DebuggerStepThrough attribute is not respected for async, task and other CEs

[vasily-kirichenko]

I find myself here stepping with F10:

which should never happen.

[dsyme]

The are (many) inner lambdas. Currently it is not possible to attribute these

Should it be automatically propagated do you think?

[vasily-kirichenko]

I expect the debugger to not step into Bind even by pressing F11, as if it were defined in a referenced assembly with no source code available. As MSDN reads:

This attribute is provided for use by source code debuggers; the common language runtime is not affected by it. For example, the Visual Studio debugger does not stop in a method that is marked with this attribute even if a breakpoint is set in the method.

Maybe I don't understand something?

[dsyme]

@vasily-kirichenko As so often in F#, the attribute applies to the compiled form of Bind, not the source form. The compiled form include multiple lambdas, whose Invoke methods are not marked with the attribute. So you are stepping into the Invoke method of one of these lamdas.

Right now, it isn't possible to reason about this without thinking about the compiled form

The only thought I have is that we could automatically propagate the attribute into those invoke methods.
We should find out what C# does with inner lambdas though