Avoid warning in MSVC compilation.

mrbgems/mruby-compiler/core/codegen.c

@@ -2378,9 +2378,9 @@ codegen(codegen_scope *s, node *tree, int val)
 #endif
       {
         if (i == -1) genop_1(s, OP_LOADI__1, cursp());
-        else if (i < 0) genop_2(s, OP_LOADINEG, cursp(), -i);
-        else if (i < 8) genop_1(s, OP_LOADI_0 + i, cursp());
-        else if (i <= 0xffff) genop_2(s, OP_LOADI, cursp(), i);
+        else if (i < 0) genop_2(s, OP_LOADINEG, cursp(), (uint16_t)-i);
+        else if (i < 8) genop_1(s, OP_LOADI_0 + (uint8_t)i, cursp());
+        else if (i <= 0xffff) genop_2(s, OP_LOADI, cursp(), (uint16_t)i);
         else {
           int off = new_lit(s, mrb_fixnum_value(i));
           genop_2(s, OP_LOADL, cursp(), off);

mrbgems/mruby-socket/test/sockettest.c

@@ -12,6 +12,7 @@
 
 #include <fcntl.h>
 #include <sys/stat.h>
+#define open  _open
 #define close _close
 #define unlink _unlink
 

src/vm.c

@@ -176,7 +176,7 @@ envadjust(mrb_state *mrb, mrb_value *oldbase, mrb_value *newbase, size_t oldsize
 /** def rec ; $deep =+ 1 ; if $deep > 1000 ; return 0 ; end ; rec ; end  */
 
 static void
-stack_extend_alloc(mrb_state *mrb, int room)
+stack_extend_alloc(mrb_state *mrb, mrb_int room)
 {
   mrb_value *oldbase = mrb->c->stbase;
   mrb_value *newstack;
@@ -333,7 +333,7 @@ ecall(mrb_state *mrb)
   struct REnv *env;
   ptrdiff_t cioff;
   int ai = mrb_gc_arena_save(mrb);
-  uint8_t i = --c->eidx;
+  uint16_t i = --c->eidx;
   int nregs;
 
   if (i<0) return;