diff --git a/pkgs/top-level/all-packages.nix b/pkgs/top-level/all-packages.nix
index e5a0e81f4a7..e0a6ab94ee4 100644
--- a/pkgs/top-level/all-packages.nix
+++ b/pkgs/top-level/all-packages.nix
@@ -7994,8 +7994,9 @@ in
       useMacosReexportHack = true;
     };
   };
-  llvm-polly = llvmPackages_latest.llvm-polly;
-  clang-polly = llvmPackages_latest.clang.override { cc = llvmPackages_latest.clang-polly-unwrapped; };
+
+  llvm-polly = throw "clang is now built with polly-plugin by default";
+  clang-polly = throw "clang is now built with polly-plugin by default";
 
   clang_10 = llvmPackages_10.clang;
   clang_9  = llvmPackages_9.clang;
@@ -8792,7 +8793,7 @@ in
     stdenv = gcc7Stdenv;
   });
 
-  llvmPackages_latest = llvmPackages_9; # llvmPackages_10: when out of RC
+  llvmPackages_latest = llvmPackages_10;
 
   lorri = callPackage ../tools/misc/lorri {
     inherit (darwin.apple_sdk.frameworks) CoreServices Security;