diff --git a/source/m3_api_wasi.c b/source/m3_api_wasi.c
index 56cef55..9fa9916 100644
--- a/source/m3_api_wasi.c
+++ b/source/m3_api_wasi.c
@@ -64,7 +64,7 @@ typedef struct wasi_iovec_t
 
 typedef struct Preopen {
     int         fd;
-    char*       path;
+    const char* path;
 } Preopen;
 
 Preopen preopen[PREOPEN_CNT] = {
diff --git a/source/m3_env.c b/source/m3_env.c
index 3e85280..4c58ce9 100644
--- a/source/m3_env.c
+++ b/source/m3_env.c
@@ -383,6 +383,8 @@ M3Result  EvaluateExpression  (IM3Module i_module, void * o_expressed, u8 i_type
     runtime.numStackSlots = i_module->runtime->numStackSlots;
     runtime.stack = i_module->runtime->stack;
 
+    m3stack_t stack = (m3stack_t)runtime.stack;
+
     IM3Runtime savedRuntime = i_module->runtime;
     i_module->runtime = & runtime;
 
@@ -406,18 +408,18 @@ M3Result  EvaluateExpression  (IM3Module i_module, void * o_expressed, u8 i_type
 
         if (not result)
         {
-            m3ret_t r = Call (m3code, runtime.stack, NULL, d_m3OpDefaultArgs);
+            m3ret_t r = Call (m3code, stack, NULL, d_m3OpDefaultArgs);
             result = runtime.runtimeError;
 
             if (r == 0 and not result)
             {
                 if (SizeOfType (i_type) == sizeof (u32))
                 {
-                    * (u32 *) o_expressed = * ((u32 *) runtime.stack);
+                    * (u32 *) o_expressed = * ((u32 *) stack);
                 }
                 else
                 {
-                    * (u64 *) o_expressed = * ((u64 *) runtime.stack);
+                    * (u64 *) o_expressed = * ((u64 *) stack);
                 }
             }
         }