diff --git a/CMakeLists.txt b/CMakeLists.txt
index f25345b..db0aab3 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 4.3)
+cmake_minimum_required(VERSION 3.16)
 project(fz-lang
 	LANGUAGES C)
 
diff --git a/src/compiler/fzl_parser.c b/src/compiler/fzl_parser.c
index 5e403c0..b7c9b9f 100644
--- a/src/compiler/fzl_parser.c
+++ b/src/compiler/fzl_parser.c
@@ -959,6 +959,9 @@ fzl_node_t *parse_block(fzl_parser_t *parser)
 // Statement parsing
 fzl_node_t *parse_statement(fzl_parser_t *parser)
 {
+  if (!peek(parser))
+    return NULL;
+
   fzl_node_t *res = NULL;
 
   if (is(parser, FZL_TOKTYPE_CLASS))
@@ -990,6 +993,9 @@ fzl_node_t *parse_statement(fzl_parser_t *parser)
 // Internal parsing entry point
 fzl_node_t *parse_program(fzl_parser_t *parser)
 {
+  if (!peek(parser))
+    return NULL;
+
   fzl_node_t *first = NULL;
   fzl_node_t *last  = NULL;
   fzl_node_t *node  = NULL;
@@ -1023,6 +1029,8 @@ fzl_node_t *parse_program(fzl_parser_t *parser)
 // Parse tokens and build AST
 int fzl_parse(fzl_parser_t *parser)
 {
+  last_known_tok = NULL;
+
   fzl_node_t *ast = parse_program(parser);
   if (!ast)
     return -1;
@@ -1121,8 +1129,9 @@ void fzl_freeast(fzl_node_t *root)
       fzl_freenode(root->memb.parent);
     }
 
-    root = root->next;
+    fzl_node_t *next = root->next;
     free(root);
+    root = root->next;
   }
 }