Speed up type checker

lib/steep/ast/types.rb

@@ -35,9 +35,11 @@ def to_s(level = 0)
           "masked(#{type}|#{mask})"
         end
 
-        def free_variables(set = Set.new)
-          type.free_variables(set)
-          mask.free_variables(set)
+        def free_variables
+          @fvs ||= Set.new.tap do |set|
+            set.merge(type.free_variables)
+            set.merge(mask.free_variables)
+          end
         end
 
         def each_type(&block)

lib/steep/ast/types/any.rb

@@ -26,9 +26,7 @@ def to_s
           "untyped"
         end
 
-        def free_variables
-          Set.new
-        end
+        include Helper::NoFreeVariables
 
         def level
           [1]

lib/steep/ast/types/boolean.rb

@@ -26,9 +26,7 @@ def to_s
           "bool"
         end
 
-        def free_variables
-          Set.new
-        end
+        include Helper::NoFreeVariables
 
         def level
           [0]

lib/steep/ast/types/bot.rb

@@ -26,9 +26,7 @@ def to_s
           "⟘"
         end
 
-        def free_variables
-          Set.new
-        end
+        include Helper::NoFreeVariables
 
         def level
           [2]

lib/steep/ast/types/class.rb

@@ -22,8 +22,8 @@ def subst(s)
           s.module_type or raise "Unexpected substitution: #{inspect}"
         end
 
-        def free_variables
-          Set.new
+        def free_variables()
+          @fvs = Set.new([self])
         end
 
         def level

lib/steep/ast/types/factory.rb

@@ -4,16 +4,24 @@ module Types
       class Factory
         attr_reader :definition_builder
 
+        attr_reader :type_name_cache
+        attr_reader :type_cache
+
         def initialize(builder:)
           @definition_builder = builder
+
+          @type_name_cache = {}
+          @type_cache = {}
         end
 
         def type_name_resolver
           @type_name_resolver ||= RBS::TypeNameResolver.from_env(definition_builder.env)
         end
 
         def type(type)
-          case type
+          ty = type_cache[type] and return ty
+
+          type_cache[type] = case type
           when RBS::Types::Bases::Any
             Any.new(location: nil)
           when RBS::Types::Bases::Class
@@ -144,14 +152,17 @@ def type_1(type)
         end
 
         def type_name(name)
-          case
-          when name.class?
-            Names::Module.new(name: name.name, namespace: namespace(name.namespace), location: nil)
-          when name.interface?
-            Names::Interface.new(name: name.name, namespace: namespace(name.namespace), location: nil)
-          when name.alias?
-            Names::Alias.new(name: name.name, namespace: namespace(name.namespace), location: nil)
-          end
+          n = type_name_cache[name] and return n
+
+          type_name_cache[name] =
+            (case
+             when name.class?
+               Names::Module.new(name: name.name, namespace: namespace(name.namespace), location: nil)
+             when name.interface?
+               Names::Interface.new(name: name.name, namespace: namespace(name.namespace), location: nil)
+             when name.alias?
+               Names::Alias.new(name: name.name, namespace: namespace(name.namespace), location: nil)
+             end)
         end
 
         def type_name_1(name)
@@ -190,7 +201,7 @@ def params(type)
           )
         end
 
-        def method_type(method_type, self_type:)
+        def method_type(method_type, self_type:, subst2: nil)
           fvs = self_type.free_variables()
 
           type_params = []
@@ -208,6 +219,7 @@ def method_type(method_type, self_type:)
             end
           end
           subst = Interface::Substitution.build(alpha_vars, alpha_types)
+          subst.merge!(subst2) if subst2
 
           type = Interface::MethodType.new(
             type_params: type_params,
@@ -332,7 +344,7 @@ def interface(type, private:, self_type: type)
 
                 interface.methods[name] = Interface::Interface::Combination.overload(
                   method.method_types.map do |type|
-                    method_type(type, self_type: self_type) {|ty| ty.subst(subst) }
+                    method_type(type, self_type: self_type, subst2: subst)
                   end,
                   incompatible: name == :initialize || name == :new
                 )
@@ -353,7 +365,7 @@ def interface(type, private:, self_type: type)
               definition.methods.each do |name, method|
                 interface.methods[name] = Interface::Interface::Combination.overload(
                   method.method_types.map do |type|
-                    method_type(type, self_type: self_type) {|type| type.subst(subst) }
+                    method_type(type, self_type: self_type, subst2: subst)
                   end,
                   incompatible: method.attributes.include?(:incompatible)
                 )
@@ -379,7 +391,7 @@ def interface(type, private:, self_type: type)
 
                 interface.methods[name] = Interface::Interface::Combination.overload(
                   method.method_types.map do |type|
-                    method_type(type, self_type: self_type) {|type| type.subst(subst) }
+                    method_type(type, self_type: self_type, subst2: subst)
                   end,
                   incompatible: method.attributes.include?(:incompatible)
                 )

lib/steep/ast/types/helper.rb

@@ -15,6 +15,12 @@ def level_of_children(children)
             end || []
           end
         end
+
+        module NoFreeVariables
+          def free_variables()
+            @fvs ||= Set.new
+          end
+        end
       end
     end
   end

lib/steep/ast/types/instance.rb

@@ -22,8 +22,8 @@ def subst(s)
           s.instance_type or raise "Unexpected substitution: #{inspect}"
         end
 
-        def free_variables
-          Set.new
+        def free_variables()
+          @fvs = Set.new([self])
         end
 
         def to_s

lib/steep/ast/types/intersection.rb

@@ -57,10 +57,14 @@ def to_s
           "(#{types.map(&:to_s).sort.join(" & ")})"
         end
 
-        def free_variables
-          types.each.with_object(Set.new) do |type, set|
-            set.merge(type.free_variables)
-          end
+        def free_variables()
+          @fvs ||= begin
+                     set = Set.new
+                     types.each do |type|
+                       set.merge(type.free_variables)
+                     end
+                     set
+                   end
         end
 
         include Helper::ChildrenLevel

lib/steep/ast/types/literal.rb

@@ -29,9 +29,7 @@ def to_s
           value.inspect
         end
 
-        def free_variables
-          Set.new
-        end
+        include Helper::NoFreeVariables
 
         def level
           [0]

lib/steep/ast/types/name.rb

@@ -11,9 +11,7 @@ def initialize(name:, location: nil)
             @name = name
           end
 
-          def free_variables
-            Set.new
-          end
+          include Helper::NoFreeVariables
 
           def subst(s)
             self
@@ -41,7 +39,7 @@ def ==(other)
           alias eql? ==
 
           def hash
-            self.class.hash ^ name.hash ^ args.hash
+            @hash ||= self.class.hash ^ name.hash ^ args.hash
           end
 
           def to_s
@@ -57,14 +55,20 @@ def with_location(new_location)
           end
 
           def subst(s)
-            self.class.new(location: location,
-                           name: name,
-                           args: args.map {|a| a.subst(s) })
+            if free_variables.intersect?(s.domain)
+              self.class.new(location: location,
+                             name: name,
+                             args: args.map {|a| a.subst(s) })
+            else
+              self
+            end
           end
 
           def free_variables
-            args.each.with_object(Set.new) do |type, vars|
-              vars.merge(type.free_variables)
+            @fvs ||= Set.new().tap do |set|
+              args.each do |type|
+                set.merge(type.free_variables)
+              end
             end
           end
 

lib/steep/ast/types/nil.rb

@@ -26,9 +26,7 @@ def to_s
           "nil"
         end
 
-        def free_variables
-          Set.new
-        end
+        include Helper::NoFreeVariables
 
         def level
           [0]

lib/steep/ast/types/proc.rb

@@ -36,8 +36,11 @@ def to_s
           "^#{params} -> #{return_type}"
         end
 
-        def free_variables
-          params.free_variables + return_type.free_variables
+        def free_variables()
+          @fvs ||= Set.new.tap do |set|
+            set.merge(params.free_variables)
+            set.merge(return_type.free_variables)
+          end
         end
 
         def level

lib/steep/ast/types/record.rb

@@ -26,12 +26,17 @@ def subst(s)
         end
 
         def to_s
-          "{ #{elements.map {|key, value| "#{key.inspect} => #{value}" }.join(", ")} }"
+          strings = elements.keys.sort.map do |key|
+            "#{key.inspect} => #{elements[key]}"
+          end
+          "{ #{strings.join(", ")} }"
         end
 
-        def free_variables
-          elements.each_value.with_object(Set.new) do |type, set|
-            set.merge(type.free_variables)
+        def free_variables()
+          @fvs ||= Set.new.tap do |set|
+            elements.each_value do |type|
+              set.merge(type.free_variables)
+            end
           end
         end
 

lib/steep/ast/types/self.rb

@@ -27,7 +27,7 @@ def subst(s)
         end
 
         def free_variables
-          Set.new
+          @fvs ||= Set.new([self])
         end
 
         def level

lib/steep/ast/types/top.rb

@@ -26,9 +26,7 @@ def to_s
           "⟙"
         end
 
-        def free_variables
-          Set.new
-        end
+        include Helper::NoFreeVariables
 
         def level
           [2]

lib/steep/ast/types/tuple.rb

@@ -30,9 +30,11 @@ def to_s
           "[#{types.join(", ")}]"
         end
 
-        def free_variables
-          types.each.with_object(Set.new) do |type, set|
-            set.merge(type.free_variables)
+        def free_variables()
+          @fvs ||= Set.new.tap do |set|
+            types.each do |type|
+              set.merge(type.free_variables)
+            end
           end
         end
 

lib/steep/ast/types/union.rb

@@ -11,6 +11,9 @@ def initialize(types:, location: nil)
         end
 
         def self.build(types:, location: nil)
+          return AST::Types::Bot.new if types.empty?
+          return types.first if types.size == 1
+
           types.flat_map do |type|
             if type.is_a?(Union)
               type.types
@@ -29,7 +32,7 @@ def self.build(types:, location: nil)
               type
             end
           end.compact.uniq.yield_self do |tys|
-            case tys.length
+            case tys.size
             when 0
               AST::Types::Bot.new
             when 1
@@ -61,8 +64,10 @@ def to_s
         end
 
         def free_variables
-          types.each.with_object(Set.new) do |type, set|
-            set.merge(type.free_variables)
+          @fvs ||= Set.new.tap do |set|
+            types.each do |type|
+              set.merge(type.free_variables)
+            end
           end
         end
 

lib/steep/ast/types/var.rb

@@ -44,8 +44,8 @@ def subst(s)
           end
         end
 
-        def free_variables
-          Set.new([name])
+        def free_variables()
+          @fvs ||= Set.new([name])
         end
 
         def level

lib/steep/ast/types/void.rb

@@ -26,9 +26,7 @@ def to_s
           "void"
         end
 
-        def free_variables
-          Set.new
-        end
+        include Helper::NoFreeVariables
 
         def level
           [0]