Add Struct.new and Data.define support

Recognize `Foo = Struct.new(:bar, :baz)` and `Foo = Data.define(:x, :y)`
patterns and generate appropriate class definitions with:
- attr_reader for all members
- attr_writer for Struct members (Data is frozen)
- initialize with positional args (Struct) or keyword args (Data)
- Block body support for additional method definitions

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: mame

lib/typeprof/core/ast.rb

@@ -102,7 +102,13 @@ def self.create_node(raw_node, lenv, use_result = true, allow_meta = false)
       when :constant_read_node, :constant_path_node
         ConstantReadNode.new(raw_node, lenv)
       when :constant_write_node, :constant_path_write_node
-        ConstantWriteNode.new(raw_node, AST.create_node(raw_node.value, lenv), lenv)
+        if (members = detect_struct_new(raw_node.value))
+          StructNewNode.new(raw_node, members, :struct, lenv)
+        elsif (members = detect_data_define(raw_node.value))
+          StructNewNode.new(raw_node, members, :data, lenv)
+        else
+          ConstantWriteNode.new(raw_node, AST.create_node(raw_node.value, lenv), lenv)
+        end
       when :constant_operator_write_node
         read = ConstantReadNode.new(raw_node, lenv)
         rhs = OperatorNode.new(raw_node, read, lenv)
@@ -526,5 +532,31 @@ def self.create_rbs_type(raw_decl, lenv)
         raise "unknown RBS type: #{ raw_decl.class }"
       end
     end
+
+    def self.detect_struct_new(raw_value)
+      return nil unless raw_value.type == :call_node
+      return nil unless raw_value.name == :new
+      recv = raw_value.receiver
+      return nil unless recv&.type == :constant_read_node && recv.name == :Struct
+      extract_symbol_args(raw_value)
+    end
+
+    def self.detect_data_define(raw_value)
+      return nil unless raw_value.type == :call_node
+      return nil unless raw_value.name == :define
+      recv = raw_value.receiver
+      return nil unless recv&.type == :constant_read_node && recv.name == :Data
+      extract_symbol_args(raw_value)
+    end
+
+    def self.extract_symbol_args(raw_call)
+      return nil unless raw_call.arguments
+      members = []
+      raw_call.arguments.arguments.each do |arg|
+        return nil unless arg.type == :symbol_node
+        members << arg.value.to_sym
+      end
+      members
+    end
   end
 end

lib/typeprof/core/ast/meta.rb

@@ -208,5 +208,135 @@ def install0(genv)
         Source.new
       end
     end
+
+    class StructNewNode < Node
+      def initialize(raw_node, members, kind, lenv)
+        super(raw_node, lenv)
+        case raw_node.type
+        when :constant_write_node
+          @static_cpath = lenv.cref.cpath + [raw_node.name]
+        when :constant_path_write_node
+          @static_cpath = AST.parse_cpath(raw_node.target, lenv.cref)
+        else
+          raise
+        end
+        @members = members
+        @kind = kind # :struct or :data
+
+        # Parse block body if present (Struct.new(:foo) do ... end)
+        raw_value = raw_node.value
+        if raw_value.block && raw_value.block.type == :block_node && raw_value.block.body
+          ncref = CRef.new(@static_cpath, :instance, nil, lenv.cref)
+          nlenv = LocalEnv.new(lenv.file_context, ncref, {}, [])
+          @block_body = AST.create_node(raw_value.block.body, nlenv)
+        end
+      end
+
+      attr_reader :static_cpath, :members, :kind, :block_body
+
+      def subnodes = { block_body: }
+      def attrs = { static_cpath:, members:, kind: }
+
+      # Interface expected by MethodDefBox
+      def req_positionals = @kind == :struct ? @members : []
+      def opt_positionals = []
+      def rest_positionals = nil
+      def post_positionals = []
+      def req_keywords = @kind == :data ? @members : []
+      def opt_keywords = []
+      def rest_keywords = nil
+      def no_keywords = @kind == :struct
+
+      def define0(genv)
+        mod = genv.resolve_cpath(@static_cpath)
+        # add_module_def internally calls get_const(name).add_def(self)
+        cdef = mod.add_module_def(genv, self)
+        @members.each do |member|
+          ive = genv.resolve_ivar(@static_cpath, false, member)
+          ive.add_def(self)
+        end
+        @block_body.define(genv) if @block_body
+        cdef
+      end
+
+      def define_copy(genv)
+        mod = genv.resolve_cpath(@static_cpath)
+        mod.add_module_def(genv, self)
+        mod.remove_module_def(genv, @prev_node)
+        @members.each do |member|
+          ive = genv.resolve_ivar(@static_cpath, false, member)
+          ive.add_def(self)
+          ive.remove_def(@prev_node)
+        end
+        super(genv)
+      end
+
+      def undefine0(genv)
+        mod = genv.resolve_cpath(@static_cpath)
+        mod.remove_module_def(genv, self)
+        @members.each do |member|
+          ive = genv.resolve_ivar(@static_cpath, false, member)
+          ive.remove_def(self)
+        end
+        @block_body.undefine(genv) if @block_body
+      end
+
+      def install0(genv)
+        # Register the class singleton type as the constant value
+        mod_val = Source.new(Type::Singleton.new(genv, genv.resolve_cpath(@static_cpath)))
+        if @static_cpath
+          @changes.add_edge(genv, mod_val, @static_ret.vtx)
+        end
+
+        cpath = @static_cpath
+        @members.each do |member|
+          # Use bare `:member` (not `:@member`) so the slot can't collide with a
+          # user-written @member ivar — Struct/Data fields are not real ivars.
+          ivar_box = @changes.add_ivar_read_box(genv, cpath, false, member)
+          ret_box = @changes.add_escape_box(genv, ivar_box.ret)
+          @changes.add_method_def_box(genv, cpath, false, member, FormalArguments::Empty, [ret_box])
+
+          if @kind == :struct
+            # attr_writer (Struct only, Data is frozen)
+            ive = genv.resolve_ivar(cpath, false, member)
+            vtx = Vertex.new(self)
+            @changes.add_edge(genv, vtx, ive.vtx)
+            writer_ret = @changes.add_escape_box(genv, vtx)
+            f_args = FormalArguments.new([vtx], [], nil, [], [], [], nil, nil)
+            @changes.add_method_def_box(genv, cpath, false, :"#{ member }=", f_args, [writer_ret])
+          end
+        end
+
+        # initialize
+        init_vtxs = @members.map do |member|
+          ive = genv.resolve_ivar(cpath, false, member)
+          vtx = Vertex.new(self)
+          @changes.add_edge(genv, vtx, ive.vtx)
+          vtx
+        end
+        init_ret = @changes.add_escape_box(genv, Source.new(genv.nil_type))
+        if @kind == :struct
+          init_f_args = FormalArguments.new(init_vtxs, [], nil, [], [], [], nil, nil)
+        else
+          # Data.define uses keyword arguments
+          init_f_args = FormalArguments.new([], [], nil, [], init_vtxs, [], nil, nil)
+        end
+        @changes.add_method_def_box(genv, cpath, false, :initialize, init_f_args, [init_ret])
+
+        # Struct.[] is an alias for Struct.new
+        if @kind == :struct
+          self_ret = @changes.add_escape_box(genv, Source.new(Type::Instance.new(genv, genv.resolve_cpath(cpath), [])))
+          @changes.add_method_def_box(genv, cpath, true, :[], init_f_args, [self_ret])
+        end
+
+        # Install block body (additional method definitions)
+        if @block_body
+          @block_body.lenv.locals[:"*self"] = @block_body.lenv.cref.get_self(genv)
+          @block_body.install(genv)
+        end
+
+        mod_val
+      end
+    end
   end
 end

lib/typeprof/core/env/module_entity.rb

@@ -261,6 +261,8 @@ def find_superclass_const_read
             next
           when AST::ModuleNode
             return nil
+          when AST::StructNewNode
+            return []  # inherits from Object (Struct < Object)
           else
             raise
           end

lib/typeprof/core/graph/box.rb

@@ -935,7 +935,9 @@ def show(output_parameter_names)
       @f_args.post_positionals.each do |var|
         args << Type.strip_parens(var.show)
       end
-      if @node.is_a?(AST::DefNode)
+      if @node.respond_to?(:req_keywords) &&
+         @node.req_keywords.size == @f_args.req_keywords.size &&
+         @node.opt_keywords.size == @f_args.opt_keywords.size
         @node.req_keywords.zip(@f_args.req_keywords) do |name, f_vtx|
           args << "#{ name }: #{Type.strip_parens(f_vtx.show)}"
         end

lib/typeprof/core/service.rb

@@ -472,7 +472,7 @@ def dump_declarations(path)
               out << "  " * stack.size + "end"
             end
           end
-        when AST::ClassNode, AST::SingletonClassNode
+        when AST::ClassNode, AST::SingletonClassNode, AST::StructNewNode
           if node.static_cpath
             next if stack.any? { node.is_a?(AST::SingletonClassNode) && (_1.is_a?(AST::ClassNode) || _1.is_a?(AST::ModuleNode)) && node.static_cpath == _1.static_cpath }
 
@@ -496,6 +496,10 @@ def dump_declarations(path)
                   out << "  " * stack.size + "include #{ inc_mod.show_cpath }"
                 end
               end
+              # Output method definitions from meta nodes (StructNewNode etc.)
+              node.boxes(:mdef) do |mdef|
+                out << "  " * stack.size + "def #{ mdef.singleton ? "self." : "" }#{ mdef.mid }: " + mdef.show(@options[:output_parameter_names])
+              end
             else
               stack.pop
               out << "  " * stack.size + "end"

scenario/known-issues/struct-new-as-superclass.rb

@@ -0,0 +1,14 @@
+## update
+class Point < Struct.new(:x, :y)
+end
+Point.new(1, "hello").x
+
+## assert
+class Point < Struct[untyped]
+  def x: -> Integer
+  def y: -> String
+  def x=: (Integer) -> Integer
+  def y=: (untyped) -> untyped
+  def initialize: (Integer, String) -> void
+  def self.[]: (Integer, String) -> Point
+end

scenario/misc/struct_new.rb

@@ -0,0 +1,71 @@
+## update
+Foo = Struct.new(:bar, :baz)
+f = Foo.new(1, "hello")
+f.bar
+f.baz
+f.bar = 2
+g = Foo[3, "world"]
+
+## assert
+class Foo
+  def bar: -> Integer
+  def bar=: (Integer) -> Integer
+  def baz: -> String
+  def baz=: (untyped) -> untyped
+  def initialize: (Integer, String) -> void
+  def self.[]: (Integer, String) -> Foo
+end
+
+## update
+Pt = Data.define(:x, :y)
+p = Pt.new(x: 1, y: "hello")
+p.x
+p.y
+
+## assert
+class Pt
+  def x: -> Integer
+  def y: -> String
+  def initialize: (x: Integer, y: String) -> void
+end
+
+## update
+Bar = Struct.new(:n) do
+  def double
+    n * 2
+  end
+end
+Bar.new(5).double
+
+## assert
+class Bar
+  def n: -> Integer
+  def n=: (untyped) -> untyped
+  def initialize: (Integer) -> void
+  def self.[]: (Integer) -> Bar
+  def double: -> Integer
+end
+
+## update
+# The Struct member `v` is not a real Ruby ivar, so a user-written @v inside
+# the block body must not share the member's type.
+Baz = Struct.new(:v) do
+  def set_label
+    @v = "label"
+  end
+  def ivar
+    @v
+  end
+end
+Baz.new(42).v
+Baz.new(42).ivar
+
+## assert
+class Baz
+  def v: -> Integer
+  def v=: (untyped) -> untyped
+  def initialize: (Integer) -> void
+  def self.[]: (Integer) -> Baz
+  def set_label: -> String
+  def ivar: -> String
+end