Fix hash code for compiler functions and mixins

Author: ntkme

lib/sass/compiler/host/function_registry.rb

@@ -12,7 +12,7 @@ class FunctionRegistry
         def initialize(functions, alert_color:)
           functions = functions.transform_keys(&:to_s)
 
-          @environment = BasicObject.new
+          @environment = Object.new
           @global_functions = functions.keys
           @functions_by_name = functions.transform_keys do |signature|
             index = signature.index('(')

lib/sass/value/function.rb

@@ -38,7 +38,7 @@ def ==(other)
 
       # @return [Integer]
       def hash
-        @hash ||= id.nil? ? signature.hash : id.hash
+        @hash ||= id.nil? ? signature.hash : [environment, id].hash
       end
 
       # @return [Function]

lib/sass/value/mixin.rb

@@ -25,7 +25,7 @@ def ==(other)
 
       # @return [Integer]
       def hash
-        @hash ||= id.hash
+        @hash ||= [environment, id].hash
       end
 
       # @return [Mixin]