[Concurrency] Remove swift::computeRequiredIsolation and change all callers to go

through the DefaultInitializerIsolation request.

Author: hborla

include/swift/AST/Decl.h

@@ -2273,7 +2273,9 @@ class PatternBindingDecl final : public Decl,
   void setInitializerSubsumed(unsigned i) {
     getMutablePatternList()[i].setInitializerSubsumed();
   }
-  
+
+  ActorIsolation getInitializerIsolation(unsigned i) const;
+
   /// Does this binding declare something that requires storage?
   bool hasStorage() const;
 

lib/AST/Decl.cpp

@@ -2088,6 +2088,14 @@ bool PatternBindingDecl::isAsyncLet() const {
   return false;
 }
 
+ActorIsolation
+PatternBindingDecl::getInitializerIsolation(unsigned i) const {
+  auto *var = getPatternList()[i].getAnchoringVarDecl();
+  if (!var)
+    return ActorIsolation::forUnspecified();
+
+  return var->getInitializerIsolation();
+}
 
 bool PatternBindingDecl::hasStorage() const {
   // Walk the pattern, to check to see if any of the VarDecls included in it

lib/Sema/TypeCheckConcurrency.cpp

@@ -3582,12 +3582,6 @@ void swift::checkFunctionActorIsolation(AbstractFunctionDecl *decl) {
   }
 }
 
-ActorIsolation 
-swift::computeRequiredIsolation(Initializer *init, Expr *expr) {
-  ActorIsolationChecker checker(init);
-  return checker.computeRequiredIsolation(expr);
-}
-
 void swift::checkEnumElementActorIsolation(
     EnumElementDecl *element, Expr *expr) {
   ActorIsolationChecker checker(element);
@@ -4618,6 +4612,48 @@ bool HasIsolatedSelfRequest::evaluate(
   return true;
 }
 
+ActorIsolation
+DefaultInitializerIsolation::evaluate(Evaluator &evaluator,
+                                      VarDecl *var) const {
+  if (var->isInvalid())
+    return ActorIsolation::forUnspecified();
+
+  Initializer *dc = nullptr;
+  Expr *initExpr = nullptr;
+
+  if (auto *pbd = var->getParentPatternBinding()) {
+    if (!var->isParentInitialized())
+      return ActorIsolation::forUnspecified();
+
+    auto i = pbd->getPatternEntryIndexForVarDecl(var);
+    dc = cast<Initializer>(pbd->getInitContext(i));
+    initExpr = var->getParentInitializer();
+  } else if (auto *param = dyn_cast<ParamDecl>(var)) {
+    // If this parameter corresponds to a stored property for a
+    // memberwise initializer, the default argument is the default
+    // initializer expression.
+    if (auto *property = param->getStoredProperty()) {
+      // FIXME: Force computation of property wrapper initializers.
+      if (auto *wrapped = property->getOriginalWrappedProperty())
+        (void)property->getPropertyWrapperInitializerInfo();
+
+      return property->getInitializerIsolation();
+    }
+
+    if (!param->hasDefaultExpr())
+      return ActorIsolation::forUnspecified();
+
+    dc = param->getDefaultArgumentInitContext();
+    initExpr = param->getTypeCheckedDefaultExpr();
+  }
+
+  if (!dc || !initExpr)
+    return ActorIsolation::forUnspecified();
+
+  ActorIsolationChecker checker(dc);
+  return checker.computeRequiredIsolation(initExpr);
+}
+
 void swift::checkOverrideActorIsolation(ValueDecl *value) {
   if (isa<TypeDecl>(value))
     return;

lib/Sema/TypeCheckConcurrency.h

@@ -59,10 +59,6 @@ void checkFunctionActorIsolation(AbstractFunctionDecl *decl);
 void checkEnumElementActorIsolation(EnumElementDecl *element, Expr *expr);
 void checkPropertyWrapperActorIsolation(VarDecl *wrappedVar, Expr *expr);
 
-/// Compute the actor isolation required in order to evaluate the given
-/// initializer expression synchronously.
-ActorIsolation computeRequiredIsolation(Initializer *init, Expr *expr);
-
 /// States the reason for checking the Sendability of a given declaration.
 enum class SendableCheckReason {
   /// A reference to an actor from outside that actor.

lib/Sema/TypeCheckDeclPrimary.cpp

@@ -1156,47 +1156,6 @@ Expr *DefaultArgumentExprRequest::evaluate(Evaluator &evaluator,
   return initExpr;
 }
 
-ActorIsolation 
-DefaultInitializerIsolation::evaluate(Evaluator &evaluator,
-                                      VarDecl *var) const {
-  if (var->isInvalid())
-    return ActorIsolation::forUnspecified();
-
-  Initializer *dc = nullptr;
-  Expr *initExpr = nullptr;
-
-  if (auto *pbd = var->getParentPatternBinding()) {
-    if (!var->isParentInitialized())
-      return ActorIsolation::forUnspecified();
-
-    auto i = pbd->getPatternEntryIndexForVarDecl(var);
-    dc = cast<Initializer>(pbd->getInitContext(i));
-    initExpr = var->getParentInitializer();
-  } else if (auto *param = dyn_cast<ParamDecl>(var)) {
-    // If this parameter corresponds to a stored property for a
-    // memberwise initializer, the default argument is the default
-    // initializer expression.
-    if (auto *property = param->getStoredProperty()) {
-      // FIXME: Force computation of property wrapper initializers.
-      if (auto *wrapped = property->getOriginalWrappedProperty())
-        (void)property->getPropertyWrapperInitializerInfo();
-
-      return property->getInitializerIsolation();
-    }
-
-    if (!param->hasDefaultExpr())
-      return ActorIsolation::forUnspecified();
-
-    dc = param->getDefaultArgumentInitContext();
-    initExpr = param->getTypeCheckedDefaultExpr();
-  }
-
-  if (!dc || !initExpr)
-    return ActorIsolation::forUnspecified();
-
-  return computeRequiredIsolation(dc, initExpr);
-}
-
 Type DefaultArgumentTypeRequest::evaluate(Evaluator &evaluator,
                                           ParamDecl *param) const {
   if (auto *expr = param->getTypeCheckedDefaultExpr()) {
@@ -2507,11 +2466,7 @@ class DeclChecker : public DeclVisitor<DeclChecker> {
               PBD->getInitContext(i));
           if (initContext) {
             TypeChecker::contextualizeInitializer(initContext, init);
-            if (auto *singleVar = PBD->getSingleVar()) {
-              (void)singleVar->getInitializerIsolation();
-            } else {
-              computeRequiredIsolation(initContext, init);
-            }
+            (void)PBD->getInitializerIsolation(i);
             TypeChecker::checkInitializerEffects(initContext, init);
           }
         }

test/Concurrency/isolated_default_arguments.swift

@@ -147,6 +147,11 @@ struct S2 {
   static var z: Int = requiresSomeGlobalActor()
 }
 
+struct S3 {
+  // expected-error@+1 {{default argument cannot be both main actor-isolated and global actor 'SomeGlobalActor'-isolated}}
+  var (x, y, z) = (requiresMainActor(), requiresSomeGlobalActor(), 10)
+}
+
 @MainActor
 func initializeFromMainActor() {
   _ = S1(required: 10)