diff --git a/cc.sh b/cc.sh
index 4156eed..059ab87 100755
--- a/cc.sh
+++ b/cc.sh
@@ -32,17 +32,6 @@ unset IFS
 # NOTE: Depending on your editor this may look empty, but it is not.
 readonly lsep=''
 
-# This is an array of environment variables that need to be set before
-# the script runs. They are set by routines in spack.build_environment
-# as part of the package installation process.
-readonly params="\
-SPACK_COMPILER_WRAPPER_PATH
-SPACK_DEBUG_LOG_DIR
-SPACK_DEBUG_LOG_ID
-SPACK_SHORT_SPEC
-SPACK_SYSTEM_DIRS
-SPACK_MANAGED_DIRS"
-
 # Optional parameters that aren't required to be set
 
 # Boolean (true/false/custom) if we want to add debug flags
@@ -212,12 +201,13 @@ if eval "[ \"\${*#*${lsep}}\" != \"\$*\" ]"; then
     die "Compiler command line contains our separator ('${lsep}'). Cannot parse."
 fi
 
-# ensure required variables are set
-for param in $params; do
-    if eval "test -z \"\${${param}:-}\""; then
-        die "Spack compiler must be run from Spack! Input '$param' is missing."
-    fi
-done
+# Ensure required variables are set
+: "${SPACK_COMPILER_WRAPPER_PATH:?Error: the compiler wrapper must be invoked from Spack}"
+: "${SPACK_DEBUG_LOG_DIR:?Error: the compiler wrapper must be invoked from Spack}"
+: "${SPACK_DEBUG_LOG_ID:?Error: the compiler wrapper must be invoked from Spack}"
+: "${SPACK_SHORT_SPEC:?Error: the compiler wrapper must be invoked from Spack}"
+: "${SPACK_SYSTEM_DIRS:?Error: the compiler wrapper must be invoked from Spack}"
+: "${SPACK_MANAGED_DIRS:?Error: the compiler wrapper must be invoked from Spack}"
 
 # eval this because SPACK_MANAGED_DIRS and SPACK_SYSTEM_DIRS are inputs we don't wanna loop over.
 # moving the eval inside the function would eval it every call.
diff --git a/test/run.sh b/test/run.sh
index a59b0a9..af58b3e 100644
--- a/test/run.sh
+++ b/test/run.sh
@@ -358,8 +358,8 @@ test_no_wrapper_environment() {
         fail "cc with no env unexpectedly exited 0"
     fi
     case "$_out" in
-        *"Spack compiler must be run from Spack"*) ;;
-        *) fail "expected 'Spack compiler must be run from Spack' in: $_out" ;;
+        *"compiler wrapper must be invoked from Spack"*) ;;
+        *) fail "expected 'compiler wrapper must be invoked from Spack' in: $_out" ;;
     esac
 }