Please answer these questions before submitting your issue. Thanks!

What version of Go are you using (go version)?

go version devel +a6b9385 Thu Jan 4 21:55:42 2018 +0000 darwin/amd64

Does this issue reproduce with the latest release?

Yes

What operating system and processor architecture are you using (go env)?

GOARCH="amd64"
GOBIN="/Users/emmanuelodeke/go/bin"
GOCACHE="/Users/emmanuelodeke/Library/Caches/go-build"
GOEXE=""
GOHOSTARCH="amd64"
GOHOSTOS="darwin"
GOOS="darwin"
GOPATH="/Users/emmanuelodeke/go"
GORACE=""
GOROOT="/Users/emmanuelodeke/go/src/go.googlesource.com/go"
GOTMPDIR=""
GOTOOLDIR="/Users/emmanuelodeke/go/src/go.googlesource.com/go/pkg/tool/darwin_amd64"
GCCGO="gccgo"
CC="clang"
CXX="clang++"
CGO_ENABLED="1"
CGO_CFLAGS="-g -O2"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-g -O2"
CGO_FFLAGS="-g -O2"
CGO_LDFLAGS="-g -O2"
PKG_CONFIG="pkg-config"
GOGCCFLAGS="-fPIC -m64 -pthread -fno-caret-diagnostics -Qunused-arguments -fmessage-length=0 -fdebug-prefix-map=/var/folders/v3/7z434qpx5v3bw0wh8h2myfpw0000gn/T/go-build865828038=/tmp/go-build -gno-record-gcc-switches -fno-common"

What did you do?

Given this code https://play.golang.org/p/aDVRtb8yKMe
or inlined below

package main

func main() {
	if i := 0; i == nil {
	}
}

What did you expect to see?

prog.go:4:15: cannot convert nil to type int
as it does for Go1.9 and before

What did you see instead?

prog.go:4:15: cannot convert nil () to type int

While the current disambiguation of including the type in the error is quite nice, it's a minor oversight that we forgot to check first if the type is nil before trying to print the type by it's print verb. I think this issue is a low hanging fruit that we can fix for Go1.10 since it is even a regression anyways but more importantly IMHO we'll have a whole lot of odd error messages for Go1.10 if we don't fix it #elevatorPitchToFixIt