Fix ordering of imported rules in syntax packages.

core/parser/syntax-package-merger.stanza

@@ -76,7 +76,19 @@ public defn merge (pkgs:Tuple<SyntaxPackage>) -> MergedSyntaxPackage :
   ;Scan through all DefRule and add them to the local-rules and foreign-rules
   ;tables.  
   defn fill-rule-tables () :
-    for pkg in pkgs do :
+    ;The packages are traversed in reverse order so that the
+    ;foreign rules come out in the proper order.
+    ;Given base + p1, p2, the final ordering of foreign rules are:
+    ;  p2 / rule1
+    ;  p2 / rule2
+    ;  p2 / ...
+    ;  p1 / rule1
+    ;  p1 / rule2
+    ;  p1 / ...
+    ;  base / rule1
+    ;  base / rule2
+    ;  base / ...
+    for pkg in in-reverse(pkgs) do :
       for rule in rules(pkg) do :
         val rec = local-table[ProdName(name(pkg), name(rule))]
         val local? = package(rec) == name(pkg)
@@ -157,9 +169,12 @@ public defn merge (pkgs:Tuple<SyntaxPackage>) -> MergedSyntaxPackage :
               add(new-rules, rule)
 
         ;If no InlinedRules patterns were executed, then by default
-        ;add all foreign rules to the end of the list.
+        ;add all foreign rules to the start of the list.
         if not inlined-foreign-rules? :
-          add-all(new-rules, foreign-rules[key(entry)])
+          if not empty?(foreign-rules[key(entry)]) :
+            val saved-rules = to-tuple(new-rules)
+            clear(new-rules)
+            add-all(new-rules, cat(foreign-rules[key(entry)], saved-rules))
 
         key(entry) => new-rules