New Rules for `Lock` class usage and to avoid public usage of `lock (this)`

[elachlan]

Describe the problem you are trying to solve

In C#13 there is a new system.threading.lock class (dotnet/csharplang#7104). It may be more performant to use over a standard object lock. An analyzer that identifies object properties which are exclusively used for locking and suggests using the new Lock class instead, with a code fix.

Additionally, it would be nice to have a rule that identifies usages of lock (this) inside public classes to discourage the practice.

Additional context

References:

• Add first class System.Threading.Lock type #34812
• [Proposal]: Lock statement pattern (VS 17.10, .NET 9) csharplang#7104
• https://learn.microsoft.com/en-us/dotnet/api/system.threading.lock?view=net-9.0

[buyaa-n]

Moving to runtime as it is a new analyzer proposal

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[CyrusNajmabadi]

Roslyn already added an analyzer for this: dotnet/roslyn#74170

Source: me :-)

[elachlan]

@CyrusNajmabadi that just leaves the usage of lock(this) on public apis.

[CyrusNajmabadi]

That seems entirely different and unrelated to c#13 or the new Lock type.