René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Array indexing does not get +1 in transpiled output in a rather specific scenario with optional chaining","articleBody":"When all:\r\n- `Foo` is an interface from extending `Array` or `ReadonlyArray`\r\n- An object `bar` has a property with type Foo | undefined\r\n- Optional chaining used to array-index `Foo`\r\n- ..._after_ a property access to `bar`\r\n\r\nThen, the transpiled lua does not get +1 on the array indexing.\r\n\r\n```ts\r\ninterface Foo extends Array\u003cnumber\u003e {}\r\nconst b: {arr?: Foo} = {arr:[1,2]}\r\n\r\n// incorrectly prints 1\r\nprint(b.arr?.[1])\r\n\r\nconst arr: Foo | undefined = b.arr\r\nprint(arr?.[1])\r\n\r\n// all correctly prints 2\r\nprint(b.arr![1])\r\n\r\nconst arr2 : Foo | undefined = [1,2]\r\nprint(arr2?.[1])\r\n\r\nconst c: {arr?: number[]} = {arr:[1,2]}\r\nprint(c.arr?.[1])\r\n\r\nconst d: {arr: Foo} = {arr:[1,2]}\r\nprint(c.arr?.[1])\r\n```\r\nTSTL v1.28.1\r\n\r\nI'm amazed and annoyed how many stars had to align to encounter this bug, and that it can't be more miminal.\r\n\r\n","author":{"url":"https://github.com/GlassBricks","@type":"Person","name":"GlassBricks"},"datePublished":"2024-12-07T01:26:31.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":0},"url":"https://github.com/1605/TypeScriptToLua/issues/1605"}