diff --git a/src/cmp/cmpenv-declare.lsp b/src/cmp/cmpenv-declare.lsp
index a7b6c75bb..be2f63992 100644
--- a/src/cmp/cmpenv-declare.lsp
+++ b/src/cmp/cmpenv-declare.lsp
@@ -168,7 +168,7 @@ special variable declarations, as these have been extracted before."
             env)))))
 
 (defun symbol-macro-declaration-p (name type)
-  (when-let ((record (cmp-env-search-symbol-macro name)))
+  (ext:when-let ((record (cmp-env-search-symbol-macro name)))
     (let* ((expression (funcall record name nil)))
       (cmp-env-register-symbol-macro name `(the ,type ,expression)))
     t))
diff --git a/src/cmp/cmppass1-data.lsp b/src/cmp/cmppass1-data.lsp
index 1e9d2ff03..89f57cc54 100644
--- a/src/cmp/cmppass1-data.lsp
+++ b/src/cmp/cmppass1-data.lsp
@@ -86,7 +86,7 @@
                                            *permanent-data*))
                    &aux load-form-p)
   ;; FIXME add-static-constant is tied to the C target.
-  (when-let ((vv (add-static-constant object)))
+  (ext:when-let ((vv (add-static-constant object)))
     (when used-p
       (setf (vv-used-p vv) t))
     (return-from add-object vv))
@@ -147,7 +147,7 @@
   ;; can reuse keywords lists from other functions when they coincide with ours.
   ;; We search for keyword lists that are similar. However, the list *OBJECTS*
   ;; contains elements in decreasing order!!!
-  (if-let ((x (search keywords *permanent-objects*
+  (ext:if-let ((x (search keywords *permanent-objects*
                       :test #'(lambda (k record) (eq k (vv-value record))))))
     (elt *permanent-objects* x)
     (prog1 (add-object (pop keywords) :duplicate t :permanent t)
diff --git a/src/cmp/cmppass1-eval.lsp b/src/cmp/cmppass1-eval.lsp
index 02aba9676..55d17cd09 100644
--- a/src/cmp/cmppass1-eval.lsp
+++ b/src/cmp/cmppass1-eval.lsp
@@ -120,7 +120,7 @@
 (defun c1constant-value (val &key always only-small-values)
   (cond
     ;; FIXME includes in c1 pass.
-    ((when-let ((x (assoc val *optimizable-constants*)))
+    ((ext:when-let ((x (assoc val *optimizable-constants*)))
        (pushnew "#include <float.h>" *clines-string-list*)
        (pushnew "#include <complex.h>" *clines-string-list*)
        (setf x (cdr x))
diff --git a/src/cmp/cmppass1-ffi.lsp b/src/cmp/cmppass1-ffi.lsp
index d3c19ae3e..45cca79be 100644
--- a/src/cmp/cmppass1-ffi.lsp
+++ b/src/cmp/cmppass1-ffi.lsp
@@ -134,7 +134,7 @@
                     (:void               . "ECL_FFI_VOID")))
 
 (defun foreign-elt-type-code (type)
-  (if-let ((x (assoc type +foreign-elt-type-codes+)))
+  (ext:if-let ((x (assoc type +foreign-elt-type-codes+)))
     (cdr x)
     (cmperr "DEFCALLBACK: ~a is not a valid elementary FFI type." type)))
 
diff --git a/src/cmp/cmppass2-data.lsp b/src/cmp/cmppass2-data.lsp
index 8574a8dd5..c287d05d6 100644
--- a/src/cmp/cmppass2-data.lsp
+++ b/src/cmp/cmppass2-data.lsp
@@ -224,9 +224,9 @@
                    #+sse2
                    (not (typep object 'ext:sse-pack)))
               (not (listp *static-constants*)))
-    (if-let ((record (find object *static-constants* :key #'first :test #'equal)))
+    (ext:if-let ((record (find object *static-constants* :key #'first :test #'equal)))
       (second record)
-      (when-let ((builder (static-constant-expression object)))
+      (ext:when-let ((builder (static-constant-expression object)))
         (let ((c-name (format nil "_ecl_static_~D" (length *static-constants*))))
           (push (list object c-name builder) *static-constants*)
           (make-vv :location c-name :value object))))))
diff --git a/src/cmp/cmppass2-ffi.lsp b/src/cmp/cmppass2-ffi.lsp
index 09d367cf2..d9f583e8e 100644
--- a/src/cmp/cmppass2-ffi.lsp
+++ b/src/cmp/cmppass2-ffi.lsp
@@ -23,7 +23,7 @@
   (gethash rep-type (machine-rep-type-hash *machine*)))
 
 (defun rep-type-record (rep-type)
-  (if-let ((record (gethash rep-type (machine-rep-type-hash *machine*))))
+  (ext:if-let ((record (gethash rep-type (machine-rep-type-hash *machine*))))
     record
     (cmperr "Not a valid C type name ~A" rep-type)))
 
diff --git a/src/cmp/cmppass2-top.lsp b/src/cmp/cmppass2-top.lsp
index 8ba0c8c4c..334484a1b 100644
--- a/src/cmp/cmppass2-top.lsp
+++ b/src/cmp/cmppass2-top.lsp
@@ -5,7 +5,7 @@
 
 (defun t2expr (form)
   (when form
-    (if-let ((def (gethash (c1form-name form) *t2-dispatch-table*)))
+    (ext:if-let ((def (gethash (c1form-name form) *t2-dispatch-table*)))
       (let ((*compile-file-truename* (c1form-file form))
             (*compile-file-position* (c1form-file-position form))
             (*current-toplevel-form* (c1form-form form))
diff --git a/src/cmp/cmpprop.lsp b/src/cmp/cmpprop.lsp
index 1ff327d6a..1d4f3b010 100644
--- a/src/cmp/cmpprop.lsp
+++ b/src/cmp/cmpprop.lsp
@@ -37,7 +37,7 @@
           (*current-form* (c1form-form form))
           (*current-toplevel-form* (c1form-toplevel-form form))
           (name (c1form-name form)))
-      (when-let ((propagator (gethash name *p1-dispatch-table*)))
+      (ext:when-let ((propagator (gethash name *p1-dispatch-table*)))
         (prop-message "~&;;; Entering type propagation for ~A" name)
         (multiple-value-bind (new-type assumptions)
             (apply propagator form assumptions (c1form-args form))
diff --git a/src/cmp/cmputil.lsp b/src/cmp/cmputil.lsp
index 3d5c438a9..4a79f1978 100644
--- a/src/cmp/cmputil.lsp
+++ b/src/cmp/cmputil.lsp
@@ -511,7 +511,7 @@ keyword argument, the compiler-macro declines to provide an expansion.
       (when (eq (first lambda-list) '&whole)
         (push `(,(second lambda-list) ,whole) bindings-for-body)
         (setf lambda-list (cddr lambda-list)))
-      (when-let ((env (member '&environment lambda-list)))
+      (ext:when-let ((env (member '&environment lambda-list)))
         (push '&environment new-lambda-list)
         (push (second env) new-lambda-list)
         (setq lambda-list (nconc (ldiff lambda-list env) (cddr env))))