C#: Add flow summary for 'Task.ConfigureAwait()'

[tamasvajk]

No description provided.

[tamasvajk]

Let's suppose the AccessPath::cons is working. How would I verify that the added flow summaries are working for the following two cases?

var i = new Task<int>(() => 42).ConfigureAwait(false).GetAwaiter().GetResult();
var j = await new Task<int>(() => 42).ConfigureAwait(false);

This question is actually not specific to .ConfigureAwait(). Which checks rely on flow summaries on .GetAwaiter().GetResult()?

[tamasvajk]

@hvitved This is missing from the test expected file.
When I try to debug this on a codeql database create DB with the following:

private predicate test(
  SystemRuntimeCompilerServicesConfiguredTaskAwaitableTConfiguredTaskAwaiterStruct a, Field f
) {
  a.getAField() = f
}

I only get two fields: _dummy and _dummyPrimitive, and therefore I get no fields in .getUnderlyingTaskField(). It looks to me that Roslyn reports these field names.

• What is the difference between the test and a codeql database create extraction?
• How do I extract the correct field names with codeql database create?
• Why doesn't this AccessPath::cons work?

[tamasvajk]

@hvitved The only change I did since your fix is that I've squashed the first two commits.

[hvitved]

This comment is not correct. I think this class is so special that there is no need to have it, instead inline the logic where it is used below.