diff --git a/pkgs/development/compilers/abcl/default.nix b/pkgs/development/compilers/abcl/default.nix
index 7e7d110d4b42..f94503b40a31 100644
--- a/pkgs/development/compilers/abcl/default.nix
+++ b/pkgs/development/compilers/abcl/default.nix
@@ -4,7 +4,7 @@
 , commonLispPackagesFor
 , lispWithPackages
 , build-asdf-system
-, spec ? { faslExt = "abcl"; program = "abcl"; flags = ""; asdf = asdf_3_3; }
+, spec ? { faslExt = "abcl"; program = "abcl"; flags = []; asdf = asdf_3_3; }
 , packageOverrides ? (self: super: {})}:
 let abcl = stdenv.mkDerivation rec {
   pname = "abcl";
diff --git a/pkgs/development/compilers/clasp/default.nix b/pkgs/development/compilers/clasp/default.nix
index 3e7cecf3ff48..9d78e846fb17 100644
--- a/pkgs/development/compilers/clasp/default.nix
+++ b/pkgs/development/compilers/clasp/default.nix
@@ -4,7 +4,7 @@
 , commonLispPackagesFor
 , lispWithPackages
 , build-asdf-system
-, spec ? { faslExt = "fasp"; program = "clasp"; flags = ""; asdf = asdf_3_3; }
+, spec ? { faslExt = "fasp"; program = "clasp"; flags = []; asdf = asdf_3_3; }
 , packageOverrides ? (self: super: {})
 , ...}:
 
diff --git a/pkgs/development/compilers/ecl/16.1.2.nix b/pkgs/development/compilers/ecl/16.1.2.nix
index e7960c153b95..32e3d387261e 100644
--- a/pkgs/development/compilers/ecl/16.1.2.nix
+++ b/pkgs/development/compilers/ecl/16.1.2.nix
@@ -19,7 +19,7 @@
 , commonLispPackagesFor
 , lispWithPackages
 , build-asdf-system
-, spec ? { faslExt = "fas"; program = "ecl"; flags = ""; asdf = asdf_3_3; }
+, spec ? { faslExt = "fas"; program = "ecl"; flags = []; asdf = asdf_3_3; }
 , packageOverrides ? (self: super: {})
 }:
 
diff --git a/pkgs/development/compilers/ecl/default.nix b/pkgs/development/compilers/ecl/default.nix
index c0bb2d6ce17c..4ae4182c52f6 100644
--- a/pkgs/development/compilers/ecl/default.nix
+++ b/pkgs/development/compilers/ecl/default.nix
@@ -20,7 +20,7 @@
 , commonLispPackagesFor
 , lispWithPackages
 , build-asdf-system
-, spec ? { faslExt = "fas"; program = "ecl"; flags = ""; asdf = asdf_3_3; }
+, spec ? { faslExt = "fas"; program = "ecl"; flags = []; asdf = asdf_3_3; }
 , packageOverrides ? (self: super: {})
 }:
 
diff --git a/pkgs/development/compilers/sbcl/2.x.nix b/pkgs/development/compilers/sbcl/2.x.nix
index 04e4a9322f27..c4bc52b085e0 100644
--- a/pkgs/development/compilers/sbcl/2.x.nix
+++ b/pkgs/development/compilers/sbcl/2.x.nix
@@ -15,7 +15,7 @@
 , commonLispPackagesFor
 , lispWithPackages
 , build-asdf-system
-, spec ? { faslExt = "fasl"; program = "sbcl"; flags = ""; asdf = asdf_3_3; }
+, spec ? { faslExt = "fasl"; program = "sbcl"; flags = []; asdf = asdf_3_3; }
 , packageOverrides ? (self: super: {})
 }:
 
diff --git a/pkgs/development/interpreters/clisp/default.nix b/pkgs/development/interpreters/clisp/default.nix
index 830d642a3a7d..1d529335172c 100644
--- a/pkgs/development/interpreters/clisp/default.nix
+++ b/pkgs/development/interpreters/clisp/default.nix
@@ -23,7 +23,7 @@
 , commonLispPackagesFor
 , lispWithPackages
 , build-asdf-system
-, spec ? { faslExt = "fas"; program = "clisp"; flags = "-E UTF-8"; asdf = asdf_3_3; }
+, spec ? { faslExt = "fas"; program = "clisp"; flags = ["-E" "UTF-8"]; asdf = asdf_3_3; }
 , packageOverrides ? (self: super: {})
 }:
 
diff --git a/pkgs/development/lisp-modules/nix-cl.nix b/pkgs/development/lisp-modules/nix-cl.nix
index 08efa7f52fae..208ca7559d83 100644
--- a/pkgs/development/lisp-modules/nix-cl.nix
+++ b/pkgs/development/lisp-modules/nix-cl.nix
@@ -80,7 +80,7 @@ let
       dontUnpack = true;
       buildPhase = ''
         cp -v ${asdf}/lib/common-lisp/asdf/build/asdf.lisp asdf.lisp
-        ${pkg}/bin/${program} ${flags} < <(echo '(compile-file "asdf.lisp")')
+        ${pkg}/bin/${program} ${toString flags} < <(echo '(compile-file "asdf.lisp")')
       '';
       installPhase = ''
         mkdir -p $out
@@ -116,7 +116,7 @@ let
       program ? pkg.pname,
 
       # General flags to the Lisp executable
-      flags ? "",
+      flags ? [],
 
       # Extension for implementation-dependent FASL files
       faslExt,
@@ -185,7 +185,7 @@ let
       buildPhase = optionalString (src != null) ''
         export CL_SOURCE_REGISTRY=$CL_SOURCE_REGISTRY:$src//
         export ASDF_OUTPUT_TRANSLATIONS="$src:$(pwd):${storeDir}:${storeDir}"
-        ${pkg}/bin/${program} ${flags} < $buildScript
+        ${pkg}/bin/${program} ${toString flags} < $buildScript
       '';
 
       # Copy compiled files to store
@@ -274,7 +274,7 @@ let
         makeWrapper \
           ${o.pkg}/bin/${o.program} \
           $out/bin/${o.program} \
-          --add-flags "${o.flags}" \
+          --add-flags "${toString o.flags}" \
           --set ASDF "${o.asdfFasl}/asdf.${o.faslExt}" \
           --prefix CL_SOURCE_REGISTRY : "$CL_SOURCE_REGISTRY" \
           --prefix ASDF_OUTPUT_TRANSLATIONS : "$(echo $CL_SOURCE_REGISTRY | sed s,//:,::,g):" \
diff --git a/pkgs/development/lisp-modules/packages.nix b/pkgs/development/lisp-modules/packages.nix
index 72bdffba40d6..73e33e26111b 100644
--- a/pkgs/development/lisp-modules/packages.nix
+++ b/pkgs/development/lisp-modules/packages.nix
@@ -29,7 +29,7 @@ let
             mkdir __fasls
             export ASDF_OUTPUT_TRANSLATIONS="$(pwd):$(pwd)/__fasls:${storeDir}:${storeDir}"
             export CL_SOURCE_REGISTRY=$CL_SOURCE_REGISTRY:$(pwd)//
-            ${o.pkg}/bin/${o.program} ${o.flags or ""} < ${o.buildScript}
+            ${o.pkg}/bin/${o.program} ${toString (o.flags or [])} < ${o.buildScript}
           '';
           installPhase = ''
             mkdir -pv $out