diff --git a/go/gcimporter15/gcimporter.go b/go/gcimporter15/gcimporter.go
index 7b19b081..123d5d6f 100644
--- a/go/gcimporter15/gcimporter.go
+++ b/go/gcimporter15/gcimporter.go
@@ -396,7 +396,7 @@ func (p *parser) getPkg(id, name string) *types.Package {
 		if pname := pkg.Name(); pname == "" {
 			setName(pkg, name)
 		} else if pname != name {
-			p.errorf("%s package name mismatch: %s (given) vs %s (expected)", pname, name)
+			p.errorf("%s package name mismatch: %s (given) vs %s (expected)", id, pname, name)
 		}
 	}
 	return pkg