Support rules with 'at' greater than 24:00 or less than 00:00.

Required for Asia/Tokyo in tzdata 2018f.

lib/tzinfo/data/tzdataparser.rb

@@ -1041,26 +1041,28 @@ def calculate_time(utc_offset, std_offset)
       end
     end
 
-    # A tz data time definition - an hour, minute, second and reference. Reference
-    # is either :utc, :standard or :wall_clock.
+    # A tz data time definition - a sign (1 or -1), hour, minute, second and
+    # reference (:utc, :standard or :wall_clock).
     #
     # @private
     class TZDataTime #:nodoc:
+      attr_reader :sign
       attr_reader :hour
       attr_reader :minute
       attr_reader :second
       attr_reader :ref
 
       def initialize(spec)
-        raise "Invalid time: #{spec}" if spec !~ /^([0-9]+)(:([0-9]+)(:([0-9]+))?)?([wguzs])?$/
+        raise "Invalid time: #{spec}" if spec !~ /^(-?)([0-9]+)(:([0-9]+)(:([0-9]+))?)?([wguzs])?$/
 
-        @hour = $1.to_i
-        @minute = $3.nil? ? 0 : $3.to_i
-        @second = $5.nil? ? 0 : $5.to_i
+        @sign = $1 == '-' ? -1 : 1
+        @hour = $2.to_i
+        @minute = $4.nil? ? 0 : $4.to_i
+        @second = $6.nil? ? 0 : $6.to_i
 
-        if $6 == 's'
+        if $7 == 's'
           @ref = :standard
-        elsif $6 == 'g' || $6 == 'u' || $6 == 'z'
+        elsif $7 == 'g' || $7 == 'u' || $7 == 'z'
           @ref = :utc
         else
           @ref = :wall_clock
@@ -1069,7 +1071,12 @@ def initialize(spec)
 
       # Converts the time to UTC given a utc_offset and std_offset.
       def to_utc(utc_offset, std_offset, year, month, day)      
-        result = DateTime.new(year, month, day, @hour, @minute, @second)
+        result = if @hour > 24 || @hour == 24 && (@minute > 0 || @second > 0) || @sign != 1
+          DateTime.new(year, month, day, 0, 0, 0) + Rational(@sign * (@second + (@minute + @hour * 60) * 60), 86400)
+        else
+          DateTime.new(year, month, day, @hour, @minute, @second)
+        end
+
         offset = 0
         offset = offset + utc_offset if @ref == :standard || @ref == :wall_clock            
         offset = offset + std_offset if @ref == :wall_clock