Fix type support for readonly arrays

Author: JounQin

index.test-d.ts

@@ -204,6 +204,20 @@ visit(sampleTree, 'definition', function (node) {
   })
 })
 
+visit(sampleTree, ['definition'], function (node) {
+  visit(node, function (node, _, parent) {
+    expectNotType<Definition>(node)
+    expectNotType<never>(parent)
+  })
+})
+
+visit(sampleTree, ['definition'] as const, function (node) {
+  visit(node, function (node, _, parent) {
+    expectType<Definition>(node)
+    expectType<never>(parent)
+  })
+})
+
 function isHeading(node: Node): node is Heading {
   return node ? node.type === 'heading' : false
 }

lib/index.js

@@ -51,8 +51,8 @@
 
 /**
  * @typedef {(
- *   Check extends Array<any>
- *   ? MatchesOne<Value, Check[keyof Check]>
+ *   Check extends ReadonlyArray<any>
+ *   ? MatchesOne<Value, Check[number]>
  *   : MatchesOne<Value, Check>
  * )} Matches
  *   Check whether a node matches a check in the type system.