Allow alias to module-self-type from module

lib/rbs/definition_builder.rb

@@ -37,7 +37,7 @@ def define_interface(definition, type_name, subst)
       interface_methods = interface_methods(included_interfaces)
       methods = method_builder.build_interface(type_name)
 
-      import_methods(definition, type_name, methods, interface_methods, subst)
+      import_methods(definition, type_name, methods, interface_methods, subst, nil)
     end
 
     def build_interface(type_name)
@@ -86,6 +86,19 @@ def define_instance(definition, type_name, subst)
       one_ancestors = ancestor_builder.one_instance_ancestors(type_name)
       methods = method_builder.build_instance(type_name)
 
+      self_type_methods = one_ancestors.each_self_type.with_object({}) do |self_type, hash| #$ Hash[Symbol, Definition::Method]
+        self_type.args.each do |arg|
+          validate_type_presence(arg)
+        end
+
+        self_type_defn = self_type.name.interface? ? build_interface(self_type.name) : build_instance(self_type.name)
+
+        s = subst + tapp_subst(self_type.name, self_type.args)
+        self_type_defn.methods.each do |method_name, method_def|
+          hash[method_name] = method_def.sub(s)
+        end
+      end
+
       one_ancestors.each_included_module do |mod|
         mod.args.each do |arg|
           validate_type_presence(arg)
@@ -100,7 +113,7 @@ def define_instance(definition, type_name, subst)
         [interface, *other_interfaces]
       end
       interface_methods = interface_methods(all_interfaces)
-      import_methods(definition, type_name, methods, interface_methods, subst)
+      import_methods(definition, type_name, methods, interface_methods, subst, self_type_methods)
 
       one_ancestors.each_prepended_module do |mod|
         mod.args.each do |arg|
@@ -254,7 +267,7 @@ def build_singleton0(type_name)
             [interface, *other_interfaces]
           end
           interface_methods = interface_methods(all_interfaces)
-          import_methods(definition, type_name, methods, interface_methods, Substitution.new)
+          import_methods(definition, type_name, methods, interface_methods, Substitution.new, nil)
 
           entry.decls.each do |d|
             d.decl.members.each do |member|
@@ -529,7 +542,7 @@ def insert_variable(type_name, variables, name:, type:)
       )
     end
 
-    def import_methods(definition, module_name, module_methods, interfaces_methods, subst)
+    def import_methods(definition, module_name, module_methods, interfaces_methods, subst, self_type_methods)
       new_methods = {} #: Hash[Symbol, Definition::Method]
       interface_method_duplicates = Set[] #: Set[Symbol]
 
@@ -567,6 +580,7 @@ def import_methods(definition, module_name, module_methods, interfaces_methods,
             definition,
             method,
             subst_,
+            nil,
             defined_in: interface.name,
             implemented_in: module_name
           )
@@ -579,6 +593,7 @@ def import_methods(definition, module_name, module_methods, interfaces_methods,
           definition,
           method,
           subst,
+          self_type_methods,
           defined_in: module_name,
           implemented_in: module_name.interface? ? nil : module_name
         )
@@ -587,12 +602,12 @@ def import_methods(definition, module_name, module_methods, interfaces_methods,
       definition.methods.merge!(new_methods)
     end
 
-    def define_method(methods, definition, method, subst, defined_in:, implemented_in: defined_in)
+    def define_method(methods, definition, method, subst, self_type_methods, defined_in:, implemented_in: defined_in)
       existing_method = methods[method.name] || definition.methods[method.name]
 
       case original = method.original
       when AST::Members::Alias
-        original_method = methods[original.old_name] || definition.methods[original.old_name]
+        original_method = methods[original.old_name] || definition.methods[original.old_name] || self_type_methods&.fetch(original.old_name, nil)
 
         unless original_method
           raise UnknownMethodAliasError.new(

sig/definition_builder.rbs

@@ -116,6 +116,7 @@ module RBS
       Definition class_definition,
       MethodBuilder::Methods::Definition method_definition,
       Substitution subst,
+      Hash[Symbol, Definition::Method]? self_type_methods,
       defined_in: TypeName,
       ?implemented_in: TypeName?
     ) -> void
@@ -137,7 +138,8 @@ module RBS
       TypeName module_name,
       MethodBuilder::Methods module_methods,
       interface_methods interface_methods,
-      Substitution subst
+      Substitution subst,
+      Hash[Symbol, Definition::Method]? self_type_methods,
     ) -> void
 
     # Updates `definition` with methods and variables of `type_name` that can be a module or a class

test/rbs/definition_builder_test.rb

@@ -2686,4 +2686,23 @@ module Bar : Foo
       end
     end
   end
+
+  def test_alias__to_module_self_indierect_method
+    SignatureManager.new(system_builtin: false) do |manager|
+      manager.add_file("foo.rbs", <<-EOF)
+module Kernel
+  alias foo __id__
+end
+
+module Foo
+end
+      EOF
+
+      manager.build do |env|
+        builder = DefinitionBuilder.new(env: env)
+
+        builder.build_instance(type_name("::Foo"))
+      end
+    end
+  end
 end