💥 Only Array inputs to SequenceSet may be nested

Other enumerable types are no longer valid inputs.

Author: nevans

lib/net/imap/sequence_set.rb

@@ -37,8 +37,8 @@ class IMAP
     #
     # SequenceSet.new may receive a single optional argument: a non-zero 32 bit
     # unsigned integer, a range, a <tt>sequence-set</tt> formatted string,
-    # another sequence set, a Set (containing only numbers), or an enumerable
-    # containing any of these (which may be nested).
+    # another sequence set, a Set (containing only numbers), or an Array
+    # containing any of these (array inputs may be nested).
     #
     #     set = Net::IMAP::SequenceSet.new(1)
     #     set.valid_string  #=> "1"
@@ -290,8 +290,7 @@ class SequenceSet
       private_constant :STAR_INT, :STARS
 
       COERCIBLE = ->{ _1.respond_to? :to_sequence_set }
-      ENUMABLE  = ->{ _1.respond_to?(:each) && _1.respond_to?(:empty?) }
-      private_constant :COERCIBLE, :ENUMABLE
+      private_constant :COERCIBLE
 
       class << self
 
@@ -1273,7 +1272,7 @@ def input_to_tuples(obj)
         when String      then str_to_tuples obj
         when SequenceSet then obj.tuples
         when Set         then obj.map      { to_tuple_int _1 }
-        when ENUMABLE    then obj.flat_map { input_to_tuples _1 }
+        when Array       then obj.flat_map { input_to_tuples _1 }
         when nil         then []
         else
           raise DataFormatError,