--- a/src/testdir/test_vim9_assign.vim
+++ b/src/testdir/test_vim9_assign.vim
@@ -1,2894 +1,2894 @@
-" Test Vim9 assignments
-
-source check.vim
-import './vim9.vim' as v9
-source term_util.vim
-
-let s:appendToMe = 'xxx'
-let s:addToMe = 111
-let s:newVar = ''
-let g:existing = 'yes'
-let g:inc_counter = 1
-let $SOME_ENV_VAR = 'some'
-let g:alist = [7]
-let g:adict = #{a: 1}
-let g:astring = 'text'
-
-def Test_assignment_bool()
-  var bool1: bool = true
-  assert_equal(v:true, bool1)
-  var bool2: bool = false
-  assert_equal(v:false, bool2)
-
-  var bool3: bool = 0
-  assert_equal(false, bool3)
-  var bool4: bool = 1
-  assert_equal(true, bool4)
-
-  var bool5: bool = 1 && true
-  assert_equal(true, bool5)
-  var bool6: bool = 0 && 1
-  assert_equal(false, bool6)
-  var bool7: bool = 0 || 1 && true
-  assert_equal(true, bool7)
-
-  var lines =<< trim END
-    vim9script
-    def GetFlag(): bool
-      var flag: bool = 1
-      return flag
-    enddef
-    var flag: bool = GetFlag()
-    assert_equal(true, flag)
-    flag = 0
-    assert_equal(false, flag)
-    flag = 1
-    assert_equal(true, flag)
-    flag = 1 || true
-    assert_equal(true, flag)
-    flag = 1 && false
-    assert_equal(false, flag)
-
-    var cp: bool = &cp
-    var fen: bool = &l:fen
-  END
-  v9.CheckScriptSuccess(lines)
-  v9.CheckDefAndScriptFailure(['var x: bool = 2'], 'E1012:')
-  v9.CheckDefAndScriptFailure(['var x: bool = -1'], 'E1012:')
-  v9.CheckDefAndScriptFailure(['var x: bool = [1]'], 'E1012:')
-  v9.CheckDefAndScriptFailure(['var x: bool = {}'], 'E1012:')
-  v9.CheckDefAndScriptFailure(['var x: bool = "x"'], 'E1012:')
-
-  v9.CheckDefAndScriptFailure(['var x: bool = "x"', '', 'eval 0'], 'E1012:', 1)
-enddef
-
-def Test_syntax()
-  var name = 234
-  var other: list<string> = ['asdf']
-enddef
-
-def Test_assignment()
-  v9.CheckDefFailure(['var x:string'], 'E1069:')
-  v9.CheckDefFailure(['var x:string = "x"'], 'E1069:')
-  v9.CheckDefFailure(['var a:string = "x"'], 'E1069:')
-  v9.CheckDefFailure(['var lambda = () => "lambda"'], 'E704:')
-  v9.CheckScriptFailure(['var x = "x"'], 'E1124:')
-
-  # lower case name is OK for a list
-  var lambdaLines =<< trim END
-      var lambdaList: list<func> = [g:Test_syntax]
-      lambdaList[0] = () => "lambda"
-  END
-  v9.CheckDefAndScriptSuccess(lambdaLines)
-
-  var nr: number = 1234
-  v9.CheckDefFailure(['var nr: number = "asdf"'], 'E1012:')
-
-  var a: number = 6 #comment
-  assert_equal(6, a)
-
-  if has('channel')
-    var chan1: channel
-    assert_equal('fail', ch_status(chan1))
-
-    var job1: job
-    assert_equal('fail', job_status(job1))
-
-    # calling job_start() is in test_vim9_fails.vim, it causes leak reports
-  endif
-  var float1: float = 3.4
-  var Funky1: func
-  var Funky2: func = function('len')
-  var Party2: func = funcref('g:Test_syntax')
-
-  g:newvar = 'new'  #comment
-  assert_equal('new', g:newvar)
-
-  assert_equal('yes', g:existing)
-  g:existing = 'no'
-  assert_equal('no', g:existing)
-
-  v:char = 'abc'
-  assert_equal('abc', v:char)
-
-  $ENVVAR = 'foobar'
-  assert_equal('foobar', $ENVVAR)
-  $ENVVAR = ''
-
-  var lines =<< trim END
-    vim9script
-    $ENVVAR = 'barfoo'
-    assert_equal('barfoo', $ENVVAR)
-    $ENVVAR = ''
-  END
-  v9.CheckScriptSuccess(lines)
-
-  appendToMe ..= 'yyy'
-  assert_equal('xxxyyy', appendToMe)
-  addToMe += 222
-  assert_equal(333, addToMe)
-  newVar = 'new'
-  assert_equal('new', newVar)
-
-  set ts=7
-  var ts: number = &ts
-  assert_equal(7, ts)
-  &ts += 1
-  assert_equal(8, &ts)
-  &ts -= 3
-  assert_equal(5, &ts)
-  &ts *= 2
-  assert_equal(10, &ts)
-  &ts /= 3
-  assert_equal(3, &ts)
-  set ts=10
-  &ts %= 4
-  assert_equal(2, &ts)
-
-  assert_fails('&ts /= 0', ['E1154:', 'E1154:'])
-  assert_fails('&ts %= 0', ['E1154:', 'E1154:'])
-  assert_fails('&ts /= []', ['E745:', 'E745:'])
-  assert_fails('&ts %= []', ['E745:', 'E745:'])
-  assert_equal(2, &ts)
-
-  var f100: float = 100.0
-  f100 /= 5
-  assert_equal(20.0, f100)
-
-  var f200: float = 200.0
-  f200 /= 5.0
-  assert_equal(40.0, f200)
-
-  v9.CheckDefFailure(['var nr: number = 200', 'nr /= 5.0'], 'E1012:')
-
-  lines =<< trim END
-    &ts = 6
-    &ts += 3
-    assert_equal(9, &ts)
-
-    &l:ts = 6
-    assert_equal(6, &ts)
-    &l:ts += 2
-    assert_equal(8, &ts)
-
-    &g:ts = 6
-    assert_equal(6, &g:ts)
-    &g:ts += 2
-    assert_equal(8, &g:ts)
-
-    &number = true
-    assert_equal(true, &number)
-    &number = 0
-    assert_equal(false, &number)
-    &number = 1
-    assert_equal(true, &number)
-    &number = false
-    assert_equal(false, &number)
-  END
-  v9.CheckDefAndScriptSuccess(lines)
-
-  v9.CheckDefFailure(['&notex += 3'], 'E113:')
-  v9.CheckDefFailure(['&ts ..= "xxx"'], 'E1019:')
-  v9.CheckDefFailure(['&ts = [7]'], 'E1012:')
-  v9.CheckDefExecFailure(['&ts = g:alist'], 'E1012: Type mismatch; expected number but got list<number>')
-  v9.CheckDefFailure(['&ts = "xx"'], 'E1012:')
-  v9.CheckDefExecFailure(['&ts = g:astring'], 'E1012: Type mismatch; expected number but got string')
-  v9.CheckDefFailure(['&path += 3'], 'E1012:')
-  v9.CheckDefExecFailure(['&bs = "asdf"'], 'E474:')
-  # test freeing ISN_STOREOPT
-  v9.CheckDefFailure(['&ts = 3', 'var asdf'], 'E1022:')
-  &ts = 8
-
-  lines =<< trim END
-    var save_TI = &t_TI
-    &t_TI = ''
-    assert_equal('', &t_TI)
-    &t_TI = 'xxx'
-    assert_equal('xxx', &t_TI)
-    &t_TI = save_TI
-  END
-  v9.CheckDefAndScriptSuccess(lines)
-
-  v9.CheckDefFailure(['&t_TI = 123'], 'E1012:')
-  v9.CheckScriptFailure(['vim9script', '&t_TI = 123'], 'E928:')
-
-  v9.CheckDefFailure(['var s:var = 123'], 'E1101:')
-  v9.CheckDefFailure(['var s:var: number'], 'E1101:')
-
-  v9.CheckDefAndScriptFailure(['var $VAR: number'], ['E1016:', 'E475:'])
-
-  lines =<< trim END
-    vim9script
-    def SomeFunc()
-      s:var = 123
-    enddef
-    defcompile
-  END
-  v9.CheckScriptFailure(lines, 'E1268:')
-
-  g:inc_counter += 1
-  assert_equal(2, g:inc_counter)
-
-  var f: float
-  f += 1
-  assert_equal(1.0, f)
-
-  $SOME_ENV_VAR ..= 'more'
-  assert_equal('somemore', $SOME_ENV_VAR)
-  v9.CheckDefFailure(['$SOME_ENV_VAR += "more"'], 'E1051:')
-  v9.CheckDefFailure(['$SOME_ENV_VAR += 123'], 'E1012:')
-
-  v:errmsg = 'none'
-  v:errmsg ..= 'again'
-  assert_equal('noneagain', v:errmsg)
-  v9.CheckDefFailure(['v:errmsg += "more"'], 'E1051:')
-  v9.CheckDefFailure(['v:errmsg += 123'], 'E1012:')
-
-  var text =<< trim END
-    some text
-  END
-enddef
-
-def Test_float_and_number()
-  var lines =<< trim END
-       var f: float
-       f += 2
-       f -= 1
-       assert_equal(1.0, f)
-       ++f
-       --f
-       assert_equal(1.0, f)
-  END
-  v9.CheckDefAndScriptSuccess(lines)
-enddef
-
-let g:someNumber = 43
-
-def Test_assign_concat()
-  var lines =<< trim END
-    var s = '-'
-    s ..= 99
-    s ..= true
-    s ..= '-'
-    s ..= v:null
-    s ..= g:someNumber
-    assert_equal('-99true-null43', s)
-  END
-  v9.CheckDefAndScriptSuccess(lines)
-
-  lines =<< trim END
-    var s = '-'
-    s ..= [1, 2]
-  END
-  v9.CheckDefAndScriptFailure(lines, ['E1105: Cannot convert list to string', 'E734: Wrong variable type for .='], 2)
-  lines =<< trim END
-    var s = '-'
-    s ..= {a: 2}
-  END
-  v9.CheckDefAndScriptFailure(lines, ['E1105: Cannot convert dict to string', 'E734: Wrong variable type for .='], 2)
-
-  lines =<< trim END
-      var ls: list<string> = []
-      ls[-1] ..= 'foo'
-  END
-  v9.CheckDefExecAndScriptFailure(lines, 'E684: List index out of range: -1', 2)
-enddef
-
-def Test_assign_register()
-  var lines =<< trim END
-    @c = 'areg'
-    @c ..= 'add'
-    assert_equal('aregadd', @c)
-
-    @@ = 'some text'
-    assert_equal('some text', getreg('"'))
-  END
-  v9.CheckDefAndScriptSuccess(lines)
-
-  v9.CheckDefFailure(['@a += "more"'], 'E1051:')
-  v9.CheckDefFailure(['@a += 123'], 'E1012:')
-enddef
-
-def Test_reserved_name()
-  var more_names = ['null_job', 'null_channel']
-  if !has('job')
-    more_names = []
-  endif
-
-  for name in ['true',
-               'false',
-               'this',
-               'super',
-               'null',
-               'null_blob',
-               'null_dict',
-               'null_function',
-               'null_list',
-               'null_partial',
-               'null_string',
-               ] + more_names
-    v9.CheckDefExecAndScriptFailure(['var ' .. name .. ' =  0'], 'E1034:')
-    v9.CheckDefExecAndScriptFailure(['var ' .. name .. ': bool'], 'E1034:')
-  endfor
-
-  var lines =<< trim END
-      vim9script
-      def Foo(super: bool)
-	echo 'something'
-      enddef
-      defcompile
-  END
-  v9.CheckScriptFailure(lines, 'E1034:')
-enddef
-
-def Test_null_values()
-  var lines =<< trim END
-      var b: blob = null_blob
-      var dn: dict<number> = null_dict
-      var ds: dict<string> = null_dict
-      var ln: list<number> = null_list
-      var ls: list<string> = null_list
-      var Ff: func(string): string = null_function
-      var Fp: func(number): number = null_partial
-      var s: string = null_string
-      if has('job')
-        var j: job = null_job
-        var c: channel = null_channel
-      endif
-
-      var d: dict<func> = {a: function('tr'), b: null_function}
-
-      var bl: list<blob> = [0z12, null_blob]
-      var dnl: list<dict<number>> = [{a: 1}, null_dict]
-      var dsl: list<dict<string>> = [{a: 'x'}, null_dict]
-      var lnl: list<list<number>> = [[1], null_list]
-      var lsl: list<list<string>> = [['x'], null_list]
-      def Len(v: string): number
-        return len(v)
-      enddef
-      var Ffl: list<func(string): number> = [Len, null_function]
-      var Fpl: list<func(string): number> = [Len, null_partial]
-      var sl: list<string> = ['x', null_string]
-      if has('job')
-        var jl: list<job> = [null_job]
-        var cl: list<channel> = [null_channel]
-      endif
-  END
-  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
-      b = null_blob
-      b = 'text'
-  END
-  v9.CheckDefExecAndScriptFailure(lines, 'E1012: Type mismatch; expected blob but got string')
-
-  lines =<< trim END
-      var l: list<number>
-      l = null_list
-      l = ['text']
-  END
-  v9.CheckDefExecAndScriptFailure(lines, 'E1012: Type mismatch; expected list<number> but got list<string>')
-
-  lines =<< trim END
-      var d: dict<string>
-      d = null_dict
-      d = {a: 1, b: 2}
-  END
-  v9.CheckDefExecAndScriptFailure(lines, 'E1012: Type mismatch; expected dict<string> but got dict<number>')
-enddef
-
-def Test_skipped_assignment()
-  var lines =<< trim END
-      for x in []
-        var i: number = 1
-        while false
-          i += 1
-        endwhile
-      endfor
-  END
-  v9.CheckDefAndScriptSuccess(lines)
-enddef
-
-def Test_assign_keep_type()
-  var lines =<< trim END
-      vim9script
-      var l: list<number> = [123]
-      l = [123]
-      l->add('string')
-  END
-  v9.CheckScriptFailure(lines, 'E1012:', 4)
-enddef
-
-def Test_assign_unpack()
-  var lines =<< trim END
-    var v1: number
-    var v2: number
-    [v1, v2] = [1, 2]
-    assert_equal(1, v1)
-    assert_equal(2, v2)
-
-    [v1, _, v2, _] = [1, 99, 2, 77]
-    assert_equal(1, v1)
-    assert_equal(2, v2)
-
-    [v1, v2; _] = [1, 2, 3, 4, 5]
-    assert_equal(1, v1)
-    assert_equal(2, v2)
-
-    var _x: number
-    [_x, v2] = [6, 7]
-    assert_equal(6, _x)
-    assert_equal(7, v2)
-
-    var reslist = []
-    for text in ['aaa {bbb} ccc', 'ddd {eee} fff']
-      var before: string
-      var middle: string
-      var after: string
-      [_, before, middle, after; _] = text->matchlist('\(.\{-\}\){\(.\{-\}\)}\(.*\)')
-      reslist->add(before)->add(middle)->add(after)
-    endfor
-    assert_equal(['aaa ', 'bbb', ' ccc', 'ddd ', 'eee', ' fff'], reslist)
-
-    var a = 1
-    var b = 3
-    [a, b] += [2, 4]
-    assert_equal(3, a)
-    assert_equal(7, b)
-
-    [a, b] -= [1, 2]
-    assert_equal(2, a)
-    assert_equal(5, b)
-
-    [a, b] *= [3, 2]
-    assert_equal(6, a)
-    assert_equal(10, b)
-
-    [a, b] /= [2, 4]
-    assert_equal(3, a)
-    assert_equal(2, b)
-
-    [a, b] = [17, 15]
-    [a, b] %= [5, 3]
-    assert_equal(2, a)
-    assert_equal(0, b)
-  END
-  v9.CheckDefAndScriptSuccess(lines)
-
-  lines =<< trim END
-      var v1: number
-      var v2: number
-      [v1, v2] = [1, 2, 3]
-  END
-  v9.CheckDefFailure(lines, 'E1093: Expected 2 items but got 3', 3)
-
-  lines =<< trim END
-      var v1: number
-      var v2: number
-      [v1, v2] = [1]
-  END
-  v9.CheckDefFailure(lines, 'E1093: Expected 2 items but got 1', 3)
-
-  lines =<< trim END
-      var v1: number
-      var v2: number
-      [v1, v2; _] = [1]
-  END
-  v9.CheckDefFailure(lines, 'E1093: Expected 2 items but got 1', 3)
-
-  lines =<< trim END
-      var v1: number
-      var v2: number
-      [v1, v2] = 
-  END
-  v9.CheckDefFailure(lines, 'E1097:', 5)
-
-  lines =<< trim END
-      var v1: number
-      var v2: number
-      [v1, v2] = xxx
-  END
-  v9.CheckDefFailure(lines, 'E1001:', 3)
-
-  lines =<< trim END
-      var v1: number
-      var v2: number
-      [v1, v2] = popup_clear()
-  END
-  v9.CheckDefFailure(lines, 'E1031:', 3)
-
-  lines =<< trim END
-      [v1, v2] = [1, 2]
-  END
-  v9.CheckDefFailure(lines, 'E1089', 1)
-  v9.CheckScriptFailure(['vim9script'] + lines, 'E1089', 2)
-
-  lines =<< trim END
-      var v1: number
-      var v2: number
-      [v1, v2] = ''
-  END
-  v9.CheckDefFailure(lines, 'E1012: Type mismatch; expected list<any> but got string', 3)
-
-  lines =<< trim END
-    g:values = [false, 0]
-    var x: bool
-    var y: string
-    [x, y] = g:values
-  END
-  v9.CheckDefExecAndScriptFailure(lines, 'E1163: Variable 2: type mismatch, expected string but got number')
-
-  lines =<< trim END
-    var x: number
-    var y: number
-    var z: string
-    [x, y, z] = [1, 2, 3]
-  END
-  v9.CheckDefAndScriptFailure(lines, 'E1163: Variable 3: type mismatch, expected string but got number')
-
-  lines =<< trim END
-    var x: number
-    var y: string
-    var z: string
-    [x, y, z] = [1, '2', 3]
-  END
-  v9.CheckDefExecAndScriptFailure(lines, 'E1163: Variable 3: type mismatch, expected string but got number')
-enddef
-
-def Test_assign_linebreak()
-  var nr: number
-  nr =
-      123
-  assert_equal(123, nr)
-
-  var n2: number
-  [nr, n2] =
-     [12, 34]
-  assert_equal(12, nr)
-  assert_equal(34, n2)
-
-  v9.CheckDefFailure(["var x = #"], 'E1097:', 3)
-
-  var lines =<< trim END
-      var x: list<string> = ['a']
-      var y: list<number> = x
-          ->copy()
-          ->copy()
-  END
-  v9.CheckDefExecFailure(lines, 'E1012:', 4)
-
-  lines =<< trim END
-      var x: any
-      x.key = 1
-          + 2
-          + 3
-          + 4
-          + 5
-  END
-  v9.CheckDefExecAndScriptFailure(lines, ['E1148:', 'E1203:'], 2)
-enddef
-
-def Test_assign_index()
-  # list of list
-  var l1: list<number>
-  l1[0] = 123
-  assert_equal([123], l1)
-
-  var l2: list<list<number>>
-  l2[0] = []
-  l2[0][0] = 123
-  assert_equal([[123]], l2)
-
-  var l3: list<list<list<number>>>
-  l3[0] = []
-  l3[0][0] = []
-  l3[0][0][0] = 123
-  assert_equal([[[123]]], l3)
-
-  var lines =<< trim END
-      var l3: list<list<number>>
-      l3[0] = []
-      l3[0][0] = []
-  END
-  v9.CheckDefFailure(lines, 'E1012: Type mismatch; expected number but got list<unknown>', 3)
-
-  # dict of dict
-  var d1: dict<number>
-  d1.one = 1
-  assert_equal({one: 1}, d1)
-
-  var d2: dict<dict<number>>
-  d2.one = {}
-  d2.one.two = 123
-  assert_equal({one: {two: 123}}, d2)
-
-  var d3: dict<dict<dict<number>>>
-  d3.one = {}
-  d3.one.two = {}
-  d3.one.two.three = 123
-  assert_equal({one: {two: {three: 123}}}, d3)
-
-  # blob
-  var bl: blob = 0z11223344
-  bl[0] = 0x77
-  assert_equal(0z77223344, bl)
-  bl[-2] = 0x66
-  assert_equal(0z77226644, bl)
-
-  lines =<< trim END
-      g:val = '22'
-      var bl = 0z11
-      bl[1] = g:val
-  END
-  v9.CheckDefExecAndScriptFailure(lines, 'E1030: Using a String as a Number: "22"')
-
-  # should not read the next line when generating "a.b"
-  var a = {}
-  a.b = {}
-  a.b.c = {}
-          ->copy()
-
-  lines =<< trim END
-      var d3: dict<dict<number>>
-      d3.one = {}
-      d3.one.two = {}
-  END
-  v9.CheckDefFailure(lines, 'E1012: Type mismatch; expected number but got dict<unknown>', 3)
-
-  lines =<< trim END
-    var lines: list<string>
-    lines['a'] = 'asdf'
-  END
-  v9.CheckDefFailure(lines, 'E1012:', 2)
-
-  lines =<< trim END
-    var lines: string
-    lines[9] = 'asdf'
-  END
-  v9.CheckDefFailure(lines, 'E1141:', 2)
-
-  # list of dict
-  var ld: list<dict<number>>
-  ld[0] = {}
-  ld[0].one = 123
-  assert_equal([{one: 123}], ld)
-
-  lines =<< trim END
-      var ld: list<dict<number>>
-      ld[0] = []
-  END
-  v9.CheckDefFailure(lines, 'E1012: Type mismatch; expected dict<number> but got list<unknown>', 2)
-
-  # dict of list
-  var dl: dict<list<number>>
-  dl.one = []
-  dl.one[0] = 123
-  assert_equal({one: [123]}, dl)
-
-  lines =<< trim END
-      var dl: dict<list<number>>
-      dl.one = {}
-  END
-  v9.CheckDefFailure(lines, 'E1012: Type mismatch; expected list<number> but got dict<unknown>', 2)
-
-  lines =<< trim END
-      g:l = [1, 2]
-      g:l['x'] = 3
-  END
-  v9.CheckDefExecAndScriptFailure(lines, ['E39:', 'E1030:'], 2)
-
-  lines =<< trim END
-    var bl: blob = test_null_blob()
-    bl[1] = 8
-  END
-  v9.CheckDefExecAndScriptFailure(lines, ['E1184:', 'E979:'], 2)
-
-  lines =<< trim END
-    g:bl = 'not a blob'
-    g:bl[1 : 2] = 8
-  END
-  v9.CheckDefExecAndScriptFailure(lines, ['E897:', 'E689:'], 2)
-enddef
-
-def Test_init_in_for_loop()
-  var lines =<< trim END
-      var l: list<number> = []
-      for i in [3, 4]
-        var n: number
-        add(l, n)
-        n = 123
-      endfor
-      assert_equal([0, 0], l)
-  END
-  v9.CheckDefAndScriptSuccess(lines)
-
-  lines =<< trim END
-      var l: list<number> = []
-      for i in [3, 4]
-        var n: number = 0
-        add(l, n)
-        n = 123
-      endfor
-      assert_equal([0, 0], l)
-  END
-  v9.CheckDefAndScriptSuccess(lines)
-
-  lines =<< trim END
-      var l: list<number> = []
-      for i in [3, 4]
-        var n: number = 3
-        add(l, n)
-        n = 123
-      endfor
-      assert_equal([3, 3], l)
-  END
-  v9.CheckDefAndScriptSuccess(lines)
-enddef
-
-def Test_redir_is_not_assign()
-  if false
-    redir => res
-    echo var_job
-    redir END
-  endif
-enddef
-
-def Test_extend_list()
-  # using uninitialized list assigns empty list
-  var lines =<< trim END
-      var l1: list<number>
-      var l2 = l1
-      assert_true(l1 is l2)
-      l1 += [123]
-      assert_equal([123], l1)
-      assert_true(l1 is l2)
-  END
-  v9.CheckDefAndScriptSuccess(lines)
-
-  lines =<< trim END
-      var list: list<string>
-      extend(list, ['x'])
-      assert_equal(['x'], list)
-  END
-  v9.CheckDefAndScriptSuccess(lines)
-
-  # appending to uninitialized list from a function works
-  lines =<< trim END
-      vim9script
-      var list: list<string>
-      def Func()
-        list += ['a', 'b']
-      enddef
-      Func()
-      assert_equal(['a', 'b'], list)
-  END
-  v9.CheckScriptSuccess(lines)
-  lines =<< trim END
-      vim9script
-      var list: list<string>
-      def Func()
-        extend(list, ['x', 'b'])
-      enddef
-      Func()
-      assert_equal(['x', 'b'], list)
-  END
-  v9.CheckScriptSuccess(lines)
-
-  # initialized to null, with type, does not default to empty list
-  lines =<< trim END
-      vim9script
-      var l: list<string> = test_null_list()
-      extend(l, ['x'])
-  END
-  v9.CheckScriptFailure(lines, 'E1134:', 3)
-
-  # initialized to null, without type, does not default to empty list
-  lines =<< trim END
-      vim9script
-      var l = null_list
-      extend(l, ['x'])
-  END
-  v9.CheckScriptFailure(lines, 'E1134:', 3)
-
-  # assigned null, does not default to empty list
-  lines =<< trim END
-      vim9script
-      var l: list<string>
-      l = null_list
-      extend(l, ['x'])
-  END
-  v9.CheckScriptFailure(lines, 'E1134:', 4)
-
-  lines =<< trim END
-      vim9script
-      extend(test_null_list(), ['x'])
-  END
-  v9.CheckScriptFailure(lines, 'E1134:', 2)
-
-  # using global var has no declared type
-  g:myList = []
-  g:myList->extend([1])
-  g:myList->extend(['x'])
-  assert_equal([1, 'x'], g:myList)
-  unlet g:myList
-
-  # using declared list gives an error
-  lines =<< trim END
-      var l: list<number>
-      g:myList = l
-      g:myList->extend([1])
-      g:myList->extend(['x'])
-  END
-  v9.CheckDefExecAndScriptFailure(lines, 'E1013: Argument 2: type mismatch, expected list<number> but got list<string>', 4)
-  unlet g:myList
-
-  lines =<< trim END
-      vim9script
-      var lds = [1, 2, 3]
-      def Func()
-          echo lds->extend(['x'])
-      enddef
-      defcompile
-  END
-  v9.CheckScriptFailure(lines, 'E1013:')
-enddef
-
-def Test_extend_dict()
-  var lines =<< trim END
-      vim9script
-      var d: dict<number>
-      extend(d, {a: 1})
-      assert_equal({a: 1}, d)
-
-      var d2: dict<number>
-      d2['one'] = 1
-      assert_equal({one: 1}, d2)
-  END
-  v9.CheckScriptSuccess(lines)
-
-  lines =<< trim END
-      vim9script
-      var d: dict<string> = test_null_dict()
-      extend(d, {a: 'x'})
-  END
-  v9.CheckScriptFailure(lines, 'E1133:', 3)
-
-  lines =<< trim END
-      vim9script
-      extend(test_null_dict(), {a: 'x'})
-  END
-  v9.CheckScriptFailure(lines, 'E1133:', 2)
-enddef
-
-def Test_single_letter_vars()
-  # single letter variables
-  var a: number = 123
-  a = 123
-  assert_equal(123, a)
-  var b: number
-  b = 123
-  assert_equal(123, b)
-  var g: number
-  g = 123
-  assert_equal(123, g)
-  var s: number
-  s = 123
-  assert_equal(123, s)
-  var t: number
-  t = 123
-  assert_equal(123, t)
-  var v: number
-  v = 123
-  assert_equal(123, v)
-  var w: number
-  w = 123
-  assert_equal(123, w)
-enddef
-
-def Test_vim9_single_char_vars()
-  var lines =<< trim END
-      vim9script
-
-      # single character variable declarations work
-      var a: string
-      var b: number
-      var l: list<any>
-      var s: string
-      var t: number
-      var v: number
-      var w: number
-
-      # script-local variables can be used without s: prefix
-      a = 'script-a'
-      b = 111
-      l = [1, 2, 3]
-      s = 'script-s'
-      t = 222
-      v = 333
-      w = 444
-
-      assert_equal('script-a', a)
-      assert_equal(111, b)
-      assert_equal([1, 2, 3], l)
-      assert_equal('script-s', s)
-      assert_equal(222, t)
-      assert_equal(333, v)
-      assert_equal(444, w)
-  END
-  writefile(lines, 'Xsinglechar', 'D')
-  source Xsinglechar
-enddef
-
-def Test_assignment_list()
-  var list1: list<bool> = [false, true, false]
-  var list2: list<number> = [1, 2, 3]
-  var list3: list<string> = ['sdf', 'asdf']
-  var list4: list<any> = ['yes', true, 1234]
-  var list5: list<blob> = [0z01, 0z02]
-
-  var listS: list<string> = []
-  var listN: list<number> = []
-
-  assert_equal([1, 2, 3], list2)
-  list2[-1] = 99
-  assert_equal([1, 2, 99], list2)
-  list2[-2] = 88
-  assert_equal([1, 88, 99], list2)
-  list2[-3] = 77
-  assert_equal([77, 88, 99], list2)
-  list2 += [100]
-  assert_equal([77, 88, 99, 100], list2)
-
-  list3 += ['end']
-  assert_equal(['sdf', 'asdf', 'end'], list3)
-
-  v9.CheckDefExecFailure(['var ll = [1, 2, 3]', 'll[-4] = 6'], 'E684:')
-  v9.CheckDefExecFailure(['var ll = [1, 2, 3]', 'unlet ll[8 : 9]'], 'E684:')
-  v9.CheckDefExecFailure(['var ll = [1, 2, 3]', 'unlet ll[1 : -9]'], 'E684:')
-  v9.CheckDefExecFailure(['var ll = [1, 2, 3]', 'unlet ll[2 : 1]'], 'E684:')
-
-  # type becomes list<any>
-  var somelist = rand() > 0 ? [1, 2, 3] : ['a', 'b', 'c']
-
-  # type is list<any> even though initializer is list<number>
-  var anyList: list<any> = [0]
-  assert_equal([0, 'x'], extend(anyList, ['x']))
-
-  var lines =<< trim END
-    var d = {dd: test_null_list()}
-    d.dd[0] = 0
-  END
-  v9.CheckDefExecFailure(lines, 'E1147:', 2)
-
-  lines =<< trim END
-      def OneArg(x: bool)
-      enddef
-      def TwoArgs(x: bool, y: bool)
-      enddef
-      var fl: list<func(bool, bool, bool)> = [OneArg, TwoArgs]
-  END
-  v9.CheckDefExecAndScriptFailure(lines, 'E1012:', 5)
-enddef
-
-def Test_list_declaration()
-  var [v1, v2] = [1, 2]
-  v1 += 3
-  assert_equal(4, v1)
-  v2 *= 3
-  assert_equal(6, v2)
-
-  var lines =<< trim END
-      var [v1, v2] = [1]
-  END
-  v9.CheckDefExecAndScriptFailure(lines, ['E1093: Expected 2 items but got 1', 'E688:'])
-  lines =<< trim END
-      var testlist = [1]
-      var [v1, v2] = testlist
-  END
-  v9.CheckDefExecAndScriptFailure(lines, ['E1093: Expected 2 items but got 1', 'E688:'])
-  lines =<< trim END
-      var [v1, v2] = [1, 2, 3]
-  END
-  v9.CheckDefExecAndScriptFailure(lines, ['E1093: Expected 2 items but got 3', 'E687:'])
-  lines =<< trim END
-      var testlist = [1, 2, 3]
-      var [v1, v2] = testlist
-  END
-  v9.CheckDefExecAndScriptFailure(lines, ['E1093: Expected 2 items but got 3', 'E687:'])
-
-  var [vnr, vstr] = [123, 'text']
-  vnr += 3
-  assert_equal(126, vnr)
-  vstr ..= 'end'
-  assert_equal('textend', vstr)
-
-  var [vnr2: number, vstr2: string] = [123, 'text']
-  vnr2 += 3
-  assert_equal(126, vnr2)
-  vstr2 ..= 'end'
-  assert_equal('textend', vstr2)
-
-  var [vnr3: number; vlist: list<string>] = [123, 'foo', 'bar']
-  vnr3 += 5
-  assert_equal(128, vnr3)
-  assert_equal(['foo', 'bar'], vlist)
-
-  lines =<< trim END
-      var [vnr2: number, vstr2: number] = [123, 'text']
-  END
-  v9.CheckDefExecAndScriptFailure(lines, ['E1163: Variable 2: type mismatch, expected number but got string', 'E1012: Type mismatch; expected number but got string'])
-  lines =<< trim END
-      var testlist = [234, 'text']
-      var [vnr2: number, vstr2: number] = testlist
-  END
-  v9.CheckDefExecAndScriptFailure(lines, ['E1163: Variable 2: type mismatch, expected number but got string', 'E1012: Type mismatch; expected number but got string'])
-enddef
-
-def PartFuncBool(b: bool): string
-  return 'done'
-enddef
-
-def Test_assignment_partial()
-  var lines =<< trim END
-      var Partial: func(): string = function(g:PartFuncBool, [true])
-      assert_equal('done', Partial())
-  END
-  v9.CheckDefAndScriptSuccess(lines)
-
-  lines =<< trim END
-      vim9script
-      def Func(b: bool)
-      enddef
-      var Ref: func = function(Func, [true])
-      assert_equal('func()', typename(Ref))
-      Ref()
-  END
-  v9.CheckScriptSuccess(lines)
-
-  lines =<< trim END
-      vim9script
-
-      var nres: any
-      var sres: any
-      def Func(nr: number, s = '')
-        nres = nr
-        sres = s
-      enddef
-
-      var n: number
-      var Ref = function(Func, [n])
-      Ref('x')
-      assert_equal(0, nres)
-      assert_equal('x', sres)
-  END
-  v9.CheckScriptSuccess(lines)
-
-  lines =<< trim END
-      vim9script
-
-      def Func(nr: number, s = '')
-      enddef
-
-      var n: number
-      var Ref = function(Func, [n])
-      Ref(0)
-  END
-  v9.CheckScriptFailure(lines, 'E1013: Argument 2: type mismatch, expected string but got number')
-enddef
-
-def Test_assignment_list_any_index()
-   var l: list<number> = [1, 2]
-  for  [x, y, _]
-  in  [[0, 1, ''], [1, 3, '']]
-      l[x] = l[x] + y
-  endfor
-  assert_equal([2, 5], l)
-enddef
-
-def Test_assignment_list_vim9script()
-  var lines =<< trim END
-    vim9script
-    var v1: number
-    var v2: number
-    var v3: number
-    [v1, v2, v3] = [1, 2, 3]
-    assert_equal([1, 2, 3], [v1, v2, v3])
-  END
-  v9.CheckScriptSuccess(lines)
-enddef
-
-def Test_assignment_dict()
-  var dict1: dict<bool> = {one: false, two: true}
-  var dict2: dict<number> = {one: 1, two: 2}
-  var dict3: dict<string> = {key: 'value'}
-  var dict4: dict<any> = {one: 1, two: '2'}
-  var dict5: dict<blob> = {one: 0z01, two: 0z02}
-
-  # check the type is OK
-  var events: dict<string> = v:event
-
-  # overwrite
-  dict3['key'] = 'another'
-  assert_equal(dict3, {key: 'another'})
-  dict3.key = 'yet another'
-  assert_equal(dict3, {key: 'yet another'})
-
-  # member "any" can also be a dict and assigned to
-  var anydict: dict<any> = {nest: {}, nr: 0}
-  anydict.nest['this'] = 123
-  anydict.nest.that = 456
-  assert_equal({nest: {this: 123, that: 456}, nr: 0}, anydict)
-
-  var lines =<< trim END
-    var dd = {}
-    dd.two = 2
-    assert_equal({two: 2}, dd)
-  END
-  v9.CheckDefAndScriptSuccess(lines)
-
-  lines =<< trim END
-    var d = {dd: {}}
-    d.dd[0] = 2
-    d.dd['x'] = 3
-    d.dd.y = 4
-    assert_equal({dd: {0: 2, x: 3, y: 4}}, d)
-  END
-  v9.CheckDefAndScriptSuccess(lines)
-
-  lines =<< trim END
-    var key = 'foo'
-    g:[key] = 'value'
-    assert_equal('value', g:foo)
-    unlet g:foo
-  END
-  v9.CheckDefAndScriptSuccess(lines)
-
-  lines =<< trim END
-    var dd = {one: 1}
-    dd.one) = 2
-  END
-  v9.CheckDefFailure(lines, 'E488:', 2)
-
-  lines =<< trim END
-    var dd = {one: 1}
-    var dd.one = 2
-  END
-  v9.CheckDefAndScriptFailure(lines, 'E1017:', 2)
-
-  # empty key can be used
-  var dd = {}
-  dd[""] = 6
-  assert_equal({['']: 6}, dd)
-
-  # type becomes dict<any>
-  var somedict = rand() > 0 ? {a: 1, b: 2} : {a: 'a', b: 'b'}
-
-  # type is dict<any> even though initializer is dict<number>
-  var anyDict: dict<any> = {a: 0}
-  assert_equal({a: 0, b: 'x'}, extend(anyDict, {b: 'x'}))
-
-  # using global var, which has no declared type
-  g:myDict = {}
-  g:myDict->extend({a: 1})
-  g:myDict->extend({b: 'x'})
-  assert_equal({a: 1, b: 'x'}, g:myDict)
-  unlet g:myDict
-
-  # using list with declared type gives an error
-  lines =<< trim END
-      var d: dict<number>
-      g:myDict = d
-      g:myDict->extend({a: 1})
-      g:myDict->extend({b: 'x'})
-  END
-  v9.CheckDefExecAndScriptFailure(lines, 'E1013: Argument 2: type mismatch, expected dict<number> but got dict<string>', 4)
-  unlet g:myDict
-
-  # assignment to script-local dict
-  lines =<< trim END
-    vim9script
-    var test: dict<any> = {}
-    def FillDict(): dict<any>
-      test['a'] = 43
-      return test
-    enddef
-    assert_equal({a: 43}, FillDict())
-  END
-  v9.CheckScriptSuccess(lines)
-
-  lines =<< trim END
-    vim9script
-    var test: dict<any>
-    def FillDict(): dict<any>
-      test['a'] = 43
-      return test
-    enddef
-    FillDict()
-    assert_equal({a: 43}, test)
-  END
-  v9.CheckScriptSuccess(lines)
-
-  # assignment to global dict
-  lines =<< trim END
-    vim9script
-    g:test = {}
-    def FillDict(): dict<any>
-      g:test['a'] = 43
-      return g:test
-    enddef
-    assert_equal({a: 43}, FillDict())
-  END
-  v9.CheckScriptSuccess(lines)
-
-  # assignment to buffer dict
-  lines =<< trim END
-    vim9script
-    b:test = {}
-    def FillDict(): dict<any>
-      b:test['a'] = 43
-      return b:test
-    enddef
-    assert_equal({a: 43}, FillDict())
-  END
-  v9.CheckScriptSuccess(lines)
-
-  lines =<< trim END
-    var d = {dd: test_null_dict()}
-    d.dd[0] = 0
-  END
-  v9.CheckDefExecFailure(lines, 'E1103:', 2)
-
-  lines =<< trim END
-    var d = {dd: 'string'}
-    d.dd[0] = 0
-  END
-  v9.CheckDefExecFailure(lines, 'E1148:', 2)
-
-  lines =<< trim END
-    var n: any
-    n.key = 5
-  END
-  v9.CheckDefExecAndScriptFailure(lines, ['E1148:', 'E1203: Dot can only be used on a dictionary: n.key = 5'], 2)
-enddef
-
-def Test_assignment_local()
-  # Test in a separated file in order not to the current buffer/window/tab is
-  # changed.
-  var script_lines: list<string> =<< trim END
-    let b:existing = 'yes'
-    let w:existing = 'yes'
-    let t:existing = 'yes'
-
-    def Test_assignment_local_internal()
-      b:newvar = 'new'
-      assert_equal('new', b:newvar)
-      assert_equal('yes', b:existing)
-      b:existing = 'no'
-      assert_equal('no', b:existing)
-      b:existing ..= 'NO'
-      assert_equal('noNO', b:existing)
-
-      w:newvar = 'new'
-      assert_equal('new', w:newvar)
-      assert_equal('yes', w:existing)
-      w:existing = 'no'
-      assert_equal('no', w:existing)
-      w:existing ..= 'NO'
-      assert_equal('noNO', w:existing)
-
-      t:newvar = 'new'
-      assert_equal('new', t:newvar)
-      assert_equal('yes', t:existing)
-      t:existing = 'no'
-      assert_equal('no', t:existing)
-      t:existing ..= 'NO'
-      assert_equal('noNO', t:existing)
-    enddef
-    call Test_assignment_local_internal()
-  END
-  v9.CheckScriptSuccess(script_lines)
-enddef
-
-def Test_assignment_default()
-  # Test default values.
-  var thebool: bool
-  assert_equal(v:false, thebool)
-
-  var thenumber: number
-  assert_equal(0, thenumber)
-
-  var thefloat: float
-  assert_equal(0.0, thefloat)
-
-  var thestring: string
-  assert_equal('', thestring)
-
-  var theblob: blob
-  assert_equal(0z, theblob)
-
-  var Thefunc: func
-  assert_equal(test_null_function(), Thefunc)
-
-  var thelist: list<any>
-  assert_equal([], thelist)
-
-  var thedict: dict<any>
-  assert_equal({}, thedict)
-
-  if has('channel')
-    var thejob: job
-    assert_equal(test_null_job(), thejob)
-
-    var thechannel: channel
-    assert_equal(test_null_channel(), thechannel)
-
-    if has('unix') && executable('cat')
-      # check with non-null job and channel, types must match
-      thejob = job_start("cat ", {})
-      thechannel = job_getchannel(thejob)
-      job_stop(thejob, 'kill')
-    endif
-  endif
-
-  var nr = 1234 | nr = 5678
-  assert_equal(5678, nr)
-enddef
-
-def Test_script_var_default()
-  var lines =<< trim END
-      vim9script
-      var l: list<number>
-      var li = [1, 2]
-      var bl: blob
-      var bli = 0z12
-      var d: dict<number>
-      var di = {'a': 1, 'b': 2}
-      def Echo()
-        assert_equal([], l)
-        assert_equal([1, 2], li)
-        assert_equal(0z, bl)
-        assert_equal(0z12, bli)
-        assert_equal({}, d)
-        assert_equal({'a': 1, 'b': 2}, di)
-      enddef
-      Echo()
-  END
-  v9.CheckScriptSuccess(lines)
-enddef
-
-let s:scriptvar = 'init'
-
-def Test_assignment_var_list()
-  var lines =<< trim END
-      var v1: string
-      var v2: string
-      var vrem: list<string>
-      [v1] = ['aaa']
-      assert_equal('aaa', v1)
-
-      [v1, v2] = ['one', 'two']
-      assert_equal('one', v1)
-      assert_equal('two', v2)
-
-      [v1, v2; vrem] = ['one', 'two']
-      assert_equal('one', v1)
-      assert_equal('two', v2)
-      assert_equal([], vrem)
-
-      [v1, v2; vrem] = ['one', 'two', 'three']
-      assert_equal('one', v1)
-      assert_equal('two', v2)
-      assert_equal(['three'], vrem)
-
-      [&ts, &sw] = [3, 4]
-      assert_equal(3, &ts)
-      assert_equal(4, &sw)
-      set ts=8 sw=4
-
-      [@a, @z] = ['aa', 'zz']
-      assert_equal('aa', @a)
-      assert_equal('zz', @z)
-
-      [$SOME_VAR, $OTHER_VAR] = ['some', 'other']
-      assert_equal('some', $SOME_VAR)
-      assert_equal('other', $OTHER_VAR)
-
-      [g:globalvar, b:bufvar, w:winvar, t:tabvar, v:errmsg] =
-            ['global', 'buf', 'win', 'tab', 'error']
-      assert_equal('global', g:globalvar)
-      assert_equal('buf', b:bufvar)
-      assert_equal('win', w:winvar)
-      assert_equal('tab', t:tabvar)
-      assert_equal('error', v:errmsg)
-      unlet g:globalvar
-  END
-  v9.CheckDefAndScriptSuccess(lines)
-
-  [g:globalvar, scriptvar, b:bufvar] = ['global', 'script', 'buf']
-  assert_equal('global', g:globalvar)
-  assert_equal('script', scriptvar)
-  assert_equal('buf', b:bufvar)
-
-  lines =<< trim END
-      vim9script
-      var scriptvar = 'init'
-      [g:globalvar, scriptvar, w:winvar] = ['global', 'script', 'win']
-      assert_equal('global', g:globalvar)
-      assert_equal('script', scriptvar)
-      assert_equal('win', w:winvar)
-  END
-  v9.CheckScriptSuccess(lines)
-enddef
-
-def Test_assignment_empty_list()
-  var lines =<< trim END
-      var l2: list<any> = []
-      var l: list<string>
-      l = l2
-  END
-  v9.CheckDefAndScriptSuccess(lines)
-enddef
-
-def Test_assignment_vim9script()
-  var lines =<< trim END
-    vim9script
-    def Func(): list<number>
-      return [1, 2]
-    enddef
-    var name1: number
-    var name2: number
-    [name1, name2] =
-          Func()
-    assert_equal(1, name1)
-    assert_equal(2, name2)
-    var ll =
-          Func()
-    assert_equal([1, 2], ll)
-
-    @/ = 'text'
-    assert_equal('text', @/)
-    @0 = 'zero'
-    assert_equal('zero', @0)
-    @1 = 'one'
-    assert_equal('one', @1)
-    @9 = 'nine'
-    assert_equal('nine', @9)
-    @- = 'minus'
-    assert_equal('minus', @-)
-    if has('clipboard_working')
-      @* = 'star'
-      assert_equal('star', @*)
-      @+ = 'plus'
-      assert_equal('plus', @+)
-    endif
-
-    var a: number = 123
-    assert_equal(123, a)
-    var s: string = 'yes'
-    assert_equal('yes', s)
-    var b: number = 42
-    assert_equal(42, b)
-    var w: number = 43
-    assert_equal(43, w)
-    var t: number = 44
-    assert_equal(44, t)
-
-    var to_var = 0
-    to_var = 3
-    assert_equal(3, to_var)
-  END
-  v9.CheckScriptSuccess(lines)
-
-  lines =<< trim END
-      vim9script
-      var n: number
-      def Func()
-        n = 'string'
-      enddef
-      defcompile
-  END
-  v9.CheckScriptFailure(lines, 'E1012: Type mismatch; expected number but got string')
-enddef
-
-def Mess(): string
-  v:foldstart = 123
-  return 'xxx'
-enddef
-
-def Test_assignment_failure()
-  v9.CheckDefFailure(['var name=234'], 'E1004:')
-  v9.CheckDefFailure(['var name =234'], 'E1004:')
-  v9.CheckDefFailure(['var name= 234'], 'E1004:')
-
-  v9.CheckScriptFailure(['vim9script', 'var name=234'], 'E1004:')
-  v9.CheckScriptFailure(['vim9script', 'var name=234'], "before and after '='")
-  v9.CheckScriptFailure(['vim9script', 'var name =234'], 'E1004:')
-  v9.CheckScriptFailure(['vim9script', 'var name= 234'], 'E1004:')
-  v9.CheckScriptFailure(['vim9script', 'var name = 234', 'name+=234'], 'E1004:')
-  v9.CheckScriptFailure(['vim9script', 'var name = 234', 'name+=234'], "before and after '+='")
-  v9.CheckScriptFailure(['vim9script', 'var name = "x"', 'name..="y"'], 'E1004:')
-  v9.CheckScriptFailure(['vim9script', 'var name = "x"', 'name..="y"'], "before and after '..='")
-
-  v9.CheckDefFailure(['var true = 1'], 'E1034:')
-  v9.CheckDefFailure(['var false = 1'], 'E1034:')
-  v9.CheckDefFailure(['var null = 1'], 'E1034:')
-  v9.CheckDefFailure(['var this = 1'], 'E1034:')
-  v9.CheckDefFailure(['var super = 1'], 'E1034:')
-
-  v9.CheckDefFailure(['[a; b; c] = g:list'], 'E1001:')
-  v9.CheckDefFailure(['var [a; b; c] = g:list'], 'E1080:')
-  v9.CheckDefExecFailure(['var a: number',
-                       '[a] = test_null_list()'], 'E1093:')
-  v9.CheckDefExecFailure(['var a: number',
-                       '[a] = []'], 'E1093:')
-  v9.CheckDefExecFailure(['var x: number',
-                       'var y: number',
-                       '[x, y] = [1]'], 'E1093:')
-  v9.CheckDefExecFailure(['var x: string',
-                       'var y: string',
-                       '[x, y] = ["x"]'], 'E1093:')
-  v9.CheckDefExecFailure(['var x: number',
-                       'var y: number',
-                       'var z: list<number>',
-                       '[x, y; z] = [1]'], 'E1093:')
-
-  v9.CheckDefFailure(['var somevar'], "E1022:")
-  v9.CheckDefFailure(['var &tabstop = 4'], 'E1052:')
-  v9.CheckDefFailure(['&g:option = 5'], 'E113:')
-  v9.CheckScriptFailure(['vim9script', 'var &tabstop = 4'], 'E1052:')
-
-  v9.CheckDefFailure(['var $VAR = 5'], 'E1016: Cannot declare an environment variable:')
-  v9.CheckScriptFailure(['vim9script', 'var $ENV = "xxx"'], 'E1016:')
-
-  if has('dnd')
-    v9.CheckDefFailure(['var @~ = 5'], 'E1066:')
-  else
-    v9.CheckDefFailure(['var @~ = 5'], 'E354:')
-    v9.CheckDefFailure(['@~ = 5'], 'E354:')
-  endif
-  v9.CheckDefFailure(['var @a = 5'], 'E1066:')
-  v9.CheckDefFailure(['var @/ = "x"'], 'E1066:')
-  v9.CheckScriptFailure(['vim9script', 'var @a = "abc"'], 'E1066:')
-
-  v9.CheckDefFailure(['var g:var = 5'], 'E1016: Cannot declare a global variable:')
-  v9.CheckDefFailure(['var w:var = 5'], 'E1016: Cannot declare a window variable:')
-  v9.CheckDefFailure(['var b:var = 5'], 'E1016: Cannot declare a buffer variable:')
-  v9.CheckDefFailure(['var t:var = 5'], 'E1016: Cannot declare a tab variable:')
-
-  v9.CheckDefFailure(['var anr = 4', 'anr ..= "text"'], 'E1019:')
-  v9.CheckDefFailure(['var xnr += 4'], 'E1020:', 1)
-  v9.CheckScriptFailure(['vim9script', 'var xnr += 4'], 'E1020:')
-  v9.CheckDefFailure(["var xnr = xnr + 1"], 'E1001:', 1)
-  v9.CheckScriptFailure(['vim9script', 'var xnr = xnr + 4'], 'E121:')
-
-  v9.CheckScriptFailure(['vim9script', 'def Func()', 'var dummy = notfound', 'enddef', 'defcompile'], 'E1001:')
-
-  v9.CheckDefFailure(['var name: list<string> = [123]'], 'expected list<string> but got list<number>')
-  v9.CheckDefFailure(['var name: list<number> = ["xx"]'], 'expected list<number> but got list<string>')
-
-  v9.CheckDefFailure(['var name: dict<string> = {key: 123}'], 'expected dict<string> but got dict<number>')
-  v9.CheckDefFailure(['var name: dict<number> = {key: "xx"}'], 'expected dict<number> but got dict<string>')
-
-  v9.CheckDefFailure(['var name = feedkeys("0")'], 'E1031:')
-  v9.CheckDefFailure(['var name: number = feedkeys("0")'], 'expected number but got void')
-
-  v9.CheckDefFailure(['var name: dict <number>'], 'E1068:')
-  v9.CheckDefFailure(['var name: dict<number'], 'E1009: Missing > after type: <number')
-
-  assert_fails('s/^/\=g:Mess()/n', 'E794:')
-  v9.CheckDefFailure(['var name: dict<number'], 'E1009:')
-
-  v9.CheckDefFailure(['w:foo: number = 10'],
-                  'E1016: Cannot declare a window variable: w:foo')
-  v9.CheckDefFailure(['t:foo: bool = true'],
-                  'E1016: Cannot declare a tab variable: t:foo')
-  v9.CheckDefFailure(['b:foo: string = "x"'],
-                  'E1016: Cannot declare a buffer variable: b:foo')
-  v9.CheckDefFailure(['g:foo: number = 123'],
-                  'E1016: Cannot declare a global variable: g:foo')
-
-  v9.CheckScriptFailure(['vim9script', 'w:foo: number = 123'],
-                  'E1304: Cannot use type with this variable: w:foo:')
-  v9.CheckScriptFailure(['vim9script', 't:foo: number = 123'],
-                  'E1304: Cannot use type with this variable: t:foo:')
-  v9.CheckScriptFailure(['vim9script', 'b:foo: number = 123'],
-                  'E1304: Cannot use type with this variable: b:foo:')
-  v9.CheckScriptFailure(['vim9script', 'g:foo: number = 123'],
-                  'E1304: Cannot use type with this variable: g:foo:')
-
-  v9.CheckScriptFailure(['vim9script', 'const w:FOO: number = 123'],
-                  'E1304: Cannot use type with this variable: w:FOO:')
-  v9.CheckScriptFailure(['vim9script', 'const t:FOO: number = 123'],
-                  'E1304: Cannot use type with this variable: t:FOO:')
-  v9.CheckScriptFailure(['vim9script', 'const b:FOO: number = 123'],
-                  'E1304: Cannot use type with this variable: b:FOO:')
-  v9.CheckScriptFailure(['vim9script', 'const g:FOO: number = 123'],
-                  'E1304: Cannot use type with this variable: g:FOO:')
-enddef
-
-def Test_assign_list()
-  var lines =<< trim END
-      var l: list<string> = []
-      l[0] = 'value'
-      assert_equal('value', l[0])
-
-      l[1] = 'asdf'
-      assert_equal('value', l[0])
-      assert_equal('asdf', l[1])
-      assert_equal('asdf', l[-1])
-      assert_equal('value', l[-2])
-
-      var nrl: list<number> = []
-      for i in range(5)
-        nrl[i] = i
-      endfor
-      assert_equal([0, 1, 2, 3, 4], nrl)
-
-      var ul: list<any>
-      ul[0] = 1
-      ul[1] = 2
-      ul[2] = 3
-      assert_equal([1, 2, 3], ul)
-  END
-  v9.CheckDefAndScriptSuccess(lines)
-
-  lines =<< trim END
-      var l = [1, 2]
-      g:idx = 'x'
-      l[g:idx : 1] = [0]
-      echo l
-  END
-  v9.CheckDefExecAndScriptFailure(lines, ['E1012: Type mismatch; expected number but got string', 'E1030: Using a String as a Number: "x"'])
-
-  lines =<< trim END
-      var l = [1, 2]
-      g:idx = 3
-      l[g:idx : 1] = [0]
-      echo l
-  END
-  v9.CheckDefExecAndScriptFailure(lines, 'E684: List index out of range: 3')
-
-  lines =<< trim END
-      var l = [1, 2]
-      g:idx = 'y'
-      l[1 : g:idx] = [0]
-      echo l
-  END
-  v9.CheckDefExecAndScriptFailure(lines, ['E1012: Type mismatch; expected number but got string', 'E1030: Using a String as a Number: "y"'])
-
-  v9.CheckDefFailure(["var l: list<number> = ['', true]"], 'E1012: Type mismatch; expected list<number> but got list<any>', 1)
-  v9.CheckDefFailure(["var l: list<list<number>> = [['', true]]"], 'E1012: Type mismatch; expected list<list<number>> but got list<list<any>>', 1)
-enddef
-
-def Test_assign_dict()
-  var lines =<< trim END
-      var d: dict<string> = {}
-      d['key'] = 'value'
-      assert_equal('value', d['key'])
-
-      d[123] = 'qwerty'
-      assert_equal('qwerty', d[123])
-      assert_equal('qwerty', d['123'])
-
-      var nrd: dict<number> = {}
-      for i in range(3)
-        nrd[i] = i
-      endfor
-      assert_equal({0: 0, 1: 1, 2: 2}, nrd)
-
-      d.somekey = 'someval'
-      assert_equal({key: 'value', '123': 'qwerty', somekey: 'someval'}, d)
-      unlet d.somekey
-      assert_equal({key: 'value', '123': 'qwerty'}, d)
-  END
-  v9.CheckDefAndScriptSuccess(lines)
-
-  v9.CheckDefFailure(["var d: dict<number> = {a: '', b: true}"], 'E1012: Type mismatch; expected dict<number> but got dict<any>', 1)
-  v9.CheckDefFailure(["var d: dict<dict<number>> = {x: {a: '', b: true}}"], 'E1012: Type mismatch; expected dict<dict<number>> but got dict<dict<any>>', 1)
-  v9.CheckDefFailure(["var d = {x: 1}", "d[1 : 2] = {y: 2}"], 'E1165: Cannot use a range with an assignment: d[1 : 2] =', 2)
-enddef
-
-def Test_assign_dict_unknown_type()
-  var lines =<< trim END
-      vim9script
-      var mylist = []
-      mylist += [{one: 'one'}]
-      def Func()
-        var dd = mylist[0]
-        assert_equal('one', dd.one)
-      enddef
-      Func()
-  END
-  v9.CheckScriptSuccess(lines)
-
-  lines =<< trim END
-      vim9script
-      var mylist = [[]]
-      mylist[0] += [{one: 'one'}]
-      def Func()
-        var dd = mylist[0][0]
-        assert_equal('one', dd.one)
-      enddef
-      Func()
-  END
-  v9.CheckScriptSuccess(lines)
-enddef
-
-def Test_assign_dict_with_op()
-  var lines =<< trim END
-    var ds: dict<string> = {a: 'x'}
-    ds['a'] ..= 'y'
-    ds.a ..= 'z'
-    assert_equal('xyz', ds.a)
-
-    var dn: dict<number> = {a: 9}
-    dn['a'] += 2
-    assert_equal(11, dn.a)
-    dn.a += 2
-    assert_equal(13, dn.a)
-
-    dn['a'] -= 3
-    assert_equal(10, dn.a)
-    dn.a -= 2
-    assert_equal(8, dn.a)
-
-    dn['a'] *= 2
-    assert_equal(16, dn.a)
-    dn.a *= 2
-    assert_equal(32, dn.a)
-
-    dn['a'] /= 3
-    assert_equal(10, dn.a)
-    dn.a /= 2
-    assert_equal(5, dn.a)
-
-    dn['a'] %= 3
-    assert_equal(2, dn.a)
-    dn.a %= 6
-    assert_equal(2, dn.a)
-
-    var dd: dict<dict<list<any>>>
-    dd.a = {}
-    dd.a.b = [0]
-    dd.a.b += [1]
-    assert_equal({a: {b: [0, 1]}}, dd)
-
-    var dab = {a: ['b']}
-    dab.a[0] ..= 'c'
-    assert_equal({a: ['bc']}, dab)
-  END
-  v9.CheckDefAndScriptSuccess(lines)
-enddef
-
-def Test_assign_list_with_op()
-  var lines =<< trim END
-    var ls: list<string> = ['x']
-    ls[0] ..= 'y'
-    assert_equal('xy', ls[0])
-
-    var ln: list<number> = [9]
-    ln[0] += 2
-    assert_equal(11, ln[0])
-
-    ln[0] -= 3
-    assert_equal(8, ln[0])
-
-    ln[0] *= 2
-    assert_equal(16, ln[0])
-
-    ln[0] /= 3
-    assert_equal(5, ln[0])
-
-    ln[0] %= 3
-    assert_equal(2, ln[0])
-  END
-  v9.CheckDefAndScriptSuccess(lines)
-enddef
-
-def Test_assign_with_op_fails()
-  var lines =<< trim END
-      var s = 'abc'
-      s[1] += 'x'
-  END
-  v9.CheckDefAndScriptFailure(lines, ['E1141:', 'E689:'], 2)
-
-  lines =<< trim END
-      var s = 'abc'
-      s[1] ..= 'x'
-  END
-  v9.CheckDefAndScriptFailure(lines, ['E1141:', 'E689:'], 2)
-
-  lines =<< trim END
-      var dd: dict<dict<list<any>>>
-      dd.a = {}
-      dd.a.b += [1]
-  END
-  v9.CheckDefExecAndScriptFailure(lines, 'E716:', 3)
-enddef
-
-def Test_assign_lambda()
-  # check if assign a lambda to a variable which type is func or any.
-  var lines =<< trim END
-      vim9script
-      var FuncRef = () => 123
-      assert_equal(123, FuncRef())
-      var FuncRef_Func: func = () => 123
-      assert_equal(123, FuncRef_Func())
-      var FuncRef_Any: any = () => 123
-      assert_equal(123, FuncRef_Any())
-      var FuncRef_Number: func(): number = () => 321
-      assert_equal(321, FuncRef_Number())
-  END
-  v9.CheckScriptSuccess(lines)
-
-  lines =<< trim END
-      var Ref: func(number)
-      Ref = (j) => !j
-  END
-  v9.CheckDefAndScriptFailure(lines, 'E1012: Type mismatch; expected func(number) but got func(any): bool')
-
-  lines =<< trim END
-      echo filter([1, 2, 3], (_, v: string) => v + 1)
-  END
-  v9.CheckDefAndScriptFailure(lines, 'E1051:')
-enddef
-
-def Test_heredoc()
-  # simple heredoc
-  var lines =<< trim END
-      var text =<< trim TEXT # comment
-        abc
-      TEXT
-      assert_equal(['abc'], text)
-  END
-  v9.CheckDefAndScriptSuccess(lines)
-
-  # empty heredoc
-  lines =<< trim END
-       var text =<< trim TEXT
-       TEXT
-       assert_equal([], text)
-  END
-  v9.CheckDefAndScriptSuccess(lines)
-
-  # heredoc with a single empty line
-  lines =<< trim END
-      var text =<< trim TEXT
-
-      TEXT
-      assert_equal([''], text)
-  END
-  v9.CheckDefAndScriptSuccess(lines)
-
-  # assign heredoc to variable with type
-  lines =<< trim END
-      var text: list<string> =<< trim TEXT
-        var foo =<< trim FOO
-      TEXT
-      assert_equal(['var foo =<< trim FOO'], text)
-  END
-  v9.CheckDefAndScriptSuccess(lines)
-
-  # extra whitespace before type is allowed
-  lines =<< trim END
-      var text:   list<string> =<< trim TEXT
-        var foo =<< trim FOO
-      TEXT
-      assert_equal(['var foo =<< trim FOO'], text)
-  END
-  v9.CheckDefAndScriptSuccess(lines)
-
-  # missing whitespace before type is an error
-  lines =<< trim END
-      var text:list<string> =<< trim TEXT
-        var foo =<< trim FOO
-      TEXT
-      assert_equal(['var foo =<< trim FOO'], text)
-  END
-  v9.CheckDefAndScriptFailure(lines, 'E1069:')
-
-  # assign heredoc to list slice
-  lines =<< trim END
-      var text = ['']
-      text[ : ] =<< trim TEXT
-        var foo =<< trim FOO
-      TEXT
-      assert_equal(['var foo =<< trim FOO'], text)
-  END
-  v9.CheckDefAndScriptSuccess(lines)
-
-  # assign heredoc to curly braces name in legacy function in Vim9 script
-  lines =<< trim END
-      vim9script
-      func Func()
-        let foo_3_bar = ['']
-        let foo_{1 + 2}_bar[ : ] =<< trim TEXT
-          var foo =<< trim FOO
-        TEXT
-        call assert_equal(['var foo =<< trim FOO'], foo_3_bar)
-      endfunc
-      Func()
-  END
-  v9.CheckScriptSuccess(lines)
-
-  v9.CheckDefFailure(['var lines =<< trim END X', 'END'], 'E488:')
-  v9.CheckDefFailure(['var lines =<< trim END " comment', 'END'], 'E488:')
-
-  lines =<< trim [END]
-      def Func()
-        var&lines =<< trim END
-        x
-        x
-      enddef
-      defcompile
-  [END]
-  v9.CheckScriptFailure(lines, 'E1145: Missing heredoc end marker: END')
-  delfunc! g:Func
-
-  lines =<< trim [END]
-      def Func()
-        var lines =<< trim END
-        x
-        x
-        x
-        x
-        x
-        x
-        x
-        x
-      enddef
-      call Func()
-  [END]
-  v9.CheckScriptFailure(lines, 'E1145: Missing heredoc end marker: END')
-  delfunc! g:Func
-
-  lines =<< trim END
-      var lines: number =<< trim STOP
-        aaa
-        bbb
-      STOP
-  END
-  v9.CheckDefAndScriptFailure(lines, 'E1012: Type mismatch; expected number but got list<string>', 1)
-
-  lines =<< trim END
-      var lines=<< STOP
-        xxx
-      STOP
-  END
-  v9.CheckDefAndScriptFailure(lines, 'E1004: White space required before and after ''=<<'' at "=<< STOP"', 1)
-  lines =<< trim END
-      var lines =<<STOP
-        xxx
-      STOP
-  END
-  v9.CheckDefAndScriptFailure(lines, 'E1004: White space required before and after ''=<<'' at "=<<STOP"', 1)
-  lines =<< trim END
-      var lines=<<STOP
-        xxx
-      STOP
-  END
-  v9.CheckDefAndScriptFailure(lines, 'E1004: White space required before and after ''=<<'' at "=<<STOP"', 1)
-enddef
-
-def Test_var_func_call()
-  var lines =<< trim END
-    vim9script
-    func GetValue()
-      if exists('g:count')
-        let g:count += 1
-      else
-        let g:count = 1
-      endif
-      return 'this'
-    endfunc
-    var val: string = GetValue()
-    # env var is always a string
-    var env = $TERM
-  END
-  writefile(lines, 'Xfinished', 'D')
-  source Xfinished
-  # GetValue() is not called during discovery phase
-  assert_equal(1, g:count)
-
-  unlet g:count
-enddef
-
-def Test_var_missing_type()
-  var lines =<< trim END
-    vim9script
-    var name = g:unknown
-  END
-  v9.CheckScriptFailure(lines, 'E121:')
-
-  lines =<< trim END
-    vim9script
-    var nr: number = 123
-    var name = nr
-  END
-  v9.CheckScriptSuccess(lines)
-enddef
-
-def Test_var_declaration()
-  var lines =<< trim END
-    vim9script
-    var name: string
-    g:var_uninit = name
-    name = 'text'
-    g:var_test = name
-    # prefixing s: is not allowed
-    name = 'prefixed'
-    g:var_prefixed = name
-
-    const FOO: number = 123
-    assert_equal(123, FOO)
-    const FOOS = 'foos'
-    assert_equal('foos', FOOS)
-    final FLIST = [1]
-    assert_equal([1], FLIST)
-    FLIST[0] = 11
-    assert_equal([11], FLIST)
-
-    const g:FOOS = 'gfoos'
-    assert_equal('gfoos', g:FOOS)
-    final g:FLIST = [2]
-    assert_equal([2], g:FLIST)
-    g:FLIST[0] = 22
-    assert_equal([22], g:FLIST)
-
-    def SetGlobalConst()
-      const g:globConst = 123
-    enddef
-    SetGlobalConst()
-    assert_equal(123, g:globConst)
-    assert_true(islocked('g:globConst'))
-
-    const w:FOOS = 'wfoos'
-    assert_equal('wfoos', w:FOOS)
-    final w:FLIST = [3]
-    assert_equal([3], w:FLIST)
-    w:FLIST[0] = 33
-    assert_equal([33], w:FLIST)
-
-    var s:other: number
-    other = 1234
-    g:other_var = other
-
-    var xyz: string  # comment
-
-    # type is inferred
-    var dict = {['a']: 222}
-    def GetDictVal(key: any)
-      g:dict_val = dict[key]
-    enddef
-    GetDictVal('a')
-
-    final adict: dict<string> = {}
-    def ChangeAdict()
-      adict.foo = 'foo'
-    enddef
-    ChangeAdict()
-  END
-  v9.CheckScriptSuccess(lines)
-  assert_equal('', g:var_uninit)
-  assert_equal('text', g:var_test)
-  assert_equal('prefixed', g:var_prefixed)
-  assert_equal(1234, g:other_var)
-  assert_equal(222, g:dict_val)
-
-  unlet g:var_uninit
-  unlet g:var_test
-  unlet g:var_prefixed
-  unlet g:other_var
-  unlet g:globConst
-  unlet g:FOOS
-  unlet g:FLIST
-  unlet w:FOOS
-  unlet w:FLIST
-enddef
-
-def Test_create_list_after_const()
-  const a = 1
-  g:ll = []
-  assert_equal(0, islocked('g:ll'))
-  unlet g:ll
-enddef
-
-def Test_var_declaration_fails()
-  var lines =<< trim END
-    vim9script
-    final var: string
-  END
-  v9.CheckScriptFailure(lines, 'E1125:')
-
-  lines =<< trim END
-    vim9script
-    const g:constvar = 'string'
-    g:constvar = 'xx'
-  END
-  v9.CheckScriptFailure(lines, 'E741:')
-  unlet g:constvar
-
-  lines =<< trim END
-    vim9script
-    var name = 'one'
-    lockvar name
-    def SetLocked()
-      name = 'two'
-    enddef
-    SetLocked()
-  END
-  v9.CheckScriptFailure(lines, 'E741: Value is locked: name', 1)
-
-  lines =<< trim END
-    let s:legacy = 'one'
-    lockvar s:legacy
-    def SetLocked()
-      s:legacy = 'two'
-    enddef
-    call SetLocked()
-  END
-  v9.CheckScriptFailure(lines, 'E741: Value is locked: s:legacy', 1)
-
-  lines =<< trim END
-    vim9script
-    def SetGlobalConst()
-      const g:globConst = 123
-    enddef
-    SetGlobalConst()
-    g:globConst = 234
-  END
-  v9.CheckScriptFailure(lines, 'E741: Value is locked: g:globConst', 6)
-  unlet g:globConst
-
-  lines =<< trim END
-    vim9script
-    const cdict: dict<string> = {}
-    def Change()
-      cdict.foo = 'foo'
-    enddef
-    defcompile
-  END
-  v9.CheckScriptFailure(lines, 'E46:')
-
-  lines =<< trim END
-    vim9script
-    final w:finalvar = [9]
-    w:finalvar = [8]
-  END
-  v9.CheckScriptFailure(lines, 'E1122:')
-  unlet w:finalvar
-
-  lines =<< trim END
-    vim9script
-    const var: string
-  END
-  v9.CheckScriptFailure(lines, 'E1021:')
-
-  lines =<< trim END
-    vim9script
-    var 9var: string
-  END
-  v9.CheckScriptFailure(lines, 'E488:')
-
-  v9.CheckDefFailure(['var foo.bar = 2'], 'E1087:')
-  v9.CheckDefFailure(['var foo[3] = 2'], 'E1087:')
-  v9.CheckDefFailure(['const foo: number'], 'E1021:')
-
-  lines =<< trim END
-      va foo = 123
-  END
-  v9.CheckDefAndScriptFailure(lines, 'E1065:', 1)
-
-  lines =<< trim END
-      var foo: func(number
-  END
-  v9.CheckDefAndScriptFailure(lines, 'E110:', 1)
-
-  lines =<< trim END
-      var foo: func(number): func(
-  END
-  v9.CheckDefAndScriptFailure(lines, 'E110:', 1)
-
-  for type in ['num_ber',
-               'anys', 'ani',
-               'bools', 'boel',
-               'blobs', 'blub',
-               'channels', 'channol',
-               'dicts', 'duct',
-               'floats', 'floot',
-               'funcs', 'funk',
-               'jobs', 'jop',
-               'lists', 'last',
-               'numbers', 'numbar',
-               'strings', 'strung',
-               'voids', 'viod']
-    v9.CheckDefAndScriptFailure([$'var foo: {type}'], 'E1010:', 1)
-  endfor
-enddef
-
-def Test_var_declaration_inferred()
-  # check that type is set on the list so that extend() fails
-  var lines =<< trim END
-      vim9script
-      def GetList(): list<number>
-        var l = [1, 2, 3]
-        return l
-      enddef
-      echo GetList()->extend(['x'])
-  END
-  v9.CheckScriptFailure(lines, 'E1013:', 6)
-
-  lines =<< trim END
-      vim9script
-      def GetNr(): number
-        return 5
-      enddef
-      def TestOne()
-        var some = [function('len'), GetNr]
-        g:res = typename(some)
-      enddef
-      TestOne()
-      assert_equal('list<func(): number>', g:res)
-
-      def TestTwo()
-        var some = [function('len'), GetNr]
-        g:res = typename(some)
-      enddef
-      TestTwo()
-      assert_equal('list<func(): number>', g:res)
-      unlet g:res
-
-      # FIXME: why is the type different?
-      var first = [function('len'), GetNr]
-      assert_equal('list<func(...): number>', typename(first))
-      var second = [GetNr, function('len')]
-      assert_equal('list<func(...): number>', typename(second))
-  END
-  v9.CheckScriptSuccess(lines)
-enddef
-
-def Test_script_local_in_legacy()
-  # OK to define script-local later but before compiling
-  var lines =<< trim END
-    def SetLater()
-      legvar = 'two'
-    enddef
-    let s:legvar = 'one'
-    defcompile
-    call SetLater()
-    call assert_equal('two', s:legvar)
-  END
-  v9.CheckScriptSuccess(lines)
-
-  # OK to leave out s: prefix when script-local already defined
-  lines =<< trim END
-    let s:legvar = 'one'
-    def SetNoPrefix()
-      legvar = 'two'
-    enddef
-    call SetNoPrefix()
-    call assert_equal('two', s:legvar)
-  END
-  v9.CheckScriptSuccess(lines)
-
-  # Not OK to leave out s: prefix when script-local defined after compiling
-  lines =<< trim END
-    def SetLaterNoPrefix()
-      legvar = 'two'
-    enddef
-    defcompile
-    let s:legvar = 'one'
-  END
-  v9.CheckScriptFailure(lines, 'E476:', 1)
-
-  edit! Xslfile
-  lines =<< trim END
-      var edit: bool
-      legacy edit
-  END
-  v9.CheckDefAndScriptSuccess(lines)
-enddef
-
-def Test_var_type_check()
-  var lines =<< trim END
-    vim9script
-    var name: string
-    name = 1234
-  END
-  v9.CheckScriptFailure(lines, 'E1012:')
-
-  lines =<< trim END
-    vim9script
-    var name:string
-  END
-  v9.CheckScriptFailure(lines, 'E1069:')
-
-  v9.CheckDefAndScriptFailure(['var n:number = 42'], 'E1069:')
-
-  lines =<< trim END
-    vim9script
-    var name: asdf
-  END
-  v9.CheckScriptFailure(lines, 'E1010:')
-
-  lines =<< trim END
-    vim9script
-    var l: list<number>
-    l = []
-  END
-  v9.CheckScriptSuccess(lines)
-
-  lines =<< trim END
-    vim9script
-    var d: dict<number>
-    d = {}
-  END
-  v9.CheckScriptSuccess(lines)
-
-  lines =<< trim END
-    vim9script
-    var d = {a: 1, b: [2]}
-    def Func(b: bool)
-      var l: list<number> = b ? d.b : [3]
-    enddef
-    defcompile
-  END
-  v9.CheckScriptSuccess(lines)
-enddef
-
-let g:dict_number = #{one: 1, two: 2}
-
-def Test_var_list_dict_type()
-  var ll: list<number>
-  ll = [1, 2, 2, 3, 3, 3]->uniq()
-  ll->assert_equal([1, 2, 3])
-
-  var dd: dict<number>
-  dd = g:dict_number
-  dd->assert_equal(g:dict_number)
-
-  var lines =<< trim END
-      var ll: list<number>
-      ll = [1, 2, 3]->map('"one"')
-  END
-  v9.CheckDefExecFailure(lines, 'E1012: Type mismatch; expected list<number> but got list<string>')
-enddef
-
-def Test_cannot_use_let()
-  v9.CheckDefAndScriptFailure(['let a = 34'], 'E1126:', 1)
-enddef
-
-def Test_unlet()
-  g:somevar = 'yes'
-  assert_true(exists('g:somevar'))
-  unlet g:somevar
-  assert_false(exists('g:somevar'))
-  unlet! g:somevar
-
-  # also works for script-local variable in legacy Vim script
-  s:somevar = 'legacy'
-  assert_true(exists('s:somevar'))
-  unlet s:somevar
-  assert_false(exists('s:somevar'))
-  unlet! s:somevar
-
-  if 0
-    unlet g:does_not_exist
-  endif
-
-  v9.CheckDefExecFailure(['unlet v:notfound.key'], 'E1001:')
-
-  v9.CheckDefExecFailure([
-    'var dd = 111',
-    'unlet dd',
-    ], 'E1081:', 2)
-
-  # dict unlet
-  var dd = {a: 1, b: 2, c: 3, 4: 4}
-  unlet dd['a']
-  unlet dd.c
-  unlet dd[4]
-  assert_equal({b: 2}, dd)
-
-  # null key works like empty string
-  dd = {'': 1, x: 9}
-  unlet dd[null_string]
-  assert_equal({x: 9}, dd)
-
-  # list unlet
-  var ll = [1, 2, 3, 4]
-  unlet ll[1]
-  unlet ll[-1]
-  assert_equal([1, 3], ll)
-
-  ll = [1, 2, 3, 4]
-  unlet ll[0 : 1]
-  assert_equal([3, 4], ll)
-
-  ll = [1, 2, 3, 4]
-  unlet ll[2 : 8]
-  assert_equal([1, 2], ll)
-
-  ll = [1, 2, 3, 4]
-  unlet ll[-2 : -1]
-  assert_equal([1, 2], ll)
-
-  g:nrdict = {1: 1, 2: 2}
-  g:idx = 1
-  unlet g:nrdict[g:idx]
-  assert_equal({2: 2}, g:nrdict)
-  unlet g:nrdict
-  unlet g:idx
-
-  v9.CheckDefFailure([
-    'var ll = [1, 2]',
-    'll[1 : 2] = 7',
-    ], 'E1012: Type mismatch; expected list<number> but got number', 2)
-  v9.CheckDefFailure([
-    'var dd = {a: 1}',
-    'unlet dd["a" : "a"]',
-    ], 'E1166:', 2)
-  v9.CheckDefExecFailure([
-    'unlet g:adict[0 : 1]',
-    ], 'E1148:', 1)
-  v9.CheckDefFailure([
-    'var ll = [1, 2]',
-    'unlet ll[0:1]',
-    ], 'E1004:', 2)
-  v9.CheckDefFailure([
-    'var ll = [1, 2]',
-    'unlet ll[0 :1]',
-    ], 'E1004:', 2)
-  v9.CheckDefFailure([
-    'var ll = [1, 2]',
-    'unlet ll[0: 1]',
-    ], 'E1004:', 2)
-
-  v9.CheckDefExecFailure([
-    'g:ll = [1, 2]',
-    'g:idx = "x"',
-    'unlet g:ll[g:idx]',
-    ], 'E1029: Expected number but got string', 3)
-
-  v9.CheckDefExecFailure([
-    'g:ll = [1, 2, 3]',
-    'g:idx = "x"',
-    'unlet g:ll[g:idx : 2]',
-    ], 'E1029: Expected number but got string', 3)
-
-  v9.CheckDefExecFailure([
-    'g:ll = [1, 2, 3]',
-    'g:idx = "x"',
-    'unlet g:ll[0 : g:idx]',
-    ], 'E1029: Expected number but got string', 3)
-
-  # command recognized as assignment when skipping, should not give an error
-  v9.CheckScriptSuccess([
-    'vim9script',
-    'for i in []',
-    "  put =''",
-    'endfor'])
-
-  v9.CheckDefFailure([
-    'var ll = [1, 2]',
-    'unlet ll["x" : 1]',
-    ], 'E1012:', 2)
-  v9.CheckDefFailure([
-    'var ll = [1, 2]',
-    'unlet ll[0 : "x"]',
-    ], 'E1012:', 2)
-
-  # list of dict unlet
-  var dl = [{a: 1, b: 2}, {c: 3}]
-  unlet dl[0]['b']
-  assert_equal([{a: 1}, {c: 3}], dl)
-
-  v9.CheckDefExecFailure([
-    'var ll = test_null_list()',
-    'unlet ll[0]',
-    ], 'E684:', 2)
-  v9.CheckDefExecFailure([
-    'var ll = [1]',
-    'unlet ll[2]',
-    ], 'E684:', 2)
-  v9.CheckDefExecFailure([
-    'var ll = [1]',
-    'unlet ll[g:astring]',
-    ], 'E1012:', 2)
-  v9.CheckDefExecFailure([
-    'var dd = test_null_dict()',
-    'unlet dd["a"]',
-    ], 'E716:', 2)
-  v9.CheckDefExecFailure([
-    'var dd = {a: 1}',
-    'unlet dd["b"]',
-    ], 'E716:', 2)
-  v9.CheckDefExecFailure([
-    'var dd = {a: 1}',
-    'unlet dd[g:alist]',
-    ], 'E1105:', 2)
-
-  v9.CheckDefExecFailure([
-    'g:dd = {"a": 1, 2: 2}',
-    'unlet g:dd[0z11]',
-    ], 'E1029:', 2)
-  v9.CheckDefExecFailure([
-    'g:str = "a string"',
-    'unlet g:str[0]',
-    ], 'E1148: Cannot index a string', 2)
-
-  # can compile unlet before variable exists
-  g:someDict = {key: 'val'}
-  var k = 'key'
-  unlet g:someDict[k]
-  assert_equal({}, g:someDict)
-  unlet g:someDict
-  assert_false(exists('g:someDict'))
-
-  v9.CheckScriptFailure([
-   'vim9script',
-   'var svar = 123',
-   'unlet svar',
-   ], 'E1081:')
-  v9.CheckScriptFailure([
-   'vim9script',
-   'var svar = 123',
-   'unlet s:svar',
-   ], 'E1268:')
-  v9.CheckScriptFailure([
-   'vim9script',
-   'var svar = 123',
-   'def Func()',
-   '  unlet svar',
-   'enddef',
-   'defcompile',
-   ], 'E1081:')
-  v9.CheckScriptFailure([
-   'vim9script',
-   'var svar = 123',
-   'func Func()',
-   '  unlet s:svar',
-   'endfunc',
-   'Func()',
-   ], 'E1081:')
-  v9.CheckScriptFailure([
-   'vim9script',
-   'var svar = 123',
-   'def Func()',
-   '  unlet s:svar',
-   'enddef',
-   'defcompile',
-   ], 'E1081:')
-
-  v9.CheckScriptFailure([
-   'vim9script',
-   'def Delcount(dict: dict<any>)',
-   '  unlet dict.count',
-   'enddef',
-   'Delcount(v:)',
-   ], 'E742:')
-
-  v9.CheckScriptFailure([
-   'vim9script',
-   'def DelChangedtick(dict: dict<any>)',
-   '  unlet dict.changedtick',
-   'enddef',
-   'DelChangedtick(b:)',
-   ], 'E795:')
-
-  writefile(['vim9script', 'export var svar = 1234'], 'XunletExport.vim', 'D')
-  var lines =<< trim END
-    vim9script
-    import './XunletExport.vim' as exp
-    def UnletSvar()
-      unlet exp.svar
-    enddef
-    defcompile
-  END
-  v9.CheckScriptFailure(lines, 'E1260:', 1)
-
-  $ENVVAR = 'foobar'
-  assert_equal('foobar', $ENVVAR)
-  unlet $ENVVAR
-  assert_equal('', $ENVVAR)
-enddef
-
-def Test_expr_error_no_assign()
-  var lines =<< trim END
-      vim9script
-      var x = invalid
-      echo x
-  END
-  v9.CheckScriptFailureList(lines, ['E121:', 'E121:'])
-
-  lines =<< trim END
-      vim9script
-      var x = 1 / 0
-      echo x
-  END
-  v9.CheckScriptFailure(lines, 'E1154:')
-
-  lines =<< trim END
-      vim9script
-      var x = 1 % 0
-      echo x
-  END
-  v9.CheckScriptFailure(lines, 'E1154:')
-
-  lines =<< trim END
-      var x: string  'string'
-  END
-  v9.CheckDefAndScriptFailure(lines, 'E488:')
-enddef
-
-
-def Test_assign_command_modifier()
-  var lines =<< trim END
-      var verbose = 0
-      verbose = 1
-      assert_equal(1, verbose)
-      silent verbose = 2
-      assert_equal(2, verbose)
-      silent verbose += 2
-      assert_equal(4, verbose)
-      silent verbose -= 1
-      assert_equal(3, verbose)
-
-      var topleft = {one: 1}
-      sandbox topleft.one = 3
-      assert_equal({one: 3}, topleft)
-      leftabove topleft[' '] = 4
-      assert_equal({one: 3, ' ': 4}, topleft)
-
-      var x: number
-      var y: number
-      silent [x, y] = [1, 2]
-      assert_equal(1, x)
-      assert_equal(2, y)
-  END
-  v9.CheckDefAndScriptSuccess(lines)
-enddef
-
-def Test_assign_alt_buf_register()
-  var lines =<< trim END
-      edit 'file_b1'
-      var b1 = bufnr()
-      edit 'file_b2'
-      var b2 = bufnr()
-      assert_equal(b1, bufnr('#'))
-      @# = b2
-      assert_equal(b2, bufnr('#'))
-  END
-  v9.CheckDefAndScriptSuccess(lines)
-enddef
-
-def Test_script_funcref_case()
-  var lines =<< trim END
-      var Len = (s: string): number => len(s) + 1
-      assert_equal(5, Len('asdf'))
-  END
-  v9.CheckDefAndScriptSuccess(lines)
-
-  lines =<< trim END
-      var len = (s: string): number => len(s) + 1
-  END
-  v9.CheckDefAndScriptFailure(lines, 'E704:')
-
-  lines =<< trim END
-      vim9script
-      var Len = (s: string): number => len(s) + 2
-      assert_equal(6, Len('asdf'))
-  END
-  v9.CheckScriptSuccess(lines)
-
-  lines =<< trim END
-      vim9script
-      var len = (s: string): number => len(s) + 1
-  END
-  v9.CheckScriptFailure(lines, 'E704:')
-enddef
-
-def Test_script_funcref_runtime_type_check()
-  var lines =<< trim END
-      vim9script
-      def FuncWithNumberArg(n: number)
-      enddef
-      def Test()
-        var Ref: func(string) = function(FuncWithNumberArg)
-      enddef
-      defcompile
-  END
-  # OK at compile time
-  v9.CheckScriptSuccess(lines)
-
-  # Type check fails at runtime
-  v9.CheckScriptFailure(lines + ['Test()'], 'E1012: Type mismatch; expected func(string) but got func(number)')
-enddef
-
-def Test_inc_dec()
-  var lines =<< trim END
-      var nr = 7
-      ++nr
-      assert_equal(8, nr)
-      --nr
-      assert_equal(7, nr)
-      ++nr | ++nr
-      assert_equal(9, nr)
-      ++nr # comment
-      assert_equal(10, nr)
-
-      var ll = [1, 2]
-      --ll[0]
-      ++ll[1]
-      assert_equal([0, 3], ll)
-
-      g:count = 1
-      ++g:count
-      --g:count
-      assert_equal(1, g:count)
-      unlet g:count
-  END
-  v9.CheckDefAndScriptSuccess(lines)
-
-  lines =<< trim END
-      var nr = 7
-      ++ nr
-  END
-  v9.CheckDefAndScriptFailure(lines, "E1202: No white space allowed after '++': ++ nr")
-enddef
-
-def Test_abort_after_error()
-  # should abort after strpart() fails, not give another type error
-  var lines =<< trim END
-      vim9script
-      var x: string
-      x = strpart(1, 2)
-  END
-  writefile(lines, 'Xtestscript', 'D')
-  var expected = 'E1174: String required for argument 1'
-  assert_fails('so Xtestscript', [expected, expected], 3)
-enddef
-
-def Test_using_s_var_in_function()
-  var lines =<< trim END
-      vim9script
-      var scriptlevel = 123
-      def SomeFunc()
-        echo s:scriptlevel
-      enddef
-      SomeFunc()
-  END
-  v9.CheckScriptFailure(lines, 'E1268:')
-
-  # OK in legacy script
-  lines =<< trim END
-      let s:scriptlevel = 123
-      def s:SomeFunc()
-        echo s:scriptlevel
-      enddef
-      call s:SomeFunc()
-  END
-  v9.CheckScriptSuccess(lines)
-
-  lines =<< trim END
-      vim9script
-      var scriptlevel = 123
-      def SomeFunc()
-        s:scriptlevel = 456
-      enddef
-      SomeFunc()
-  END
-  v9.CheckScriptFailure(lines, 'E1268:')
-
-  # OK in legacy script
-  lines =<< trim END
-      let s:scriptlevel = 123
-      def s:SomeFunc()
-        s:scriptlevel = 456
-      enddef
-      call s:SomeFunc()
-      call assert_equal(456, s:scriptlevel)
-  END
-  v9.CheckScriptSuccess(lines)
-enddef
-
-let g:someVar = 'X'
-
-" Test for heredoc with Vim expressions.
-" This messes up highlighting, keep it near the end.
-def Test_heredoc_expr()
-  var lines =<< trim CODE
-    var s = "local"
-    var a1 = "1"
-    var a2 = "2"
-    var a3 = "3"
-    var a4 = ""
-    var code =<< trim eval END
-      var a = {5 + 10}
-      var b = {min([10, 6])} + {max([4, 6])}
-      var c = "{s}"
-      var d = x{a1}x{a2}x{a3}x{a4}
-    END
-    assert_equal(['var a = 15', 'var b = 6 + 6', 'var c = "local"', 'var d = x1x2x3x'], code)
-  CODE
-  v9.CheckDefAndScriptSuccess(lines)
-
-  lines =<< trim CODE
-    var code =<< eval trim END
-      var s = "{$SOME_ENV_VAR}"
-    END
-    assert_equal(['var s = "somemore"'], code)
-  CODE
-  v9.CheckDefAndScriptSuccess(lines)
-
-  lines =<< trim CODE
-    var code =<< eval END
-      var s = "{$SOME_ENV_VAR}"
-    END
-    assert_equal(['  var s = "somemore"'], code)
-  CODE
-  v9.CheckDefAndScriptSuccess(lines)
-
-  lines =<< trim CODE
-    var code =<< eval trim END
-      let a = {{abc}}
-      let b = {g:someVar}
-      let c = {{
-    END
-    assert_equal(['let a = {abc}', 'let b = X', 'let c = {'], code)
-  CODE
-  v9.CheckDefAndScriptSuccess(lines)
-
-  lines =<< trim LINES
-      var text =<< eval trim END
-        let b = {
-      END
-  LINES
-  v9.CheckDefAndScriptFailure(lines, "E1279: Missing '}'")
-
-  lines =<< trim LINES
-      var text =<< eval trim END
-        let b = {abc
-      END
-  LINES
-  v9.CheckDefAndScriptFailure(lines, "E1279: Missing '}'")
-
-  lines =<< trim LINES
-      var text =<< eval trim END
-        let b = {}
-      END
-  LINES
-  v9.CheckDefAndScriptFailure(lines, 'E15: Invalid expression: "}"')
-enddef
-
-" vim: ts=8 sw=2 sts=2 expandtab tw=80 fdm=marker
+" Test Vim9 assignments
+
+source check.vim
+import './vim9.vim' as v9
+source term_util.vim
+
+let s:appendToMe = 'xxx'
+let s:addToMe = 111
+let s:newVar = ''
+let g:existing = 'yes'
+let g:inc_counter = 1
+let $SOME_ENV_VAR = 'some'
+let g:alist = [7]
+let g:adict = #{a: 1}
+let g:astring = 'text'
+
+def Test_assignment_bool()
+  var bool1: bool = true
+  assert_equal(v:true, bool1)
+  var bool2: bool = false
+  assert_equal(v:false, bool2)
+
+  var bool3: bool = 0
+  assert_equal(false, bool3)
+  var bool4: bool = 1
+  assert_equal(true, bool4)
+
+  var bool5: bool = 1 && true
+  assert_equal(true, bool5)
+  var bool6: bool = 0 && 1
+  assert_equal(false, bool6)
+  var bool7: bool = 0 || 1 && true
+  assert_equal(true, bool7)
+
+  var lines =<< trim END
+    vim9script
+    def GetFlag(): bool
+      var flag: bool = 1
+      return flag
+    enddef
+    var flag: bool = GetFlag()
+    assert_equal(true, flag)
+    flag = 0
+    assert_equal(false, flag)
+    flag = 1
+    assert_equal(true, flag)
+    flag = 1 || true
+    assert_equal(true, flag)
+    flag = 1 && false
+    assert_equal(false, flag)
+
+    var cp: bool = &cp
+    var fen: bool = &l:fen
+  END
+  v9.CheckScriptSuccess(lines)
+  v9.CheckDefAndScriptFailure(['var x: bool = 2'], 'E1012:')
+  v9.CheckDefAndScriptFailure(['var x: bool = -1'], 'E1012:')
+  v9.CheckDefAndScriptFailure(['var x: bool = [1]'], 'E1012:')
+  v9.CheckDefAndScriptFailure(['var x: bool = {}'], 'E1012:')
+  v9.CheckDefAndScriptFailure(['var x: bool = "x"'], 'E1012:')
+
+  v9.CheckDefAndScriptFailure(['var x: bool = "x"', '', 'eval 0'], 'E1012:', 1)
+enddef
+
+def Test_syntax()
+  var name = 234
+  var other: list<string> = ['asdf']
+enddef
+
+def Test_assignment()
+  v9.CheckDefFailure(['var x:string'], 'E1069:')
+  v9.CheckDefFailure(['var x:string = "x"'], 'E1069:')
+  v9.CheckDefFailure(['var a:string = "x"'], 'E1069:')
+  v9.CheckDefFailure(['var lambda = () => "lambda"'], 'E704:')
+  v9.CheckScriptFailure(['var x = "x"'], 'E1124:')
+
+  # lower case name is OK for a list
+  var lambdaLines =<< trim END
+      var lambdaList: list<func> = [g:Test_syntax]
+      lambdaList[0] = () => "lambda"
+  END
+  v9.CheckDefAndScriptSuccess(lambdaLines)
+
+  var nr: number = 1234
+  v9.CheckDefFailure(['var nr: number = "asdf"'], 'E1012:')
+
+  var a: number = 6 #comment
+  assert_equal(6, a)
+
+  if has('channel')
+    var chan1: channel
+    assert_equal('fail', ch_status(chan1))
+
+    var job1: job
+    assert_equal('fail', job_status(job1))
+
+    # calling job_start() is in test_vim9_fails.vim, it causes leak reports
+  endif
+  var float1: float = 3.4
+  var Funky1: func
+  var Funky2: func = function('len')
+  var Party2: func = funcref('g:Test_syntax')
+
+  g:newvar = 'new'  #comment
+  assert_equal('new', g:newvar)
+
+  assert_equal('yes', g:existing)
+  g:existing = 'no'
+  assert_equal('no', g:existing)
+
+  v:char = 'abc'
+  assert_equal('abc', v:char)
+
+  $ENVVAR = 'foobar'
+  assert_equal('foobar', $ENVVAR)
+  $ENVVAR = ''
+
+  var lines =<< trim END
+    vim9script
+    $ENVVAR = 'barfoo'
+    assert_equal('barfoo', $ENVVAR)
+    $ENVVAR = ''
+  END
+  v9.CheckScriptSuccess(lines)
+
+  appendToMe ..= 'yyy'
+  assert_equal('xxxyyy', appendToMe)
+  addToMe += 222
+  assert_equal(333, addToMe)
+  newVar = 'new'
+  assert_equal('new', newVar)
+
+  set ts=7
+  var ts: number = &ts
+  assert_equal(7, ts)
+  &ts += 1
+  assert_equal(8, &ts)
+  &ts -= 3
+  assert_equal(5, &ts)
+  &ts *= 2
+  assert_equal(10, &ts)
+  &ts /= 3
+  assert_equal(3, &ts)
+  set ts=10
+  &ts %= 4
+  assert_equal(2, &ts)
+
+  assert_fails('&ts /= 0', ['E1154:', 'E1154:'])
+  assert_fails('&ts %= 0', ['E1154:', 'E1154:'])
+  assert_fails('&ts /= []', ['E745:', 'E745:'])
+  assert_fails('&ts %= []', ['E745:', 'E745:'])
+  assert_equal(2, &ts)
+
+  var f100: float = 100.0
+  f100 /= 5
+  assert_equal(20.0, f100)
+
+  var f200: float = 200.0
+  f200 /= 5.0
+  assert_equal(40.0, f200)
+
+  v9.CheckDefFailure(['var nr: number = 200', 'nr /= 5.0'], 'E1012:')
+
+  lines =<< trim END
+    &ts = 6
+    &ts += 3
+    assert_equal(9, &ts)
+
+    &l:ts = 6
+    assert_equal(6, &ts)
+    &l:ts += 2
+    assert_equal(8, &ts)
+
+    &g:ts = 6
+    assert_equal(6, &g:ts)
+    &g:ts += 2
+    assert_equal(8, &g:ts)
+
+    &number = true
+    assert_equal(true, &number)
+    &number = 0
+    assert_equal(false, &number)
+    &number = 1
+    assert_equal(true, &number)
+    &number = false
+    assert_equal(false, &number)
+  END
+  v9.CheckDefAndScriptSuccess(lines)
+
+  v9.CheckDefFailure(['&notex += 3'], 'E113:')
+  v9.CheckDefFailure(['&ts ..= "xxx"'], 'E1019:')
+  v9.CheckDefFailure(['&ts = [7]'], 'E1012:')
+  v9.CheckDefExecFailure(['&ts = g:alist'], 'E1012: Type mismatch; expected number but got list<number>')
+  v9.CheckDefFailure(['&ts = "xx"'], 'E1012:')
+  v9.CheckDefExecFailure(['&ts = g:astring'], 'E1012: Type mismatch; expected number but got string')
+  v9.CheckDefFailure(['&path += 3'], 'E1012:')
+  v9.CheckDefExecFailure(['&bs = "asdf"'], 'E474:')
+  # test freeing ISN_STOREOPT
+  v9.CheckDefFailure(['&ts = 3', 'var asdf'], 'E1022:')
+  &ts = 8
+
+  lines =<< trim END
+    var save_TI = &t_TI
+    &t_TI = ''
+    assert_equal('', &t_TI)
+    &t_TI = 'xxx'
+    assert_equal('xxx', &t_TI)
+    &t_TI = save_TI
+  END
+  v9.CheckDefAndScriptSuccess(lines)
+
+  v9.CheckDefFailure(['&t_TI = 123'], 'E1012:')
+  v9.CheckScriptFailure(['vim9script', '&t_TI = 123'], 'E928:')
+
+  v9.CheckDefFailure(['var s:var = 123'], 'E1101:')
+  v9.CheckDefFailure(['var s:var: number'], 'E1101:')
+
+  v9.CheckDefAndScriptFailure(['var $VAR: number'], ['E1016:', 'E475:'])
+
+  lines =<< trim END
+    vim9script
+    def SomeFunc()
+      s:var = 123
+    enddef
+    defcompile
+  END
+  v9.CheckScriptFailure(lines, 'E1268:')
+
+  g:inc_counter += 1
+  assert_equal(2, g:inc_counter)
+
+  var f: float
+  f += 1
+  assert_equal(1.0, f)
+
+  $SOME_ENV_VAR ..= 'more'
+  assert_equal('somemore', $SOME_ENV_VAR)
+  v9.CheckDefFailure(['$SOME_ENV_VAR += "more"'], 'E1051:')
+  v9.CheckDefFailure(['$SOME_ENV_VAR += 123'], 'E1012:')
+
+  v:errmsg = 'none'
+  v:errmsg ..= 'again'
+  assert_equal('noneagain', v:errmsg)
+  v9.CheckDefFailure(['v:errmsg += "more"'], 'E1051:')
+  v9.CheckDefFailure(['v:errmsg += 123'], 'E1012:')
+
+  var text =<< trim END
+    some text
+  END
+enddef
+
+def Test_float_and_number()
+  var lines =<< trim END
+       var f: float
+       f += 2
+       f -= 1
+       assert_equal(1.0, f)
+       ++f
+       --f
+       assert_equal(1.0, f)
+  END
+  v9.CheckDefAndScriptSuccess(lines)
+enddef
+
+let g:someNumber = 43
+
+def Test_assign_concat()
+  var lines =<< trim END
+    var s = '-'
+    s ..= 99
+    s ..= true
+    s ..= '-'
+    s ..= v:null
+    s ..= g:someNumber
+    assert_equal('-99true-null43', s)
+  END
+  v9.CheckDefAndScriptSuccess(lines)
+
+  lines =<< trim END
+    var s = '-'
+    s ..= [1, 2]
+  END
+  v9.CheckDefAndScriptFailure(lines, ['E1105: Cannot convert list to string', 'E734: Wrong variable type for .='], 2)
+  lines =<< trim END
+    var s = '-'
+    s ..= {a: 2}
+  END
+  v9.CheckDefAndScriptFailure(lines, ['E1105: Cannot convert dict to string', 'E734: Wrong variable type for .='], 2)
+
+  lines =<< trim END
+      var ls: list<string> = []
+      ls[-1] ..= 'foo'
+  END
+  v9.CheckDefExecAndScriptFailure(lines, 'E684: List index out of range: -1', 2)
+enddef
+
+def Test_assign_register()
+  var lines =<< trim END
+    @c = 'areg'
+    @c ..= 'add'
+    assert_equal('aregadd', @c)
+
+    @@ = 'some text'
+    assert_equal('some text', getreg('"'))
+  END
+  v9.CheckDefAndScriptSuccess(lines)
+
+  v9.CheckDefFailure(['@a += "more"'], 'E1051:')
+  v9.CheckDefFailure(['@a += 123'], 'E1012:')
+enddef
+
+def Test_reserved_name()
+  var more_names = ['null_job', 'null_channel']
+  if !has('job')
+    more_names = []
+  endif
+
+  for name in ['true',
+               'false',
+               'this',
+               'super',
+               'null',
+               'null_blob',
+               'null_dict',
+               'null_function',
+               'null_list',
+               'null_partial',
+               'null_string',
+               ] + more_names
+    v9.CheckDefExecAndScriptFailure(['var ' .. name .. ' =  0'], 'E1034:')
+    v9.CheckDefExecAndScriptFailure(['var ' .. name .. ': bool'], 'E1034:')
+  endfor
+
+  var lines =<< trim END
+      vim9script
+      def Foo(super: bool)
+	echo 'something'
+      enddef
+      defcompile
+  END
+  v9.CheckScriptFailure(lines, 'E1034:')
+enddef
+
+def Test_null_values()
+  var lines =<< trim END
+      var b: blob = null_blob
+      var dn: dict<number> = null_dict
+      var ds: dict<string> = null_dict
+      var ln: list<number> = null_list
+      var ls: list<string> = null_list
+      var Ff: func(string): string = null_function
+      var Fp: func(number): number = null_partial
+      var s: string = null_string
+      if has('job')
+        var j: job = null_job
+        var c: channel = null_channel
+      endif
+
+      var d: dict<func> = {a: function('tr'), b: null_function}
+
+      var bl: list<blob> = [0z12, null_blob]
+      var dnl: list<dict<number>> = [{a: 1}, null_dict]
+      var dsl: list<dict<string>> = [{a: 'x'}, null_dict]
+      var lnl: list<list<number>> = [[1], null_list]
+      var lsl: list<list<string>> = [['x'], null_list]
+      def Len(v: string): number
+        return len(v)
+      enddef
+      var Ffl: list<func(string): number> = [Len, null_function]
+      var Fpl: list<func(string): number> = [Len, null_partial]
+      var sl: list<string> = ['x', null_string]
+      if has('job')
+        var jl: list<job> = [null_job]
+        var cl: list<channel> = [null_channel]
+      endif
+  END
+  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
+      b = null_blob
+      b = 'text'
+  END
+  v9.CheckDefExecAndScriptFailure(lines, 'E1012: Type mismatch; expected blob but got string')
+
+  lines =<< trim END
+      var l: list<number>
+      l = null_list
+      l = ['text']
+  END
+  v9.CheckDefExecAndScriptFailure(lines, 'E1012: Type mismatch; expected list<number> but got list<string>')
+
+  lines =<< trim END
+      var d: dict<string>
+      d = null_dict
+      d = {a: 1, b: 2}
+  END
+  v9.CheckDefExecAndScriptFailure(lines, 'E1012: Type mismatch; expected dict<string> but got dict<number>')
+enddef
+
+def Test_skipped_assignment()
+  var lines =<< trim END
+      for x in []
+        var i: number = 1
+        while false
+          i += 1
+        endwhile
+      endfor
+  END
+  v9.CheckDefAndScriptSuccess(lines)
+enddef
+
+def Test_assign_keep_type()
+  var lines =<< trim END
+      vim9script
+      var l: list<number> = [123]
+      l = [123]
+      l->add('string')
+  END
+  v9.CheckScriptFailure(lines, 'E1012:', 4)
+enddef
+
+def Test_assign_unpack()
+  var lines =<< trim END
+    var v1: number
+    var v2: number
+    [v1, v2] = [1, 2]
+    assert_equal(1, v1)
+    assert_equal(2, v2)
+
+    [v1, _, v2, _] = [1, 99, 2, 77]
+    assert_equal(1, v1)
+    assert_equal(2, v2)
+
+    [v1, v2; _] = [1, 2, 3, 4, 5]
+    assert_equal(1, v1)
+    assert_equal(2, v2)
+
+    var _x: number
+    [_x, v2] = [6, 7]
+    assert_equal(6, _x)
+    assert_equal(7, v2)
+
+    var reslist = []
+    for text in ['aaa {bbb} ccc', 'ddd {eee} fff']
+      var before: string
+      var middle: string
+      var after: string
+      [_, before, middle, after; _] = text->matchlist('\(.\{-\}\){\(.\{-\}\)}\(.*\)')
+      reslist->add(before)->add(middle)->add(after)
+    endfor
+    assert_equal(['aaa ', 'bbb', ' ccc', 'ddd ', 'eee', ' fff'], reslist)
+
+    var a = 1
+    var b = 3
+    [a, b] += [2, 4]
+    assert_equal(3, a)
+    assert_equal(7, b)
+
+    [a, b] -= [1, 2]
+    assert_equal(2, a)
+    assert_equal(5, b)
+
+    [a, b] *= [3, 2]
+    assert_equal(6, a)
+    assert_equal(10, b)
+
+    [a, b] /= [2, 4]
+    assert_equal(3, a)
+    assert_equal(2, b)
+
+    [a, b] = [17, 15]
+    [a, b] %= [5, 3]
+    assert_equal(2, a)
+    assert_equal(0, b)
+  END
+  v9.CheckDefAndScriptSuccess(lines)
+
+  lines =<< trim END
+      var v1: number
+      var v2: number
+      [v1, v2] = [1, 2, 3]
+  END
+  v9.CheckDefFailure(lines, 'E1093: Expected 2 items but got 3', 3)
+
+  lines =<< trim END
+      var v1: number
+      var v2: number
+      [v1, v2] = [1]
+  END
+  v9.CheckDefFailure(lines, 'E1093: Expected 2 items but got 1', 3)
+
+  lines =<< trim END
+      var v1: number
+      var v2: number
+      [v1, v2; _] = [1]
+  END
+  v9.CheckDefFailure(lines, 'E1093: Expected 2 items but got 1', 3)
+
+  lines =<< trim END
+      var v1: number
+      var v2: number
+      [v1, v2] = 
+  END
+  v9.CheckDefFailure(lines, 'E1097:', 5)
+
+  lines =<< trim END
+      var v1: number
+      var v2: number
+      [v1, v2] = xxx
+  END
+  v9.CheckDefFailure(lines, 'E1001:', 3)
+
+  lines =<< trim END
+      var v1: number
+      var v2: number
+      [v1, v2] = popup_clear()
+  END
+  v9.CheckDefFailure(lines, 'E1031:', 3)
+
+  lines =<< trim END
+      [v1, v2] = [1, 2]
+  END
+  v9.CheckDefFailure(lines, 'E1089', 1)
+  v9.CheckScriptFailure(['vim9script'] + lines, 'E1089', 2)
+
+  lines =<< trim END
+      var v1: number
+      var v2: number
+      [v1, v2] = ''
+  END
+  v9.CheckDefFailure(lines, 'E1012: Type mismatch; expected list<any> but got string', 3)
+
+  lines =<< trim END
+    g:values = [false, 0]
+    var x: bool
+    var y: string
+    [x, y] = g:values
+  END
+  v9.CheckDefExecAndScriptFailure(lines, 'E1163: Variable 2: type mismatch, expected string but got number')
+
+  lines =<< trim END
+    var x: number
+    var y: number
+    var z: string
+    [x, y, z] = [1, 2, 3]
+  END
+  v9.CheckDefAndScriptFailure(lines, 'E1163: Variable 3: type mismatch, expected string but got number')
+
+  lines =<< trim END
+    var x: number
+    var y: string
+    var z: string
+    [x, y, z] = [1, '2', 3]
+  END
+  v9.CheckDefExecAndScriptFailure(lines, 'E1163: Variable 3: type mismatch, expected string but got number')
+enddef
+
+def Test_assign_linebreak()
+  var nr: number
+  nr =
+      123
+  assert_equal(123, nr)
+
+  var n2: number
+  [nr, n2] =
+     [12, 34]
+  assert_equal(12, nr)
+  assert_equal(34, n2)
+
+  v9.CheckDefFailure(["var x = #"], 'E1097:', 3)
+
+  var lines =<< trim END
+      var x: list<string> = ['a']
+      var y: list<number> = x
+          ->copy()
+          ->copy()
+  END
+  v9.CheckDefExecFailure(lines, 'E1012:', 4)
+
+  lines =<< trim END
+      var x: any
+      x.key = 1
+          + 2
+          + 3
+          + 4
+          + 5
+  END
+  v9.CheckDefExecAndScriptFailure(lines, ['E1148:', 'E1203:'], 2)
+enddef
+
+def Test_assign_index()
+  # list of list
+  var l1: list<number>
+  l1[0] = 123
+  assert_equal([123], l1)
+
+  var l2: list<list<number>>
+  l2[0] = []
+  l2[0][0] = 123
+  assert_equal([[123]], l2)
+
+  var l3: list<list<list<number>>>
+  l3[0] = []
+  l3[0][0] = []
+  l3[0][0][0] = 123
+  assert_equal([[[123]]], l3)
+
+  var lines =<< trim END
+      var l3: list<list<number>>
+      l3[0] = []
+      l3[0][0] = []
+  END
+  v9.CheckDefFailure(lines, 'E1012: Type mismatch; expected number but got list<unknown>', 3)
+
+  # dict of dict
+  var d1: dict<number>
+  d1.one = 1
+  assert_equal({one: 1}, d1)
+
+  var d2: dict<dict<number>>
+  d2.one = {}
+  d2.one.two = 123
+  assert_equal({one: {two: 123}}, d2)
+
+  var d3: dict<dict<dict<number>>>
+  d3.one = {}
+  d3.one.two = {}
+  d3.one.two.three = 123
+  assert_equal({one: {two: {three: 123}}}, d3)
+
+  # blob
+  var bl: blob = 0z11223344
+  bl[0] = 0x77
+  assert_equal(0z77223344, bl)
+  bl[-2] = 0x66
+  assert_equal(0z77226644, bl)
+
+  lines =<< trim END
+      g:val = '22'
+      var bl = 0z11
+      bl[1] = g:val
+  END
+  v9.CheckDefExecAndScriptFailure(lines, 'E1030: Using a String as a Number: "22"')
+
+  # should not read the next line when generating "a.b"
+  var a = {}
+  a.b = {}
+  a.b.c = {}
+          ->copy()
+
+  lines =<< trim END
+      var d3: dict<dict<number>>
+      d3.one = {}
+      d3.one.two = {}
+  END
+  v9.CheckDefFailure(lines, 'E1012: Type mismatch; expected number but got dict<unknown>', 3)
+
+  lines =<< trim END
+    var lines: list<string>
+    lines['a'] = 'asdf'
+  END
+  v9.CheckDefFailure(lines, 'E1012:', 2)
+
+  lines =<< trim END
+    var lines: string
+    lines[9] = 'asdf'
+  END
+  v9.CheckDefFailure(lines, 'E1141:', 2)
+
+  # list of dict
+  var ld: list<dict<number>>
+  ld[0] = {}
+  ld[0].one = 123
+  assert_equal([{one: 123}], ld)
+
+  lines =<< trim END
+      var ld: list<dict<number>>
+      ld[0] = []
+  END
+  v9.CheckDefFailure(lines, 'E1012: Type mismatch; expected dict<number> but got list<unknown>', 2)
+
+  # dict of list
+  var dl: dict<list<number>>
+  dl.one = []
+  dl.one[0] = 123
+  assert_equal({one: [123]}, dl)
+
+  lines =<< trim END
+      var dl: dict<list<number>>
+      dl.one = {}
+  END
+  v9.CheckDefFailure(lines, 'E1012: Type mismatch; expected list<number> but got dict<unknown>', 2)
+
+  lines =<< trim END
+      g:l = [1, 2]
+      g:l['x'] = 3
+  END
+  v9.CheckDefExecAndScriptFailure(lines, ['E39:', 'E1030:'], 2)
+
+  lines =<< trim END
+    var bl: blob = test_null_blob()
+    bl[1] = 8
+  END
+  v9.CheckDefExecAndScriptFailure(lines, ['E1184:', 'E979:'], 2)
+
+  lines =<< trim END
+    g:bl = 'not a blob'
+    g:bl[1 : 2] = 8
+  END
+  v9.CheckDefExecAndScriptFailure(lines, ['E897:', 'E689:'], 2)
+enddef
+
+def Test_init_in_for_loop()
+  var lines =<< trim END
+      var l: list<number> = []
+      for i in [3, 4]
+        var n: number
+        add(l, n)
+        n = 123
+      endfor
+      assert_equal([0, 0], l)
+  END
+  v9.CheckDefAndScriptSuccess(lines)
+
+  lines =<< trim END
+      var l: list<number> = []
+      for i in [3, 4]
+        var n: number = 0
+        add(l, n)
+        n = 123
+      endfor
+      assert_equal([0, 0], l)
+  END
+  v9.CheckDefAndScriptSuccess(lines)
+
+  lines =<< trim END
+      var l: list<number> = []
+      for i in [3, 4]
+        var n: number = 3
+        add(l, n)
+        n = 123
+      endfor
+      assert_equal([3, 3], l)
+  END
+  v9.CheckDefAndScriptSuccess(lines)
+enddef
+
+def Test_redir_is_not_assign()
+  if false
+    redir => res
+    echo var_job
+    redir END
+  endif
+enddef
+
+def Test_extend_list()
+  # using uninitialized list assigns empty list
+  var lines =<< trim END
+      var l1: list<number>
+      var l2 = l1
+      assert_true(l1 is l2)
+      l1 += [123]
+      assert_equal([123], l1)
+      assert_true(l1 is l2)
+  END
+  v9.CheckDefAndScriptSuccess(lines)
+
+  lines =<< trim END
+      var list: list<string>
+      extend(list, ['x'])
+      assert_equal(['x'], list)
+  END
+  v9.CheckDefAndScriptSuccess(lines)
+
+  # appending to uninitialized list from a function works
+  lines =<< trim END
+      vim9script
+      var list: list<string>
+      def Func()
+        list += ['a', 'b']
+      enddef
+      Func()
+      assert_equal(['a', 'b'], list)
+  END
+  v9.CheckScriptSuccess(lines)
+  lines =<< trim END
+      vim9script
+      var list: list<string>
+      def Func()
+        extend(list, ['x', 'b'])
+      enddef
+      Func()
+      assert_equal(['x', 'b'], list)
+  END
+  v9.CheckScriptSuccess(lines)
+
+  # initialized to null, with type, does not default to empty list
+  lines =<< trim END
+      vim9script
+      var l: list<string> = test_null_list()
+      extend(l, ['x'])
+  END
+  v9.CheckScriptFailure(lines, 'E1134:', 3)
+
+  # initialized to null, without type, does not default to empty list
+  lines =<< trim END
+      vim9script
+      var l = null_list
+      extend(l, ['x'])
+  END
+  v9.CheckScriptFailure(lines, 'E1134:', 3)
+
+  # assigned null, does not default to empty list
+  lines =<< trim END
+      vim9script
+      var l: list<string>
+      l = null_list
+      extend(l, ['x'])
+  END
+  v9.CheckScriptFailure(lines, 'E1134:', 4)
+
+  lines =<< trim END
+      vim9script
+      extend(test_null_list(), ['x'])
+  END
+  v9.CheckScriptFailure(lines, 'E1134:', 2)
+
+  # using global var has no declared type
+  g:myList = []
+  g:myList->extend([1])
+  g:myList->extend(['x'])
+  assert_equal([1, 'x'], g:myList)
+  unlet g:myList
+
+  # using declared list gives an error
+  lines =<< trim END
+      var l: list<number>
+      g:myList = l
+      g:myList->extend([1])
+      g:myList->extend(['x'])
+  END
+  v9.CheckDefExecAndScriptFailure(lines, 'E1013: Argument 2: type mismatch, expected list<number> but got list<string>', 4)
+  unlet g:myList
+
+  lines =<< trim END
+      vim9script
+      var lds = [1, 2, 3]
+      def Func()
+          echo lds->extend(['x'])
+      enddef
+      defcompile
+  END
+  v9.CheckScriptFailure(lines, 'E1013:')
+enddef
+
+def Test_extend_dict()
+  var lines =<< trim END
+      vim9script
+      var d: dict<number>
+      extend(d, {a: 1})
+      assert_equal({a: 1}, d)
+
+      var d2: dict<number>
+      d2['one'] = 1
+      assert_equal({one: 1}, d2)
+  END
+  v9.CheckScriptSuccess(lines)
+
+  lines =<< trim END
+      vim9script
+      var d: dict<string> = test_null_dict()
+      extend(d, {a: 'x'})
+  END
+  v9.CheckScriptFailure(lines, 'E1133:', 3)
+
+  lines =<< trim END
+      vim9script
+      extend(test_null_dict(), {a: 'x'})
+  END
+  v9.CheckScriptFailure(lines, 'E1133:', 2)
+enddef
+
+def Test_single_letter_vars()
+  # single letter variables
+  var a: number = 123
+  a = 123
+  assert_equal(123, a)
+  var b: number
+  b = 123
+  assert_equal(123, b)
+  var g: number
+  g = 123
+  assert_equal(123, g)
+  var s: number
+  s = 123
+  assert_equal(123, s)
+  var t: number
+  t = 123
+  assert_equal(123, t)
+  var v: number
+  v = 123
+  assert_equal(123, v)
+  var w: number
+  w = 123
+  assert_equal(123, w)
+enddef
+
+def Test_vim9_single_char_vars()
+  var lines =<< trim END
+      vim9script
+
+      # single character variable declarations work
+      var a: string
+      var b: number
+      var l: list<any>
+      var s: string
+      var t: number
+      var v: number
+      var w: number
+
+      # script-local variables can be used without s: prefix
+      a = 'script-a'
+      b = 111
+      l = [1, 2, 3]
+      s = 'script-s'
+      t = 222
+      v = 333
+      w = 444
+
+      assert_equal('script-a', a)
+      assert_equal(111, b)
+      assert_equal([1, 2, 3], l)
+      assert_equal('script-s', s)
+      assert_equal(222, t)
+      assert_equal(333, v)
+      assert_equal(444, w)
+  END
+  writefile(lines, 'Xsinglechar', 'D')
+  source Xsinglechar
+enddef
+
+def Test_assignment_list()
+  var list1: list<bool> = [false, true, false]
+  var list2: list<number> = [1, 2, 3]
+  var list3: list<string> = ['sdf', 'asdf']
+  var list4: list<any> = ['yes', true, 1234]
+  var list5: list<blob> = [0z01, 0z02]
+
+  var listS: list<string> = []
+  var listN: list<number> = []
+
+  assert_equal([1, 2, 3], list2)
+  list2[-1] = 99
+  assert_equal([1, 2, 99], list2)
+  list2[-2] = 88
+  assert_equal([1, 88, 99], list2)
+  list2[-3] = 77
+  assert_equal([77, 88, 99], list2)
+  list2 += [100]
+  assert_equal([77, 88, 99, 100], list2)
+
+  list3 += ['end']
+  assert_equal(['sdf', 'asdf', 'end'], list3)
+
+  v9.CheckDefExecFailure(['var ll = [1, 2, 3]', 'll[-4] = 6'], 'E684:')
+  v9.CheckDefExecFailure(['var ll = [1, 2, 3]', 'unlet ll[8 : 9]'], 'E684:')
+  v9.CheckDefExecFailure(['var ll = [1, 2, 3]', 'unlet ll[1 : -9]'], 'E684:')
+  v9.CheckDefExecFailure(['var ll = [1, 2, 3]', 'unlet ll[2 : 1]'], 'E684:')
+
+  # type becomes list<any>
+  var somelist = rand() > 0 ? [1, 2, 3] : ['a', 'b', 'c']
+
+  # type is list<any> even though initializer is list<number>
+  var anyList: list<any> = [0]
+  assert_equal([0, 'x'], extend(anyList, ['x']))
+
+  var lines =<< trim END
+    var d = {dd: test_null_list()}
+    d.dd[0] = 0
+  END
+  v9.CheckDefExecFailure(lines, 'E1147:', 2)
+
+  lines =<< trim END
+      def OneArg(x: bool)
+      enddef
+      def TwoArgs(x: bool, y: bool)
+      enddef
+      var fl: list<func(bool, bool, bool)> = [OneArg, TwoArgs]
+  END
+  v9.CheckDefExecAndScriptFailure(lines, 'E1012:', 5)
+enddef
+
+def Test_list_declaration()
+  var [v1, v2] = [1, 2]
+  v1 += 3
+  assert_equal(4, v1)
+  v2 *= 3
+  assert_equal(6, v2)
+
+  var lines =<< trim END
+      var [v1, v2] = [1]
+  END
+  v9.CheckDefExecAndScriptFailure(lines, ['E1093: Expected 2 items but got 1', 'E688:'])
+  lines =<< trim END
+      var testlist = [1]
+      var [v1, v2] = testlist
+  END
+  v9.CheckDefExecAndScriptFailure(lines, ['E1093: Expected 2 items but got 1', 'E688:'])
+  lines =<< trim END
+      var [v1, v2] = [1, 2, 3]
+  END
+  v9.CheckDefExecAndScriptFailure(lines, ['E1093: Expected 2 items but got 3', 'E687:'])
+  lines =<< trim END
+      var testlist = [1, 2, 3]
+      var [v1, v2] = testlist
+  END
+  v9.CheckDefExecAndScriptFailure(lines, ['E1093: Expected 2 items but got 3', 'E687:'])
+
+  var [vnr, vstr] = [123, 'text']
+  vnr += 3
+  assert_equal(126, vnr)
+  vstr ..= 'end'
+  assert_equal('textend', vstr)
+
+  var [vnr2: number, vstr2: string] = [123, 'text']
+  vnr2 += 3
+  assert_equal(126, vnr2)
+  vstr2 ..= 'end'
+  assert_equal('textend', vstr2)
+
+  var [vnr3: number; vlist: list<string>] = [123, 'foo', 'bar']
+  vnr3 += 5
+  assert_equal(128, vnr3)
+  assert_equal(['foo', 'bar'], vlist)
+
+  lines =<< trim END
+      var [vnr2: number, vstr2: number] = [123, 'text']
+  END
+  v9.CheckDefExecAndScriptFailure(lines, ['E1163: Variable 2: type mismatch, expected number but got string', 'E1012: Type mismatch; expected number but got string'])
+  lines =<< trim END
+      var testlist = [234, 'text']
+      var [vnr2: number, vstr2: number] = testlist
+  END
+  v9.CheckDefExecAndScriptFailure(lines, ['E1163: Variable 2: type mismatch, expected number but got string', 'E1012: Type mismatch; expected number but got string'])
+enddef
+
+def PartFuncBool(b: bool): string
+  return 'done'
+enddef
+
+def Test_assignment_partial()
+  var lines =<< trim END
+      var Partial: func(): string = function(g:PartFuncBool, [true])
+      assert_equal('done', Partial())
+  END
+  v9.CheckDefAndScriptSuccess(lines)
+
+  lines =<< trim END
+      vim9script
+      def Func(b: bool)
+      enddef
+      var Ref: func = function(Func, [true])
+      assert_equal('func()', typename(Ref))
+      Ref()
+  END
+  v9.CheckScriptSuccess(lines)
+
+  lines =<< trim END
+      vim9script
+
+      var nres: any
+      var sres: any
+      def Func(nr: number, s = '')
+        nres = nr
+        sres = s
+      enddef
+
+      var n: number
+      var Ref = function(Func, [n])
+      Ref('x')
+      assert_equal(0, nres)
+      assert_equal('x', sres)
+  END
+  v9.CheckScriptSuccess(lines)
+
+  lines =<< trim END
+      vim9script
+
+      def Func(nr: number, s = '')
+      enddef
+
+      var n: number
+      var Ref = function(Func, [n])
+      Ref(0)
+  END
+  v9.CheckScriptFailure(lines, 'E1013: Argument 2: type mismatch, expected string but got number')
+enddef
+
+def Test_assignment_list_any_index()
+   var l: list<number> = [1, 2]
+  for  [x, y, _]
+  in  [[0, 1, ''], [1, 3, '']]
+      l[x] = l[x] + y
+  endfor
+  assert_equal([2, 5], l)
+enddef
+
+def Test_assignment_list_vim9script()
+  var lines =<< trim END
+    vim9script
+    var v1: number
+    var v2: number
+    var v3: number
+    [v1, v2, v3] = [1, 2, 3]
+    assert_equal([1, 2, 3], [v1, v2, v3])
+  END
+  v9.CheckScriptSuccess(lines)
+enddef
+
+def Test_assignment_dict()
+  var dict1: dict<bool> = {one: false, two: true}
+  var dict2: dict<number> = {one: 1, two: 2}
+  var dict3: dict<string> = {key: 'value'}
+  var dict4: dict<any> = {one: 1, two: '2'}
+  var dict5: dict<blob> = {one: 0z01, two: 0z02}
+
+  # check the type is OK
+  var events: dict<string> = v:event
+
+  # overwrite
+  dict3['key'] = 'another'
+  assert_equal(dict3, {key: 'another'})
+  dict3.key = 'yet another'
+  assert_equal(dict3, {key: 'yet another'})
+
+  # member "any" can also be a dict and assigned to
+  var anydict: dict<any> = {nest: {}, nr: 0}
+  anydict.nest['this'] = 123
+  anydict.nest.that = 456
+  assert_equal({nest: {this: 123, that: 456}, nr: 0}, anydict)
+
+  var lines =<< trim END
+    var dd = {}
+    dd.two = 2
+    assert_equal({two: 2}, dd)
+  END
+  v9.CheckDefAndScriptSuccess(lines)
+
+  lines =<< trim END
+    var d = {dd: {}}
+    d.dd[0] = 2
+    d.dd['x'] = 3
+    d.dd.y = 4
+    assert_equal({dd: {0: 2, x: 3, y: 4}}, d)
+  END
+  v9.CheckDefAndScriptSuccess(lines)
+
+  lines =<< trim END
+    var key = 'foo'
+    g:[key] = 'value'
+    assert_equal('value', g:foo)
+    unlet g:foo
+  END
+  v9.CheckDefAndScriptSuccess(lines)
+
+  lines =<< trim END
+    var dd = {one: 1}
+    dd.one) = 2
+  END
+  v9.CheckDefFailure(lines, 'E488:', 2)
+
+  lines =<< trim END
+    var dd = {one: 1}
+    var dd.one = 2
+  END
+  v9.CheckDefAndScriptFailure(lines, 'E1017:', 2)
+
+  # empty key can be used
+  var dd = {}
+  dd[""] = 6
+  assert_equal({['']: 6}, dd)
+
+  # type becomes dict<any>
+  var somedict = rand() > 0 ? {a: 1, b: 2} : {a: 'a', b: 'b'}
+
+  # type is dict<any> even though initializer is dict<number>
+  var anyDict: dict<any> = {a: 0}
+  assert_equal({a: 0, b: 'x'}, extend(anyDict, {b: 'x'}))
+
+  # using global var, which has no declared type
+  g:myDict = {}
+  g:myDict->extend({a: 1})
+  g:myDict->extend({b: 'x'})
+  assert_equal({a: 1, b: 'x'}, g:myDict)
+  unlet g:myDict
+
+  # using list with declared type gives an error
+  lines =<< trim END
+      var d: dict<number>
+      g:myDict = d
+      g:myDict->extend({a: 1})
+      g:myDict->extend({b: 'x'})
+  END
+  v9.CheckDefExecAndScriptFailure(lines, 'E1013: Argument 2: type mismatch, expected dict<number> but got dict<string>', 4)
+  unlet g:myDict
+
+  # assignment to script-local dict
+  lines =<< trim END
+    vim9script
+    var test: dict<any> = {}
+    def FillDict(): dict<any>
+      test['a'] = 43
+      return test
+    enddef
+    assert_equal({a: 43}, FillDict())
+  END
+  v9.CheckScriptSuccess(lines)
+
+  lines =<< trim END
+    vim9script
+    var test: dict<any>
+    def FillDict(): dict<any>
+      test['a'] = 43
+      return test
+    enddef
+    FillDict()
+    assert_equal({a: 43}, test)
+  END
+  v9.CheckScriptSuccess(lines)
+
+  # assignment to global dict
+  lines =<< trim END
+    vim9script
+    g:test = {}
+    def FillDict(): dict<any>
+      g:test['a'] = 43
+      return g:test
+    enddef
+    assert_equal({a: 43}, FillDict())
+  END
+  v9.CheckScriptSuccess(lines)
+
+  # assignment to buffer dict
+  lines =<< trim END
+    vim9script
+    b:test = {}
+    def FillDict(): dict<any>
+      b:test['a'] = 43
+      return b:test
+    enddef
+    assert_equal({a: 43}, FillDict())
+  END
+  v9.CheckScriptSuccess(lines)
+
+  lines =<< trim END
+    var d = {dd: test_null_dict()}
+    d.dd[0] = 0
+  END
+  v9.CheckDefExecFailure(lines, 'E1103:', 2)
+
+  lines =<< trim END
+    var d = {dd: 'string'}
+    d.dd[0] = 0
+  END
+  v9.CheckDefExecFailure(lines, 'E1148:', 2)
+
+  lines =<< trim END
+    var n: any
+    n.key = 5
+  END
+  v9.CheckDefExecAndScriptFailure(lines, ['E1148:', 'E1203: Dot can only be used on a dictionary: n.key = 5'], 2)
+enddef
+
+def Test_assignment_local()
+  # Test in a separated file in order not to the current buffer/window/tab is
+  # changed.
+  var script_lines: list<string> =<< trim END
+    let b:existing = 'yes'
+    let w:existing = 'yes'
+    let t:existing = 'yes'
+
+    def Test_assignment_local_internal()
+      b:newvar = 'new'
+      assert_equal('new', b:newvar)
+      assert_equal('yes', b:existing)
+      b:existing = 'no'
+      assert_equal('no', b:existing)
+      b:existing ..= 'NO'
+      assert_equal('noNO', b:existing)
+
+      w:newvar = 'new'
+      assert_equal('new', w:newvar)
+      assert_equal('yes', w:existing)
+      w:existing = 'no'
+      assert_equal('no', w:existing)
+      w:existing ..= 'NO'
+      assert_equal('noNO', w:existing)
+
+      t:newvar = 'new'
+      assert_equal('new', t:newvar)
+      assert_equal('yes', t:existing)
+      t:existing = 'no'
+      assert_equal('no', t:existing)
+      t:existing ..= 'NO'
+      assert_equal('noNO', t:existing)
+    enddef
+    call Test_assignment_local_internal()
+  END
+  v9.CheckScriptSuccess(script_lines)
+enddef
+
+def Test_assignment_default()
+  # Test default values.
+  var thebool: bool
+  assert_equal(v:false, thebool)
+
+  var thenumber: number
+  assert_equal(0, thenumber)
+
+  var thefloat: float
+  assert_equal(0.0, thefloat)
+
+  var thestring: string
+  assert_equal('', thestring)
+
+  var theblob: blob
+  assert_equal(0z, theblob)
+
+  var Thefunc: func
+  assert_equal(test_null_function(), Thefunc)
+
+  var thelist: list<any>
+  assert_equal([], thelist)
+
+  var thedict: dict<any>
+  assert_equal({}, thedict)
+
+  if has('channel')
+    var thejob: job
+    assert_equal(test_null_job(), thejob)
+
+    var thechannel: channel
+    assert_equal(test_null_channel(), thechannel)
+
+    if has('unix') && executable('cat')
+      # check with non-null job and channel, types must match
+      thejob = job_start("cat ", {})
+      thechannel = job_getchannel(thejob)
+      job_stop(thejob, 'kill')
+    endif
+  endif
+
+  var nr = 1234 | nr = 5678
+  assert_equal(5678, nr)
+enddef
+
+def Test_script_var_default()
+  var lines =<< trim END
+      vim9script
+      var l: list<number>
+      var li = [1, 2]
+      var bl: blob
+      var bli = 0z12
+      var d: dict<number>
+      var di = {'a': 1, 'b': 2}
+      def Echo()
+        assert_equal([], l)
+        assert_equal([1, 2], li)
+        assert_equal(0z, bl)
+        assert_equal(0z12, bli)
+        assert_equal({}, d)
+        assert_equal({'a': 1, 'b': 2}, di)
+      enddef
+      Echo()
+  END
+  v9.CheckScriptSuccess(lines)
+enddef
+
+let s:scriptvar = 'init'
+
+def Test_assignment_var_list()
+  var lines =<< trim END
+      var v1: string
+      var v2: string
+      var vrem: list<string>
+      [v1] = ['aaa']
+      assert_equal('aaa', v1)
+
+      [v1, v2] = ['one', 'two']
+      assert_equal('one', v1)
+      assert_equal('two', v2)
+
+      [v1, v2; vrem] = ['one', 'two']
+      assert_equal('one', v1)
+      assert_equal('two', v2)
+      assert_equal([], vrem)
+
+      [v1, v2; vrem] = ['one', 'two', 'three']
+      assert_equal('one', v1)
+      assert_equal('two', v2)
+      assert_equal(['three'], vrem)
+
+      [&ts, &sw] = [3, 4]
+      assert_equal(3, &ts)
+      assert_equal(4, &sw)
+      set ts=8 sw=4
+
+      [@a, @z] = ['aa', 'zz']
+      assert_equal('aa', @a)
+      assert_equal('zz', @z)
+
+      [$SOME_VAR, $OTHER_VAR] = ['some', 'other']
+      assert_equal('some', $SOME_VAR)
+      assert_equal('other', $OTHER_VAR)
+
+      [g:globalvar, b:bufvar, w:winvar, t:tabvar, v:errmsg] =
+            ['global', 'buf', 'win', 'tab', 'error']
+      assert_equal('global', g:globalvar)
+      assert_equal('buf', b:bufvar)
+      assert_equal('win', w:winvar)
+      assert_equal('tab', t:tabvar)
+      assert_equal('error', v:errmsg)
+      unlet g:globalvar
+  END
+  v9.CheckDefAndScriptSuccess(lines)
+
+  [g:globalvar, scriptvar, b:bufvar] = ['global', 'script', 'buf']
+  assert_equal('global', g:globalvar)
+  assert_equal('script', scriptvar)
+  assert_equal('buf', b:bufvar)
+
+  lines =<< trim END
+      vim9script
+      var scriptvar = 'init'
+      [g:globalvar, scriptvar, w:winvar] = ['global', 'script', 'win']
+      assert_equal('global', g:globalvar)
+      assert_equal('script', scriptvar)
+      assert_equal('win', w:winvar)
+  END
+  v9.CheckScriptSuccess(lines)
+enddef
+
+def Test_assignment_empty_list()
+  var lines =<< trim END
+      var l2: list<any> = []
+      var l: list<string>
+      l = l2
+  END
+  v9.CheckDefAndScriptSuccess(lines)
+enddef
+
+def Test_assignment_vim9script()
+  var lines =<< trim END
+    vim9script
+    def Func(): list<number>
+      return [1, 2]
+    enddef
+    var name1: number
+    var name2: number
+    [name1, name2] =
+          Func()
+    assert_equal(1, name1)
+    assert_equal(2, name2)
+    var ll =
+          Func()
+    assert_equal([1, 2], ll)
+
+    @/ = 'text'
+    assert_equal('text', @/)
+    @0 = 'zero'
+    assert_equal('zero', @0)
+    @1 = 'one'
+    assert_equal('one', @1)
+    @9 = 'nine'
+    assert_equal('nine', @9)
+    @- = 'minus'
+    assert_equal('minus', @-)
+    if has('clipboard_working')
+      @* = 'star'
+      assert_equal('star', @*)
+      @+ = 'plus'
+      assert_equal('plus', @+)
+    endif
+
+    var a: number = 123
+    assert_equal(123, a)
+    var s: string = 'yes'
+    assert_equal('yes', s)
+    var b: number = 42
+    assert_equal(42, b)
+    var w: number = 43
+    assert_equal(43, w)
+    var t: number = 44
+    assert_equal(44, t)
+
+    var to_var = 0
+    to_var = 3
+    assert_equal(3, to_var)
+  END
+  v9.CheckScriptSuccess(lines)
+
+  lines =<< trim END
+      vim9script
+      var n: number
+      def Func()
+        n = 'string'
+      enddef
+      defcompile
+  END
+  v9.CheckScriptFailure(lines, 'E1012: Type mismatch; expected number but got string')
+enddef
+
+def Mess(): string
+  v:foldstart = 123
+  return 'xxx'
+enddef
+
+def Test_assignment_failure()
+  v9.CheckDefFailure(['var name=234'], 'E1004:')
+  v9.CheckDefFailure(['var name =234'], 'E1004:')
+  v9.CheckDefFailure(['var name= 234'], 'E1004:')
+
+  v9.CheckScriptFailure(['vim9script', 'var name=234'], 'E1004:')
+  v9.CheckScriptFailure(['vim9script', 'var name=234'], "before and after '='")
+  v9.CheckScriptFailure(['vim9script', 'var name =234'], 'E1004:')
+  v9.CheckScriptFailure(['vim9script', 'var name= 234'], 'E1004:')
+  v9.CheckScriptFailure(['vim9script', 'var name = 234', 'name+=234'], 'E1004:')
+  v9.CheckScriptFailure(['vim9script', 'var name = 234', 'name+=234'], "before and after '+='")
+  v9.CheckScriptFailure(['vim9script', 'var name = "x"', 'name..="y"'], 'E1004:')
+  v9.CheckScriptFailure(['vim9script', 'var name = "x"', 'name..="y"'], "before and after '..='")
+
+  v9.CheckDefFailure(['var true = 1'], 'E1034:')
+  v9.CheckDefFailure(['var false = 1'], 'E1034:')
+  v9.CheckDefFailure(['var null = 1'], 'E1034:')
+  v9.CheckDefFailure(['var this = 1'], 'E1034:')
+  v9.CheckDefFailure(['var super = 1'], 'E1034:')
+
+  v9.CheckDefFailure(['[a; b; c] = g:list'], 'E1001:')
+  v9.CheckDefFailure(['var [a; b; c] = g:list'], 'E1080:')
+  v9.CheckDefExecFailure(['var a: number',
+                       '[a] = test_null_list()'], 'E1093:')
+  v9.CheckDefExecFailure(['var a: number',
+                       '[a] = []'], 'E1093:')
+  v9.CheckDefExecFailure(['var x: number',
+                       'var y: number',
+                       '[x, y] = [1]'], 'E1093:')
+  v9.CheckDefExecFailure(['var x: string',
+                       'var y: string',
+                       '[x, y] = ["x"]'], 'E1093:')
+  v9.CheckDefExecFailure(['var x: number',
+                       'var y: number',
+                       'var z: list<number>',
+                       '[x, y; z] = [1]'], 'E1093:')
+
+  v9.CheckDefFailure(['var somevar'], "E1022:")
+  v9.CheckDefFailure(['var &tabstop = 4'], 'E1052:')
+  v9.CheckDefFailure(['&g:option = 5'], 'E113:')
+  v9.CheckScriptFailure(['vim9script', 'var &tabstop = 4'], 'E1052:')
+
+  v9.CheckDefFailure(['var $VAR = 5'], 'E1016: Cannot declare an environment variable:')
+  v9.CheckScriptFailure(['vim9script', 'var $ENV = "xxx"'], 'E1016:')
+
+  if has('dnd')
+    v9.CheckDefFailure(['var @~ = 5'], 'E1066:')
+  else
+    v9.CheckDefFailure(['var @~ = 5'], 'E354:')
+    v9.CheckDefFailure(['@~ = 5'], 'E354:')
+  endif
+  v9.CheckDefFailure(['var @a = 5'], 'E1066:')
+  v9.CheckDefFailure(['var @/ = "x"'], 'E1066:')
+  v9.CheckScriptFailure(['vim9script', 'var @a = "abc"'], 'E1066:')
+
+  v9.CheckDefFailure(['var g:var = 5'], 'E1016: Cannot declare a global variable:')
+  v9.CheckDefFailure(['var w:var = 5'], 'E1016: Cannot declare a window variable:')
+  v9.CheckDefFailure(['var b:var = 5'], 'E1016: Cannot declare a buffer variable:')
+  v9.CheckDefFailure(['var t:var = 5'], 'E1016: Cannot declare a tab variable:')
+
+  v9.CheckDefFailure(['var anr = 4', 'anr ..= "text"'], 'E1019:')
+  v9.CheckDefFailure(['var xnr += 4'], 'E1020:', 1)
+  v9.CheckScriptFailure(['vim9script', 'var xnr += 4'], 'E1020:')
+  v9.CheckDefFailure(["var xnr = xnr + 1"], 'E1001:', 1)
+  v9.CheckScriptFailure(['vim9script', 'var xnr = xnr + 4'], 'E121:')
+
+  v9.CheckScriptFailure(['vim9script', 'def Func()', 'var dummy = notfound', 'enddef', 'defcompile'], 'E1001:')
+
+  v9.CheckDefFailure(['var name: list<string> = [123]'], 'expected list<string> but got list<number>')
+  v9.CheckDefFailure(['var name: list<number> = ["xx"]'], 'expected list<number> but got list<string>')
+
+  v9.CheckDefFailure(['var name: dict<string> = {key: 123}'], 'expected dict<string> but got dict<number>')
+  v9.CheckDefFailure(['var name: dict<number> = {key: "xx"}'], 'expected dict<number> but got dict<string>')
+
+  v9.CheckDefFailure(['var name = feedkeys("0")'], 'E1031:')
+  v9.CheckDefFailure(['var name: number = feedkeys("0")'], 'expected number but got void')
+
+  v9.CheckDefFailure(['var name: dict <number>'], 'E1068:')
+  v9.CheckDefFailure(['var name: dict<number'], 'E1009: Missing > after type: <number')
+
+  assert_fails('s/^/\=g:Mess()/n', 'E794:')
+  v9.CheckDefFailure(['var name: dict<number'], 'E1009:')
+
+  v9.CheckDefFailure(['w:foo: number = 10'],
+                  'E1016: Cannot declare a window variable: w:foo')
+  v9.CheckDefFailure(['t:foo: bool = true'],
+                  'E1016: Cannot declare a tab variable: t:foo')
+  v9.CheckDefFailure(['b:foo: string = "x"'],
+                  'E1016: Cannot declare a buffer variable: b:foo')
+  v9.CheckDefFailure(['g:foo: number = 123'],
+                  'E1016: Cannot declare a global variable: g:foo')
+
+  v9.CheckScriptFailure(['vim9script', 'w:foo: number = 123'],
+                  'E1304: Cannot use type with this variable: w:foo:')
+  v9.CheckScriptFailure(['vim9script', 't:foo: number = 123'],
+                  'E1304: Cannot use type with this variable: t:foo:')
+  v9.CheckScriptFailure(['vim9script', 'b:foo: number = 123'],
+                  'E1304: Cannot use type with this variable: b:foo:')
+  v9.CheckScriptFailure(['vim9script', 'g:foo: number = 123'],
+                  'E1304: Cannot use type with this variable: g:foo:')
+
+  v9.CheckScriptFailure(['vim9script', 'const w:FOO: number = 123'],
+                  'E1304: Cannot use type with this variable: w:FOO:')
+  v9.CheckScriptFailure(['vim9script', 'const t:FOO: number = 123'],
+                  'E1304: Cannot use type with this variable: t:FOO:')
+  v9.CheckScriptFailure(['vim9script', 'const b:FOO: number = 123'],
+                  'E1304: Cannot use type with this variable: b:FOO:')
+  v9.CheckScriptFailure(['vim9script', 'const g:FOO: number = 123'],
+                  'E1304: Cannot use type with this variable: g:FOO:')
+enddef
+
+def Test_assign_list()
+  var lines =<< trim END
+      var l: list<string> = []
+      l[0] = 'value'
+      assert_equal('value', l[0])
+
+      l[1] = 'asdf'
+      assert_equal('value', l[0])
+      assert_equal('asdf', l[1])
+      assert_equal('asdf', l[-1])
+      assert_equal('value', l[-2])
+
+      var nrl: list<number> = []
+      for i in range(5)
+        nrl[i] = i
+      endfor
+      assert_equal([0, 1, 2, 3, 4], nrl)
+
+      var ul: list<any>
+      ul[0] = 1
+      ul[1] = 2
+      ul[2] = 3
+      assert_equal([1, 2, 3], ul)
+  END
+  v9.CheckDefAndScriptSuccess(lines)
+
+  lines =<< trim END
+      var l = [1, 2]
+      g:idx = 'x'
+      l[g:idx : 1] = [0]
+      echo l
+  END
+  v9.CheckDefExecAndScriptFailure(lines, ['E1012: Type mismatch; expected number but got string', 'E1030: Using a String as a Number: "x"'])
+
+  lines =<< trim END
+      var l = [1, 2]
+      g:idx = 3
+      l[g:idx : 1] = [0]
+      echo l
+  END
+  v9.CheckDefExecAndScriptFailure(lines, 'E684: List index out of range: 3')
+
+  lines =<< trim END
+      var l = [1, 2]
+      g:idx = 'y'
+      l[1 : g:idx] = [0]
+      echo l
+  END
+  v9.CheckDefExecAndScriptFailure(lines, ['E1012: Type mismatch; expected number but got string', 'E1030: Using a String as a Number: "y"'])
+
+  v9.CheckDefFailure(["var l: list<number> = ['', true]"], 'E1012: Type mismatch; expected list<number> but got list<any>', 1)
+  v9.CheckDefFailure(["var l: list<list<number>> = [['', true]]"], 'E1012: Type mismatch; expected list<list<number>> but got list<list<any>>', 1)
+enddef
+
+def Test_assign_dict()
+  var lines =<< trim END
+      var d: dict<string> = {}
+      d['key'] = 'value'
+      assert_equal('value', d['key'])
+
+      d[123] = 'qwerty'
+      assert_equal('qwerty', d[123])
+      assert_equal('qwerty', d['123'])
+
+      var nrd: dict<number> = {}
+      for i in range(3)
+        nrd[i] = i
+      endfor
+      assert_equal({0: 0, 1: 1, 2: 2}, nrd)
+
+      d.somekey = 'someval'
+      assert_equal({key: 'value', '123': 'qwerty', somekey: 'someval'}, d)
+      unlet d.somekey
+      assert_equal({key: 'value', '123': 'qwerty'}, d)
+  END
+  v9.CheckDefAndScriptSuccess(lines)
+
+  v9.CheckDefFailure(["var d: dict<number> = {a: '', b: true}"], 'E1012: Type mismatch; expected dict<number> but got dict<any>', 1)
+  v9.CheckDefFailure(["var d: dict<dict<number>> = {x: {a: '', b: true}}"], 'E1012: Type mismatch; expected dict<dict<number>> but got dict<dict<any>>', 1)
+  v9.CheckDefFailure(["var d = {x: 1}", "d[1 : 2] = {y: 2}"], 'E1165: Cannot use a range with an assignment: d[1 : 2] =', 2)
+enddef
+
+def Test_assign_dict_unknown_type()
+  var lines =<< trim END
+      vim9script
+      var mylist = []
+      mylist += [{one: 'one'}]
+      def Func()
+        var dd = mylist[0]
+        assert_equal('one', dd.one)
+      enddef
+      Func()
+  END
+  v9.CheckScriptSuccess(lines)
+
+  lines =<< trim END
+      vim9script
+      var mylist = [[]]
+      mylist[0] += [{one: 'one'}]
+      def Func()
+        var dd = mylist[0][0]
+        assert_equal('one', dd.one)
+      enddef
+      Func()
+  END
+  v9.CheckScriptSuccess(lines)
+enddef
+
+def Test_assign_dict_with_op()
+  var lines =<< trim END
+    var ds: dict<string> = {a: 'x'}
+    ds['a'] ..= 'y'
+    ds.a ..= 'z'
+    assert_equal('xyz', ds.a)
+
+    var dn: dict<number> = {a: 9}
+    dn['a'] += 2
+    assert_equal(11, dn.a)
+    dn.a += 2
+    assert_equal(13, dn.a)
+
+    dn['a'] -= 3
+    assert_equal(10, dn.a)
+    dn.a -= 2
+    assert_equal(8, dn.a)
+
+    dn['a'] *= 2
+    assert_equal(16, dn.a)
+    dn.a *= 2
+    assert_equal(32, dn.a)
+
+    dn['a'] /= 3
+    assert_equal(10, dn.a)
+    dn.a /= 2
+    assert_equal(5, dn.a)
+
+    dn['a'] %= 3
+    assert_equal(2, dn.a)
+    dn.a %= 6
+    assert_equal(2, dn.a)
+
+    var dd: dict<dict<list<any>>>
+    dd.a = {}
+    dd.a.b = [0]
+    dd.a.b += [1]
+    assert_equal({a: {b: [0, 1]}}, dd)
+
+    var dab = {a: ['b']}
+    dab.a[0] ..= 'c'
+    assert_equal({a: ['bc']}, dab)
+  END
+  v9.CheckDefAndScriptSuccess(lines)
+enddef
+
+def Test_assign_list_with_op()
+  var lines =<< trim END
+    var ls: list<string> = ['x']
+    ls[0] ..= 'y'
+    assert_equal('xy', ls[0])
+
+    var ln: list<number> = [9]
+    ln[0] += 2
+    assert_equal(11, ln[0])
+
+    ln[0] -= 3
+    assert_equal(8, ln[0])
+
+    ln[0] *= 2
+    assert_equal(16, ln[0])
+
+    ln[0] /= 3
+    assert_equal(5, ln[0])
+
+    ln[0] %= 3
+    assert_equal(2, ln[0])
+  END
+  v9.CheckDefAndScriptSuccess(lines)
+enddef
+
+def Test_assign_with_op_fails()
+  var lines =<< trim END
+      var s = 'abc'
+      s[1] += 'x'
+  END
+  v9.CheckDefAndScriptFailure(lines, ['E1141:', 'E689:'], 2)
+
+  lines =<< trim END
+      var s = 'abc'
+      s[1] ..= 'x'
+  END
+  v9.CheckDefAndScriptFailure(lines, ['E1141:', 'E689:'], 2)
+
+  lines =<< trim END
+      var dd: dict<dict<list<any>>>
+      dd.a = {}
+      dd.a.b += [1]
+  END
+  v9.CheckDefExecAndScriptFailure(lines, 'E716:', 3)
+enddef
+
+def Test_assign_lambda()
+  # check if assign a lambda to a variable which type is func or any.
+  var lines =<< trim END
+      vim9script
+      var FuncRef = () => 123
+      assert_equal(123, FuncRef())
+      var FuncRef_Func: func = () => 123
+      assert_equal(123, FuncRef_Func())
+      var FuncRef_Any: any = () => 123
+      assert_equal(123, FuncRef_Any())
+      var FuncRef_Number: func(): number = () => 321
+      assert_equal(321, FuncRef_Number())
+  END
+  v9.CheckScriptSuccess(lines)
+
+  lines =<< trim END
+      var Ref: func(number)
+      Ref = (j) => !j
+  END
+  v9.CheckDefAndScriptFailure(lines, 'E1012: Type mismatch; expected func(number) but got func(any): bool')
+
+  lines =<< trim END
+      echo filter([1, 2, 3], (_, v: string) => v + 1)
+  END
+  v9.CheckDefAndScriptFailure(lines, 'E1051:')
+enddef
+
+def Test_heredoc()
+  # simple heredoc
+  var lines =<< trim END
+      var text =<< trim TEXT # comment
+        abc
+      TEXT
+      assert_equal(['abc'], text)
+  END
+  v9.CheckDefAndScriptSuccess(lines)
+
+  # empty heredoc
+  lines =<< trim END
+       var text =<< trim TEXT
+       TEXT
+       assert_equal([], text)
+  END
+  v9.CheckDefAndScriptSuccess(lines)
+
+  # heredoc with a single empty line
+  lines =<< trim END
+      var text =<< trim TEXT
+
+      TEXT
+      assert_equal([''], text)
+  END
+  v9.CheckDefAndScriptSuccess(lines)
+
+  # assign heredoc to variable with type
+  lines =<< trim END
+      var text: list<string> =<< trim TEXT
+        var foo =<< trim FOO
+      TEXT
+      assert_equal(['var foo =<< trim FOO'], text)
+  END
+  v9.CheckDefAndScriptSuccess(lines)
+
+  # extra whitespace before type is allowed
+  lines =<< trim END
+      var text:   list<string> =<< trim TEXT
+        var foo =<< trim FOO
+      TEXT
+      assert_equal(['var foo =<< trim FOO'], text)
+  END
+  v9.CheckDefAndScriptSuccess(lines)
+
+  # missing whitespace before type is an error
+  lines =<< trim END
+      var text:list<string> =<< trim TEXT
+        var foo =<< trim FOO
+      TEXT
+      assert_equal(['var foo =<< trim FOO'], text)
+  END
+  v9.CheckDefAndScriptFailure(lines, 'E1069:')
+
+  # assign heredoc to list slice
+  lines =<< trim END
+      var text = ['']
+      text[ : ] =<< trim TEXT
+        var foo =<< trim FOO
+      TEXT
+      assert_equal(['var foo =<< trim FOO'], text)
+  END
+  v9.CheckDefAndScriptSuccess(lines)
+
+  # assign heredoc to curly braces name in legacy function in Vim9 script
+  lines =<< trim END
+      vim9script
+      func Func()
+        let foo_3_bar = ['']
+        let foo_{1 + 2}_bar[ : ] =<< trim TEXT
+          var foo =<< trim FOO
+        TEXT
+        call assert_equal(['var foo =<< trim FOO'], foo_3_bar)
+      endfunc
+      Func()
+  END
+  v9.CheckScriptSuccess(lines)
+
+  v9.CheckDefFailure(['var lines =<< trim END X', 'END'], 'E488:')
+  v9.CheckDefFailure(['var lines =<< trim END " comment', 'END'], 'E488:')
+
+  lines =<< trim [END]
+      def Func()
+        var&lines =<< trim END
+        x
+        x
+      enddef
+      defcompile
+  [END]
+  v9.CheckScriptFailure(lines, 'E1145: Missing heredoc end marker: END')
+  delfunc! g:Func
+
+  lines =<< trim [END]
+      def Func()
+        var lines =<< trim END
+        x
+        x
+        x
+        x
+        x
+        x
+        x
+        x
+      enddef
+      call Func()
+  [END]
+  v9.CheckScriptFailure(lines, 'E1145: Missing heredoc end marker: END')
+  delfunc! g:Func
+
+  lines =<< trim END
+      var lines: number =<< trim STOP
+        aaa
+        bbb
+      STOP
+  END
+  v9.CheckDefAndScriptFailure(lines, 'E1012: Type mismatch; expected number but got list<string>', 1)
+
+  lines =<< trim END
+      var lines=<< STOP
+        xxx
+      STOP
+  END
+  v9.CheckDefAndScriptFailure(lines, 'E1004: White space required before and after ''=<<'' at "=<< STOP"', 1)
+  lines =<< trim END
+      var lines =<<STOP
+        xxx
+      STOP
+  END
+  v9.CheckDefAndScriptFailure(lines, 'E1004: White space required before and after ''=<<'' at "=<<STOP"', 1)
+  lines =<< trim END
+      var lines=<<STOP
+        xxx
+      STOP
+  END
+  v9.CheckDefAndScriptFailure(lines, 'E1004: White space required before and after ''=<<'' at "=<<STOP"', 1)
+enddef
+
+def Test_var_func_call()
+  var lines =<< trim END
+    vim9script
+    func GetValue()
+      if exists('g:count')
+        let g:count += 1
+      else
+        let g:count = 1
+      endif
+      return 'this'
+    endfunc
+    var val: string = GetValue()
+    # env var is always a string
+    var env = $TERM
+  END
+  writefile(lines, 'Xfinished', 'D')
+  source Xfinished
+  # GetValue() is not called during discovery phase
+  assert_equal(1, g:count)
+
+  unlet g:count
+enddef
+
+def Test_var_missing_type()
+  var lines =<< trim END
+    vim9script
+    var name = g:unknown
+  END
+  v9.CheckScriptFailure(lines, 'E121:')
+
+  lines =<< trim END
+    vim9script
+    var nr: number = 123
+    var name = nr
+  END
+  v9.CheckScriptSuccess(lines)
+enddef
+
+def Test_var_declaration()
+  var lines =<< trim END
+    vim9script
+    var name: string
+    g:var_uninit = name
+    name = 'text'
+    g:var_test = name
+    # prefixing s: is not allowed
+    name = 'prefixed'
+    g:var_prefixed = name
+
+    const FOO: number = 123
+    assert_equal(123, FOO)
+    const FOOS = 'foos'
+    assert_equal('foos', FOOS)
+    final FLIST = [1]
+    assert_equal([1], FLIST)
+    FLIST[0] = 11
+    assert_equal([11], FLIST)
+
+    const g:FOOS = 'gfoos'
+    assert_equal('gfoos', g:FOOS)
+    final g:FLIST = [2]
+    assert_equal([2], g:FLIST)
+    g:FLIST[0] = 22
+    assert_equal([22], g:FLIST)
+
+    def SetGlobalConst()
+      const g:globConst = 123
+    enddef
+    SetGlobalConst()
+    assert_equal(123, g:globConst)
+    assert_true(islocked('g:globConst'))
+
+    const w:FOOS = 'wfoos'
+    assert_equal('wfoos', w:FOOS)
+    final w:FLIST = [3]
+    assert_equal([3], w:FLIST)
+    w:FLIST[0] = 33
+    assert_equal([33], w:FLIST)
+
+    var s:other: number
+    other = 1234
+    g:other_var = other
+
+    var xyz: string  # comment
+
+    # type is inferred
+    var dict = {['a']: 222}
+    def GetDictVal(key: any)
+      g:dict_val = dict[key]
+    enddef
+    GetDictVal('a')
+
+    final adict: dict<string> = {}
+    def ChangeAdict()
+      adict.foo = 'foo'
+    enddef
+    ChangeAdict()
+  END
+  v9.CheckScriptSuccess(lines)
+  assert_equal('', g:var_uninit)
+  assert_equal('text', g:var_test)
+  assert_equal('prefixed', g:var_prefixed)
+  assert_equal(1234, g:other_var)
+  assert_equal(222, g:dict_val)
+
+  unlet g:var_uninit
+  unlet g:var_test
+  unlet g:var_prefixed
+  unlet g:other_var
+  unlet g:globConst
+  unlet g:FOOS
+  unlet g:FLIST
+  unlet w:FOOS
+  unlet w:FLIST
+enddef
+
+def Test_create_list_after_const()
+  const a = 1
+  g:ll = []
+  assert_equal(0, islocked('g:ll'))
+  unlet g:ll
+enddef
+
+def Test_var_declaration_fails()
+  var lines =<< trim END
+    vim9script
+    final var: string
+  END
+  v9.CheckScriptFailure(lines, 'E1125:')
+
+  lines =<< trim END
+    vim9script
+    const g:constvar = 'string'
+    g:constvar = 'xx'
+  END
+  v9.CheckScriptFailure(lines, 'E741:')
+  unlet g:constvar
+
+  lines =<< trim END
+    vim9script
+    var name = 'one'
+    lockvar name
+    def SetLocked()
+      name = 'two'
+    enddef
+    SetLocked()
+  END
+  v9.CheckScriptFailure(lines, 'E741: Value is locked: name', 1)
+
+  lines =<< trim END
+    let s:legacy = 'one'
+    lockvar s:legacy
+    def SetLocked()
+      s:legacy = 'two'
+    enddef
+    call SetLocked()
+  END
+  v9.CheckScriptFailure(lines, 'E741: Value is locked: s:legacy', 1)
+
+  lines =<< trim END
+    vim9script
+    def SetGlobalConst()
+      const g:globConst = 123
+    enddef
+    SetGlobalConst()
+    g:globConst = 234
+  END
+  v9.CheckScriptFailure(lines, 'E741: Value is locked: g:globConst', 6)
+  unlet g:globConst
+
+  lines =<< trim END
+    vim9script
+    const cdict: dict<string> = {}
+    def Change()
+      cdict.foo = 'foo'
+    enddef
+    defcompile
+  END
+  v9.CheckScriptFailure(lines, 'E46:')
+
+  lines =<< trim END
+    vim9script
+    final w:finalvar = [9]
+    w:finalvar = [8]
+  END
+  v9.CheckScriptFailure(lines, 'E1122:')
+  unlet w:finalvar
+
+  lines =<< trim END
+    vim9script
+    const var: string
+  END
+  v9.CheckScriptFailure(lines, 'E1021:')
+
+  lines =<< trim END
+    vim9script
+    var 9var: string
+  END
+  v9.CheckScriptFailure(lines, 'E488:')
+
+  v9.CheckDefFailure(['var foo.bar = 2'], 'E1087:')
+  v9.CheckDefFailure(['var foo[3] = 2'], 'E1087:')
+  v9.CheckDefFailure(['const foo: number'], 'E1021:')
+
+  lines =<< trim END
+      va foo = 123
+  END
+  v9.CheckDefAndScriptFailure(lines, 'E1065:', 1)
+
+  lines =<< trim END
+      var foo: func(number
+  END
+  v9.CheckDefAndScriptFailure(lines, 'E110:', 1)
+
+  lines =<< trim END
+      var foo: func(number): func(
+  END
+  v9.CheckDefAndScriptFailure(lines, 'E110:', 1)
+
+  for type in ['num_ber',
+               'anys', 'ani',
+               'bools', 'boel',
+               'blobs', 'blub',
+               'channels', 'channol',
+               'dicts', 'duct',
+               'floats', 'floot',
+               'funcs', 'funk',
+               'jobs', 'jop',
+               'lists', 'last',
+               'numbers', 'numbar',
+               'strings', 'strung',
+               'voids', 'viod']
+    v9.CheckDefAndScriptFailure([$'var foo: {type}'], 'E1010:', 1)
+  endfor
+enddef
+
+def Test_var_declaration_inferred()
+  # check that type is set on the list so that extend() fails
+  var lines =<< trim END
+      vim9script
+      def GetList(): list<number>
+        var l = [1, 2, 3]
+        return l
+      enddef
+      echo GetList()->extend(['x'])
+  END
+  v9.CheckScriptFailure(lines, 'E1013:', 6)
+
+  lines =<< trim END
+      vim9script
+      def GetNr(): number
+        return 5
+      enddef
+      def TestOne()
+        var some = [function('len'), GetNr]
+        g:res = typename(some)
+      enddef
+      TestOne()
+      assert_equal('list<func(): number>', g:res)
+
+      def TestTwo()
+        var some = [function('len'), GetNr]
+        g:res = typename(some)
+      enddef
+      TestTwo()
+      assert_equal('list<func(): number>', g:res)
+      unlet g:res
+
+      # FIXME: why is the type different?
+      var first = [function('len'), GetNr]
+      assert_equal('list<func(...): number>', typename(first))
+      var second = [GetNr, function('len')]
+      assert_equal('list<func(...): number>', typename(second))
+  END
+  v9.CheckScriptSuccess(lines)
+enddef
+
+def Test_script_local_in_legacy()
+  # OK to define script-local later but before compiling
+  var lines =<< trim END
+    def SetLater()
+      legvar = 'two'
+    enddef
+    let s:legvar = 'one'
+    defcompile
+    call SetLater()
+    call assert_equal('two', s:legvar)
+  END
+  v9.CheckScriptSuccess(lines)
+
+  # OK to leave out s: prefix when script-local already defined
+  lines =<< trim END
+    let s:legvar = 'one'
+    def SetNoPrefix()
+      legvar = 'two'
+    enddef
+    call SetNoPrefix()
+    call assert_equal('two', s:legvar)
+  END
+  v9.CheckScriptSuccess(lines)
+
+  # Not OK to leave out s: prefix when script-local defined after compiling
+  lines =<< trim END
+    def SetLaterNoPrefix()
+      legvar = 'two'
+    enddef
+    defcompile
+    let s:legvar = 'one'
+  END
+  v9.CheckScriptFailure(lines, 'E476:', 1)
+
+  edit! Xslfile
+  lines =<< trim END
+      var edit: bool
+      legacy edit
+  END
+  v9.CheckDefAndScriptSuccess(lines)
+enddef
+
+def Test_var_type_check()
+  var lines =<< trim END
+    vim9script
+    var name: string
+    name = 1234
+  END
+  v9.CheckScriptFailure(lines, 'E1012:')
+
+  lines =<< trim END
+    vim9script
+    var name:string
+  END
+  v9.CheckScriptFailure(lines, 'E1069:')
+
+  v9.CheckDefAndScriptFailure(['var n:number = 42'], 'E1069:')
+
+  lines =<< trim END
+    vim9script
+    var name: asdf
+  END
+  v9.CheckScriptFailure(lines, 'E1010:')
+
+  lines =<< trim END
+    vim9script
+    var l: list<number>
+    l = []
+  END
+  v9.CheckScriptSuccess(lines)
+
+  lines =<< trim END
+    vim9script
+    var d: dict<number>
+    d = {}
+  END
+  v9.CheckScriptSuccess(lines)
+
+  lines =<< trim END
+    vim9script
+    var d = {a: 1, b: [2]}
+    def Func(b: bool)
+      var l: list<number> = b ? d.b : [3]
+    enddef
+    defcompile
+  END
+  v9.CheckScriptSuccess(lines)
+enddef
+
+let g:dict_number = #{one: 1, two: 2}
+
+def Test_var_list_dict_type()
+  var ll: list<number>
+  ll = [1, 2, 2, 3, 3, 3]->uniq()
+  ll->assert_equal([1, 2, 3])
+
+  var dd: dict<number>
+  dd = g:dict_number
+  dd->assert_equal(g:dict_number)
+
+  var lines =<< trim END
+      var ll: list<number>
+      ll = [1, 2, 3]->map('"one"')
+  END
+  v9.CheckDefExecFailure(lines, 'E1012: Type mismatch; expected list<number> but got list<string>')
+enddef
+
+def Test_cannot_use_let()
+  v9.CheckDefAndScriptFailure(['let a = 34'], 'E1126:', 1)
+enddef
+
+def Test_unlet()
+  g:somevar = 'yes'
+  assert_true(exists('g:somevar'))
+  unlet g:somevar
+  assert_false(exists('g:somevar'))
+  unlet! g:somevar
+
+  # also works for script-local variable in legacy Vim script
+  s:somevar = 'legacy'
+  assert_true(exists('s:somevar'))
+  unlet s:somevar
+  assert_false(exists('s:somevar'))
+  unlet! s:somevar
+
+  if 0
+    unlet g:does_not_exist
+  endif
+
+  v9.CheckDefExecFailure(['unlet v:notfound.key'], 'E1001:')
+
+  v9.CheckDefExecFailure([
+    'var dd = 111',
+    'unlet dd',
+    ], 'E1081:', 2)
+
+  # dict unlet
+  var dd = {a: 1, b: 2, c: 3, 4: 4}
+  unlet dd['a']
+  unlet dd.c
+  unlet dd[4]
+  assert_equal({b: 2}, dd)
+
+  # null key works like empty string
+  dd = {'': 1, x: 9}
+  unlet dd[null_string]
+  assert_equal({x: 9}, dd)
+
+  # list unlet
+  var ll = [1, 2, 3, 4]
+  unlet ll[1]
+  unlet ll[-1]
+  assert_equal([1, 3], ll)
+
+  ll = [1, 2, 3, 4]
+  unlet ll[0 : 1]
+  assert_equal([3, 4], ll)
+
+  ll = [1, 2, 3, 4]
+  unlet ll[2 : 8]
+  assert_equal([1, 2], ll)
+
+  ll = [1, 2, 3, 4]
+  unlet ll[-2 : -1]
+  assert_equal([1, 2], ll)
+
+  g:nrdict = {1: 1, 2: 2}
+  g:idx = 1
+  unlet g:nrdict[g:idx]
+  assert_equal({2: 2}, g:nrdict)
+  unlet g:nrdict
+  unlet g:idx
+
+  v9.CheckDefFailure([
+    'var ll = [1, 2]',
+    'll[1 : 2] = 7',
+    ], 'E1012: Type mismatch; expected list<number> but got number', 2)
+  v9.CheckDefFailure([
+    'var dd = {a: 1}',
+    'unlet dd["a" : "a"]',
+    ], 'E1166:', 2)
+  v9.CheckDefExecFailure([
+    'unlet g:adict[0 : 1]',
+    ], 'E1148:', 1)
+  v9.CheckDefFailure([
+    'var ll = [1, 2]',
+    'unlet ll[0:1]',
+    ], 'E1004:', 2)
+  v9.CheckDefFailure([
+    'var ll = [1, 2]',
+    'unlet ll[0 :1]',
+    ], 'E1004:', 2)
+  v9.CheckDefFailure([
+    'var ll = [1, 2]',
+    'unlet ll[0: 1]',
+    ], 'E1004:', 2)
+
+  v9.CheckDefExecFailure([
+    'g:ll = [1, 2]',
+    'g:idx = "x"',
+    'unlet g:ll[g:idx]',
+    ], 'E1029: Expected number but got string', 3)
+
+  v9.CheckDefExecFailure([
+    'g:ll = [1, 2, 3]',
+    'g:idx = "x"',
+    'unlet g:ll[g:idx : 2]',
+    ], 'E1029: Expected number but got string', 3)
+
+  v9.CheckDefExecFailure([
+    'g:ll = [1, 2, 3]',
+    'g:idx = "x"',
+    'unlet g:ll[0 : g:idx]',
+    ], 'E1029: Expected number but got string', 3)
+
+  # command recognized as assignment when skipping, should not give an error
+  v9.CheckScriptSuccess([
+    'vim9script',
+    'for i in []',
+    "  put =''",
+    'endfor'])
+
+  v9.CheckDefFailure([
+    'var ll = [1, 2]',
+    'unlet ll["x" : 1]',
+    ], 'E1012:', 2)
+  v9.CheckDefFailure([
+    'var ll = [1, 2]',
+    'unlet ll[0 : "x"]',
+    ], 'E1012:', 2)
+
+  # list of dict unlet
+  var dl = [{a: 1, b: 2}, {c: 3}]
+  unlet dl[0]['b']
+  assert_equal([{a: 1}, {c: 3}], dl)
+
+  v9.CheckDefExecFailure([
+    'var ll = test_null_list()',
+    'unlet ll[0]',
+    ], 'E684:', 2)
+  v9.CheckDefExecFailure([
+    'var ll = [1]',
+    'unlet ll[2]',
+    ], 'E684:', 2)
+  v9.CheckDefExecFailure([
+    'var ll = [1]',
+    'unlet ll[g:astring]',
+    ], 'E1012:', 2)
+  v9.CheckDefExecFailure([
+    'var dd = test_null_dict()',
+    'unlet dd["a"]',
+    ], 'E716:', 2)
+  v9.CheckDefExecFailure([
+    'var dd = {a: 1}',
+    'unlet dd["b"]',
+    ], 'E716:', 2)
+  v9.CheckDefExecFailure([
+    'var dd = {a: 1}',
+    'unlet dd[g:alist]',
+    ], 'E1105:', 2)
+
+  v9.CheckDefExecFailure([
+    'g:dd = {"a": 1, 2: 2}',
+    'unlet g:dd[0z11]',
+    ], 'E1029:', 2)
+  v9.CheckDefExecFailure([
+    'g:str = "a string"',
+    'unlet g:str[0]',
+    ], 'E1148: Cannot index a string', 2)
+
+  # can compile unlet before variable exists
+  g:someDict = {key: 'val'}
+  var k = 'key'
+  unlet g:someDict[k]
+  assert_equal({}, g:someDict)
+  unlet g:someDict
+  assert_false(exists('g:someDict'))
+
+  v9.CheckScriptFailure([
+   'vim9script',
+   'var svar = 123',
+   'unlet svar',
+   ], 'E1081:')
+  v9.CheckScriptFailure([
+   'vim9script',
+   'var svar = 123',
+   'unlet s:svar',
+   ], 'E1268:')
+  v9.CheckScriptFailure([
+   'vim9script',
+   'var svar = 123',
+   'def Func()',
+   '  unlet svar',
+   'enddef',
+   'defcompile',
+   ], 'E1081:')
+  v9.CheckScriptFailure([
+   'vim9script',
+   'var svar = 123',
+   'func Func()',
+   '  unlet s:svar',
+   'endfunc',
+   'Func()',
+   ], 'E1081:')
+  v9.CheckScriptFailure([
+   'vim9script',
+   'var svar = 123',
+   'def Func()',
+   '  unlet s:svar',
+   'enddef',
+   'defcompile',
+   ], 'E1081:')
+
+  v9.CheckScriptFailure([
+   'vim9script',
+   'def Delcount(dict: dict<any>)',
+   '  unlet dict.count',
+   'enddef',
+   'Delcount(v:)',
+   ], 'E742:')
+
+  v9.CheckScriptFailure([
+   'vim9script',
+   'def DelChangedtick(dict: dict<any>)',
+   '  unlet dict.changedtick',
+   'enddef',
+   'DelChangedtick(b:)',
+   ], 'E795:')
+
+  writefile(['vim9script', 'export var svar = 1234'], 'XunletExport.vim', 'D')
+  var lines =<< trim END
+    vim9script
+    import './XunletExport.vim' as exp
+    def UnletSvar()
+      unlet exp.svar
+    enddef
+    defcompile
+  END
+  v9.CheckScriptFailure(lines, 'E1260:', 1)
+
+  $ENVVAR = 'foobar'
+  assert_equal('foobar', $ENVVAR)
+  unlet $ENVVAR
+  assert_equal('', $ENVVAR)
+enddef
+
+def Test_expr_error_no_assign()
+  var lines =<< trim END
+      vim9script
+      var x = invalid
+      echo x
+  END
+  v9.CheckScriptFailureList(lines, ['E121:', 'E121:'])
+
+  lines =<< trim END
+      vim9script
+      var x = 1 / 0
+      echo x
+  END
+  v9.CheckScriptFailure(lines, 'E1154:')
+
+  lines =<< trim END
+      vim9script
+      var x = 1 % 0
+      echo x
+  END
+  v9.CheckScriptFailure(lines, 'E1154:')
+
+  lines =<< trim END
+      var x: string  'string'
+  END
+  v9.CheckDefAndScriptFailure(lines, 'E488:')
+enddef
+
+
+def Test_assign_command_modifier()
+  var lines =<< trim END
+      var verbose = 0
+      verbose = 1
+      assert_equal(1, verbose)
+      silent verbose = 2
+      assert_equal(2, verbose)
+      silent verbose += 2
+      assert_equal(4, verbose)
+      silent verbose -= 1
+      assert_equal(3, verbose)
+
+      var topleft = {one: 1}
+      sandbox topleft.one = 3
+      assert_equal({one: 3}, topleft)
+      leftabove topleft[' '] = 4
+      assert_equal({one: 3, ' ': 4}, topleft)
+
+      var x: number
+      var y: number
+      silent [x, y] = [1, 2]
+      assert_equal(1, x)
+      assert_equal(2, y)
+  END
+  v9.CheckDefAndScriptSuccess(lines)
+enddef
+
+def Test_assign_alt_buf_register()
+  var lines =<< trim END
+      edit 'file_b1'
+      var b1 = bufnr()
+      edit 'file_b2'
+      var b2 = bufnr()
+      assert_equal(b1, bufnr('#'))
+      @# = b2
+      assert_equal(b2, bufnr('#'))
+  END
+  v9.CheckDefAndScriptSuccess(lines)
+enddef
+
+def Test_script_funcref_case()
+  var lines =<< trim END
+      var Len = (s: string): number => len(s) + 1
+      assert_equal(5, Len('asdf'))
+  END
+  v9.CheckDefAndScriptSuccess(lines)
+
+  lines =<< trim END
+      var len = (s: string): number => len(s) + 1
+  END
+  v9.CheckDefAndScriptFailure(lines, 'E704:')
+
+  lines =<< trim END
+      vim9script
+      var Len = (s: string): number => len(s) + 2
+      assert_equal(6, Len('asdf'))
+  END
+  v9.CheckScriptSuccess(lines)
+
+  lines =<< trim END
+      vim9script
+      var len = (s: string): number => len(s) + 1
+  END
+  v9.CheckScriptFailure(lines, 'E704:')
+enddef
+
+def Test_script_funcref_runtime_type_check()
+  var lines =<< trim END
+      vim9script
+      def FuncWithNumberArg(n: number)
+      enddef
+      def Test()
+        var Ref: func(string) = function(FuncWithNumberArg)
+      enddef
+      defcompile
+  END
+  # OK at compile time
+  v9.CheckScriptSuccess(lines)
+
+  # Type check fails at runtime
+  v9.CheckScriptFailure(lines + ['Test()'], 'E1012: Type mismatch; expected func(string) but got func(number)')
+enddef
+
+def Test_inc_dec()
+  var lines =<< trim END
+      var nr = 7
+      ++nr
+      assert_equal(8, nr)
+      --nr
+      assert_equal(7, nr)
+      ++nr | ++nr
+      assert_equal(9, nr)
+      ++nr # comment
+      assert_equal(10, nr)
+
+      var ll = [1, 2]
+      --ll[0]
+      ++ll[1]
+      assert_equal([0, 3], ll)
+
+      g:count = 1
+      ++g:count
+      --g:count
+      assert_equal(1, g:count)
+      unlet g:count
+  END
+  v9.CheckDefAndScriptSuccess(lines)
+
+  lines =<< trim END
+      var nr = 7
+      ++ nr
+  END
+  v9.CheckDefAndScriptFailure(lines, "E1202: No white space allowed after '++': ++ nr")
+enddef
+
+def Test_abort_after_error()
+  # should abort after strpart() fails, not give another type error
+  var lines =<< trim END
+      vim9script
+      var x: string
+      x = strpart(1, 2)
+  END
+  writefile(lines, 'Xtestscript', 'D')
+  var expected = 'E1174: String required for argument 1'
+  assert_fails('so Xtestscript', [expected, expected], 3)
+enddef
+
+def Test_using_s_var_in_function()
+  var lines =<< trim END
+      vim9script
+      var scriptlevel = 123
+      def SomeFunc()
+        echo s:scriptlevel
+      enddef
+      SomeFunc()
+  END
+  v9.CheckScriptFailure(lines, 'E1268:')
+
+  # OK in legacy script
+  lines =<< trim END
+      let s:scriptlevel = 123
+      def s:SomeFunc()
+        echo s:scriptlevel
+      enddef
+      call s:SomeFunc()
+  END
+  v9.CheckScriptSuccess(lines)
+
+  lines =<< trim END
+      vim9script
+      var scriptlevel = 123
+      def SomeFunc()
+        s:scriptlevel = 456
+      enddef
+      SomeFunc()
+  END
+  v9.CheckScriptFailure(lines, 'E1268:')
+
+  # OK in legacy script
+  lines =<< trim END
+      let s:scriptlevel = 123
+      def s:SomeFunc()
+        s:scriptlevel = 456
+      enddef
+      call s:SomeFunc()
+      call assert_equal(456, s:scriptlevel)
+  END
+  v9.CheckScriptSuccess(lines)
+enddef
+
+let g:someVar = 'X'
+
+" Test for heredoc with Vim expressions.
+" This messes up highlighting, keep it near the end.
+def Test_heredoc_expr()
+  var lines =<< trim CODE
+    var s = "local"
+    var a1 = "1"
+    var a2 = "2"
+    var a3 = "3"
+    var a4 = ""
+    var code =<< trim eval END
+      var a = {5 + 10}
+      var b = {min([10, 6])} + {max([4, 6])}
+      var c = "{s}"
+      var d = x{a1}x{a2}x{a3}x{a4}
+    END
+    assert_equal(['var a = 15', 'var b = 6 + 6', 'var c = "local"', 'var d = x1x2x3x'], code)
+  CODE
+  v9.CheckDefAndScriptSuccess(lines)
+
+  lines =<< trim CODE
+    var code =<< eval trim END
+      var s = "{$SOME_ENV_VAR}"
+    END
+    assert_equal(['var s = "somemore"'], code)
+  CODE
+  v9.CheckDefAndScriptSuccess(lines)
+
+  lines =<< trim CODE
+    var code =<< eval END
+      var s = "{$SOME_ENV_VAR}"
+    END
+    assert_equal(['  var s = "somemore"'], code)
+  CODE
+  v9.CheckDefAndScriptSuccess(lines)
+
+  lines =<< trim CODE
+    var code =<< eval trim END
+      let a = {{abc}}
+      let b = {g:someVar}
+      let c = {{
+    END
+    assert_equal(['let a = {abc}', 'let b = X', 'let c = {'], code)
+  CODE
+  v9.CheckDefAndScriptSuccess(lines)
+
+  lines =<< trim LINES
+      var text =<< eval trim END
+        let b = {
+      END
+  LINES
+  v9.CheckDefAndScriptFailure(lines, "E1279: Missing '}'")
+
+  lines =<< trim LINES
+      var text =<< eval trim END
+        let b = {abc
+      END
+  LINES
+  v9.CheckDefAndScriptFailure(lines, "E1279: Missing '}'")
+
+  lines =<< trim LINES
+      var text =<< eval trim END
+        let b = {}
+      END
+  LINES
+  v9.CheckDefAndScriptFailure(lines, 'E15: Invalid expression: "}"')
+enddef
+
+" vim: ts=8 sw=2 sts=2 expandtab tw=80 fdm=marker