diff --git a/pkgs/top-level/perl-packages.nix b/pkgs/top-level/perl-packages.nix
index 237438d9ceb..aed2b89b0e2 100644
--- a/pkgs/top-level/perl-packages.nix
+++ b/pkgs/top-level/perl-packages.nix
@@ -14354,7 +14354,7 @@ let
      pname = "Net-DNS-Resolver-Mock";
      version = "1.20200215";
      src = fetchurl {
-       url = mirror://cpan/authors/id/M/MB/MBRADSHAW/Net-DNS-Resolver-Mock-1.20200215.tar.gz;
+       url = "mirror://cpan/authors/id/M/MB/MBRADSHAW/Net-DNS-Resolver-Mock-1.20200215.tar.gz";
        sha256 = "1rv745c16l3m3w6xx2hjmmgzkdklmzm9imdfiddmdr9hwm8g3xxy";
      };
      propagatedBuildInputs = [ NetDNS ];