Preserving ExcludeFromCodeCoverage attribute

[jakubch1]

Hello,
Currently ExcludeFromCodeCoverage attribute is not preserved when roslyn generates additional methods/classes (async methods, lambda... etc). To fix it code coverage tools needs to add logic which depends on internal roslyn implementation:

        // Check if the name is synthesized by the compiler
        // Refer to https://github.com/dotnet/roslyn/blob/master/src/Compilers/CSharp/Portable/Symbols/Synthesized/GeneratedNames.cs
        // to see how the compiler generate names for lambda, local function, yield or async/await expressions
        internal bool IsSynthesizedNameOf(string name, string methodName, int methodOrdinal)
        {
            return
                // Lambda method
                name.IndexOf($"<{methodName}>b__{methodOrdinal}") != -1 ||
                // Lambda display class
                name.IndexOf($"<>c__DisplayClass{methodOrdinal}_") != -1 ||
                // State machine
                name.IndexOf($"<{methodName}>d__{methodOrdinal}") != -1 ||
                // Local function
                (name.IndexOf($"<{methodName}>g__") != -1 && name.IndexOf($"|{methodOrdinal}_") != -1);
        }

[from https://github.com/coverlet-coverage/coverlet/pull/671/files]

Is there any better way of fixing it?

For dynamic code coverage we received also several issues. For example:
dotnet/core#4361
dotnet/core#5664

We are wondering if we should create similar logic as coverlet.

BR,
Jakub

[tmat]

@jaredpar @jcouv

[tmat]

One option would be to add an attribute that can be applied to attributes and indicate that specified attribute should be emitted to all members generated for the annotated member. Another option would be to propagate all attributes - but that might not be desirable (e.g. [Fact] attribute probably shouldn't be).

[jakubch1]

@jaredpar @tmat @jcouv any update on this?