Inline rb_to_float in its only usage

Author: eregon

src/main/ruby/core/type.rb

@@ -200,7 +200,12 @@ def self.rb_big2ulong(val)
     end
 
     def self.rb_to_f(val)
-      rb_to_float(val, :to_f);
+      return val if object_kind_of?(val, Float)
+      res = convert_type(val, Float, :to_f, true)
+      unless object_kind_of?(res, Float)
+        conversion_mismatch(val, Float, :to_f, res)
+      end
+      res
     end
 
     def self.rb_to_int(val)
@@ -212,15 +217,6 @@ def self.rb_to_int(val)
       res
     end
 
-    def self.rb_to_float(val, meth)
-      return val if object_kind_of?(val, Float)
-      res = convert_type(val, Float, meth, true)
-      unless object_kind_of?(res, Float)
-        conversion_mismatch(val, Float, meth, res)
-      end
-      res
-    end
-
     def self.conversion_mismatch(val, cls, meth, res)
       raise TypeError, "can't convert #{object_class(val)} to #{cls} (#{object_class(val)}##{meth} gives #{object_class(res)})"
     end