diff --git a/error.c b/error.c
index a085afd800..beae3b8138 100644
--- a/error.c
+++ b/error.c
@@ -1451,12 +1451,15 @@ name_err_init_attr(VALUE exc, VALUE recv, VALUE method)
 
 /*
  * call-seq:
- *   NameError.new(msg [, name])  -> name_error
- *   NameError.new(msg [, name], receiver:)  -> name_error
+ *   NameError.new(msg=nil, name=nil, receiver: nil)  -> name_error
  *
  * Construct a new NameError exception. If given the <i>name</i>
  * parameter may subsequently be examined using the <code>NameError#name</code>
- * method.
+ * method. <i>receiver</i> parameter allows to pass object in
+ * context of which the error happened. Example:
+ *
+ *    [1, 2, 3].method(:rject) # NameError with name "rject" and receiver: Array
+ *    [1, 2, 3].singleton_method(:rject) # NameError with name "rject" and receiver: [1, 2, 3]
  */
 
 static VALUE
@@ -1535,12 +1538,18 @@ nometh_err_init_attr(VALUE exc, VALUE args, int priv)
 
 /*
  * call-seq:
- *   NoMethodError.new([msg, *, name [, args [, priv]]])  -> no_method_error
+ *   NoMethodError.new(msg=nil, name=nil, args=nil, private=false, receiver: nil)  -> no_method_error
  *
  * Construct a NoMethodError exception for a method of the given name
  * called with the given arguments. The name may be accessed using
  * the <code>#name</code> method on the resulting object, and the
  * arguments using the <code>#args</code> method.
+ *
+ * If <i>private</i> argument were passed, it designates method was
+ * attempted to call in private context, and can be accessed with
+ * <code>#private_call?</code> method.
+ *
+ * <i>receiver</i> argument stores an object whose method was called.
  */
 
 static VALUE