fix golang/go#34053 (comment)

.github/run-tests.sh

@@ -1,13 +1,15 @@
 #!/bin/sh
+set -e
+DIR="$(dirname "$(command -v greadlink >/dev/null 2>&1 && greadlink -f "$0" || readlink -f "$0")")"
 
 # Install tools to test our code-quality.
 go get -u golang.org/x/lint/golint
-go get -u golang.org/x/tools/go/analysis/passes/shadow/cmd/shadow
+go install "$DIR/shadow-fix.go"
 go get -u honnef.co/go/tools/cmd/staticcheck
 
 # Run the static-check tool
 t=$(mktemp)
-staticcheck -checks all ./... | grep -v " is overwritten before first use " >$t
+staticcheck -checks all ./... | grep -v " is overwritten before first use " >$t || true
 if [ -s $t ]; then
   echo "Found errors via 'staticcheck'"
   cat $t
@@ -16,17 +18,14 @@ if [ -s $t ]; then
 fi
 rm $t
 
-# At this point failures cause aborts
-set -e
-
 # Run the linter
 echo "Launching linter .."
 golint ./...
 echo "Completed linter .."
 
 # Run the shadow-checker
 echo "Launching shadowed-variable check .."
-go vet -vettool=$(which shadow) ./...
+go vet -vettool=$(which shadow-fix) ./...
 echo "Completed shadowed-variable check .."
 
 # Run golang tests

.github/shadow-fix.go

@@ -0,0 +1,27 @@
+package main
+
+// https://github.com/golang/go/issues/34053#issuecomment-532386030
+
+import (
+	"flag"
+
+	"golang.org/x/tools/go/analysis/passes/shadow"
+	"golang.org/x/tools/go/analysis/unitchecker"
+)
+
+func main() {
+	unitchecker.Main(
+		shadow.Analyzer,
+		// ... other custom analyzers
+	)
+}
+
+func init() {
+	// go vet always adds this flag for certain packages in the standard library,
+	// which causes "flag provided but not defined" errors when running with
+	// custom vet tools.
+	// So we just declare it here and swallow the flag.
+	// See https://github.com/golang/go/issues/34053 for details.
+	// TODO: Remove this once above issue is resolved.
+	flag.String("unsafeptr", "", "")
+}