diff --git a/pkgs/top-level/php-packages.nix b/pkgs/top-level/php-packages.nix
index 5f1e9a5f24c..e07930a94db 100644
--- a/pkgs/top-level/php-packages.nix
+++ b/pkgs/top-level/php-packages.nix
@@ -176,7 +176,7 @@ let
 
   redis = if isPhp7 then redisPhp7 else redis22;
 
-  redis22 = buildPecl {
+  redis22 = assert !isPhp7; buildPecl {
     name = "redis-2.2.7";
     sha256 = "00n9dpk9ak0bl35sbcd3msr78sijrxdlb727nhg7f2g7swf37rcm";
   };