x/tools/gopls: Hover: nil deref in parseDocLink

[adonovan]

Issue created by stacks.

This stack rKM8Ow was reported by telemetry:

• crash/crash
• runtime.gopanic:+69
• runtime.panicmem:=262
• runtime.sigpanic:+9
• go/types.(*Scope).Lookup:+10
• golang.org/x/tools/gopls/internal/golang.lookupDocLinkSymbol:+8
• golang.org/x/tools/gopls/internal/golang.parseDocLink:+58
• golang.org/x/tools/gopls/internal/golang.hover:+78
• golang.org/x/tools/gopls/internal/golang.Hover:+4
• golang.org/x/tools/gopls/internal/server.(*server).Hover:+30
• golang.org/x/tools/gopls/internal/protocol.serverDispatch:+335
• golang.org/x/tools/gopls/internal/lsprpc.(*streamServer).ServeStream.ServerHandler.func3:+5
• golang.org/x/tools/gopls/internal/lsprpc.(*streamServer).ServeStream.handshaker.func4:+52
• golang.org/x/tools/gopls/internal/protocol.Handlers.MustReplyHandler.func1:+2
• golang.org/x/tools/gopls/internal/protocol.Handlers.AsyncHandler.func2.2:+3
• runtime.goexit:+0

golang.org/x/tools/gopls@v0.17.0-pre.2 go1.23.2 windows/amd64 other,vscode-insiders (3)

[gabyhelp]

Related Issues

• x/tools/gopls: crash in Hover (telemetry) #69362
• x/tools/gopls: Hover: panic in lookupObjectByName #69616
• x/tools/gopls: Hover bug reported by telemetry [PE4R3g] #64244 (closed)
• x/tools/gopls: panic in hover #52211 (closed)
• gopls: automated issue report (crash) #40464 (closed)
• x/tools/gopls: analysisinternal.ZeroValue crash on (presumably) unsafe.Pointer #70585 (closed)
• x/tools/gopls: nil Signature (?) deref in Completion #70634
• x/tools/gopls: Hover bug reported by telemetry #64239 (closed)
• x/tools/gopls: automated issue report (crash) #44300 (closed)
• x/tools/gopls: automated issue report (crash) #48492 (closed)

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[adonovan]

Like #69616 (comment), this is another instance where the compiler's pclntab mapping appears to be inconsistent.

[findleyr]

This is actually just a dupe of #69616: the function was renamed.