The closure analizer gets run once more when a lambda form appears in a FUNCTION special form, and also after compiling the body of a FLET/LABELS form, because both can change the nature of the function.

src/CHANGELOG

@@ -128,6 +128,13 @@ ECL 1.0:
  - ENOUGH-NAMESTRING did not simplify a pathname when it had the same directory
    as the default pathname.
 
+ - Some toplevel forms with closures caused the compiler to abort, for example
+	(let ((data '(a b)))
+	  (flet ((get-it ()
+	          (second data)))
+	    (defun print-it-1 ()
+	      (print (get-it)))))
+
 * Unicode:
 
  - MAKE-STRING only allowed :ELEMENT-TYPE to be one of CHARACTER, BASE-CHAR, or

src/cmp/cmpflet.lsp

@@ -72,6 +72,15 @@
     ;; in a LABELS can reference each other.
     (setf local-funs (remove-if-not #'plusp local-funs :key #'fun-ref))
 
+    ;; Keep on inspecting the functions until the closure type does not
+    ;; change.
+    (loop while
+	 (let ((x nil))
+	   (loop for f in local-funs
+	      when (compute-fun-closure-type f)
+	      do (setf x t))
+	   x))
+
     (if local-funs
 	(make-c1form* 'LOCALS :type (c1form-type body-c1form)
 		      :args local-funs body-c1form (eq origin 'LABELS))
@@ -130,6 +139,10 @@
       (setf (fun-closure fun) new-type)
       ;; All external, non-global variables become of type closure
       (when (eq new-type 'CLOSURE)
+	(when (fun-global fun)
+	  (error "Function ~A is global but is closed over some variables.~%~
+~{~A ~}"
+	       (fun-name fun) (mapcar #'var-name (fun-referred-vars fun))))
 	(dolist (var (fun-referred-local-vars fun))
 	  (setf (var-ref-clb var) nil
 		(var-ref-ccb var) t

src/cmp/cmpspecial.lsp

@@ -71,12 +71,15 @@
           ((and (consp fun) (member (car fun) '(LAMBDA EXT::LAMBDA-BLOCK)))
            (cmpck (endp (cdr fun))
                   "The lambda expression ~s is illegal." fun)
-           (let* ((name (when (eq (first fun) 'EXT::LAMBDA-BLOCK)
-			  (or (first (setf fun (rest fun)))
-			      (cmpwarn "LAMBDA-BLOCK has block name NIL~%Name will be ignored."))))
-		  (fun (c1compile-function (rest fun) :name name))
-		  (lambda-form (fun-lambda fun)))
-	     (make-c1form 'FUNCTION lambda-form 'CLOSURE lambda-form fun)))
+	   (let (name body)
+	     (if (eq (first fun) 'EXT::LAMBDA)
+		 (setf name (gensym) body (rest fun))
+		 (setf name (second fun) body (cddr fun)))
+	     (let* ((funob (c1compile-function body :name name))
+		    (lambda-form (fun-lambda funob)))
+	       (setf (fun-ref-ccb funob) t)
+	       (compute-fun-closure-type funob)
+	       (make-c1form 'FUNCTION lambda-form 'CLOSURE lambda-form funob))))
 	  (t (cmperr "The function ~s is illegal." fun)))))
 
 (defun c2function (kind funob fun)