diff --git a/lc.vim b/lc.vim
index 59703a9..e784061 100644
--- a/lc.vim
+++ b/lc.vim
@@ -5,26 +5,29 @@ class Item
     const val: string
 endclass
 
-def GetLongestSuffix(hay: string, ndl: string): string
+def GetLongestSuffix(hay: string, ndl: string): tuple<string, number>
     var s = ndl
     var l = len(ndl)
-    while stridx(hay, s) == -1
-        s = strpart(s, 1)
+    while true
+        const idx = stridx(hay, s)
+        if idx != -1
+            return (s, idx)
+        endif
         l = l - 1
         if l == 0
-            return ""
+            break
         endif
+        s = strpart(s, 1)
     endwhile
-    return s
+    return ("", 0)
 enddef
-# echo GetLongestSuffix("hello world", "world")->assert_equal("world")
-# echo GetLongestSuffix("hello world", "foo world")->assert_equal("o world")
-# echo GetLongestSuffix("hello world foo bar blah", "foo world")->assert_equal("o world")
+# echo GetLongestSuffix("hello world", "world")->assert_equal(("world", 6))
+# echo GetLongestSuffix("hello world", "foo world")->assert_equal(("o world", 4))
+# echo GetLongestSuffix("hello world foo bar blah", "foo world")->assert_equal(("o world", 4))
 # echo v:errors
 
 def GetMatch(base: string, line: string): Item
-    const s = GetLongestSuffix(line, base)
-    const idx = stridx(line, s)
+    const [s, idx] = GetLongestSuffix(line, base)
     const slen = strlen(s)
     const  m = strpart(line, idx + slen)
     return Item.new(slen, base .. m)