feat: allow type in generic types

Author: amaanq

grammar.js

@@ -943,15 +943,21 @@ module.exports = grammar({
     )),
 
     type: $ => choice(
-      $.expression,
+      prec(1, $.expression),
       $.splat_type,
       $.generic_type,
       $.union_type,
       $.constrained_type,
       $.member_type,
     ),
     splat_type: $ => prec(1, seq(choice('*', '**'), $.identifier)),
-    generic_type: $ => prec(1, seq($.identifier, $.type_parameter)),
+    generic_type: $ => prec(1, seq(
+      choice(
+        $.identifier,
+        alias('type', $.identifier),
+      ),
+      $.type_parameter,
+    )),
     union_type: $ => prec.left(seq($.type, '|', $.type)),
     constrained_type: $ => prec.right(seq($.type, ':', $.type)),
     member_type: $ => seq($.type, '.', $.identifier),

test/corpus/expressions.txt

@@ -1200,6 +1200,7 @@ Type expressions
 ================================================================================
 
 a: A[T] | B
+y: type[int] = int
 
 --------------------------------------------------------------------------------
 
@@ -1216,4 +1217,14 @@ a: A[T] | B
                 (type
                   (identifier)))))
           (type
-            (identifier)))))))
+            (identifier))))))
+  (expression_statement
+    (assignment
+      (identifier)
+      (type
+        (generic_type
+          (identifier)
+          (type_parameter
+            (type
+              (identifier)))))
+      (identifier))))