Deploy nameof throughout corefx

[stephentoub]

Via the power of Roslyn and @jaredpar's handy https://github.com/jaredpar/UseNameOf (with a few tweaks), this deploys usage of C# 6's nameof throughout corefx when constructing exceptions, e.g. replacing throw new ArgumentOutOfRangeException("index", ...) with throw new ArgumentOutOfRangeException(nameof(index), ...). This helps to find problems when later refactoring, to remove hand-written strings from the codebase, and to help point out places where the wrong strings are being passed (e.g. a subsequent search for new ArgumentException(nameof(...) is likely to turn up places where the args are being passed in the wrong order, and a subsequent search for new ArgumentOutOfRangeException(" is likely to turn up places where the wrong parameter name is being used).

Separately, I fixed up our usage of MemberData and ConditionalFact/Theory to use nameof for the name of the target member rather than having it written as a string. In addition to helping with refactoring, this makes navigation in VS much easier, as you can now Go To Definition on these.

I've attributed the changes to dotnet-bot.

This will not pass until #6181 is merged and the LangVer constraint is removed.

cc: @weshaggard, @jaredpar, @ellismg

[jaredpar]

nameof all the things!!!

👍

[weshaggard]

👍

[stephentoub]

@dotnet-bot test this please

[stephentoub]

@saurabh500, do you want to review the data changes here?
@davidsh, networking?

(And generally let me know if you have concerns about these kinds of changes to those codebases.)

[davidsh]

This is a great positive step to having a more maintainable codebase.
LGTM

[saurabh500]

LGTM

[stephentoub]

Thanks, all.