diff --git a/runtime/syntax/testdir/input/vim9_expr.vim b/runtime/syntax/testdir/input/vim9_expr.vim
index 7faaa5f..fd9cbb0 100644
--- a/runtime/syntax/testdir/input/vim9_expr.vim
+++ b/runtime/syntax/testdir/input/vim9_expr.vim
@@ -30,6 +30,7 @@
 echo $FOO ? $FOO : $BAR
 echo True() ? True() : False()
 echo @a ? @a : @b
+echo (true) ? (true) : (false)
 echo (1) ? (1) : (0)
 
 # Falsy
@@ -52,9 +53,15 @@
 echo $FOO ?? $FOO
 echo True() ?? True()
 echo @a ?? @a
+echo (true) ?? (true)
 echo (1) ?? (1)
 
 
+# Function calls
+
+Foo(true, false, null)
+
+
 # Command {expr} arguments
 
 if true
diff --git a/runtime/syntax/testdir/input/vim_expr.vim b/runtime/syntax/testdir/input/vim_expr.vim
index ddaf519..d71166d 100644
--- a/runtime/syntax/testdir/input/vim_expr.vim
+++ b/runtime/syntax/testdir/input/vim_expr.vim
@@ -100,6 +100,15 @@
 " Issue #5830 (Incorrect syntax highlighting in Vim script when omitting space in list of string)
 let l = ['a','b','c']
 
+" Register
+
+echo @" 
+echo @0 @1 @2 @3 @4 @5 @6 @7 @8 @9
+echo @-
+echo @a @b @c @d @e @f @g @h @i @j @k @l @m @n @o @p @q @r @s @t @u @v @w @x @y @z
+echo @A @B @C @D @E @F @G @H @I @J @K @L @M @N @O @P @Q @R @S @T @U @V @W @X @Y @Z
+echo @: @. @% @# @= @* @+ @~ @_ @/
+
 " Operators
 
 " Ternary
@@ -204,6 +213,10 @@
       \ bar +
       \ "baz"
 
+" Function calls
+
+call Foo(v:true, v:false, v:null)
+
 
 " Issue #16221 (vimString becomes vimVar when preceded by !)
 let bar = !'g:bar'->exists()