Allow literal types to be operands of an infix type

grammar.js

@@ -1,4 +1,4 @@
 const PREC = {
   comment: 1,
   using_directive: 2,
   control: 1,
@@ -875,7 +875,7 @@
     _infix_type_choice: $ =>
       prec.left(
         PREC.infix,
-        choice($.compound_type, $.infix_type, $._annotated_type),
+        choice($.compound_type, $.infix_type, $._annotated_type, $.literal_type),
       ),
 
     infix_type: $ =>

test/corpus/types.txt

@@ -623,4 +623,35 @@ class A[
         (identifier)
         (upper_bound
           (type_identifier))
-        (type_identifier)))))
+        (type_identifier)))))
+
+================================================================================
+Union and Intersection Types (Scala 3)
+================================================================================
+
+type A = Foo | Bar & Buz
+type B = "foo" | "bar" & "buz"
+
+--------------------------------------------------------------------------------
+(compilation_unit
+  (type_definition
+    (type_identifier)
+    (infix_type
+      (infix_type
+        (type_identifier)
+        (operator_identifier)
+        (type_identifier))
+      (operator_identifier)
+      (type_identifier)))
+  (type_definition
+    (type_identifier)
+    (infix_type
+      (infix_type
+        (literal_type
+          (string))
+        (operator_identifier)
+        (literal_type
+          (string)))
+      (operator_identifier)
+      (literal_type
+        (string)))))