add invoke_two fast path for single-arg filter invocation, avoids splat chain

lib/liquid/context.rb

@@ -115,6 +115,11 @@ module Liquid
       strainer.invoke_single(method, input).to_liquid
     end
 
+    # Fast path for two-argument filter invocation (e.g. {{ value | default: 'x' }})
+    def invoke_two(method, input, arg1)
+      strainer.invoke_two(method, input, arg1).to_liquid
+    end
+
     # Push new local scope on the stack. use <tt>Context#stack</tt> instead
     def push(new_scope = {})
       @scopes.unshift(new_scope)

lib/liquid/strainer_template.rb

@@ -72,5 +72,18 @@ module Liquid
     rescue ::ArgumentError => e
       raise Liquid::ArgumentError, e.message, e.backtrace
     end
+
+    # Fast path for two-argument filter invocation (input + one arg).
+    def invoke_two(method, input, arg1)
+      if self.class.invokable?(method)
+        send(method, input, arg1)
+      elsif @context.strict_filters
+        raise Liquid::UndefinedFilter, "undefined filter #{method}"
+      else
+        input
+      end
+    rescue ::ArgumentError => e
+      raise Liquid::ArgumentError, e.message, e.backtrace
+    end
   end
 end

lib/liquid/variable.rb

@@ -307,6 +307,9 @@ module Liquid
       @filters.each do |filter_name, filter_args, filter_kwargs|
         if filter_args.empty? && !filter_kwargs
           obj = context.invoke_single(filter_name, obj)
+        elsif !filter_kwargs && filter_args.length == 1
+          # Single positional arg — most common after no-arg
+          obj = context.invoke_two(filter_name, obj, context.evaluate(filter_args[0]))
         else
           filter_args = evaluate_filter_expressions(context, filter_args, filter_kwargs)
           obj = context.invoke(filter_name, obj, *filter_args)