Enable IDE0060 (Remove unused parameter) analyzer

[marek-safar]

Follow up on #67527 which was closed meantime

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Issue Details

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Author:	marek-safar
Assignees:	-
Labels:	area-Meta
Milestone:	-

[danmoseley]

More violations to fix..

[danmoseley]

@marek-safar do you plan to continue?

[danmoseley]

Might be easiest to just merge some fixes at first and not attempt to get clean and enable the rule all in one PR

[stephentoub]

@jkoritzinsky, if in such situations we statically know these methods will never be used, can we update the generator to be ok with them not existing, and then just delete them rather than having these throw new UnreachableException() dummy implementations?

[jkoritzinsky]

There was a lot of desire on the interop team to always require specific methods for particular shapes to reduce the concept count we'd have to teach users. cc: @AaronRobinsonMSFT since he felt the most strongly about it.

[AaronRobinsonMSFT]

can we update the generator to be ok with them not existing, and then just delete them

This breaks the interop contract and is something we are being very explicit about going forward. The intent here is to avoid at all costs magic from the source generator scenarios. We expect functions (A), (B), and (C), if that shape isn't there then it is a broken interop contract.

[stephentoub]

Understood. I'm saying today it is:

• "We expect functions (A), (B), and (C), if that shape isn't there then it is a broken interop contract.

but it could be:

• "If (A) is available, we'll use A. If (B) is available, we'll use B. If (C) is available, we'll use C.".

The C# compiler does this in many places, for example.

[AaronRobinsonMSFT]

The C# compiler does this in many places, for example.

Can you share an example?

[stephentoub]

Can you share an example?

e.g.

• If you foreach something where the enumerator implements IDisposable, the code will be emitted with a try/finally calling Dispose; if it doesn't, no try/finally, no Dispose call.
• When calling M(params T[] args) with no args, it'll use Array.Empty<T>() if it's available, or else new T[0].
• When emitting code for $"Hello, {name}", it'll use DefaultInterpolatedStringBuilder if available, otherwise it'll use string.Format.
• When emitting code for await, if the thing you're awaiting has UnsafeOnCompleted it'll use it, otherwise it'll use OnCompleted.
  ...

[stephentoub]

Why is deleting all of this valid?

[marek-safar]

It was probably bad merge, reverted the change

[stephentoub]

Thanks. Other than my remaining pending comments, LGTM. I don't intend to review again ;-)

[marek-safar]

Failures are timeouts

[jakobbotsch]

@marek-safar After this change I can no longer build locally. .\build.cmd clr+libs -rc checked -c release gives me tons of

C:\dev\dotnet\runtime\src\libraries\System.Private.CoreLib\src\System\Runtime\Intrinsics\Wasm\WasmBase.PlatformNotSupported.cs(36,49
): error IDE0060: Remove unused parameter 'value' [C:\dev\dotnet\runtime\src\coreclr\System.Private.CoreLib\System.Private.CoreLib.c
sproj]

[jakobbotsch]

Looks like unlucky timing with #77777

[stephentoub]

Looking...