diff --git a/collects/macro-debugger/syntax-browser/properties.rkt b/collects/macro-debugger/syntax-browser/properties.rkt
index 65dbcafadd..77695d1f3a 100644
--- a/collects/macro-debugger/syntax-browser/properties.rkt
+++ b/collects/macro-debugger/syntax-browser/properties.rkt
@@ -212,16 +212,16 @@
       (define s-line (syntax-line stx))
       (define s-column (syntax-column stx))
       (define s-position (syntax-position stx))
-      (define s-span0 (syntax-span stx))
-      (define s-span (if (zero? s-span0) #f s-span0))
+      (define s-span (syntax-span stx))
+      (define s-span-known? (not (memv s-span '(0 #f))))
       (display "Source location\n" key-sd)
-      (if (or s-source s-line s-column s-position s-span)
+      (if (or s-source s-line s-column s-position s-span-known?)
           (begin
             (display-subkv "source" (prettify-source s-source))
             (display-subkv "line" s-line)
             (display-subkv "column" s-column)
             (display-subkv "position" s-position)
-            (display-subkv "span" s-span0))
+            (display-subkv "span" s-span))
           (display "No source location available\n" n/a-sd))
       (display "\n" #f))