This is a regression. It seems dotnet sdks above 10.0.202 are affected, so probably introduced by #19297
Repro steps
compile the following in Debug configuration:
module ReproMixedBuilders
open System.Threading.Tasks
type TaskMaybeBuilder() =
member inline _.Zero() = Task.FromResult None
member inline _.Delay([<InlineIfLambda>] f) = task { return! f () }
member inline _.Bind(value, [<InlineIfLambda>] f) =
task {
match value with
| None -> return None
| Some result -> return! f result
}
let taskMaybe = TaskMaybeBuilder()
let trigger() =
taskMaybe {
do! None
}
Actual behavior
❯ dotnet build -c Debug
Restore complete (0.3s)
info NETSDK1057: You are using a preview version of .NET. See: https://aka.ms/dotnet-support-policy
BuilderRepro net472 failed with 5 error(s) (1.3s)
E:\repos\BuilderRepro\Library.fs(20,5): error FS0971: Undefined value 'builder@'
E:\repos\BuilderRepro\Library.fs(20,5): error FS0971: Undefined value 'builder@'
E:\repos\BuilderRepro\Library.fs(20,5): error FS0971: Undefined value 'builder@'
E:\repos\BuilderRepro\Library.fs(20,5): error FS0971: Undefined value 'builder@'
E:\repos\BuilderRepro\Library.fs(20,5): error FS0971: Undefined value 'builder@'
This is a regression. It seems dotnet sdks above 10.0.202 are affected, so probably introduced by #19297
Repro steps
compile the following in Debug configuration:
Actual behavior