Make TypeNameResolver more compatible with Ruby

lib/rbs/resolver/type_name_resolver.rb

@@ -29,22 +29,50 @@ def resolve(type_name, context:)
         end
 
         try_cache([type_name, context]) do
-          resolve_in(type_name, context)
+          head, tail = partition(type_name)
+
+          head = resolve_in(head, context)
+
+          if head
+            if tail
+              has_name?(tail.with_prefix(head.to_namespace))
+            else
+              head
+            end
+          end
+        end
+      end
+
+      def partition(type_name)
+        if type_name.namespace.empty?
+          head = type_name.name
+          tail = nil
+        else
+          head, *tail = type_name.namespace.path
+
+          head or raise
+
+          tail = TypeName.new(
+            name: type_name.name,
+            namespace: Namespace.new(absolute: false, path: tail)
+          )
         end
+
+        [head, tail]
       end
 
-      def resolve_in(type_name, context)
+      def resolve_in(head, context)
         if context
           parent, child = context
           case child
           when false
-            resolve_in(type_name, parent)
+            resolve_in(head, parent)
           when TypeName
-            name = type_name.with_prefix(child.to_namespace)
-            has_name?(name) || resolve_in(type_name, parent)
+            name = TypeName.new(name: head, namespace: child.to_namespace)
+            has_name?(name) || resolve_in(head, parent)
           end
         else
-          has_name?(type_name.absolute!)
+          has_name?(TypeName.new(name: head, namespace: Namespace.root))
         end
       end
 

sig/resolver/type_name_resolver.rbs

@@ -25,7 +25,9 @@ module RBS
 
       def try_cache: (query) { () -> TypeName? } -> TypeName?
 
-      def resolve_in: (TypeName, context) -> TypeName?
+      def resolve_in: (Symbol, context) -> TypeName?
+
+      def partition: (TypeName) -> [Symbol, TypeName?]
     end
   end
 end

test/rbs/resolver/type_name_resolver_test.rb

@@ -42,6 +42,26 @@ class Bar
     end
   end
 
+  def test_resolve_failure
+    SignatureManager.new do |manager|
+      manager.files[Pathname("foo.rbs")] = <<EOF
+class Foo
+  class Foo
+  end
+
+  class Bar
+  end
+end
+EOF
+      manager.build do |env|
+        resolver = Resolver::TypeNameResolver.new(env)
+
+        assert_nil resolver.resolve(type_name("Foo::Bar"), context: [[nil, TypeName("::Foo")], TypeName("::Foo::Foo")])
+      end
+    end
+  end
+
+
   def test_duplicated_resolve
     SignatureManager.new do |manager|
       manager.files[Pathname("foo.rbs")] = <<EOF