Fixes the false positive reported in
https://github.com/github/codeql/issues/18910
Adds a new `Annotation` class (subclass of `Expr`) which encompasses all
possible kinds of annotations in Python.
Using this, we look for string literals which are part of an annotation,
and which have the same content as the name of a (potentially) unused
global variable, and in that case we do not produce an alert.
In future, we may want to support inspecting such string literals more
deeply (e.g. to support stuff like "list[unused_var]"), but I think for
now this level of support is sufficient.
Adds two test cases having to do with type annotations. The first one
demonstrates that type annotations (even if they are never executed by
the Python interpreter) count as uses for the purposes of the unused
variable query. The second one demonstrates that this is _not_ the case
if all such uses are inside strings (i.e. forward declarations), as we
do not currently inspect the content of these strings.
These seem generally useful outside of points-to, and so it might be
better to add them to the `Function` class instead.
I took the liberty of renaming these to say `Arguments` rather than
`Parameters`, as this is more in line with the nomenclature that we're
using elsewhere. (The internal points-to methods retain the old names.)
I'm somewhat ambivalent about the behaviour of `getMaxParameters` on
functions with `*varargs`. The hard-coded `INT_MAX` return value is
somewhat awkward, but the alternative (to only have the predicate
defined when a specific maximum exists) seems like it would potentially
cause a lot of headaches.
Extends the mechanism introduced in
https://github.com/github/codeql/pull/18030
to behave the same for _all_ `MatchLiteralPattern`s, not just the ones
that happen to be the constant `True` or `False`.
Co-authored-by: yoff <yoff@github.com>
Observed on some test files in Nuitka/Nuitka, having `break` and
`continue` outside of loops in Python is (to Python) a syntax error, but
our parser happily accepted this broken syntax.
This then caused issues further downstream in the control-flow
construction, as it broke some invariants.
To fix this we now skip the code that would previously fail when the
invariants are broken.
Co-authored-by: yoff <yoff@github.com>
