Return pm_local_index_t when looking up local indexes

instead of returning the index and updating found_depth in the parent
scope

prism_compile.c

@@ -791,9 +791,14 @@ pm_interpolated_node_compile(pm_node_list_t *parts, rb_iseq_t *iseq, NODE dummy_
 // This recurses through scopes and finds the local index at any scope level
 // It also takes a pointer to depth, and increments depth appropriately
 // according to the depth of the local
-static int
+static pm_local_index_t
 pm_lookup_local_index_any_scope(rb_iseq_t *iseq, pm_scope_node_t *scope_node, pm_constant_id_t constant_id, int *found_depth)
 {
+    int level = 0;
+    pm_local_index_t lindex = {0};
+    if (found_depth) {
+        level = *found_depth;
+    }
     if (!scope_node) {
         // We have recursed up all scope nodes
         // and have not found the local yet
@@ -805,28 +810,27 @@ pm_lookup_local_index_any_scope(rb_iseq_t *iseq, pm_scope_node_t *scope_node, pm
     if (!st_lookup(scope_node->index_lookup_table, constant_id, &local_index)) {
         // Local does not exist at this level, continue recursing up
         if (found_depth) {
+            level++;
             (*found_depth)++;
+            RUBY_ASSERT(level == *found_depth);
         }
         return pm_lookup_local_index_any_scope(iseq, scope_node->previous, constant_id, found_depth);
     }
 
-    return scope_node->local_table_for_iseq_size - (int)local_index;
+    lindex.level = level;
+    lindex.index = scope_node->local_table_for_iseq_size - (int)local_index;
+    return lindex;
 }
 
 static pm_local_index_t
 pm_lookup_local_index_with_depth(rb_iseq_t *iseq, pm_scope_node_t *scope_node, pm_constant_id_t constant_id, uint32_t depth)
 {
-    pm_local_index_t lindex = {0};
-
     for(uint32_t i = 0; i < depth; i++) {
         scope_node = scope_node->previous;
         iseq = (rb_iseq_t *)ISEQ_BODY(iseq)->parent_iseq;
     }
 
-    lindex.level = (int)depth;
-    lindex.index = pm_lookup_local_index_any_scope(iseq, scope_node, constant_id, NULL);
-
-    return lindex;
+    return pm_lookup_local_index_any_scope(iseq, scope_node, constant_id, (int *)&depth);
 }
 
 // This returns the CRuby ID which maps to the pm_constant_id_t
@@ -4975,9 +4979,9 @@ pm_compile_node(rb_iseq_t *iseq, const pm_node_t *node, LINK_ANCHOR *const ret,
 
         pm_constant_id_t constant_id = local_write_node->name;
         int found_depth = 0;
-        int index = pm_lookup_local_index_any_scope(iseq, scope_node, constant_id, &found_depth);
+        pm_local_index_t index = pm_lookup_local_index_any_scope(iseq, scope_node, constant_id, &found_depth);
 
-        ADD_SETLOCAL(ret, &dummy_line_node, index, found_depth);
+        ADD_SETLOCAL(ret, &dummy_line_node, index.index, found_depth);
         return;
       }
       case PM_LOCAL_VARIABLE_WRITE_NODE: {
@@ -4989,9 +4993,9 @@ pm_compile_node(rb_iseq_t *iseq, const pm_node_t *node, LINK_ANCHOR *const ret,
         pm_constant_id_t constant_id = local_write_node->name;
 
         int found_depth = 0;
-        int index = pm_lookup_local_index_any_scope(iseq, scope_node, constant_id, &found_depth);
+        pm_local_index_t index = pm_lookup_local_index_any_scope(iseq, scope_node, constant_id, &found_depth);
 
-        ADD_SETLOCAL(ret, &dummy_line_node, index, found_depth);
+        ADD_SETLOCAL(ret, &dummy_line_node, index.index, found_depth);
         return;
       }
       case PM_MATCH_LAST_LINE_NODE: {