Rename `Kernel#__method__` to `Kernel#__callee__`

Because the current behavior of `__method__` is equivalent to `__callee__`.

Example:

  # example.rb
  def src
    __send__(ARGV[0])
  end
  alias dst src
  %w[src dst].each {|n| puts "call #{n} => #{__send__(n).inspect}"}

  Ruby:

    $ ruby example.rb __method__
    call src => :src
    call dst => :src

    $ ruby example.rb __callee__
    call src => :src
    call dst => :dst

  mruby:

    $ mruby example.rb __method__
    call src => :src
    call dst => :dst

1 files changed, 13 insertions, 4 deletions

diff --git a/mrbgems/mruby-kernel-ext/test/kernel.rb b/mrbgems/mruby-kernel-ext/test/kernel.rb
index fc4402b3d..1f682c42e 100644
--- a/mrbgems/mruby-kernel-ext/test/kernel.rb
+++ b/mrbgems/mruby-kernel-ext/test/kernel.rb
@@ -37,13 +37,22 @@ assert('Kernel.caller, Kernel#caller') do
   assert_raise(TypeError) { c.new.baz(nil) }
 end
 
-assert('Kernel#__method__') do
-  assert_equal(:m, Class.new {def m; __method__; end}.new.m)
-  assert_equal(:m, Class.new {define_method(:m) {__method__}}.new.m)
+assert('Kernel#__callee__') do
+  c = Class.new do
+    def m1; __callee__ end
+    define_method(:m2) {__callee__}
+    alias m3 m1
+    alias_method :m4, :m2
+  end
+  assert_equal(:m1, c.new.m1)
+  assert_equal(:m2, c.new.m2)
+  assert_equal(:m3, c.new.m3)
+  assert_equal(:m4, c.new.m4)
+
   c = Class.new do
     [:m1, :m2].each do |m|
       define_method(m) do
-        __method__
+        __callee__
       end
     end
   end