patch 8.2.3169: Vim9: cannot handle nested inline function

Problem:    Vim9: cannot handle nested inline function.
Solution:   Check for nested inline function. (closes #8575)
diff --git a/src/testdir/test_vim9_expr.vim b/src/testdir/test_vim9_expr.vim
index ae48a89..cd6ffa4 100644
--- a/src/testdir/test_vim9_expr.vim
+++ b/src/testdir/test_vim9_expr.vim
@@ -2082,7 +2082,8 @@
       var Func = (nr: number): int => {
               return nr
   END
-  CheckDefAndScriptFailure(lines, 'E1171', 1)  # line nr is function start
+  CheckDefFailure(lines, 'E1171', 0)  # line nr is function start
+  CheckScriptFailure(['vim9script'] + lines, 'E1171', 2)
 
   lines =<< trim END
       var Func = (nr: number): int => {
diff --git a/src/testdir/test_vim9_func.vim b/src/testdir/test_vim9_func.vim
index 08e68d1..c89c13e 100644
--- a/src/testdir/test_vim9_func.vim
+++ b/src/testdir/test_vim9_func.vim
@@ -2255,6 +2255,16 @@
       assert_equal('--there', F('unused')('there')('--'))
   END
   CheckScriptSuccess(lines)
+
+  lines =<< trim END
+      vim9script
+      echo range(4)->mapnew((_, v) => {
+        return range(v) ->mapnew((_, s) => {
+          return string(s)
+          })
+        })
+  END
+  CheckScriptSuccess(lines)
 enddef
 
 def Shadowed(): list<number>