From a124f53628f5bdcbd16fba49cfcf1d1ea601975d Mon Sep 17 00:00:00 2001
From: Lily Brown <31936135+AmaranthineCodices@users.noreply.github.com>
Date: Fri, 26 Mar 2021 16:07:34 -0700
Subject: [PATCH] Document variadic types (#17)

---
 docs/_pages/typecheck.md | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/docs/_pages/typecheck.md b/docs/_pages/typecheck.md
index d53fbc71..14b8463d 100644
--- a/docs/_pages/typecheck.md
+++ b/docs/_pages/typecheck.md
@@ -234,6 +234,26 @@ Note: it's impossible to create an intersection type of some primitive types, e.
 
 Note: Luau still does not support user-defined overloaded functions. Some of Roblox and Lua 5.1 functions have different function signature, so inherently requires overloaded functions.
 
+## Variadic types
+
+Luau permits assigning a type to the `...` variadic symbol like any other parameter:
+
+```lua
+local function f(...: number)
+end
+
+f(1, 2, 3)     -- ok
+f(1, "string") -- not ok
+```
+
+`f` accepts any number of `number` values.
+
+In type annotations, this is written as `...T`:
+
+```lua
+type F = (...number) -> ...string
+```
+
 ## Typing idiomatic OOP
 
 One common pattern we see throughout Roblox is this OOP idiom. A downside with this pattern is that it does not automatically create a type binding for an instance of that class, so one has to write `type Account = typeof(Account.new("", 0))`.