Struct.new crashed if no arguments are given. Fixed.

src/struct.c

@@ -368,30 +368,35 @@ mrb_struct_s_def(mrb_state *mrb, mrb_value klass)
   name = mrb_nil_value();
   rest = mrb_nil_value();
   mrb_get_args(mrb, "*&", &argv, &argc, &b);
-  if (argc > 0) name = argv[0];
-  if (argc > 1) rest = argv[1];
-  if (mrb_type(rest) == MRB_TT_ARRAY) {
-    if (!mrb_nil_p(name) && SYMBOL_P(name)) {
-      /* 1stArgument:symbol -> name=nil rest=argv[0]-[n] */
-      mrb_ary_unshift(mrb, rest, name);
-      name = mrb_nil_value();
+  if (argc == 0) { /* special case to avoid crash */
+    rest = mrb_ary_new(mrb);
+  } 
+  else {   
+    if (argc > 0) name = argv[0];
+    if (argc > 1) rest = argv[1];
+    if (mrb_type(rest) == MRB_TT_ARRAY) {
+      if (!mrb_nil_p(name) && SYMBOL_P(name)) {
+        /* 1stArgument:symbol -> name=nil rest=argv[0]-[n] */
+        mrb_ary_unshift(mrb, rest, name);
+        name = mrb_nil_value();
+      }
     }
-  }
-  else {
-    pargv = &argv[1];
-    argcnt = argc-1;
-    if (!mrb_nil_p(name) && SYMBOL_P(name)) {
-      /* 1stArgument:symbol -> name=nil rest=argv[0]-[n] */
-      name = mrb_nil_value();
-      pargv = &argv[0];
-      argcnt++;
+    else {
+      pargv = &argv[1];
+      argcnt = argc-1;
+      if (!mrb_nil_p(name) && SYMBOL_P(name)) {
+        /* 1stArgument:symbol -> name=nil rest=argv[0]-[n] */
+        name = mrb_nil_value();
+        pargv = &argv[0];
+        argcnt++;
+      }
+      rest = mrb_ary_new_from_values(mrb, argcnt, pargv);
     }
-    rest = mrb_ary_new_from_values(mrb, argcnt, pargv);
-  }
-  for (i=0; i<RARRAY_LEN(rest); i++) {
-    id = mrb_to_id(mrb, RARRAY_PTR(rest)[i]);
-    RARRAY_PTR(rest)[i] = mrb_symbol_value(id);
-  }
+    for (i=0; i<RARRAY_LEN(rest); i++) {
+      id = mrb_to_id(mrb, RARRAY_PTR(rest)[i]);
+      RARRAY_PTR(rest)[i] = mrb_symbol_value(id);
+    }
+  }  
   st = make_struct(mrb, name, rest, struct_class(mrb));
   if (!mrb_nil_p(b)) {
     mrb_funcall(mrb, b, "call", 1, &st);

test/t/struct.rb

@@ -16,6 +16,12 @@ if Object.const_defined?(:Struct)
       c.members == [:m1,:m2]
   end
 
+  # Crash bug withStruc.new and no params, should make empty struct?
+  # assert('Struct.new', '15.2.18.3.1') do
+  #   c = Struct.new()
+  #   c.superclass == Struct   
+  # end
+
   assert('Struct#==', '15.2.18.4.1') do
     c = Struct.new(:m1, :m2)
     cc1 = c.new(1,2)