LibJS: Convert can_declare_global_function() to ThrowCompletionOr

Userland/Libraries/LibJS/AST.cpp

@@ -3626,10 +3626,10 @@ ThrowCompletionOr<void> Program::global_declaration_instantiation(Interpreter& i
         if (declared_function_names.set(function.name()) != AK::HashSetResult::InsertedNewEntry)
             return IterationDecision::Continue;
 
-        auto function_definable = global_environment.can_declare_global_function(function.name());
-
-        if (interpreter.exception())
+        auto function_definable_or_error = global_environment.can_declare_global_function(function.name());
+        if (function_definable_or_error.is_error())
             return IterationDecision::Break;
+        auto function_definable = function_definable_or_error.release_value();
 
         if (!function_definable) {
             interpreter.vm().throw_exception<TypeError>(global_object, ErrorType::CannotDeclareGlobalFunction, function.name());
@@ -3677,10 +3677,10 @@ ThrowCompletionOr<void> Program::global_declaration_instantiation(Interpreter& i
             if (global_environment.has_lexical_declaration(function_name))
                 return IterationDecision::Continue;
 
-            auto function_definable = global_environment.can_declare_global_function(function_name);
-
-            if (interpreter.exception())
+            auto function_definable_or_error = global_environment.can_declare_global_function(function_name);
+            if (function_definable_or_error.is_error())
                 return IterationDecision::Break;
+            auto function_definable = function_definable_or_error.release_value();
 
             if (!function_definable) {
                 interpreter.vm().throw_exception<TypeError>(global_object, ErrorType::CannotDeclareGlobalFunction, function_name);

Userland/Libraries/LibJS/Runtime/AbstractOperations.cpp

@@ -627,9 +627,11 @@ ThrowCompletionOr<void> eval_declaration_instantiation(VM& vm, GlobalObject& glo
             return IterationDecision::Continue;
 
         if (global_var_environment) {
-            auto function_definable = global_var_environment->can_declare_global_function(function.name());
-            if (vm.exception())
+            auto function_definable_or_error = global_var_environment->can_declare_global_function(function.name());
+            if (function_definable_or_error.is_error())
                 return IterationDecision::Break;
+            auto function_definable = function_definable_or_error.release_value();
+
             if (!function_definable) {
                 vm.throw_exception<TypeError>(global_object, ErrorType::CannotDeclareGlobalFunction, function.name());
                 return IterationDecision::Break;

Userland/Libraries/LibJS/Runtime/GlobalEnvironment.cpp

@@ -215,18 +215,18 @@ ThrowCompletionOr<bool> GlobalEnvironment::can_declare_global_var(FlyString cons
 }
 
 // 9.1.1.4.16 CanDeclareGlobalFunction ( N ), https://tc39.es/ecma262/#sec-candeclareglobalfunction
-bool GlobalEnvironment::can_declare_global_function(FlyString const& name) const
+ThrowCompletionOr<bool> GlobalEnvironment::can_declare_global_function(FlyString const& name) const
 {
     // 1. Let ObjRec be envRec.[[ObjectRecord]].
     // 2. Let globalObject be ObjRec.[[BindingObject]].
     auto& global_object = m_object_record->binding_object();
 
     // 3. Let existingProp be ? globalObject.[[GetOwnProperty]](N).
-    auto existing_prop = TRY_OR_DISCARD(global_object.internal_get_own_property(name));
+    auto existing_prop = TRY(global_object.internal_get_own_property(name));
 
     // 4. If existingProp is undefined, return ? IsExtensible(globalObject).
     if (!existing_prop.has_value())
-        return TRY_OR_DISCARD(global_object.is_extensible());
+        return TRY(global_object.is_extensible());
 
     // 5. If existingProp.[[Configurable]] is true, return true.
     if (*existing_prop->configurable)

Userland/Libraries/LibJS/Runtime/GlobalEnvironment.h

@@ -35,7 +35,7 @@ public:
     bool has_lexical_declaration(FlyString const& name) const;
     ThrowCompletionOr<bool> has_restricted_global_property(FlyString const& name) const;
     ThrowCompletionOr<bool> can_declare_global_var(FlyString const& name) const;
-    bool can_declare_global_function(FlyString const& name) const;
+    ThrowCompletionOr<bool> can_declare_global_function(FlyString const& name) const;
     void create_global_var_binding(FlyString const& name, bool can_be_deleted);
     void create_global_function_binding(FlyString const& name, Value, bool can_be_deleted);