Symptom
Go-to-definition on an imported F# type navigates to a path that does not exist.
DateTime → FilePath = "startup", Line = 0List.sum → D:\a\_work\1\s\src\fsharp\src\FSharp.Core\list.fsi (a Microsoft build-server path)
The editor opens a file the user does not have. Members are unaffected: DateTime.UtcNow correctly reaches the decompiled System.DateTime.cs:126.
Root cause
src/sidecars/SharpLsp.Sidecar.FSharp/FSharpSemanticNavigation.fs:154-160 — extractDefinition prefers symbol.DeclarationLocation over FSharpMetadataNavigator.tryResolve. FCS fills DeclarationLocation with rangeStartup for imported entities, so the phantom range wins before the metadata navigator is ever consulted.
A consequence: the FSharpEntity arm at FSharpMetadataNavigator.fs:18 is unreachable dead code.
Fix direction
Consult FSharpMetadataNavigator.tryResolve first for imported symbols, or reject a DeclarationLocation that is rangeStartup / names a file that is not in the workspace, before falling back to it.
Why this matters
CLAUDE.md aim #2 makes F# a first-class citizen. C# go-to-definition decompiles metadata correctly; F# does not for types, so F# is strictly behind here.
Provenance
Found while raising F# sidecar coverage for PR #218 (94.03% → 95.58%). Deliberately not fixed there — adding a failing test would have reddened the coverage gate, and the defect predates that PR.
Symptom
Go-to-definition on an imported F# type navigates to a path that does not exist.
DateTime→FilePath = "startup", Line = 0List.sum→D:\a\_work\1\s\src\fsharp\src\FSharp.Core\list.fsi(a Microsoft build-server path)The editor opens a file the user does not have. Members are unaffected:
DateTime.UtcNowcorrectly reaches the decompiledSystem.DateTime.cs:126.Root cause
src/sidecars/SharpLsp.Sidecar.FSharp/FSharpSemanticNavigation.fs:154-160—extractDefinitionpreferssymbol.DeclarationLocationoverFSharpMetadataNavigator.tryResolve. FCS fillsDeclarationLocationwithrangeStartupfor imported entities, so the phantom range wins before the metadata navigator is ever consulted.A consequence: the
FSharpEntityarm atFSharpMetadataNavigator.fs:18is unreachable dead code.Fix direction
Consult
FSharpMetadataNavigator.tryResolvefirst for imported symbols, or reject aDeclarationLocationthat israngeStartup/ names a file that is not in the workspace, before falling back to it.Why this matters
CLAUDE.md aim #2 makes F# a first-class citizen. C# go-to-definition decompiles metadata correctly; F# does not for types, so F# is strictly behind here.
Provenance
Found while raising F# sidecar coverage for PR #218 (94.03% → 95.58%). Deliberately not fixed there — adding a failing test would have reddened the coverage gate, and the defect predates that PR.