Namespaced custom validating functions for properties do not work

[jasonnicholson]

Namespaced custom validating functions for properties do not work. It works fine for arguments blocks. The following creates a parsing error that stops the Sphinx build. This bug is on the master branch (385768b at the time of writing this) and not in release 0.22.1.

classdef MyClass
  properties
    Prop1 {myNamespace.myValidatorFunction(Prop1)}
  end
end

[ehennestad]

This also affects arguments blocks in some special cases, not just properties — the note that "it works fine for arguments blocks" doesn't hold in all cases.

Minimal repro (crashes the build on current master, 3de5208):

function out = f(x)
    arguments
        x {a.b.v}
    end
    out = x;
end

A namespaced validator with two or more namespace parts ({a.b.v}) in an argument that has no size/class specifier triggers it. A single-part namespace ({a.v}) parses fine, and some size/class combinations mask it, so it's intermittent in real code.

Traceback:

File "sphinxcontrib/mat_tree_sitter_parser.py", line 375, in _parse_argument_section
    for arg in arguments:
TypeError: 'NoneType' object is not iterable

So there are two separate code paths that need guarding against the query returning no captures: property parsing (the original report) and _parse_argument_section. Underlying cause looks like the tree-sitter grammar emitting an ERROR node for these namespaced-validator forms, after which the query's args capture is None.