--- a/deadcode/deadcode.go
+++ b/deadcode/deadcode.go
@@ -98,6 +98,7 @@
 	}
 	// init() is always used
 	p.used["init"] = true
+	p.used["_"] = true
 	if pkg.Name != "main" {
 		// exported names are marked used for non-main packages.
 		for name := range p.decl {