[Concurrency] Compute actor isolation for var decls before checking

decl attributes.

(cherry picked from commit 275d783)

Author: hborla

lib/Sema/TypeCheckAttr.cpp

@@ -6636,7 +6636,8 @@ void AttributeChecker::visitNonisolatedAttr(NonisolatedAttr *attr) {
     // backing storage is a stored 'var' that is part of the internal state
     // of the actor which could only be accessed in actor's isolation context.
     if (var->hasAttachedPropertyWrapper()) {
-      diagnoseAndRemoveAttr(attr, diag::nonisolated_wrapped_property);
+      diagnoseAndRemoveAttr(attr, diag::nonisolated_wrapped_property)
+        .warnUntilSwiftVersionIf(attr->isImplicit(), 6);
       return;
     }
 

lib/Sema/TypeCheckDeclPrimary.cpp

@@ -2165,6 +2165,7 @@ class DeclChecker : public DeclVisitor<DeclChecker> {
     (void) VD->getPropertyWrapperAuxiliaryVariables();
     (void) VD->getPropertyWrapperInitializerInfo();
     (void) VD->getImplInfo();
+    (void) getActorIsolation(VD);
 
     // Visit auxiliary decls first
     VD->visitAuxiliaryDecls([&](VarDecl *var) {

test/Concurrency/global_actor_inference.swift

@@ -390,7 +390,7 @@ struct HasWrapperOnActor {
     synced = 17
   }
 
-  @WrapperActor var actorSynced: Int = 0
+  @WrapperActor var actorSynced: Int = 0 // expected-warning{{'nonisolated' is not supported on properties with property wrappers}}
 
   func testActorSynced() {
     _ = actorSynced
@@ -491,10 +491,10 @@ struct SimplePropertyWrapper {
 class WrappedContainsNonisolatedAttr {
   @SimplePropertyWrapper nonisolated var value 
   // expected-error@-1 {{'nonisolated' is not supported on properties with property wrappers}}
-  // expected-note@-2 2{{property declared here}}
+  // expected-note@-2 {{property declared here}}
 
   nonisolated func test() {
-    _ = value // expected-error {{main actor-isolated property 'value' can not be referenced from a non-isolated context}}
+    _ = value
     _ = $value // expected-error {{main actor-isolated property '$value' can not be referenced from a non-isolated context}}
   }
 }

test/Concurrency/global_actor_inference_swift6.swift

@@ -117,7 +117,7 @@ struct HasWrapperOnActor {
     synced = 17
   }
 
-  @WrapperActor var actorSynced: Int = 0
+  @WrapperActor var actorSynced: Int = 0 // expected-error{{'nonisolated' is not supported on properties with property wrappers}}
 
   func testActorSynced() {
     _ = actorSynced