eth/fetcher fails nilness static analysis check

[prestonvanloon]

System information

Geth version: develop
OS & Version: Linux
Commit hash : 08e782c

Expected behaviour

go run golang.org/x/tools/go/analysis/passes/nilness/cmd/nilness github.com/ethereum/go-ethereum/eth/fetcher
# no results

Actual behaviour

go run golang.org/x/tools/go/analysis/passes/nilness/cmd/nilness github.com/ethereum/go-ethereum/eth/fetcher
-: impossible condition: non-nil == nil
exit status 3

Steps to reproduce the behaviour

go get -u golang.org/x/tools/...
go run golang.org/x/tools/go/analysis/passes/nilness/cmd/nilness github.com/ethereum/go-ethereum/eth/fetcher

Due to golang/go#31008, the nilness check results returns almost no helpful information.
I'm not sure exactly where the nilness check is failing.
The nilness check result does not return the filename, line number, or autofix.

More info on this analysis check

The nilness checker inspects the control-flow graph of each function in
a package and reports nil pointer dereferences, degenerate nil
pointers, and panics with nil values. A degenerate comparison is of the form
x==nil or x!=nil where x is statically known to be nil or non-nil. These are
often a mistake, especially in control flow related to errors. Panics with nil
values are checked because they are not detectable by
	if r := recover(); r != nil {
This check reports conditions such as:
	if f == nil { // impossible condition (f is a function)
	}
and:
	p := &v
	...
	if p != nil { // tautological condition
	}
and:
	if p == nil {
		print(*p) // nil dereference
	}
and:
	if p == nil {
		panic(p)
	}

Backtrace

[prestonvanloon]

After some hacking around with the nilness analyzer, I've identified that this is the line that causes issue (L280).

go-ethereum/eth/fetcher/tx_fetcher.go

Lines 278 to 280 in 08e782c

	errs := f.addTxs(txs)
	for i, err := range errs {
	if err != nil {

[holiman]

I suppose it's line 280 followed by line 292 ?

go-ethereum/eth/fetcher/tx_fetcher.go

Line 292 in 08e782c

case nil: // Noop, but need to handle to not count these

?