x/tools/gopls: References: bug.Report in expandMethodSearch (via telemetry)

[adonovan]

This stack xlDBRQ was reported by telemetry:

func expandMethodSearch(ctx context.Context, snapshot *cache.Snapshot, workspaceIDs []PackageID, method *types.Func, recv types.Type, addRdeps func(id PackageID, transitive bool) error, targets map[PackagePath]map[objectpath.Path]unit, expansions map[PackageID]unit) error {
	// Compute the method-set fingerprint used as a key to the global search.
	key, hasMethods := methodsets.KeyOf(recv)
	if !hasMethods {
		return bug.Errorf("KeyOf(%s)={} yet %s is a method", recv, method)
	}

gopls/bug
golang.org/x/tools/gopls/internal/util/bug.report:+35
golang.org/x/tools/gopls/internal/util/bug.Errorf:+2
golang.org/x/tools/gopls/internal/golang.expandMethodSearch:+4
golang.org/x/tools/gopls/internal/golang.ordinaryReferences:+143
golang.org/x/tools/gopls/internal/golang.references:+14
golang.org/x/tools/gopls/internal/golang.References:+1
golang.org/x/tools/gopls/internal/server.(*server).References:+18
golang.org/x/tools/gopls/internal/protocol.serverDispatch:+478
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@v0.15.3 go1.21.6 darwin/arm64 vscode (1)

Issue created by golang.org/x/tools/gopls/internal/telemetry/cmd/stacks.