patch 9.2.0347: Vim9: script-local variable not found

Problem:  Vim9: script-local variable not found after function call
          (Mao-Yining)
Solution: Accept a script local variable in a function which overrides a
          previous block-scope variable (Yegappan Lakshmanan)

fixes:  #19959
closes: #19963

Signed-off-by: Yegappan Lakshmanan <yegappan@yahoo.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>

src/testdir/test_vim9_script.vim

@@ -5759,6 +5759,28 @@ def Test_multikey_dict_in_block()
   unlet g:TestDict
 enddef
 
+" Test for overriding a block level variable with a new script level variable
+" and referring to it in a function.
+def Test_block_var_override_with_script_var()
+  var lines =<< trim END
+    vim9script
+
+    if true
+      var lines = ['a']
+      lines->filter((_, _) => true)
+    endif
+
+    var lines = []
+
+    def Fx()
+      lines->add('b')
+    enddef
+    Fx()
+    assert_equal(['b'], lines)
+  END
+  v9.CheckSourceSuccess(lines)
+enddef
+
 " Test for using the type() function with void
 def Test_type_func_with_void()
   var lines =<< trim END

src/version.c

@@ -734,6 +734,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    347,
 /**/
     346,
 /**/

src/vim9compile.c

@@ -253,6 +253,11 @@ find_script_var(char_u *name, size_t len, cctx_T *cctx, cstack_T *cstack)
     {
 	int idx;
 
+	if (ufunc->uf_block_depth == 0 && sav->sav_block_id == 0)
+	    // If the function was defined at the script level (not inside a
+	    // block), script-scope variables are always visible.
+	    return sav;
+
 	// Go over the blocks that this function was defined in.  If the
 	// variable block ID matches it was visible to the function.
 	for (idx = 0; idx < ufunc->uf_block_depth; ++idx)