Replace map.flatten(1) with flat_map

actionpack/lib/action_dispatch/journey/formatter.rb

@@ -121,9 +121,9 @@ def missing_keys(route, parts)
         def possibles(cache, options, depth = 0)
           cache.fetch(:___routes) { [] } + options.find_all { |pair|
             cache.key?(pair)
-          }.map { |pair|
+          }.flat_map { |pair|
             possibles(cache[pair], options, depth + 1)
-          }.flatten(1)
+          }
         end
 
         # Returns +true+ if no missing keys are present, otherwise +false+.

actionpack/lib/action_dispatch/journey/gtg/transition_table.rb

@@ -120,11 +120,11 @@ def states
         end
 
         def transitions
-          @string_states.map { |from, hash|
+          @string_states.flat_map { |from, hash|
             hash.map { |s, to| [from, s, to] }
-          }.flatten(1) + @regexp_states.map { |from, hash|
+          } + @regexp_states.flat_map { |from, hash|
             hash.map { |s, to| [from, s, to] }
-          }.flatten(1)
+          }
         end
 
         private