirement
 cake: Protocol P3 has added inherited protocol P4
 cake: Protocol P3 has removed inherited protocol P2

test/api-digester/Outputs/cake-abi.json

@@ -655,12 +655,6 @@
             }
           ],
           "usr": "s:SY"
-        },
-        {
-          "kind": "Conformance",
-          "name": "ConcurrentValue",
-          "printedName": "ConcurrentValue",
-          "usr": "s:s15ConcurrentValueP"
         }
       ]
     },

test/api-digester/Outputs/cake.json

@@ -675,12 +675,6 @@
             }
           ],
           "usr": "s:SY"
-        },
-        {
-          "kind": "Conformance",
-          "name": "ConcurrentValue",
-          "printedName": "ConcurrentValue",
-          "usr": "s:s15ConcurrentValueP"
         }
       ]
     },