[Repo Assist] Monthly Activity 2026-03

🤖 *Repo Assist here — I'm an automated AI assistant for this repository.*

## Activity for March 2026

## Suggested Actions for Maintainer

**Comprehensive list** of all pending actions requiring maintainer attention:

* [ ] **Review/Merge PR** #19471: Fix for #12386 — SRTP correct overload resolution in multi-submit FSI — [Review](https://github.com/dotnet/fsharp/pull/19471)
* [ ] **Review/Merge PRs** (regression tests, ready to merge): #19467, #19468, #19472, #19476, #19528, #19529, #19530, #19531 — [#19467](https://github.com/dotnet/fsharp/pull/19467) [#19468](https://github.com/dotnet/fsharp/pull/19468) [#19472](https://github.com/dotnet/fsharp/pull/19472) [#19476](https://github.com/dotnet/fsharp/pull/19476) [#19528](https://github.com/dotnet/fsharp/pull/19528) [#19529](https://github.com/dotnet/fsharp/pull/19529) [#19530](https://github.com/dotnet/fsharp/pull/19530) [#19531](https://github.com/dotnet/fsharp/pull/19531)
* [ ] **Review PRs** created in this run (branches: `regression-test/issue15070`, `regression-test/issue15987`, `regression-test/issue16056`) — #15070, #15987, #16056 now fully covered
* [ ] **Remove incorrect label** on #14454: T-Gro confirmed still broken in F# 11.0 — remove `AI-thinks-issue-fixed` — [View](https://github.com/dotnet/fsharp/issues/14454)
* [ ] **Reconsider label** on #7877: T-Gro confirmed FS0033 error is still wrong — consider removing `AI-thinks-issue-fixed` — [View](https://github.com/dotnet/fsharp/issues/7877)
* [ ] **Check comment** on #16034: confirmed still present — indexed property setter with named arg gives FS0193 — [View](https://github.com/dotnet/fsharp/issues/16034)
* [ ] **Check comment** on #15339: confirmed still present — `GenerateSignature()` drops `[]` and `[]` attributes — [View](https://github.com/dotnet/fsharp/issues/15339)
* [ ] **Check comment** on #16464: confirmed still present — FS0670 when chaining multiple `+` on `INumber<>` — [View](https://github.com/dotnet/fsharp/issues/16464)
* [ ] **Check comment** on #8353: root cause identified — optional bool attribute arg without DefaultParameterValue causes internal error — implement fix in IlxGen.fs — [View](https://github.com/dotnet/fsharp/issues/8353)
* [ ] **Check comment** on #13512: events/fields ignore `allowObsolete` in `ResolveCompletionsInType` — [View](https://github.com/dotnet/fsharp/issues/13512)
* [ ] **Issue NOT fixed** #18841: `let _ = &s` still raises FS0421 on current `main` — `AI-thinks-issue-fixed` label removed — [View](https://github.com/dotnet/fsharp/issues/18841)
* [ ] Verify and close (labelled `AI-thinks-issue-fixed`): #3532, #3841, #3939, #6715, #6929, #7177, #8098, #9382, #9878, #10043, #11127, #11398, #12064, #12067, #12384, #12839, #13114, #13194, #13350, #13519, #13697, #14057, #14308, #14310, #14580, #15070, #15655, #15987, #16007, #16056, #16154, #19456 — [Search](https://github.com/dotnet/fsharp/issues?q=label%3AAI-thinks-issue-fixed+is%3Aopen)

## Additional observations for maintainer's attention

- Issue #19527 (new, March 31): `<@@ match x with "" -> ... @@>` fails with FS0452. Root cause: `PatternMatchCompilation.fs` line 807–813 optimizes empty-string match to `mkNonNullTest` + `mkILAsmCeq`, generating `TOp.ILAsm([AI_ldnull; AI_cgt_un])` that `QuotationTranslator.fs` can't handle (falls to the catch-all FS0452 branch). Fix: add a handler for `[AI_ldnull; AI_cgt_un]` in `QuotationTranslator.fs` (convert to `arg <> null` expression). T-Gro is already engaged on this.
- Issue #18841 (`let _ = &s` raises FS0421 but `let a = &s` works): Confirmed still broken on `main` (1775f42a, 2026-03-31). Asymmetric treatment of discard vs. named bindings in address-of expressions.
- Issue #14678 (`AI-thinks-windows-only` label): Label was already removed in a previous run. The tooltip issue (wrong module for `Option.toNullable`) is backed by FCS and IS testable on Linux.
- Issue #19445 (duplicate `.cctor` in method table for generic DU with `static member val`) — confirmed **still present** in F# 11.0 dev.

## Future Work for Repo Assist

- Task 1: Continue scanning pre-2024 bugs with new activity (c=0, uses lr filter)
- Task 3: woc=15350 — all existing windows-only issues have been reviewed; monitor for new ones
- All 7 AI-thinks-issue-fixed issues now have regression test PRs — future task is to handle newly labelled issues

## Run History

### 2026-03-31 19:00 UTC — [Run](https://github.com/dotnet/fsharp/actions/runs/23813945889)
- 🔧 Created PR for #15070: regression test — `#load "./path"` dot-slash prefix no longer causes FS1141 (`regression-test/issue15070`)
- 🔧 Created PR for #15987: regression test — SRTP overload resolution returns correct typed value (`regression-test/issue15987`)
- 🔧 Created PR for #16056: regression test — auto property `DeclarationLocation` points to property name, not `get` accessor (`regression-test/issue16056`)
- 🔍 Investigated #19527: quotation empty-string match causes FS0452 — root cause identified (PatternMatchCompilation optimization + QuotationTranslator gap), noted for maintainer

### 2026-03-31 12:48 UTC — [Run](https://github.com/dotnet/fsharp/actions/runs/23798069283)
- 🔍 Discovered #18841 is **NOT** fixed: `let _ = &s` still raises FS0421 on `main` (1775f42a)
- 🏷️ Removed `AI-thinks-issue-fixed` from #18841
- 💬 Commented on #18841: test results proving issue still present
- 🔧 Created PR for #7177: regression test — FS0026 warning with active patterns in match (`regression-test/issue7177`)
- 🔧 Created PR for #16007: regression test — SRTP ctor no longer causes value restriction (`regression-test/issue16007`)
- 🔧 Created PR for #16154: regression test — task CE with IQueryable filters no longer throws VerificationException (`regression-test/issue16154`)
- 🔧 Created PR for #19456: regression test — nested `let!` in plain `let` inside task CE raises FS0750 (`regression-test/issue19456`)

### 2026-03-31 07:00 UTC — [Run](https://github.com/dotnet/fsharp/actions/runs/23784512080)
- 🔍 Task 3: Assessed #14632, #14678, #14840, #15101, #15350 for windows-only correctness
- 💬 Commented on #14678: explained not windows-only, label removal needed
- 💬 Commented on #19456: posted regression test code for maintainer to create PR
- 🔄 Updated monthly summary

### 2026-03-30 18:48 UTC — [Run](https://github.com/dotnet/fsharp/actions/runs/23761778368)
- 📋 Task 1: Cursor exhausted at #16464; reset `c=0`
- 🏷️ Task 3: Reviewed #1240, #1627, #2115, #2431, #2628 — all correctly labeled; `woc=2628`
- ✅ Task 2 (#7177): Regression test written — needs manual PR creation
- ℹ️ Task 2 (#12386): bug still present; T-Gro's fix in PR #19471
- ℹ️ Task 2 (#12796): bug still present; T-Gro's regression test in PR #19472

### 2026-03-30 07:04 UTC — [Run](https://github.com/dotnet/fsharp/actions/runs/23732177243)
- 💬 Commented on #16034, #15339, #16464: confirmed still present in F# 10.0

### 2026-03-30 01:03 UTC — [Run](https://github.com/dotnet/fsharp/actions/runs/23723489066)
- 💬 Commented on #15987, #16056: confirmed fixed; 🏷️ labelled both `AI-thinks-issue-fixed`

### 2026-03-29 18:46 UTC — [Run](https://github.com/dotnet/fsharp/actions/runs/23716322052)
- 💬 Commented on #15070: confirmed fixed; 🏷️ labelled `AI-thinks-issue-fixed`

### 2026-03-29 12:46 UTC — [Run](https://github.com/dotnet/fsharp/actions/runs/23709350262)
- 💬 Commented on #18841, #19456: confirmed fixed; 🏷️ labelled both `AI-thinks-issue-fixed`

### 2026-03-29 06:48 UTC — [Run](https://github.com/dotnet/fsharp/actions/runs/23706050440)
- 🔧 Created PR #19485: regression test for #3532; 🔧 Created PR #19484: regression test for #6648

### 2026-03-29 01:00 UTC — [Run](https://github.com/dotnet/fsharp/actions/runs/23700958440)
- 💬 Commented on #16007, #15070, #14492, #14508; 🏷️ Labelled #16007 `AI-thinks-issue-fixed`

### 2026-03-28 18:45 UTC — [Run](https://github.com/dotnet/fsharp/actions/runs/23694997059)
- 💬 Commented on #7177, #16154; 🏷️ Labelled both `AI-thinks-issue-fixed`

### Earlier runs (2026-03-22 to 2026-03-28)
- Investigated and commented on: #6131, #6379, #6715, #7177, #7877, #7931, #8098, #9382, #9878, #10043, #10273, #10540, #11127, #11398, #11785, #12064, #12067, #12300, #12384, #12839, #13114, #13194, #13350, #13512, #13519, #13697, #13849, #13981, #14057, #14160, #14284, #14308, #14310, #14492, #14508, #14580, #15655, #16056, #16410 — labeled many as `AI-thinks-issue-fixed`
- 🔧 Created regression test PRs: #19467, #19468, #19472, #19473, #19476, #19478, #19480, #19484, #19485 (by T-Gro based on Repo Assist analysis)

> Generated by [Repo Assist](https://github.com/dotnet/fsharp/actions/runs/23813945889/agentic_workflow) · [◷](https://github.com/search?q=repo%3Adotnet%2Ffsharp+is%3Aissue+%22gh-aw-workflow-call-id%3A+dotnet%2Ffsharp%2Frepo-assist%22&type=issues)
>
> To install this [agentic workflow](https://github.com/githubnext/agentics/tree/9135cdfde26838a01779aa966628308404ec1f02/workflows/repo-assist.md), run
> ```
> gh aw add githubnext/agentics/workflows/repo-assist.md@9135cdfde26838a01779aa966628308404ec1f02
> ```