fixed wandering filename problem

src/codegen.c

@@ -1157,7 +1157,7 @@ codegen(codegen_scope *s, node *tree, int val)
 
   if (!tree) return;
 
-  if (s->irep && s->pc > 0 && s->filename_index != tree->filename_index) {
+  if (s->irep && s->filename_index != tree->filename_index) {
     s->irep->filename = mrb_parser_get_filename(s->parser, s->filename_index);
     mrb_debug_info_append_file(s->mrb, s->irep, s->debug_start_pos, s->pc);
     s->debug_start_pos = s->pc;

src/parse.y

@@ -62,7 +62,12 @@ typedef unsigned int stack_type;
 #define CMDARG_P()      BITSTACK_SET_P(p->cmdarg_stack)
 
 #define SET_LINENO(c,n) ((c)->lineno = (n))
-#define NODE_LINENO(c,n) do {if (n) ((c)->lineno = (n)->lineno);} while (0)
+#define NODE_LINENO(c,n) do {\
+  if (n) {\
+     (c)->filename_index = (n)->filename_index;\
+     (c)->lineno = (n)->lineno;\
+  }\
+} while (0)
 
 #define sym(x) ((mrb_sym)(intptr_t)(x))
 #define nsym(x) ((node*)(intptr_t)(x))