* Fix union constraint for mixed pos/neg constraints

* lisp/emacs-lisp/comp-cstr.el (comp-cstr-union-1-no-mem): Fix neg
	type shadowing pos values.
	* test/lisp/emacs-lisp/comp-cstr-tests.el
	(comp-cstr-typespec-tests-alist): Add testcase.
	* test/src/comp-tests.el (comp-tests-type-spec-tests): Fix testcase.

lisp/emacs-lisp/comp-cstr.el

@@ -597,6 +597,12 @@ DST is returned."
                           (valset pos)))
               ;; Pos is a superset of neg.
               (give-up))
+             ((cl-some (lambda (x)
+                         (cl-some (lambda (y)
+                                    (comp-subtype-p y x))
+                                  (mapcar #'type-of (valset pos))))
+                       (typeset neg))
+              (give-up))
              (t
               ;; pos is a subset or eq to neg
               (setf (valset neg)

test/lisp/emacs-lisp/comp-cstr-tests.el

@@ -211,7 +211,9 @@
       ;; 85
       ((or (not string) t) . t)
       ;; 86
-      ((or (not vector) sequence) . sequence))
+      ((or (not vector) sequence) . sequence)
+      ;; 87
+      ((or (not symbol) null) . t))
     "Alist type specifier -> expected type specifier."))
 
 (defmacro comp-cstr-synthesize-tests ()

test/src/comp-tests.el

@@ -1185,7 +1185,7 @@ Return a list of results."
       ((defun comp-tests-ret-type-spec-f (x)
          (unless (symbolp x)
            x))
-       (not symbol))
+       t)
 
       ;; 55
       ((defun comp-tests-ret-type-spec-f (x)