patch 8.2.4016: Vim9: incorrect error for argument that is shadowing var

Problem:    Vim9: incorrect error for argument that is shadowing var.
Solution:   Ignore variable that is not in block where the function was
            defined.

src/testdir/test_vim9_func.vim

@@ -933,6 +933,21 @@ def Test_local_function_shadows_global()
       delfunc g:Func
   END
   CheckScriptSuccess(lines)
+
+  # This does not shadow "i" which is visible only inside the for loop
+  lines =<< trim END
+      vim9script
+
+      def Foo(i: number)
+        echo i
+      enddef
+
+      for i in range(3)
+        # Foo() is compiled here
+        Foo(i)
+      endfor
+  END
+  CheckScriptSuccess(lines)
 enddef
 
 func TakesOneArg(arg)

src/version.c

@@ -750,6 +750,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    4016,
 /**/
     4015,
 /**/

src/vim9compile.c

@@ -162,7 +162,6 @@ find_script_var(char_u *name, size_t len, cctx_T *cctx)
     hashitem_T	    *hi;
     int		    cc;
     sallvar_T	    *sav;
-    sallvar_T	    *found_sav;
     ufunc_T	    *ufunc;
 
     // Find the list of all script variables with the right name.
@@ -198,7 +197,6 @@ find_script_var(char_u *name, size_t len, cctx_T *cctx)
     // Go over the variables with this name and find one that was visible
     // from the function.
     ufunc = cctx->ctx_ufunc;
-    found_sav = sav;
     while (sav != NULL)
     {
 	int idx;
@@ -211,8 +209,8 @@ find_script_var(char_u *name, size_t len, cctx_T *cctx)
 	sav = sav->sav_next;
     }
 
-    // Not found, assume variable at script level was visible.
+    // Not found, variable was not visible.
-    return found_sav;
+    return NULL;
 }
 
 /*