Handle RBS::Types::Intersection (fallback to union type)

ReplTypeCompletor shows all possible methods for UnionType (note: there is no type narrowing), so the difference of Union and Intersection is small.
Normally, intersection type is an intersection of InterfaceType and ReplTypeCompletor doesn't support it yet.

Author: tompng

lib/repl_type_completor/types.rb

@@ -406,7 +406,8 @@ def self.from_rbs_type(return_type, self_type, extra_vars = {})
             OBJECT
           end
         end
-      when RBS::Types::Union
+      when RBS::Types::Union, RBS::Types::Intersection
+        # Intersection is unsupported. fallback to union type
         UnionType[*return_type.types.map { from_rbs_type _1, self_type, extra_vars }]
       when RBS::Types::Proc
         PROC
@@ -455,6 +456,8 @@ def self.from_rbs_type(return_type, self_type, extra_vars = {})
           params = names.map.with_index { [_1, args[_2] || OBJECT] }.to_h
         end
         InstanceType.new klass, params || {}
+      else
+        OBJECT
       end
     end
 

test/repl_type_completor/test_type_analyze.rb

@@ -744,6 +744,11 @@ def test_rbs_untyped_function
       assert_call('proc{}.call; 1.', include: Integer)
     end
 
+    def test_rbs_intersection_type_fallback
+      # One of the overloads of Kernel.Rational(a, b) has `Numeric & _RationalDiv[T]`
+      assert_call('Rational(a,b).', include: Rational)
+    end
+
     def test_rbs_instance_type
       assert_call('Thread.start{}.', include: Thread)
       assert_call('"".encode("utf-8").', include: String)