Avoid deep flatten

lib/liquid/context.rb

@@ -21,9 +21,7 @@ module Liquid
     end
 
     def initialize(environments = {}, outer_scope = {}, registers = {}, rethrow_errors = false, resource_limits = nil, static_registers = {}, static_environments = {})
-      @environments = [environments]
-      @environments.flatten!
-
+      @environments        = environments.is_a?(Array) ? environments : [environments]
       @static_environments = [static_environments].flat_map(&:freeze).freeze
       @scopes              = [(outer_scope || {})]
       @registers           = registers

lib/liquid/template.rb

@@ -183,11 +183,11 @@ module Liquid
         c
       when Liquid::Drop
         drop = args.shift
-        drop.context = Context.new([drop, assigns, instance_assigns], new_outer_scope, registers, @rethrow_errors, @resource_limits)
+        drop.context = Context.new([drop, assigns].concat(instance_assigns), new_outer_scope, registers, @rethrow_errors, @resource_limits)
       when Hash
-        Context.new([args.shift, assigns, instance_assigns], new_outer_scope, registers, @rethrow_errors, @resource_limits)
+        Context.new([args.shift, assigns].concat(instance_assigns), new_outer_scope, registers, @rethrow_errors, @resource_limits)
       when nil
-        Context.new([assigns, instance_assigns], new_outer_scope, registers, @rethrow_errors, @resource_limits)
+        Context.new([assigns].concat(instance_assigns), new_outer_scope, registers, @rethrow_errors, @resource_limits)
       else
         raise ArgumentError, "Expected Hash or Liquid::Context as parameter"
       end