stage1 人工重构ast以及type部分 修复vm的UB行为

stage0/spl_vm.c

@@ -99,9 +99,10 @@ static int spl_type_size(spl_type_t t) {
 
 #define PUSH(v)                                                                                    \
     do {                                                                                           \
+        spl_val_t _pv = (spl_val_t)(v);                                                            \
         if (vm->sp >= vm->config.max_stack_depth)                                                  \
             VM_ERROR("stack overflow");                                                            \
-        vm->stacks.data[(vm->sp)++] = (spl_val_t)(v);                                              \
+        vm->stacks.data[(vm->sp)++] = _pv;                                                         \
     } while (0)
 
 #define POP() vm->stacks.data[--(vm->sp)]