Championed issue: dotnet/csharplang#373
Speclet: https://github.com/dotnet/csharplang/blob/main/proposals/csharp-11.0/extended-nameof-scope.md

• Test with attributes on local functions
• Test with attributes on lambdas
• Test with attributes on delegates
• Test with attributes on methods/constructors/operators
• Test with main:-targeted attributes (shouldn't work, since they are not on a method declaration) (no longer applicable)
• Keep the breaks under LangVer preview for now, but remove that condition before shipping C# 11 (tracked by Remove LangVer check for nameof(parameter) feature before shipping #60640)
• Speculation in attributes on local functions is broken (Speculation within attributes on local functions is broken #60801)
• Remove LangVer condition (Remove LangVer check for nameof(parameter) feature before shipping #60640)

LDM

• Breaking change (yes, but under preview LangVer for now)
• Should we put type parameters in scope too? (yes)

Productivity

• Completion (issue Symbol completion doesn't work on empty nameof in certain attributes #60812)
• QuickInfo