fast-path find_variable: check top scope first before find_index

lib/liquid/context.rb

@@ -199,6 +199,11 @@ module Liquid
 
     # Fetches an object starting at the local scope and then moving up the hierachy
     def find_variable(key, raise_on_not_found: true)
+      # Fast path: check top scope first (most common in for loops)
+      scope = @scopes[0]
+      if scope.key?(key)
+        variable = lookup_and_evaluate(scope, key, raise_on_not_found: raise_on_not_found)
+      else
         # This was changed from find() to find_index() because this is a very hot
         # path and find_index() is optimized in MRI to reduce object allocation
         index = @scopes.find_index { |s| s.key?(key) }
@@ -208,6 +213,7 @@ module Liquid
         else
           try_variable_find_in_environments(key, raise_on_not_found: raise_on_not_found)
         end
+      end
 
       # update variable's context before invoking #to_liquid
       variable.context = self if variable.respond_to?(:context=)