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Do not classify recursive self-reference ref cells as mutable - #19918
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…bleVar) Adds positive and negative coverage for SemanticClassification of `as this` self-references in class bodies. These tests currently fail because isValRefMutable in SemanticClassification.fs treats the internal ref-cell compilation of CtorThisVal as a user-written mutable binding. Sprint 02 applies the surgical fix to make them pass. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
The compiler compiles recursive object self-references (`as this`, recursive `let rec` self-refs) through a ref cell for initialization. SemanticClassification.isValRefMutable previously treated that internal ref cell as a user-written mutable binding, causing the IDE colorizer to paint the self-reference with the MutableVar shade. Mirror the existing guard in FSharpMemberOrFunctionOrValue.IsMutable (src/Compiler/Symbols/Symbols.fs) by excluding vref.IsCtorThisVal from the isRefCellTy branch. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Apply dotnet fantomas to the SemanticClassification fix and its regression tests (both already conformant, no diff); add a release-notes entry for the service-side change. No production logic changes. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
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T-Gro
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Jun 12, 2026
T-Gro
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Clean fix. The one-line guard (not vref.IsCtorThisVal) mirrors the existing parallel logic in Symbols.fs line 2376 (IsRefCell), so both the public API and semantic classification now agree on what constitutes a mutable binding.
Tests cover the positive case (as this not marked mutable), theory variants, and negative guards (real mutable/ref-cell/byref/record-field bindings still classified correctly). Release notes entry is accurate.
LGTM — ship it.
T-Gro
enabled auto-merge (squash)
June 18, 2026 14:19
abonie
approved these changes
Jun 22, 2026
abonie
approved these changes
Jun 25, 2026
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Fixes#5229
SemanticClassification.isValRefMutabletreated compiler-generated refcells for recursive self-references (
as this,let recself-refs) asuser-written mutable bindings, causing wrong IDE colorization.