FINALLY fixed an error that took weeks. Turned out that the ParseRule was shallow copied, and the lookahead was not copied correctly. So it got extended and thus skipped over the state when it should have been redone.

src/ASTData.cpp

@@ -66,52 +66,40 @@ std::string ASTData::ASTTypeToString(ASTType type) {
 	switch (type) {
 		case translation_unit:
 			return "translation_unit";
-			break;
 		case interpreter_directive:
 			return "interpreter_directive";
-			break;
 		case identifier:
 			return "identifier";
-			break;
 		case import:
 			return "import";
-			break;
 		case function:
 			return "function";
-			break;
 		case code_block:
 			return "code_block";
-			break;
 		case typed_parameter:
 			return "typed_parameter";
-			break;
 		case expression:
 			return "expression";
-			break;
 		case boolean_expression:
 			return "boolean_expression";
-			break;
 		case statement:
 			return "statement";
-			break;
 		case if_statement:
 			return "if_statement";
-			break;
+		case while_loop:
+			return "while_loop";
+		case for_loop:
+			return "for_loop";
 		case return_statement:
 			return "return_statement";
-			break;
 		case assignment_statement:
 			return "assignment_statement";
-			break;
 		case declaration_statement:
 			return "declaration_statement";
-			break;
 		case function_call:
 			return "function_call";
-			break;
 		case value:
 			return "value";
-			break;
 		default:
 			return "unknown_ASTType";
 	}