type_check_inside_call

What it does

Checks for type(foo == "type"), instead of type(foo) == "type".

Why this is bad

This will always return "boolean", and is undoubtedly not what you intended to write.

Example

return type(foo == "number")

...should be written as...

return type(foo) == "number"

Remarks

When using the Roblox standard library, this checks typeof as well.