Where is the spec proposal for custom async method builders added in C# 7.0?

[jnm2]

Mentioned here: https://docs.microsoft.com/en-us/dotnet/csharp/whats-new/csharp-7#generalized-async-return-types

And mentioned here, with the incorrect statement that any type can be used as an async return type so long as it has a public GetAwaiter method: https://docs.microsoft.com/en-us/dotnet/csharp/programming-guide/concepts/async/async-return-types#generalized-async-return-types-and-valuetasktresult

This is not true. The AsyncMethodBuilder attribute and a valid builder type is required. I was hoping to look at the spec to see some documentation of the actual requirements of the async method builder type.

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Document Details

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• ID: 2e3f3f52-86a5-4cc9-ab1f-874cad72b821
• Version Independent ID: f69dc2c8-79bc-300c-5804-e1f7aa5c8352
• Content: Pattern matching - C# 7.0 specification proposals
• Content Source: proposals/csharp-7.0/pattern-matching.md
• Product: dotnet-csharp
• Technology: csharp-spec
• GitHub Login: @dotnet-bot
• Microsoft Alias: wiwagn

[jnm2]

/cc @BillWagner, hope this isn't a duplicate.

[BillWagner]

Thanks @jnm2

Ping @gafter @jcouv Where is the best starting point for this?

[gafter]

https://github.com/dotnet/roslyn/blob/master/docs/features/task-types.md

[BillWagner]

I'll add any of the spec proposals that have been filled in during this sprint. From there, I'll watch for updates on the placeholders and publish them as they are available.