diff --git a/pkgs/stdenv/generic/default.nix b/pkgs/stdenv/generic/default.nix
index 19443e3e6ea..fe7bec54ba0 100644
--- a/pkgs/stdenv/generic/default.nix
+++ b/pkgs/stdenv/generic/default.nix
@@ -131,6 +131,8 @@ let
         else true;
 
     in
+      assert licenseAllowed attrs;
+
       lib.addPassthru (derivation (
         (removeAttrs attrs
           ["meta" "passthru" "crossAttrs" "pos"
@@ -150,7 +152,7 @@ let
           computedPropagatedImpureHostDeps = lib.unique (lib.concatMap (input: input.__propagatedImpureHostDeps or []) (propagatedBuildInputs ++ propagatedNativeBuildInputs));
         in
         {
-          builder = assert licenseAllowed attrs; attrs.realBuilder or shell;
+          builder = attrs.realBuilder or shell;
           args = attrs.args or ["-e" (attrs.builder or ./default-builder.sh)];
           stdenv = result;
           system = result.system;