LibJS: Convert resolve_binding() to ThrowCompletionOr

The spec has a note stating that resolve binding will always return a
reference whose [[ReferencedName]] field is name. However this is not
correct as the underlying method GetIdentifierReference may throw on
env.HasBinding(name) thus it can throw. However, there are some
scenarios where it cannot throw because the reference is known to exist
in that case we use MUST with a comment.

1 files changed, 1 insertions, 3 deletions

diff --git a/Userland/Libraries/LibJS/Runtime/ECMAScriptFunctionObject.cpp b/Userland/Libraries/LibJS/Runtime/ECMAScriptFunctionObject.cpp
index 560f955d40..5f44bf8be3 100644
--- a/Userland/Libraries/LibJS/Runtime/ECMAScriptFunctionObject.cpp
+++ b/Userland/Libraries/LibJS/Runtime/ECMAScriptFunctionObject.cpp
@@ -441,9 +441,7 @@ ThrowCompletionOr<void> ECMAScriptFunctionObject::function_declaration_instantia
                 Environment* used_environment = has_duplicates ? nullptr : environment;
 
                 if constexpr (IsSame<FlyString const&, decltype(param)>) {
-                    Reference reference = vm.resolve_binding(param, used_environment);
-                    if (auto* exception = vm.exception())
-                        return throw_completion(exception->value());
+                    Reference reference = TRY(vm.resolve_binding(param, used_environment));
                     // Here the difference from hasDuplicates is important
                     if (has_duplicates)
                         return reference.put_value(global_object(), argument_value);