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Incorrect state machine compilation in debug #20466
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Area-Compiler-CodeGenIlxGen, ilwrite and things at the backendIlxGen, ilwrite and things at the backendArea-ComputationExpressionsEnd-to-end experience for computation expressions (except async and state machine compilation)End-to-end experience for computation expressions (except async and state machine compilation)BugRegression
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Large part of it is that TaskSeq's dynamic implementation is incomplete and untested. Up til recently we emitted the static implementation even in debug, so this was hidden and not exercised unless a consumer wrote code that did not statically compile.
- addedArea-ComputationExpressionsEnd-to-end experience for computation expressions (except async and state machine compilation)End-to-end experience for computation expressions (except async and state machine compilation)Area-Compiler-CodeGenIlxGen, ilwrite and things at the backendIlxGen, ilwrite and things at the backendand removed
on Sep 7, 2026 <OtherFlags>--always-inline+</OtherFlags>should help in the meantime.I would also love if we could have an addition to the regression testing matrix guarding
TaskSeq.Reacted by Jakub Majocha6 remaining items
- added 15 commits that reference this issue
on Oct 3, 2026
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Area-Compiler-CodeGenIlxGen, ilwrite and things at the backendIlxGen, ilwrite and things at the backendArea-ComputationExpressionsEnd-to-end experience for computation expressions (except async and state machine compilation)End-to-end experience for computation expressions (except async and state machine compilation)BugRegression
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edit sdk pin in global.json to "10.0.400"
dotnet test -c Debug .\src\FSharp.Control.TaskSeq.SmokeTests\builds fine, runs fine, taskSeq produces wrong values and tests fail.
This is particularly nasty, because it builds and runs, just the execution is wrong.
Tests pass up to sdk 10.0.204, fail for 10.0.400 and 11 preview.