Reviewed code comments. Fixed typos and addressed some TODOs

Author: nickolas-pohilets

lib/SIL/IR/SILFunctionType.cpp

@@ -2873,8 +2873,8 @@ static CanSILFunctionType getNativeSILFunctionType(
       // with runtime function. The latter expects 'work' argument to be
       // SWIFT_CC(swift) aka @convention(thin). But the 'self' parameter must
       // remain owned.
-      return getSILFunctionTypeForConventions(DeallocatorConventions())
-          ->getWithExtInfo(SILFunctionType::ExtInfo::getThin());
+      return getSILFunctionTypeForConventions(
+          DefaultConventions(NormalParameterConvention::Owned));
     }
 
     case SILDeclRef::Kind::AsyncEntryPoint:
@@ -4091,6 +4091,7 @@ TypeConverter::getDeclRefRepresentation(SILDeclRef c) {
     case SILDeclRef::Kind::StoredPropertyInitializer:
     case SILDeclRef::Kind::PropertyWrapperBackingInitializer:
     case SILDeclRef::Kind::PropertyWrapperInitFromProjectedValue:
+    case SILDeclRef::Kind::IsolatedDeallocator:
       return SILFunctionTypeRepresentation::Thin;
 
     case SILDeclRef::Kind::Func:
@@ -4102,7 +4103,6 @@ TypeConverter::getDeclRefRepresentation(SILDeclRef c) {
 
     case SILDeclRef::Kind::Destroyer:
     case SILDeclRef::Kind::Deallocator:
-    case SILDeclRef::Kind::IsolatedDeallocator: // TODO: Double-check this
     case SILDeclRef::Kind::Allocator:
     case SILDeclRef::Kind::Initializer:
     case SILDeclRef::Kind::EnumElement:

lib/SILGen/SILGenDestructor.cpp

@@ -373,7 +373,6 @@ void SILGenFunction::emitIsolatingDestructor(DestructorDecl *dd) {
       B.createConvertFunction(loc, dtx, workFuncType, false);
 
   // Schedule isolated execution
-  // TODO: Make sure it is a tail call
   auto result = B.createApply(loc, swiftPerformOnExecutorFunc, {},
                               {castedSelf, castedDeallocator, executor});
   B.createReturn(loc, result);

lib/Sema/TypeCheckConcurrency.cpp

@@ -4954,7 +4954,7 @@ static OverrideIsolationResult validOverrideIsolation(
   auto &ctx = declContext->getASTContext();
 
   // Normally we are checking if overriding declaration can be called by calling
-  // overriden declaration But in case of destructors, overriden declaration is
+  // overriden declaration. But in case of destructors, overriden declaration is
   // always callable by definition and we are checking that subclas deinit can
   // call super deinit.
   bool isDtor = isa<DestructorDecl>(value);
@@ -5113,7 +5113,8 @@ ActorIsolation ActorIsolationRequest::evaluate(
     assert(actor && "could not find the actor that 'self' is isolated to");
 
     // Bootstrapping hack: force _Concurrency.MainActor.deinit() to be
-    // non-isolated
+    // non-isolated even when importing from SDK's swiftmodule without
+    // `nonisolated` attribute.
     if (isa<DestructorDecl>(value) && actor->getName().is("MainActor") &&
         actor->getDeclContext()->isModuleScopeContext() &&
         actor->getDeclContext()->getParentModule()->getABIName().is("Swift")) {