panic handling request textDocument/definition: bad line number

[Zzzen]

Stack trace

 [error] panic handling request textDocument/definition: bad line number. Line: 14, lineMap length: 14
goroutine 6717536 [running]:
runtime/debug.Stack()
	runtime/debug/stack.go:26 +0x5e
github.com/microsoft/typescript-go/internal/lsp.(*Server).recover(0x42a32ed1508, 0x42afe2d0b40)
	github.com/microsoft/typescript-go/internal/lsp/server.go:873 +0x47
panic({0xc7f8a0?, 0x42a7c49af70?})
	runtime/panic.go:860 +0x13a
github.com/microsoft/typescript-go/internal/ls/lsconv.(*Converters).LineAndCharacterToPosition(0x42d50167aa0, {0x107dde8, 0x42afbc56a88}, {0xc6831888?, 0x42a?})
	github.com/microsoft/typescript-go/internal/ls/lsconv/converters.go:153 +0x2d4
github.com/microsoft/typescript-go/internal/ls.(*LanguageService).ProvideDefinition(0x42a89d263c0, {0x1080998, 0x42afbc627e0}, {0x42c6af56080, 0x7a}, {0xe?, 0x4d?})
	github.com/microsoft/typescript-go/internal/ls/definition.go:26 +0x138
github.com/microsoft/typescript-go/internal/lsp.(*Server).handleDefinition(0x42d3ab75e98?, {0x1080998?, 0x42afbc627e0?}, 0x0?, 0x1080998?)
	github.com/microsoft/typescript-go/internal/lsp/server.go:1189 +0x35
github.com/microsoft/typescript-go/internal/lsp.init.func1.registerLanguageServiceDocumentRequestHandler[...].14.1()
	github.com/microsoft/typescript-go/internal/lsp/server.go:750 +0xb4
github.com/microsoft/typescript-go/internal/lsp.(*Server).handleRequestOrNotification.func1()
	github.com/microsoft/typescript-go/internal/lsp/server.go:613 +0x95
github.com/microsoft/typescript-go/internal/lsp.(*Server).dispatchLoop.func3()
	github.com/microsoft/typescript-go/internal/lsp/server.go:488 +0x2c
created by github.com/microsoft/typescript-go/internal/lsp.(*Server).dispatchLoop in goroutine 23
	github.com/microsoft/typescript-go/internal/lsp/server.go:487 +0x4ac

Steps to reproduce

1. N/A

[samdcoding]

We have figured out some repo steps:

1. Open a TS file in vscode/cursor
2. Add a lot of code (couple hundred lines) to significantly change the line count
3. Run a git restore myFile.ts it will cause the error to show up in the ide

It seems to recover quickly afterwords but since it is an error it spams notifications to the user and is a very noisy experience.

2026-04-06 13:35:01.850 [info] handled method 'textDocument/definition' (57681) in 252.75µs
2026-04-06 13:35:01.850 [error] panic handling request textDocument/definition: bad line number. Line: 2095, lineMap length: 135
goroutine 509149 [running]:
runtime/debug.Stack()
	runtime/debug/stack.go:26 +0x64
github.com/microsoft/typescript-go/internal/lsp.(*Server).recover(0x6e9826919508, 0x6e98a4556b70)
	github.com/microsoft/typescript-go/internal/lsp/server.go:910 +0x3c
panic({0x101fda120?, 0x6e98a3d26800?})
	runtime/panic.go:860 +0x12c
github.com/microsoft/typescript-go/internal/ls/lsconv.(*Converters).LineAndCharacterToPosition(0x6e98a1bc0db0, {0x1022689e8, 0x6e989d281508}, {0x14588a0?, 0x1?})
	github.com/microsoft/typescript-go/internal/ls/lsconv/converters.go:153 +0x29c
github.com/microsoft/typescript-go/internal/ls.(*LanguageService).ProvideDefinition(0x6e98a3d23bc0, {0x10226b558, 0x6e98a3d432f0}, {0x6e983c6a9500, 0x61}, {0x82f?, 0x24?})
	github.com/microsoft/typescript-go/internal/ls/definition.go:26 +0xf0
github.com/microsoft/typescript-go/internal/lsp.(*Server).handleDefinition(0x6e989ee05048?, {0x10226b558?, 0x6e98a3d432f0?}, 0x100ee6c8c?, 0x6e98b1188648?)
	github.com/microsoft/typescript-go/internal/lsp/server.go:1251 +0x38
github.com/microsoft/typescript-go/internal/lsp.init.func1.registerLanguageServiceDocumentRequestHandler[...].14.1()
	github.com/microsoft/typescript-go/internal/lsp/server.go:781 +0x80
github.com/microsoft/typescript-go/internal/lsp.(*Server).handleRequestOrNotification.func1()
	github.com/microsoft/typescript-go/internal/lsp/server.go:639 +0x50
github.com/microsoft/typescript-go/internal/lsp.(*Server).dispatchLoop.func3()
	github.com/microsoft/typescript-go/internal/lsp/server.go:507 +0x34
created by github.com/microsoft/typescript-go/internal/lsp.(*Server).dispatchLoop in goroutine 18
	github.com/microsoft/typescript-go/internal/lsp/server.go:506 +0x3cc

2026-04-06 13:35:01.850 [error] Request textDocument/definition failed.
  Message: InternalError: panic handling request textDocument/definition: bad line number. Line: 2095, lineMap length: 135
  Code: -32603

[jakebailey]

#3365 will fix this, clamping positions to the allowed ranges (for better or for worse).