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…ions Fix code scanning alerts IONIDE-012: add [<Struct>] attribute to improve performance by avoiding heap allocations for small discriminated unions. - LiterateCodeVisibility (Document.fs): simple enum-like DU with one case carrying a single string field, ideal for struct representation - EvalKey (Transformations.fs): two-case DU used as Map keys, benefits from value semantics Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
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dsyme
approved these changes
Feb 28, 2026
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Summary
Fixes two open code scanning alerts (IONIDE-012) by adding the
[(Struct)]attribute to two small discriminated unions inFSharp.Formatting.Literate.Changes
src/FSharp.Formatting.Literate/Document.fs[(Struct)]toLiterateCodeVisibility— a 3-case DU (VisibleCode,HiddenCode,NamedCode of string) that is a good fit for struct representation since it's small and used as a value.src/FSharp.Formatting.Literate/Transformations.fs[(Struct)]toEvalKey— a 2-case DU (OutputRef of string,ValueRef of string) used as keys in an F#Map. Named the fields explicitly (outputName,valueName) as required for struct DUs with fields.Motivation
Struct DUs avoid heap allocations for small types, improving GC pressure. The Ionide.Analyzers IONIDE-012 rule flags DUs that meet the criteria for struct representation.
Test Status
✅ Build:
dotnet build src/FSharp.Formatting.Literate/FSharp.Formatting.Literate.fsproj --configuration Release— passed with 0 warnings, 0 errorsFull test suite was not run (build-only validation performed as the change is purely additive). CI will run the full suite.