Reduce integer casting warnings.

src/codedump.c

@@ -48,7 +48,7 @@ print_lv_ab(mrb_state *mrb, mrb_irep *irep, uint16_t a, uint16_t b)
 #endif
 
 static void
-print_header(mrb_irep *irep, int i)
+print_header(mrb_irep *irep, ptrdiff_t i)
 {
   int32_t line;
 
@@ -60,7 +60,7 @@ print_header(mrb_irep *irep, int i)
     printf("%5d ", line);
   }
 
-  printf("%03d ", i);
+  printf("%03d ", (int)i);
 }
 
 #define CASE(insn,ops) case insn: FETCH_ ## ops (); L_ ## insn
@@ -91,7 +91,7 @@ codedump(mrb_state *mrb, mrb_irep *irep)
   pc = irep->iseq;
   pcend = pc + irep->ilen;
   while (pc < pcend) {
-    int i;
+    ptrdiff_t i;
     uint32_t a;
     uint16_t b;
     uint8_t c;

src/load.c

@@ -68,7 +68,7 @@ read_irep_record_1(mrb_state *mrb, const uint8_t *bin, size_t *len, uint8_t flag
 
   /* Binary Data Section */
   /* ISEQ BLOCK */
-  irep->ilen = (size_t)bin_to_uint32(src);
+  irep->ilen = (uint16_t)bin_to_uint32(src);
   src += sizeof(uint32_t);
   src += skip_padding(src);
 
@@ -157,7 +157,7 @@ read_irep_record_1(mrb_state *mrb, const uint8_t *bin, size_t *len, uint8_t flag
   }
 
   /* SYMS BLOCK */
-  irep->slen = (size_t)bin_to_uint32(src);  /* syms length */
+  irep->slen = (uint16_t)bin_to_uint32(src);  /* syms length */
   src += sizeof(uint32_t);
   if (irep->slen > 0) {
     if (SIZE_ERROR_MUL(irep->slen, sizeof(mrb_sym))) {

src/vm.c

@@ -218,7 +218,7 @@ stack_extend_alloc(mrb_state *mrb, int room)
 }
 
 MRB_API void
-mrb_stack_extend(mrb_state *mrb, int room)
+mrb_stack_extend(mrb_state *mrb, mrb_int room)
 {
   if (mrb->c->stack + room >= mrb->c->stend) {
     stack_extend_alloc(mrb, room);