diff --git a/pkgs/development/compilers/ghc/8.4.3.nix b/pkgs/development/compilers/ghc/8.4.3.nix
index 182afa6b349..a5cac666e58 100644
--- a/pkgs/development/compilers/ghc/8.4.3.nix
+++ b/pkgs/development/compilers/ghc/8.4.3.nix
@@ -32,6 +32,8 @@
   ghcFlavour ? stdenv.lib.optionalString (targetPlatform != hostPlatform) "perf-cross"
 }:
 
+assert !enableIntegerSimple -> gmp != null;
+
 let
   inherit (bootPkgs) ghc;