[torque] Minor Torque fixes

This is a partial reland of https://crrev.com/c/v8/v8/+/2199640 . It
allows scoped lookups to not crash during CompileCurrentAst, fixes the
formatting in an error message, and includes an extra line for
convenience when generating macros for bitfields.

Change-Id: I7ed9f7d76b3ce5e2cc0f2580d7ba1953da340ae8
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2216301Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Commit-Queue: Seth Brenith <seth.brenith@microsoft.com>
Cr-Commit-Position: refs/heads/master@{#68018}

src/objects/debug-objects.h

@@ -28,7 +28,6 @@ class DebugInfo : public TorqueGeneratedDebugInfo<DebugInfo, Struct> {
  public:
   NEVER_READ_ONLY_SPACE
   DEFINE_TORQUE_GENERATED_DEBUG_INFO_FLAGS()
-  using Flags = base::Flags<Flag>;
 
   // DebugInfo can be detached from the SharedFunctionInfo iff it is empty.
   bool IsEmpty() const;

src/torque/declarable.cc

@@ -95,7 +95,8 @@ std::vector<Declarable*> Scope::Lookup(const QualifiedName& name) {
 
 base::Optional<std::string> TypeConstraint::IsViolated(const Type* type) const {
   if (upper_bound && !type->IsSubtypeOf(*upper_bound)) {
-    return {ToString("expected ", *type, " to be a subtype of ", *upper_bound)};
+    return {
+        ToString("expected ", *type, " to be a subtype of ", **upper_bound)};
   }
   return base::nullopt;
 }

src/torque/implementation-visitor.cc

@@ -3371,6 +3371,7 @@ void ImplementationVisitor::GenerateBitFields(
                  << " = 1 << " << field.offset << ", \\\n";
         }
         header << "  }; \\\n";
+        header << "  using Flags = base::Flags<Flag>; \\\n";
       }
 
       header << "\n";

src/torque/torque-compiler.cc

@@ -55,6 +55,7 @@ void CompileCurrentAst(TorqueCompilerOptions options) {
   }
   TargetArchitecture::Scope target_architecture(options.force_32bit_output);
   TypeOracle::Scope type_oracle;
+  CurrentScope::Scope current_namespace(GlobalContext::GetDefaultNamespace());
 
   // Two-step process of predeclaration + resolution allows to resolve type
   // declarations independent of the order they are given.