[Concurrency] correct some strict concurrency warnings to be errors in Swift 6

Author: sophiapoirier

include/swift/AST/DiagnosticsSema.def

@@ -5518,18 +5518,18 @@ ERROR(distributed_actor_remote_func_must_not_be_distributed,none,
 NOTE(actor_mutable_state,none,
      "mutation of this %0 is only permitted within the actor",
      (DescriptiveDeclKind))
-WARNING(shared_mutable_state_access,none,
-        "reference to %kind0 is not concurrency-safe because it involves "
-        "shared mutable state", (const ValueDecl *))
-WARNING(shared_mutable_state_decl,none,
-        "%kind0 is not concurrency-safe because it is non-isolated global "
-        "shared mutable state", (const ValueDecl *))
+ERROR(shared_mutable_state_access,none,
+      "reference to %kind0 is not concurrency-safe because it involves shared "
+      "mutable state", (const ValueDecl *))
+ERROR(shared_mutable_state_decl,none,
+      "%kind0 is not concurrency-safe because it is non-isolated global shared "
+      "mutable state", (const ValueDecl *))
 NOTE(shared_mutable_state_decl_note,none,
      "isolate %0 to a global actor, or convert it to a 'let' constant and "
      "conform it to 'Sendable'", (const ValueDecl *))
-WARNING(shared_immutable_state_decl,none,
-        "%kind0 is not concurrency-safe because it is not either conforming to "
-        "'Sendable' or isolated to a global actor", (const ValueDecl *))
+ERROR(shared_immutable_state_decl,none,
+      "%kind0 is not concurrency-safe because it is not either conforming to "
+      "'Sendable' or isolated to a global actor", (const ValueDecl *))
 ERROR(actor_isolated_witness,none,
      "%select{|distributed }0%1 %kind2 cannot be used to satisfy %3 protocol "
      "requirement",

lib/Sema/TypeCheckConcurrency.cpp

@@ -2962,7 +2962,8 @@ namespace {
         return false;
       }
 
-      ctx.Diags.diagnose(loc, diag::shared_mutable_state_access, value);
+      ctx.Diags.diagnose(loc, diag::shared_mutable_state_access, value)
+          .warnUntilSwiftVersion(6);
       value->diagnose(diag::kind_declared_here, value->getDescriptiveKind());
       return true;
     }

test/Concurrency/experimental_feature_strictconcurrency.swift

@@ -1,6 +1,6 @@
-// RUN: %target-swift-frontend -disable-availability-checking -parse-as-library -enable-experimental-feature StrictConcurrency -enable-experimental-feature GlobalConcurrency -emit-sil -o /dev/null -verify %s
-// RUN: %target-swift-frontend -disable-availability-checking -parse-as-library -enable-experimental-feature StrictConcurrency=complete -enable-experimental-feature GlobalConcurrency -emit-sil -o /dev/null -verify %s
-// RUN: %target-swift-frontend -disable-availability-checking -parse-as-library -enable-experimental-feature StrictConcurrency=complete -enable-experimental-feature GlobalConcurrency -emit-sil -o /dev/null -verify -verify-additional-prefix region-isolation- -enable-experimental-feature RegionBasedIsolation %s
+// RUN: %target-swift-frontend -disable-availability-checking -parse-as-library -enable-experimental-feature StrictConcurrency -enable-experimental-feature GlobalConcurrency -swift-version 6 -emit-sil -o /dev/null -verify %s
+// RUN: %target-swift-frontend -disable-availability-checking -parse-as-library -enable-experimental-feature StrictConcurrency=complete -enable-experimental-feature GlobalConcurrency -swift-version 6 -emit-sil -o /dev/null -verify %s
+// RUN: %target-swift-frontend -disable-availability-checking -parse-as-library -enable-experimental-feature StrictConcurrency=complete -enable-experimental-feature GlobalConcurrency -swift-version 6 -emit-sil -o /dev/null -verify -verify-additional-prefix region-isolation- -enable-experimental-feature RegionBasedIsolation %s
 
 // REQUIRES: concurrency
 // REQUIRES: asserts
@@ -15,11 +15,11 @@ protocol TestProtocol {
   associatedtype Value: Sendable
 }
 
-struct Test1: TestProtocol { // expected-warning{{type 'Test1.Value' (aka 'C1') does not conform to the 'Sendable' protocol}}
+struct Test1: TestProtocol { // expected-error{{type 'Test1.Value' (aka 'C1') does not conform to the 'Sendable' protocol}}
   typealias Value = C1
 }
 
-struct Test2: TestProtocol { // expected-warning{{conformance of 'C2' to 'Sendable' is unavailable}}
+struct Test2: TestProtocol { // expected-error{{conformance of 'C2' to 'Sendable' is unavailable}}
   // expected-note@-1{{in associated type 'Self.Value' (inferred as 'C2')}}
   typealias Value = C2
 }
@@ -32,7 +32,7 @@ actor TestGlobalActor {
 @TestGlobalActor
 var mutableIsolatedGlobal = 1
 
-var mutableNonisolatedGlobal = 1 // expected-warning{{var 'mutableNonisolatedGlobal' is not concurrency-safe because it is non-isolated global shared mutable state}}
+var mutableNonisolatedGlobal = 1 // expected-error{{var 'mutableNonisolatedGlobal' is not concurrency-safe because it is non-isolated global shared mutable state}}
 // expected-note@-1{{isolate 'mutableNonisolatedGlobal' to a global actor, or convert it to a 'let' constant and conform it to 'Sendable'}}
 
 let immutableGlobal = 1
@@ -57,23 +57,23 @@ public struct TestWrapper {
 
 struct TestStatics {
   static let immutableExplicitSendable = TestSendable()
-  static let immutableNonsendable = TestNonsendable() // expected-warning{{static property 'immutableNonsendable' is not concurrency-safe because it is not either conforming to 'Sendable' or isolated to a global actor}}
+  static let immutableNonsendable = TestNonsendable() // expected-error{{static property 'immutableNonsendable' is not concurrency-safe because it is not either conforming to 'Sendable' or isolated to a global actor}}
   static nonisolated(unsafe) let immutableNonisolatedUnsafe = TestNonsendable()
-  static nonisolated let immutableNonisolated = TestNonsendable() // expected-warning{{static property 'immutableNonisolated' is not concurrency-safe because it is not either conforming to 'Sendable' or isolated to a global actor}}
+  static nonisolated let immutableNonisolated = TestNonsendable() // expected-error{{static property 'immutableNonisolated' is not concurrency-safe because it is not either conforming to 'Sendable' or isolated to a global actor}}
   static let immutableInferredSendable = 0
-  static var mutable = 0 // expected-warning{{static property 'mutable' is not concurrency-safe because it is non-isolated global shared mutable state}}
+  static var mutable = 0 // expected-error{{static property 'mutable' is not concurrency-safe because it is non-isolated global shared mutable state}}
   // expected-note@-1{{isolate 'mutable' to a global actor, or convert it to a 'let' constant and conform it to 'Sendable'}}
   // expected-note@-2{{static property declared here}}
   static var computedProperty: Int { 0 } // computed property that, though static, has no storage so is not a global
-  @TestWrapper static var wrapped: Int // expected-warning{{static property 'wrapped' is not concurrency-safe because it is non-isolated global shared mutable state}}
+  @TestWrapper static var wrapped: Int // expected-error{{static property 'wrapped' is not concurrency-safe because it is non-isolated global shared mutable state}}
   // expected-note@-1{{isolate 'wrapped' to a global actor, or convert it to a 'let' constant and conform it to 'Sendable'}}
 }
 
 @TestGlobalActor
 func f() {
   print(TestStatics.immutableExplicitSendable)
   print(TestStatics.immutableInferredSendable)
-  print(TestStatics.mutable) // expected-warning{{reference to static property 'mutable' is not concurrency-safe because it involves shared mutable state}}
+  print(TestStatics.mutable) // expected-error{{reference to static property 'mutable' is not concurrency-safe because it involves shared mutable state}}
 }
 
 func testLocalNonisolatedUnsafe() async {