Change all null checking expressions to use 'is null' and 'is not null'
instead of '== null' and '!= null'.
This was mostly done with sed, so code can probably be improved in many
other ways with manual inspection, but that will come over time.
Also add code to the autoformat script to automatically fix these issues in the future.
Naming could be problematic when generating code, move the logic out of
the generator class to a helper class whose only job is to name classes
and keep track of names.
---------
Co-authored-by: GitHub Actions Autoformatter <github-actions-autoformatter@xamarin.com>
This is the first part of a 2 or more changes that will allow the APIs
to use ? as a way to mark a nullable field, parameter, property and
return method.
The way it works follows the documentation from the runtime that can be
found here:
https://github.com/dotnet/roslyn/blob/main/docs/features/nullable-metadata.md
The tldr; of the documentation is as follows:
1. If we are looking at a value type, the compiler converts int? into
Nullable<int>. This was already considered in the old code.
2. If we are inspecting a generic type we have to look for the
information in two different attributes added by the compiler: -
NullableAttribute: Each type reference in metadata may have an
associated NullableAttribute with a byte[] where each byte represents
nullability: 0 for oblivious, 1 for not annotated, and 2 for annotated.
- NullableContextAttribute is valid in metadata on type and method
declarations. The byte value represents the implicit NullableAttribute
value for type reference within that scope that do not have an explicit
NullableAttribute and would not otherwise be represented by an empty
byte[].
The API is very similar to that provided by dotnet6 but it allows us to
support classic. The move to the dotnet6 API should not be hard and
probably can be done by an IDE.
Once this API lands we will have to find the old usages of the check for
nullability and combine both. This new API should fix several issues we
have with nullability and nullability + generics.
---------
Co-authored-by: GitHub Actions Autoformatter <github-actions-autoformatter@xamarin.com>
Rolf Bjarne Kvinge
Manuel de la Pena