diff --git a/yarp/diagnostic.c b/yarp/diagnostic.c
index 4611e8e6d6..e89d96cbac 100644
--- a/yarp/diagnostic.c
+++ b/yarp/diagnostic.c
@@ -185,6 +185,7 @@ static const char* const diagnostic_messages[YP_DIAGNOSTIC_ID_LEN] = {
     [YP_ERR_NOT_EXPRESSION]                     = "Expected an expression after `not`",
     [YP_ERR_NUMBER_LITERAL_UNDERSCORE]          = "Number literal ending with a `_`",
     [YP_ERR_NUMBERED_PARAMETER_NOT_ALLOWED]     = "Numbered parameters are not allowed alongside explicit parameters",
+    [YP_ERR_NUMBERED_PARAMETER_OUTER_SCOPE]     = "Numbered parameter is already used in outer scope",
     [YP_ERR_OPERATOR_MULTI_ASSIGN]              = "Unexpected operator for a multiple assignment",
     [YP_ERR_OPERATOR_WRITE_BLOCK]               = "Unexpected operator after a call with a block",
     [YP_ERR_PARAMETER_ASSOC_SPLAT_MULTI]        = "Unexpected multiple `**` splat parameters",
@@ -193,7 +194,6 @@ static const char* const diagnostic_messages[YP_DIAGNOSTIC_ID_LEN] = {
     [YP_ERR_PARAMETER_NO_DEFAULT]               = "Expected a default value for the parameter",
     [YP_ERR_PARAMETER_NO_DEFAULT_KW]            = "Expected a default value for the keyword parameter",
     [YP_ERR_PARAMETER_NUMBERED_RESERVED]        = "Token reserved for a numbered parameter",
-    [YP_ERR_NUMBERED_PARAMETER_OUTER_SCOPE]     = "Numbered parameter is already used in outer scope",
     [YP_ERR_PARAMETER_ORDER]                    = "Unexpected parameter order",
     [YP_ERR_PARAMETER_SPLAT_MULTI]              = "Unexpected multiple `*` splat parameters",
     [YP_ERR_PARAMETER_STAR]                     = "Unexpected parameter `*`",
diff --git a/yarp/yarp.c b/yarp/yarp.c
index 242b03e2ed..d271627e2f 100644
--- a/yarp/yarp.c
+++ b/yarp/yarp.c
@@ -8435,7 +8435,6 @@ parse_write(yp_parser_t *parser, yp_node_t *target, yp_token_t *operator, yp_nod
         case YP_LOCAL_VARIABLE_READ_NODE: {
             if (token_is_numbered_parameter(target->location.start, target->location.end)) {
                 yp_diagnostic_list_append(&parser->error_list, target->location.start, target->location.end, YP_ERR_PARAMETER_NUMBERED_RESERVED);
-                return target;
             }
 
             yp_local_variable_read_node_t *local_read = (yp_local_variable_read_node_t *) target;
@@ -10119,14 +10118,7 @@ parse_alias_argument(yp_parser_t *parser, bool first) {
 // numbered parameters.
 static bool
 outer_scope_using_numbered_params_p(yp_parser_t *parser) {
-    yp_scope_t *scope = parser->current_scope;
-
-    // We can bail early here if we've already performed this lookup since it
-    // will be set on the current scope.
-    if (scope->numbered_params) return false;
-
-    // Otherwise we need to walk up the list of scopes.
-    for (scope = scope->previous; scope != NULL && !scope->closed; scope = scope->previous) {
+    for (yp_scope_t *scope = parser->current_scope->previous; scope != NULL && !scope->closed; scope = scope->previous) {
         if (scope->numbered_params) return true;
     }
 
@@ -10145,6 +10137,10 @@ parse_variable_call(yp_parser_t *parser) {
         }
 
         if (!parser->current_scope->closed && token_is_numbered_parameter(parser->previous.start, parser->previous.end)) {
+            // Indicate that this scope is using numbered params so that child
+            // scopes cannot.
+            parser->current_scope->numbered_params = true;
+
             // Now that we know we have a numbered parameter, we need to check
             // if it's allowed in this context. If it is, then we will create a
             // local variable read. If it's not, then we'll create a normal call
@@ -10154,10 +10150,6 @@ parse_variable_call(yp_parser_t *parser) {
             } else if (outer_scope_using_numbered_params_p(parser)) {
                 yp_diagnostic_list_append(&parser->error_list, parser->previous.start, parser->previous.end, YP_ERR_NUMBERED_PARAMETER_OUTER_SCOPE);
             } else {
-                // Indicate that this scope is using numbered params so that
-                // child scopes cannot.
-                parser->current_scope->numbered_params = true;
-
                 // When you use a numbered parameter, it implies the existence
                 // of all of the locals that exist before it. For example,
                 // referencing _2 means that _1 must exist. Therefore here we