patch 7.4.1742
Problem:    strgetchar() does not work correctly.
Solution:   use mb_cptr2len().  Add a test. (Naruhiko Nishino)
diff --git a/src/testdir/test_expr_utf8.vim b/src/testdir/test_expr_utf8.vim
index ec36dec..c512ddf 100644
--- a/src/testdir/test_expr_utf8.vim
+++ b/src/testdir/test_expr_utf8.vim
@@ -12,6 +12,10 @@
   call assert_equal(char2nr('a'), strgetchar('àxb', 0))
   call assert_equal(char2nr('̀'), strgetchar('àxb', 1))
   call assert_equal(char2nr('x'), strgetchar('àxb', 2))
+
+  call assert_equal(char2nr('あ'), strgetchar('あaい', 0))
+  call assert_equal(char2nr('a'), strgetchar('あaい', 1))
+  call assert_equal(char2nr('い'), strgetchar('あaい', 2))
 endfunc
 
 func Test_strcharpart()