Incorrect type deduction of generic functions with alias type arguments.

[vsaulue]

Environment

Name	Version
IDEA version	2021.2.1 (Community Edition) - Build #IC-212.5080.55
Luanalysis version	v1.3.0
OS	Windows 10

Preferences

Lua

Name	Setting
Language level	Lua 5.2

Type Safety

Name	Setting
Strict nil checks	☑️
Unknown type (any) is indexable	☑️
Unknown type (any) is callabale	☑️

What are the steps to reproduce this issue?

Create a file with the following code:

---@alias MyArray<T> table<number,T>

---@generic Y
---@param arg MyArray<Y>
local function f(arg) end

---@type MyArray<string>
local arg = {"foobar"}

f(arg)

What happens?

Error on line f(arg): Type mismatch. Required: 'MyArray<number>' Found: 'MyArray<string>'

What were you expecting to happen?

No error: this is a valid call to f(). The generic Y type should be inferred as string, but for some reasons Luanalysis tries to infer it as number.

Any logs, error output, etc?

None

Any other comments?

The problem is related to aliases. Luanalysis properly infer the generic Y if f is declared as follows:

---@generic Y
---@param arg table<number,Y>
local function f(arg) end