diff --git a/pkgs/top-level/perl-packages.nix b/pkgs/top-level/perl-packages.nix
index 47f3253d7089..6056c6f00d95 100644
--- a/pkgs/top-level/perl-packages.nix
+++ b/pkgs/top-level/perl-packages.nix
@@ -3659,7 +3659,7 @@ let
     pname = "CPANPLUS";
     version = "0.9908";
     src = fetchurl {
-      url = mirror://cpan/authors/id/B/BI/BINGOS/CPANPLUS-0.9908.tar.gz;
+      url = "mirror://cpan/authors/id/B/BI/BINGOS/CPANPLUS-0.9908.tar.gz";
       sha256 = "1m4xas67fax947kahvg4jsnsr2r1i58c5g3f1bixh7krgnsarxjq";
     };
     propagatedBuildInputs = [ ArchiveExtract ModulePluggable ObjectAccessor PackageConstants TermUI ];