"[]" in function name breaks file parsing

[lucasvinbr]

Describe the bug
Adding a "[]" to a function name causes all errors in the file containing the function to "disappear". The error "The [name] form cannot be used" is not shown unless something is written between the brackets.

If the function with the brackets is inside a file that has been added as library, all the functions and other stuff from the file won't be read/used, apparently.

To Reproduce
Steps to reproduce the behavior:

1. Create a new lua file
2. Write "function asdf[]() end"
3. Write random text in the file and notice no errors are found

Expected behavior
An error to be shown (and all the other errors in the file, if any)

Environment (please complete the following information):

• OS: Windows
• Client: VSCode

Additional context
log file

[sumneko]

Thank you for reporting!