Move Kernel#fail definition to mruby-kernel-ext mrbgem.

include/mruby/error.h

@@ -21,6 +21,9 @@ void mrb_print_backtrace(mrb_state *mrb);
 mrb_value mrb_exc_backtrace(mrb_state *mrb, mrb_value exc);
 mrb_value mrb_get_backtrace(mrb_state *mrb);
 
+/* declaration for fail method */
+mrb_value mrb_f_raise(mrb_state*, mrb_value);
+
 #if defined(__cplusplus)
 }  /* extern "C" { */
 #endif

mrbgems/mruby-kernel-ext/mrbgem.rake

+MRuby::Gem::Specification.new('mruby-kernel-ext') do |spec|
+  spec.license = 'MIT'
+  spec.author  = 'mruby developers'
+  spec.summary = 'extensional Kernel module'
+end

mrbgems/mruby-kernel-ext/src/kernel.c

+#include <mruby.h>
+#include <mruby/error.h>
+
+void
+mrb_mruby_kernel_ext_gem_init(mrb_state *mrb)
+{
+  struct RClass *krn = mrb->kernel_module;
+
+  mrb_define_module_function(mrb, krn, "fail", mrb_f_raise, MRB_ARGS_NONE());
+}
+
+void
+mrb_mruby_kernel_ext_gem_final(mrb_state *mrb)
+{
+}

mrbgems/mruby-kernel-ext/test/kernel.rb

+assert('Kernel.fail, Kernel#fail') do
+  assert_raise(RuntimeError) { fail }
+  assert_raise(RuntimeError) { Kernel.fail }
+end

src/kernel.c

@@ -924,7 +924,7 @@ mrb_obj_public_methods(mrb_state *mrb, mrb_value self)
  *     raise "Failed to create socket"
  *     raise ArgumentError, "No parameters", caller
  */
-static mrb_value
+mrb_value
 mrb_f_raise(mrb_state *mrb, mrb_value self)
 {
   mrb_value a[2], exc;
@@ -1189,8 +1189,6 @@ mrb_init_kernel(mrb_state *mrb)
   mrb_define_method(mrb, krn, "to_s",                       mrb_any_to_s,                    MRB_ARGS_NONE());    /* 15.3.1.3.46 */
   mrb_define_method(mrb, krn, "__case_eqq",                 mrb_obj_ceqq,                    MRB_ARGS_REQ(1));    /* internal */
 
-  mrb_define_module_function(mrb, krn, "fail", mrb_f_raise, MRB_ARGS_NONE());
-
   mrb_include_module(mrb, mrb->object_class, mrb->kernel_module);
   mrb_alias_method(mrb, mrb->module_class, mrb_intern_lit(mrb, "dup"), mrb_intern_lit(mrb, "clone"));
 }

test/t/kernel.rb

@@ -563,7 +563,3 @@ assert('stack extend') do
   end
 end
 
-assert('Kernel.fail, Kernel#fail') do
-  assert_raise(RuntimeError) { fail }
-  assert_raise(RuntimeError) { Kernel.fail }
-end