diff --git a/src/testdir/test_vim9_assign.vim b/src/testdir/test_vim9_assign.vim
index f016ae3..4f4e58e 100644
--- a/src/testdir/test_vim9_assign.vim
+++ b/src/testdir/test_vim9_assign.vim
@@ -360,6 +360,13 @@
   v9.CheckDefAndScriptSuccess(lines)
 enddef
 
+def Test_type_with_extra_white()
+  var lines =<< trim END
+      const x : number = 3
+  END
+  v9.CheckDefExecAndScriptFailure(lines, 'E1059')
+enddef
+
 def Test_keep_type_after_assigning_null()
   var lines =<< trim END
       var b: blob