SemanticModel doesn't reflect nullability of types calculated by flow analysis.

[AlekseyTs]

        [Fact]
        public void MethodWithGenericOutParameter()
        {
            CSharpCompilation c = CreateCompilation(new[] { @"
public class C
{
    public void Main(string? key)
    {
        Copy(key, out var s);
        s/*T:string?*/.ToString(); // warn
    }
    public static void Copy<T>(T key, out T value) => throw null;
}
", NonNullTypesTrue, NonNullTypesAttributesDefinition });

            VerifyOutVar(c, "string!"); // PROTOTYPE(NullableReferenceTypes): expecting string?
            c.VerifyTypes();
            c.VerifyDiagnostics(
                // (7,9): warning CS8602: Possible dereference of a null reference.
                //         s/*T:string?*/.ToString(); // warn
                Diagnostic(ErrorCode.WRN_NullReferenceReceiver, "s").WithLocation(7, 9)
                );
        }

[jcouv]

Relates to https://github.com/dotnet/roslyn/issues/26198 (issue tracking public APIs)

[333fred]

Note: this is just for GetSymbolInfo. GetDeclaredSymbol on the SingleVariableDesignationSyntax will return the correct result after https://github.com/dotnet/roslyn/pull/37322 is merged.

[RikkiGibson]

@333fred is this issue still present?

[333fred]

For GetSymbolInfo

[333fred]

Remaining work is for 16.4 time frame.

[333fred]

The only thing outstanding here is local functions nested inside reinferred lambdas, and any symbols that said local function contains, including:

• Locals
• Parameters
• Type Parameter usage
• Lambdas/local functions nested inside

This work is targeted for post 16.4 currently, so I'm moving this out.