x/tools/gopls: Definition: crash on [unsafe.Pointer] doc link

[adonovan]

#!stacks
"sigpanic" && "token.(*File).Name" && "mapPosition:+2" && "docLinkDefinition:+5"

Issue created by stacks.

This stack jS5AtQ was reported by telemetry:

• crash/crash
• runtime.gopanic:+69,+0x167
• runtime.panicmem:=262,+0x197
• runtime.sigpanic:+9,+0x167
• go/token.(*File).Name:=114,+0x5c
• golang.org/x/tools/gopls/internal/golang.mapPosition:+2,+0x63
• golang.org/x/tools/gopls/internal/golang.docLinkDefinition:+5,+0xba
• golang.org/x/tools/gopls/internal/golang.Definition:+53,+0x2be
• golang.org/x/tools/gopls/internal/server.(*server).Definition:+19,+0x50e
• golang.org/x/tools/gopls/internal/protocol.serverDispatch:+215,+0x26e1
• golang.org/x/tools/gopls/internal/lsprpc.(*streamServer).ServeStream.ServerHandler.func4:+5,+0x84
• golang.org/x/tools/gopls/internal/lsprpc.(*streamServer).ServeStream.handshaker.func5:+52,+0x908
• golang.org/x/tools/gopls/internal/protocol.Handlers.MustReplyHandler.func1:+2,+0xc5
• golang.org/x/tools/gopls/internal/protocol.Handlers.AsyncHandler.func2.2:+3,+0x95
• runtime.goexit:+0,+0x0

golang.org/x/tools/gopls@v0.19.1 go1.24.3 windows/amd64 vscode (1)

[adonovan]

I was able to reproduce the crash by putting [unsafe.Pointer] within a doc link.

[gopherbot]

Change https://go.dev/cl/684976 mentions this issue: gopls/internal/golang: cleanups while investigating golang/go#74434

[gabyhelp]

Related Issues

• x/tools/gopls: Hover: nil deref in parseDocLink #70635 (closed)
• x/tools/gopls: Definition: out-of-bounds panic #73797 (closed)
• x/tools/gopls: analysisinternal.ZeroValue crash on (presumably) unsafe.Pointer #70585 (closed)
• x/tools/gopls: crash in mapPosition computing OutgoingCalls to unsafe.Slice #66923 (closed)
• x/tools/gopls: Hover: nil deref in golang.StdSymbolOf #70969 (closed)
• x/tools/gopls: CodeActions: "end < start" panic #74394 (closed)
• x/tools/gopls: Hover: invalid nil entry in types.Defs map #69362 (closed)
• x/tools/gopls: Implementation (by signatures): nil panic in dynamicFuncCallType #74305 (closed)
• x/tools/gopls: nil deref in x/telemetry/internal/counter.(*Counter).add #73890
• x/tools/gopls: automated issue report (crash) #40433 (closed)

_{(Emoji vote if this was helpful or unhelpful; more detailed feedback welcome in this discussion.)}

[gopherbot]

Change https://go.dev/cl/685095 mentions this issue: gopls/internal/golang: Definition: fix crash wrt unsafe.Pointer