diff --git a/uni/udb/symtab.icn b/uni/udb/symtab.icn
index e13f39df5..89ed93eed 100644
--- a/uni/udb/symtab.icn
+++ b/uni/udb/symtab.icn
@@ -516,6 +516,8 @@ method lookup_fileline(filename, lineno)
    local symt, temp
 
    if \filename & \lineno then {
+      if not member(filetab, filename) then fail
+      
       line := numeric(lineno)
 
       # check for packages, package is a single file