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65 lines
2.1 KiB
Markdown
65 lines
2.1 KiB
Markdown
---
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layout: single
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title: "Luau Recap: November 2022"
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---
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While the team is busy to bring some bigger things in the future, we have made some small improvements this month.
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[Cross-posted to the [Roblox Developer Forum](https://devforum.roblox.com/t/luau-recap-november-2022/).]
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## Error messages
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Error about function argument count mismatch no longer points at the last argument, but instead at the function in question.
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So, instead of:
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```lua
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function myfunction(a: number, b:number) end
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myfunction(123)
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~~~
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```
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We now highlight this:
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```lua
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function myfunction(a: number, b:number) end
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myfunction(123)
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~~~~~~~~~~
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```
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Parsing now recovers with a more precise error message if you forget a comma in table constructor spanning multiple lines:
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```lua
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local t = {
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a = 1
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b = 2 -- Expected ',' after table constructor element
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c = 3 -- Expected ',' after table constructor element
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}
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```
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If you iterate over a table value that could also be `nil`, you get a better explanation in the error message:
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```lua
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local function f(t: {number}?)
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for i,v in t do -- Value of type {number}? could be nil
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--...
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end
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end
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```
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Previously it was `Cannot call non-function {number}?` which was confusing.
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And speaking of confusing, some of you might have seen an error like `Type 'string' could not be converted into 'string'`.
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This was caused by Luau having both a primitive type `string` and a table type coming from `string` library. Since the way you can get the type of the `string` library table is by using `typeof(string)`, the updated error message will mirror that and report `Type 'string' could not be converted into 'typeof(string)'`.
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## Analysis improvements
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For better inference, we updated definition of `Enum.SomeType:GetEnumItems()` to return `{Enum.SomeType}` instead of common `{EnumItem}` and the return type of `next` function now includes the possibility of key being `nil`.
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If you use `and` operator on non-boolean values, `boolean` type will no longer be added by the type inference:
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```lua
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local function f1(a: number?)
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-- 'x' is still a 'number?' and doesn't become 'boolean | number'
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local x = a and 5
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end
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```
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