Review IsTopLevelStatementsEntryPointMethod implementation

[Youssef1313]

This was implemented in https://github.com/dotnet/roslyn-analyzers/pull/4066/files#diff-b16e801c575072ba829f30b96c9d2362R692-R694

The current implementation:

        public static bool IsTopLevelStatementsEntryPointMethod([NotNullWhen(true)] this IMethodSymbol? methodSymbol)
            => methodSymbol?.ContainingType.IsTopLevelStatementsEntryPointType() == true &&
               methodSymbol.IsStatic &&
               methodSymbol.Name switch
               {
                   "$Main" => true,
                   "<$Main>$" => true,
                   _ => false
               };

The generated entry point for top-level is "<Main>$" which isn't covered by the method.

Actions needed

• Investigate how the tests passed when the method name is "<Main>$" which is not covered.

• Use the public API from Roslyn:

  https://github.com/dotnet/roslyn/blob/cf55f3a58e47298426fa971d3bd9d8857c746c65/src/Compilers/Core/Portable/Symbols/WellKnownMemberNames.cs#L348-L356

[Youssef1313]

@mavasani I debugged this. It seems like the name we get is $Main, without any <>.
Any idea where the angle brackets have gone? 😄
Edit: the compiler had the name as $Main, but that was changed in dotnet/roslyn#45930 to <Main>$.

[Youssef1313]

I'm going to close this as the implementation was corrected. Using Roslyn API isn't possible because we are not using a recent enough version of Roslyn, and I think adding something to Lightup for this case doesn't worth it.