--- a/src/testdir/test_let.vim
+++ b/src/testdir/test_let.vim
@@ -1,698 +1,698 @@
-" Tests for the :let command.
-
-import './vim9.vim' as v9
-
-func Test_let()
-  " Test to not autoload when assigning.  It causes internal error.
-  set runtimepath+=./sautest
-  let Test104#numvar = function('tr')
-  call assert_equal("function('tr')", string(Test104#numvar))
-
-  let foo#tr = function('tr')
-  call assert_equal("function('tr')", string(foo#tr))
-  unlet foo#tr
-
-  let a = 1
-  let b = 2
-
-  let out = execute('let a b')
-  let s = "\na                     #1\nb                     #2"
-  call assert_equal(s, out)
-
-  let out = execute('let {0 == 1 ? "a" : "b"}')
-  let s = "\nb                     #2"
-  call assert_equal(s, out)
-
-  let out = execute('let {0 == 1 ? "a" : "b"} a')
-  let s = "\nb                     #2\na                     #1"
-  call assert_equal(s, out)
-
-  let out = execute('let a {0 == 1 ? "a" : "b"}')
-  let s = "\na                     #1\nb                     #2"
-  call assert_equal(s, out)
-
-  " Test for displaying a string variable
-  let s = 'vim'
-  let out = execute('let s')
-  let s = "\ns                      vim"
-  call assert_equal(s, out)
-
-  " Test for displaying a list variable
-  let l = [1, 2]
-  let out = execute('let l')
-  let s = "\nl                     [1, 2]"
-  call assert_equal(s, out)
-
-  " Test for displaying a dict variable
-  let d = {'k' : 'v'}
-  let out = execute('let d')
-  let s = "\nd                     {'k': 'v'}"
-  call assert_equal(s, out)
-
-  " Test for displaying a function reference variable
-  let F = function('min')
-  let out = execute('let F')
-  let s = "\nF                     *min()"
-  call assert_equal(s, out)
-
-  let x = 0
-  if 0 | let x = 1 | endif
-  call assert_equal(0, x)
-
-  " Display a list item using an out of range index
-  let l = [10]
-  call assert_fails('let l[1]', 'E684:')
-
-  " List special variable dictionaries
-  let g:Test_Global_Var = 5
-  call assert_match("\nTest_Global_Var       #5", execute('let g:'))
-  unlet g:Test_Global_Var
-
-  let b:Test_Buf_Var = 8
-  call assert_match("\nb:Test_Buf_Var        #8", execute('let b:'))
-  unlet b:Test_Buf_Var
-
-  let w:Test_Win_Var = 'foo'
-  call assert_equal("\nw:Test_Win_Var         foo", execute('let w:'))
-  unlet w:Test_Win_Var
-
-  let t:Test_Tab_Var = 'bar'
-  call assert_equal("\nt:Test_Tab_Var         bar", execute('let t:'))
-  unlet t:Test_Tab_Var
-
-  let s:Test_Script_Var = [7]
-  call assert_match("\ns:Test_Script_Var     \\[7]", execute('let s:'))
-  unlet s:Test_Script_Var
-
-  let l:Test_Local_Var = {'k' : 5}
-  call assert_match("\nl:Test_Local_Var      {'k': 5}", execute('let l:'))
-  call assert_match("v:errors              []", execute('let v:'))
-
-  " Test for assigning multiple list items
-  let l = [1, 2, 3]
-  let [l[0], l[1]] = [10, 20]
-  call assert_equal([10, 20, 3], l)
-
-  " Test for errors in conditional expression
-  call assert_fails('let val = [] ? 1 : 2', 'E745:')
-  call assert_fails('let val = 1 ? 5+ : 6', 'E121:')
-  call assert_fails('let val = 1 ? 0 : 5+', 'E15:')
-  call assert_false(exists('val'))
-
-  " Test for errors in logical operators
-  let @a = 'if [] || 0 | let val = 2 | endif'
-  call assert_fails('exe @a', 'E745:')
-  call assert_fails('call feedkeys(":let val = 0 || []\<cr>", "xt")', 'E745:')
-  call assert_fails('exe "let val = [] && 5"', 'E745:')
-  call assert_fails('exe "let val = 6 && []"', 'E745:')
-endfunc
-
-func s:set_arg1(a) abort
-  let a:a = 1
-endfunction
-
-func s:set_arg2(a) abort
-  let a:b = 1
-endfunction
-
-func s:set_arg3(a) abort
-  let b = a:
-  let b['a'] = 1
-endfunction
-
-func s:set_arg4(a) abort
-  let b = a:
-  let b['a'] = 1
-endfunction
-
-func s:set_arg5(a) abort
-  let b = a:
-  let b['a'][0] = 1
-endfunction
-
-func s:set_arg6(a) abort
-  let a:a[0] = 1
-endfunction
-
-func s:set_arg7(a) abort
-  call extend(a:, {'a': 1})
-endfunction
-
-func s:set_arg8(a) abort
-  call extend(a:, {'b': 1})
-endfunction
-
-func s:set_arg9(a) abort
-  let a:['b'] = 1
-endfunction
-
-func s:set_arg10(a) abort
-  let b = a:
-  call extend(b, {'a': 1})
-endfunction
-
-func s:set_arg11(a) abort
-  let b = a:
-  call extend(b, {'b': 1})
-endfunction
-
-func s:set_arg12(a) abort
-  let b = a:
-  let b['b'] = 1
-endfunction
-
-func Test_let_arg_fail()
-  call assert_fails('call s:set_arg1(1)', 'E46:')
-  call assert_fails('call s:set_arg2(1)', 'E461:')
-  call assert_fails('call s:set_arg3(1)', 'E46:')
-  call assert_fails('call s:set_arg4(1)', 'E46:')
-  call assert_fails('call s:set_arg5(1)', 'E46:')
-  call s:set_arg6([0])
-  call assert_fails('call s:set_arg7(1)', 'E742:')
-  call assert_fails('call s:set_arg8(1)', 'E742:')
-  call assert_fails('call s:set_arg9(1)', 'E461:')
-  call assert_fails('call s:set_arg10(1)', 'E742:')
-  call assert_fails('call s:set_arg11(1)', 'E742:')
-  call assert_fails('call s:set_arg12(1)', 'E461:')
-endfunction
-
-func s:set_varg1(...) abort
-  let a:000 = []
-endfunction
-
-func s:set_varg2(...) abort
-  let a:000[0] = 1
-endfunction
-
-func s:set_varg3(...) abort
-  let a:000 += [1]
-endfunction
-
-func s:set_varg4(...) abort
-  call add(a:000, 1)
-endfunction
-
-func s:set_varg5(...) abort
-  let a:000[0][0] = 1
-endfunction
-
-func s:set_varg6(...) abort
-  let b = a:000
-  let b[0] = 1
-endfunction
-
-func s:set_varg7(...) abort
-  let b = a:000
-  let b += [1]
-endfunction
-
-func s:set_varg8(...) abort
-  let b = a:000
-  call add(b, 1)
-endfunction
-
-func s:set_varg9(...) abort
-  let b = a:000
-  let b[0][0] = 1
-endfunction
-
-func Test_let_varg_fail()
-  call assert_fails('call s:set_varg1(1)', 'E46:')
-  call assert_fails('call s:set_varg2(1)', 'E742:')
-  call assert_fails('call s:set_varg3(1)', 'E46:')
-  call assert_fails('call s:set_varg4(1)', 'E742:')
-  call s:set_varg5([0])
-  call assert_fails('call s:set_varg6(1)', 'E742:')
-  call assert_fails('call s:set_varg7(1)', 'E742:')
-  call assert_fails('call s:set_varg8(1)', 'E742:')
-  call s:set_varg9([0])
-endfunction
-
-func Test_let_utf8_environment()
-  let $a = 'ĀĒĪŌŪあいうえお'
-  call assert_equal('ĀĒĪŌŪあいうえお', $a)
-endfunc
-
-func Test_let_no_type_checking()
-  let v = 1
-  let v = [1,2,3]
-  let v = {'a': 1, 'b': 2}
-  let v = 3.4
-  let v = 'hello'
-endfunc
-
-func Test_let_termcap()
-  " Terminal code
-  let old_t_te = &t_te
-  let &t_te = "\<Esc>[yes;"
-  call assert_match('t_te.*^[[yes;', execute("set termcap"))
-  let &t_te = old_t_te
-
-  if exists("+t_k1")
-    " Key code
-    let old_t_k1 = &t_k1
-    let &t_k1 = "that"
-    call assert_match('t_k1.*that', execute("set termcap"))
-    let &t_k1 = old_t_k1
-  endif
-
-  call assert_fails('let x = &t_xx', 'E113:')
-  let &t_xx = "yes"
-  call assert_equal("yes", &t_xx)
-  let &t_xx = ""
-  call assert_fails('let x = &t_xx', 'E113:')
-endfunc
-
-func Test_let_option_error()
-  let _w = &tw
-  let &tw = 80
-  call assert_fails('let &tw .= 1', ['E734:', 'E734:'])
-  call assert_fails('let &tw .= []', ['E734:', 'E734:'])
-  call assert_fails('let &tw = []', ['E745:', 'E745:'])
-  call assert_fails('let &tw += []', ['E745:', 'E745:'])
-  call assert_equal(80, &tw)
-  let &tw = _w
-
-  let _w = &autoread
-  let &autoread = 1
-  call assert_fails('let &autoread .= 1', ['E734:', 'E734:'])
-  call assert_fails('let &autoread .= []', ['E734:', 'E734:'])
-  call assert_fails('let &autoread = []', ['E745:', 'E745:'])
-  call assert_fails('let &autoread += []', ['E745:', 'E745:'])
-  call assert_equal(1, &autoread)
-  let &autoread = _w
-
-  let _w = &fillchars
-  let &fillchars = "vert:|"
-  call assert_fails('let &fillchars += "diff:-"', ['E734:', 'E734:'])
-  call assert_fails('let &fillchars += []', ['E734:', 'E734:'])
-  call assert_fails('let &fillchars = []', ['E730:', 'E730:'])
-  call assert_fails('let &fillchars .= []', ['E730:', 'E730:'])
-  call assert_equal("vert:|", &fillchars)
-  let &fillchars = _w
-
-  call assert_fails('let &nosuchoption = 1', ['E355:', 'E355:'])
-  call assert_fails('let &nosuchoption = ""', ['E355:', 'E355:'])
-  call assert_fails('let &nosuchoption = []', ['E355:', 'E355:'])
-  call assert_fails('let &t_xx = []', ['E730:', 'E730:'])
-endfunc
-
-" Errors with the :let statement
-func Test_let_errors()
-  let s = 'abcd'
-  call assert_fails('let s[1] = 5', 'E689:')
-
-  let l = [1, 2, 3]
-  call assert_fails('let l[:] = 5', 'E709:')
-
-  call assert_fails('let x:lnum=5', ['E121:', 'E121:'])
-  call assert_fails('let v:=5', 'E461:')
-  call assert_fails('let [a]', 'E474:')
-  call assert_fails('let [a, b] = [', 'E697:')
-  call assert_fails('let [a, b] = [10, 20', 'E696:')
-  call assert_fails('let [a, b] = 10', 'E714:')
-  call assert_fails('let [a, , b] = [10, 20]', 'E475:')
-  call assert_fails('let [a, b&] = [10, 20]', 'E475:')
-  call assert_fails('let $ = 10', 'E475:')
-  call assert_fails('let $FOO[1] = "abc"', 'E18:')
-  call assert_fails('let &buftype[1] = "nofile"', 'E18:')
-  let s = "var"
-  let var = 1
-  call assert_fails('let var += [1,2]', 'E734:')
-  call assert_fails('let {s}.1 = 2', 'E1203:')
-  call assert_fails('let a[1] = 5', 'E121:')
-  let l = [[1,2]]
-  call assert_fails('let l[:][0] = [5]', 'E708:')
-  let d = {'k' : 4}
-  call assert_fails('let d.# = 5', 'E488:')
-  call assert_fails('let d.m += 5', 'E716:')
-  call assert_fails('let m = d[{]', 'E15:')
-  let l = [1, 2]
-  call assert_fails('let l[2] = 0', 'E684:')
-  call assert_fails('let l[0:1] = [1, 2, 3]', 'E710:')
-  call assert_fails('let l[-2:-3] = [3, 4]', 'E684:')
-  call assert_fails('let l[0:4] = [5, 6]', 'E711:')
-  call assert_fails('let l -= 2', 'E734:')
-  call assert_fails('let l += 2', 'E734:')
-  call assert_fails('let g:["a;b"] = 10', 'E461:')
-  call assert_fails('let g:.min = function("max")', 'E704:')
-  call assert_fails('let g:cos = "" | let g:.cos = {-> 42}', 'E704:')
-  if has('channel')
-    let ch = test_null_channel()
-    call assert_fails('let ch += 1', 'E734:')
-  endif
-  call assert_fails('let name = "a" .. "b",', 'E488: Trailing characters: ,')
-
-  " This test works only when the language is English
-  if v:lang == "C" || v:lang =~ '^[Ee]n'
-    call assert_fails('let [a ; b;] = [10, 20]',
-          \ 'Double ; in list of variables')
-  endif
-endfunc
-
-func Test_let_heredoc_fails()
-  call assert_fails('let v =<< marker', 'E991:')
-  try
-    exe "let v =<< TEXT | abc | TEXT"
-    call assert_report('No exception thrown')
-  catch /E488:/
-  catch
-    call assert_report('Caught exception: ' .. v:exception)
-  endtry
-
-  try
-    let &commentstring =<< trim TEXT
-      change
-      insert
-      append
-    TEXT
-    call assert_report('No exception thrown')
-  catch /E730:/
-  catch
-    call assert_report('Caught exception: ' .. v:exception)
-  endtry
-
-  try
-    let $SOME_ENV_VAR =<< trim TEXT
-      change
-      insert
-      append
-    TEXT
-    call assert_report('No exception thrown')
-  catch /E730:/
-  catch
-    call assert_report('Caught exception: ' .. v:exception)
-  endtry
-
-  try
-    let @r =<< trim TEXT
-      change
-      insert
-      append
-    TEXT
-    call assert_report('No exception thrown')
-  catch /E730:/
-  catch
-    call assert_report('Caught exception: ' .. v:exception)
-  endtry
-
-  let text =<< trim END
-  func WrongSyntax()
-    let v =<< that there
-  endfunc
-  END
-  call writefile(text, 'XheredocFail', 'D')
-  call assert_fails('source XheredocFail', 'E1145:')
-
-  let text =<< trim CodeEnd
-  func MissingEnd()
-    let v =<< END
-  endfunc
-  CodeEnd
-  call writefile(text, 'XheredocWrong', 'D')
-  call assert_fails('source XheredocWrong', 'E1145:')
-
-  let text =<< trim TEXTend
-    let v =<< " comment
-  TEXTend
-  call writefile(text, 'XheredocNoMarker', 'D')
-  call assert_fails('source XheredocNoMarker', 'E172:')
-
-  let text =<< trim TEXTend
-    let v =<< text
-  TEXTend
-  call writefile(text, 'XheredocBadMarker', 'D')
-  call assert_fails('source XheredocBadMarker', 'E221:')
-
-  call writefile(['let v =<< TEXT', 'abc'], 'XheredocMissingMarker', 'D')
-  call assert_fails('source XheredocMissingMarker', 'E990:')
-endfunc
-
-func Test_let_heredoc_trim_no_indent_marker()
-  let text =<< trim END
-  Text
-  with
-  indent
-END
-  call assert_equal(['Text', 'with', 'indent'], text)
-endfunc
-
-func Test_let_interpolated()
-  call assert_equal('{text}', $'{{text}}')
-  call assert_equal('{{text}}', $'{{{{text}}}}')
-  let text = 'text'
-  call assert_equal('text{{', $'{text .. "{{"}')
-  call assert_equal('text{{', $"{text .. '{{'}")
-  call assert_equal('text{{', $'{text .. '{{'}')
-  call assert_equal('text{{', $"{text .. "{{"}")
-endfunc
-
-" Test for the setting a variable using the heredoc syntax.
-" Keep near the end, this messes up highlighting.
-func Test_let_heredoc()
-  let var1 =<< END
-Some sample text
-	Text with indent
-  !@#$%^&*()-+_={}|[]\~`:";'<>?,./
-END
-
-  call assert_equal(["Some sample text", "\tText with indent", "  !@#$%^&*()-+_={}|[]\\~`:\";'<>?,./"], var1)
-
-  let var2 =<< XXX
-Editor
-XXX
-  call assert_equal(['Editor'], var2)
-
-  let var3 =<<END
-END
-  call assert_equal([], var3)
-
-  let var3 =<<END
-vim
-
-end
-  END
-END 
-END
-  call assert_equal(['vim', '', 'end', '  END', 'END '], var3)
-
-	let var1 =<< trim END
-	Line1
-	  Line2
-		Line3
-	 END
-	END
-  call assert_equal(['Line1', '  Line2', "\tLine3", ' END'], var1)
-
-  let var1 =<< trim !!!
-	Line1
-	 line2
-		Line3
-	!!!
-  !!!
-  call assert_equal(['Line1', ' line2', "\tLine3", '!!!',], var1)
-
-  let var1 =<< trim XX
-    Line1
-  XX
-  call assert_equal(['Line1'], var1)
-
-  " ignore "endfunc"
-  let var1 =<< END
-something
-endfunc
-END
-  call assert_equal(['something', 'endfunc'], var1)
-
-  " ignore "endfunc" with trim
-  let var1 =<< trim END
-  something
-  endfunc
-  END
-  call assert_equal(['something', 'endfunc'], var1)
-
-  " not concatenate lines
-  let var1 =<< END
-some
-  \thing
-  \ else
-END
-  call assert_equal(['some', '  \thing', '  \ else'], var1)
-
-  " ignore "python << xx"
-  let var1 =<<END
-something
-python << xx
-END
-  call assert_equal(['something', 'python << xx'], var1)
-
-  " ignore "python << xx" with trim
-  let var1 =<< trim END
-  something
-  python << xx
-  END
-  call assert_equal(['something', 'python << xx'], var1)
-
-  " ignore "append"
-  let var1 =<< E
-something
-app
-E
-  call assert_equal(['something', 'app'], var1)
-
-  " ignore "append" with trim
-  let var1 =<< trim END
-  something
-  app
-  END
-  call assert_equal(['something', 'app'], var1)
-
-  let check = []
-  if 0
-     let check =<< trim END
-       from heredoc
-     END
-  endif
-  call assert_equal([], check)
-
-  " unpack assignment
-  let [a, b, c] =<< END
-     x
-     \y
-     z
-END
-  call assert_equal(['     x', '     \y', '     z'], [a, b, c])
-
-  " unpack assignment without whitespace
-  let[a,b,c]=<<END
-change
-insert
-append
-END
-  call assert_equal(['change', 'insert', 'append'], [a, b, c])
-
-  " curly braces name and list slice assignment
-  let foo_3_bar = ['', '', '']
-  let foo_{1 + 2}_bar[ : ] =<< END
-change
-insert
-append
-END
-  call assert_equal(['change', 'insert', 'append'], foo_3_bar)
-
-  " dictionary key containing brackets and spaces
-  let d = {'abc] 123': 'baz'}
-  let d[d['abc] 123'] .. '{'] =<< END
-change
-insert
-append
-END
-  call assert_equal(['change', 'insert', 'append'], d['baz{'])
-endfunc
-
-" Test for evaluating Vim expressions in a heredoc using {expr}
-" Keep near the end, this messes up highlighting.
-func Test_let_heredoc_eval()
-  let str = ''
-  let code =<< trim eval END
-    let a = {5 + 10}
-    let b = {min([10, 6])} + {max([4, 6])}
-    {str}
-    let c = "abc{str}d"
-  END
-  call assert_equal(['let a = 15', 'let b = 6 + 6', '', 'let c = "abcd"'], code)
-
-  let $TESTVAR = "Hello"
-  let code =<< eval trim END
-    let s = "{$TESTVAR}"
-  END
-  call assert_equal(['let s = "Hello"'], code)
-
-  let code =<< eval END
-    let s = "{$TESTVAR}"
-END
-  call assert_equal(['    let s = "Hello"'], code)
-
-  let a = 10
-  let data =<< eval END
-{a}
-END
-  call assert_equal(['10'], data)
-
-  let x = 'X'
-  let code =<< eval trim END
-    let a = {{abc}}
-    let b = {x}
-    let c = {{
-  END
-  call assert_equal(['let a = {abc}', 'let b = X', 'let c = {'], code)
-
-  let code = 'xxx'
-  let code =<< eval trim END
-    let n = {5 +
-    6}
-  END
-  call assert_equal('xxx', code)
-
-  let code =<< eval trim END
-     let n = {min([1, 2]} + {max([3, 4])}
-  END
-  call assert_equal('xxx', code)
-
-  let lines =<< trim LINES
-      let text =<< eval trim END
-        let b = {
-      END
-  LINES
-  call v9.CheckScriptFailure(lines, 'E1279:')
-
-  let lines =<< trim LINES
-      let text =<< eval trim END
-        let b = {abc
-      END
-  LINES
-  call v9.CheckScriptFailure(lines, 'E1279:')
-
-  let lines =<< trim LINES
-      let text =<< eval trim END
-        let b = {}
-      END
-  LINES
-  call v9.CheckScriptFailure(lines, 'E15:')
-
-  " skipped heredoc
-  if 0
-    let msg =<< trim eval END
-        n is: {n}
-    END
-  endif
-
-  " Test for sourcing a script containing a heredoc with invalid expression.
-  " Variable assignment should fail, if expression evaluation fails
-  new
-  let g:Xvar = 'test'
-  let g:b = 10
-  let lines =<< trim END
-    let Xvar =<< eval CODE
-    let a = 1
-    let b = {5+}
-    let c = 2
-    CODE
-    let g:Count += 1
-  END
-  call setline(1, lines)
-  let g:Count = 0
-  call assert_fails('source', 'E15:')
-  call assert_equal(1, g:Count)
-  call setline(3, 'let b = {abc}')
-  call assert_fails('source', 'E121:')
-  call assert_equal(2, g:Count)
-  call setline(3, 'let b = {abc} + {min([9, 4])} + 2')
-  call assert_fails('source', 'E121:')
-  call assert_equal(3, g:Count)
-  call assert_equal('test', g:Xvar)
-  call assert_equal(10, g:b)
-  bw!
-endfunc
-
-" vim: shiftwidth=2 sts=2 expandtab
+" Tests for the :let command.
+
+import './vim9.vim' as v9
+
+func Test_let()
+  " Test to not autoload when assigning.  It causes internal error.
+  set runtimepath+=./sautest
+  let Test104#numvar = function('tr')
+  call assert_equal("function('tr')", string(Test104#numvar))
+
+  let foo#tr = function('tr')
+  call assert_equal("function('tr')", string(foo#tr))
+  unlet foo#tr
+
+  let a = 1
+  let b = 2
+
+  let out = execute('let a b')
+  let s = "\na                     #1\nb                     #2"
+  call assert_equal(s, out)
+
+  let out = execute('let {0 == 1 ? "a" : "b"}')
+  let s = "\nb                     #2"
+  call assert_equal(s, out)
+
+  let out = execute('let {0 == 1 ? "a" : "b"} a')
+  let s = "\nb                     #2\na                     #1"
+  call assert_equal(s, out)
+
+  let out = execute('let a {0 == 1 ? "a" : "b"}')
+  let s = "\na                     #1\nb                     #2"
+  call assert_equal(s, out)
+
+  " Test for displaying a string variable
+  let s = 'vim'
+  let out = execute('let s')
+  let s = "\ns                      vim"
+  call assert_equal(s, out)
+
+  " Test for displaying a list variable
+  let l = [1, 2]
+  let out = execute('let l')
+  let s = "\nl                     [1, 2]"
+  call assert_equal(s, out)
+
+  " Test for displaying a dict variable
+  let d = {'k' : 'v'}
+  let out = execute('let d')
+  let s = "\nd                     {'k': 'v'}"
+  call assert_equal(s, out)
+
+  " Test for displaying a function reference variable
+  let F = function('min')
+  let out = execute('let F')
+  let s = "\nF                     *min()"
+  call assert_equal(s, out)
+
+  let x = 0
+  if 0 | let x = 1 | endif
+  call assert_equal(0, x)
+
+  " Display a list item using an out of range index
+  let l = [10]
+  call assert_fails('let l[1]', 'E684:')
+
+  " List special variable dictionaries
+  let g:Test_Global_Var = 5
+  call assert_match("\nTest_Global_Var       #5", execute('let g:'))
+  unlet g:Test_Global_Var
+
+  let b:Test_Buf_Var = 8
+  call assert_match("\nb:Test_Buf_Var        #8", execute('let b:'))
+  unlet b:Test_Buf_Var
+
+  let w:Test_Win_Var = 'foo'
+  call assert_equal("\nw:Test_Win_Var         foo", execute('let w:'))
+  unlet w:Test_Win_Var
+
+  let t:Test_Tab_Var = 'bar'
+  call assert_equal("\nt:Test_Tab_Var         bar", execute('let t:'))
+  unlet t:Test_Tab_Var
+
+  let s:Test_Script_Var = [7]
+  call assert_match("\ns:Test_Script_Var     \\[7]", execute('let s:'))
+  unlet s:Test_Script_Var
+
+  let l:Test_Local_Var = {'k' : 5}
+  call assert_match("\nl:Test_Local_Var      {'k': 5}", execute('let l:'))
+  call assert_match("v:errors              []", execute('let v:'))
+
+  " Test for assigning multiple list items
+  let l = [1, 2, 3]
+  let [l[0], l[1]] = [10, 20]
+  call assert_equal([10, 20, 3], l)
+
+  " Test for errors in conditional expression
+  call assert_fails('let val = [] ? 1 : 2', 'E745:')
+  call assert_fails('let val = 1 ? 5+ : 6', 'E121:')
+  call assert_fails('let val = 1 ? 0 : 5+', 'E15:')
+  call assert_false(exists('val'))
+
+  " Test for errors in logical operators
+  let @a = 'if [] || 0 | let val = 2 | endif'
+  call assert_fails('exe @a', 'E745:')
+  call assert_fails('call feedkeys(":let val = 0 || []\<cr>", "xt")', 'E745:')
+  call assert_fails('exe "let val = [] && 5"', 'E745:')
+  call assert_fails('exe "let val = 6 && []"', 'E745:')
+endfunc
+
+func s:set_arg1(a) abort
+  let a:a = 1
+endfunction
+
+func s:set_arg2(a) abort
+  let a:b = 1
+endfunction
+
+func s:set_arg3(a) abort
+  let b = a:
+  let b['a'] = 1
+endfunction
+
+func s:set_arg4(a) abort
+  let b = a:
+  let b['a'] = 1
+endfunction
+
+func s:set_arg5(a) abort
+  let b = a:
+  let b['a'][0] = 1
+endfunction
+
+func s:set_arg6(a) abort
+  let a:a[0] = 1
+endfunction
+
+func s:set_arg7(a) abort
+  call extend(a:, {'a': 1})
+endfunction
+
+func s:set_arg8(a) abort
+  call extend(a:, {'b': 1})
+endfunction
+
+func s:set_arg9(a) abort
+  let a:['b'] = 1
+endfunction
+
+func s:set_arg10(a) abort
+  let b = a:
+  call extend(b, {'a': 1})
+endfunction
+
+func s:set_arg11(a) abort
+  let b = a:
+  call extend(b, {'b': 1})
+endfunction
+
+func s:set_arg12(a) abort
+  let b = a:
+  let b['b'] = 1
+endfunction
+
+func Test_let_arg_fail()
+  call assert_fails('call s:set_arg1(1)', 'E46:')
+  call assert_fails('call s:set_arg2(1)', 'E461:')
+  call assert_fails('call s:set_arg3(1)', 'E46:')
+  call assert_fails('call s:set_arg4(1)', 'E46:')
+  call assert_fails('call s:set_arg5(1)', 'E46:')
+  call s:set_arg6([0])
+  call assert_fails('call s:set_arg7(1)', 'E742:')
+  call assert_fails('call s:set_arg8(1)', 'E742:')
+  call assert_fails('call s:set_arg9(1)', 'E461:')
+  call assert_fails('call s:set_arg10(1)', 'E742:')
+  call assert_fails('call s:set_arg11(1)', 'E742:')
+  call assert_fails('call s:set_arg12(1)', 'E461:')
+endfunction
+
+func s:set_varg1(...) abort
+  let a:000 = []
+endfunction
+
+func s:set_varg2(...) abort
+  let a:000[0] = 1
+endfunction
+
+func s:set_varg3(...) abort
+  let a:000 += [1]
+endfunction
+
+func s:set_varg4(...) abort
+  call add(a:000, 1)
+endfunction
+
+func s:set_varg5(...) abort
+  let a:000[0][0] = 1
+endfunction
+
+func s:set_varg6(...) abort
+  let b = a:000
+  let b[0] = 1
+endfunction
+
+func s:set_varg7(...) abort
+  let b = a:000
+  let b += [1]
+endfunction
+
+func s:set_varg8(...) abort
+  let b = a:000
+  call add(b, 1)
+endfunction
+
+func s:set_varg9(...) abort
+  let b = a:000
+  let b[0][0] = 1
+endfunction
+
+func Test_let_varg_fail()
+  call assert_fails('call s:set_varg1(1)', 'E46:')
+  call assert_fails('call s:set_varg2(1)', 'E742:')
+  call assert_fails('call s:set_varg3(1)', 'E46:')
+  call assert_fails('call s:set_varg4(1)', 'E742:')
+  call s:set_varg5([0])
+  call assert_fails('call s:set_varg6(1)', 'E742:')
+  call assert_fails('call s:set_varg7(1)', 'E742:')
+  call assert_fails('call s:set_varg8(1)', 'E742:')
+  call s:set_varg9([0])
+endfunction
+
+func Test_let_utf8_environment()
+  let $a = 'ĀĒĪŌŪあいうえお'
+  call assert_equal('ĀĒĪŌŪあいうえお', $a)
+endfunc
+
+func Test_let_no_type_checking()
+  let v = 1
+  let v = [1,2,3]
+  let v = {'a': 1, 'b': 2}
+  let v = 3.4
+  let v = 'hello'
+endfunc
+
+func Test_let_termcap()
+  " Terminal code
+  let old_t_te = &t_te
+  let &t_te = "\<Esc>[yes;"
+  call assert_match('t_te.*^[[yes;', execute("set termcap"))
+  let &t_te = old_t_te
+
+  if exists("+t_k1")
+    " Key code
+    let old_t_k1 = &t_k1
+    let &t_k1 = "that"
+    call assert_match('t_k1.*that', execute("set termcap"))
+    let &t_k1 = old_t_k1
+  endif
+
+  call assert_fails('let x = &t_xx', 'E113:')
+  let &t_xx = "yes"
+  call assert_equal("yes", &t_xx)
+  let &t_xx = ""
+  call assert_fails('let x = &t_xx', 'E113:')
+endfunc
+
+func Test_let_option_error()
+  let _w = &tw
+  let &tw = 80
+  call assert_fails('let &tw .= 1', ['E734:', 'E734:'])
+  call assert_fails('let &tw .= []', ['E734:', 'E734:'])
+  call assert_fails('let &tw = []', ['E745:', 'E745:'])
+  call assert_fails('let &tw += []', ['E745:', 'E745:'])
+  call assert_equal(80, &tw)
+  let &tw = _w
+
+  let _w = &autoread
+  let &autoread = 1
+  call assert_fails('let &autoread .= 1', ['E734:', 'E734:'])
+  call assert_fails('let &autoread .= []', ['E734:', 'E734:'])
+  call assert_fails('let &autoread = []', ['E745:', 'E745:'])
+  call assert_fails('let &autoread += []', ['E745:', 'E745:'])
+  call assert_equal(1, &autoread)
+  let &autoread = _w
+
+  let _w = &fillchars
+  let &fillchars = "vert:|"
+  call assert_fails('let &fillchars += "diff:-"', ['E734:', 'E734:'])
+  call assert_fails('let &fillchars += []', ['E734:', 'E734:'])
+  call assert_fails('let &fillchars = []', ['E730:', 'E730:'])
+  call assert_fails('let &fillchars .= []', ['E730:', 'E730:'])
+  call assert_equal("vert:|", &fillchars)
+  let &fillchars = _w
+
+  call assert_fails('let &nosuchoption = 1', ['E355:', 'E355:'])
+  call assert_fails('let &nosuchoption = ""', ['E355:', 'E355:'])
+  call assert_fails('let &nosuchoption = []', ['E355:', 'E355:'])
+  call assert_fails('let &t_xx = []', ['E730:', 'E730:'])
+endfunc
+
+" Errors with the :let statement
+func Test_let_errors()
+  let s = 'abcd'
+  call assert_fails('let s[1] = 5', 'E689:')
+
+  let l = [1, 2, 3]
+  call assert_fails('let l[:] = 5', 'E709:')
+
+  call assert_fails('let x:lnum=5', ['E121:', 'E121:'])
+  call assert_fails('let v:=5', 'E461:')
+  call assert_fails('let [a]', 'E474:')
+  call assert_fails('let [a, b] = [', 'E697:')
+  call assert_fails('let [a, b] = [10, 20', 'E696:')
+  call assert_fails('let [a, b] = 10', 'E714:')
+  call assert_fails('let [a, , b] = [10, 20]', 'E475:')
+  call assert_fails('let [a, b&] = [10, 20]', 'E475:')
+  call assert_fails('let $ = 10', 'E475:')
+  call assert_fails('let $FOO[1] = "abc"', 'E18:')
+  call assert_fails('let &buftype[1] = "nofile"', 'E18:')
+  let s = "var"
+  let var = 1
+  call assert_fails('let var += [1,2]', 'E734:')
+  call assert_fails('let {s}.1 = 2', 'E1203:')
+  call assert_fails('let a[1] = 5', 'E121:')
+  let l = [[1,2]]
+  call assert_fails('let l[:][0] = [5]', 'E708:')
+  let d = {'k' : 4}
+  call assert_fails('let d.# = 5', 'E488:')
+  call assert_fails('let d.m += 5', 'E716:')
+  call assert_fails('let m = d[{]', 'E15:')
+  let l = [1, 2]
+  call assert_fails('let l[2] = 0', 'E684:')
+  call assert_fails('let l[0:1] = [1, 2, 3]', 'E710:')
+  call assert_fails('let l[-2:-3] = [3, 4]', 'E684:')
+  call assert_fails('let l[0:4] = [5, 6]', 'E711:')
+  call assert_fails('let l -= 2', 'E734:')
+  call assert_fails('let l += 2', 'E734:')
+  call assert_fails('let g:["a;b"] = 10', 'E461:')
+  call assert_fails('let g:.min = function("max")', 'E704:')
+  call assert_fails('let g:cos = "" | let g:.cos = {-> 42}', 'E704:')
+  if has('channel')
+    let ch = test_null_channel()
+    call assert_fails('let ch += 1', 'E734:')
+  endif
+  call assert_fails('let name = "a" .. "b",', 'E488: Trailing characters: ,')
+
+  " This test works only when the language is English
+  if v:lang == "C" || v:lang =~ '^[Ee]n'
+    call assert_fails('let [a ; b;] = [10, 20]',
+          \ 'Double ; in list of variables')
+  endif
+endfunc
+
+func Test_let_heredoc_fails()
+  call assert_fails('let v =<< marker', 'E991:')
+  try
+    exe "let v =<< TEXT | abc | TEXT"
+    call assert_report('No exception thrown')
+  catch /E488:/
+  catch
+    call assert_report('Caught exception: ' .. v:exception)
+  endtry
+
+  try
+    let &commentstring =<< trim TEXT
+      change
+      insert
+      append
+    TEXT
+    call assert_report('No exception thrown')
+  catch /E730:/
+  catch
+    call assert_report('Caught exception: ' .. v:exception)
+  endtry
+
+  try
+    let $SOME_ENV_VAR =<< trim TEXT
+      change
+      insert
+      append
+    TEXT
+    call assert_report('No exception thrown')
+  catch /E730:/
+  catch
+    call assert_report('Caught exception: ' .. v:exception)
+  endtry
+
+  try
+    let @r =<< trim TEXT
+      change
+      insert
+      append
+    TEXT
+    call assert_report('No exception thrown')
+  catch /E730:/
+  catch
+    call assert_report('Caught exception: ' .. v:exception)
+  endtry
+
+  let text =<< trim END
+  func WrongSyntax()
+    let v =<< that there
+  endfunc
+  END
+  call writefile(text, 'XheredocFail', 'D')
+  call assert_fails('source XheredocFail', 'E1145:')
+
+  let text =<< trim CodeEnd
+  func MissingEnd()
+    let v =<< END
+  endfunc
+  CodeEnd
+  call writefile(text, 'XheredocWrong', 'D')
+  call assert_fails('source XheredocWrong', 'E1145:')
+
+  let text =<< trim TEXTend
+    let v =<< " comment
+  TEXTend
+  call writefile(text, 'XheredocNoMarker', 'D')
+  call assert_fails('source XheredocNoMarker', 'E172:')
+
+  let text =<< trim TEXTend
+    let v =<< text
+  TEXTend
+  call writefile(text, 'XheredocBadMarker', 'D')
+  call assert_fails('source XheredocBadMarker', 'E221:')
+
+  call writefile(['let v =<< TEXT', 'abc'], 'XheredocMissingMarker', 'D')
+  call assert_fails('source XheredocMissingMarker', 'E990:')
+endfunc
+
+func Test_let_heredoc_trim_no_indent_marker()
+  let text =<< trim END
+  Text
+  with
+  indent
+END
+  call assert_equal(['Text', 'with', 'indent'], text)
+endfunc
+
+func Test_let_interpolated()
+  call assert_equal('{text}', $'{{text}}')
+  call assert_equal('{{text}}', $'{{{{text}}}}')
+  let text = 'text'
+  call assert_equal('text{{', $'{text .. "{{"}')
+  call assert_equal('text{{', $"{text .. '{{'}")
+  call assert_equal('text{{', $'{text .. '{{'}')
+  call assert_equal('text{{', $"{text .. "{{"}")
+endfunc
+
+" Test for the setting a variable using the heredoc syntax.
+" Keep near the end, this messes up highlighting.
+func Test_let_heredoc()
+  let var1 =<< END
+Some sample text
+	Text with indent
+  !@#$%^&*()-+_={}|[]\~`:";'<>?,./
+END
+
+  call assert_equal(["Some sample text", "\tText with indent", "  !@#$%^&*()-+_={}|[]\\~`:\";'<>?,./"], var1)
+
+  let var2 =<< XXX
+Editor
+XXX
+  call assert_equal(['Editor'], var2)
+
+  let var3 =<<END
+END
+  call assert_equal([], var3)
+
+  let var3 =<<END
+vim
+
+end
+  END
+END 
+END
+  call assert_equal(['vim', '', 'end', '  END', 'END '], var3)
+
+	let var1 =<< trim END
+	Line1
+	  Line2
+		Line3
+	 END
+	END
+  call assert_equal(['Line1', '  Line2', "\tLine3", ' END'], var1)
+
+  let var1 =<< trim !!!
+	Line1
+	 line2
+		Line3
+	!!!
+  !!!
+  call assert_equal(['Line1', ' line2', "\tLine3", '!!!',], var1)
+
+  let var1 =<< trim XX
+    Line1
+  XX
+  call assert_equal(['Line1'], var1)
+
+  " ignore "endfunc"
+  let var1 =<< END
+something
+endfunc
+END
+  call assert_equal(['something', 'endfunc'], var1)
+
+  " ignore "endfunc" with trim
+  let var1 =<< trim END
+  something
+  endfunc
+  END
+  call assert_equal(['something', 'endfunc'], var1)
+
+  " not concatenate lines
+  let var1 =<< END
+some
+  \thing
+  \ else
+END
+  call assert_equal(['some', '  \thing', '  \ else'], var1)
+
+  " ignore "python << xx"
+  let var1 =<<END
+something
+python << xx
+END
+  call assert_equal(['something', 'python << xx'], var1)
+
+  " ignore "python << xx" with trim
+  let var1 =<< trim END
+  something
+  python << xx
+  END
+  call assert_equal(['something', 'python << xx'], var1)
+
+  " ignore "append"
+  let var1 =<< E
+something
+app
+E
+  call assert_equal(['something', 'app'], var1)
+
+  " ignore "append" with trim
+  let var1 =<< trim END
+  something
+  app
+  END
+  call assert_equal(['something', 'app'], var1)
+
+  let check = []
+  if 0
+     let check =<< trim END
+       from heredoc
+     END
+  endif
+  call assert_equal([], check)
+
+  " unpack assignment
+  let [a, b, c] =<< END
+     x
+     \y
+     z
+END
+  call assert_equal(['     x', '     \y', '     z'], [a, b, c])
+
+  " unpack assignment without whitespace
+  let[a,b,c]=<<END
+change
+insert
+append
+END
+  call assert_equal(['change', 'insert', 'append'], [a, b, c])
+
+  " curly braces name and list slice assignment
+  let foo_3_bar = ['', '', '']
+  let foo_{1 + 2}_bar[ : ] =<< END
+change
+insert
+append
+END
+  call assert_equal(['change', 'insert', 'append'], foo_3_bar)
+
+  " dictionary key containing brackets and spaces
+  let d = {'abc] 123': 'baz'}
+  let d[d['abc] 123'] .. '{'] =<< END
+change
+insert
+append
+END
+  call assert_equal(['change', 'insert', 'append'], d['baz{'])
+endfunc
+
+" Test for evaluating Vim expressions in a heredoc using {expr}
+" Keep near the end, this messes up highlighting.
+func Test_let_heredoc_eval()
+  let str = ''
+  let code =<< trim eval END
+    let a = {5 + 10}
+    let b = {min([10, 6])} + {max([4, 6])}
+    {str}
+    let c = "abc{str}d"
+  END
+  call assert_equal(['let a = 15', 'let b = 6 + 6', '', 'let c = "abcd"'], code)
+
+  let $TESTVAR = "Hello"
+  let code =<< eval trim END
+    let s = "{$TESTVAR}"
+  END
+  call assert_equal(['let s = "Hello"'], code)
+
+  let code =<< eval END
+    let s = "{$TESTVAR}"
+END
+  call assert_equal(['    let s = "Hello"'], code)
+
+  let a = 10
+  let data =<< eval END
+{a}
+END
+  call assert_equal(['10'], data)
+
+  let x = 'X'
+  let code =<< eval trim END
+    let a = {{abc}}
+    let b = {x}
+    let c = {{
+  END
+  call assert_equal(['let a = {abc}', 'let b = X', 'let c = {'], code)
+
+  let code = 'xxx'
+  let code =<< eval trim END
+    let n = {5 +
+    6}
+  END
+  call assert_equal('xxx', code)
+
+  let code =<< eval trim END
+     let n = {min([1, 2]} + {max([3, 4])}
+  END
+  call assert_equal('xxx', code)
+
+  let lines =<< trim LINES
+      let text =<< eval trim END
+        let b = {
+      END
+  LINES
+  call v9.CheckScriptFailure(lines, 'E1279:')
+
+  let lines =<< trim LINES
+      let text =<< eval trim END
+        let b = {abc
+      END
+  LINES
+  call v9.CheckScriptFailure(lines, 'E1279:')
+
+  let lines =<< trim LINES
+      let text =<< eval trim END
+        let b = {}
+      END
+  LINES
+  call v9.CheckScriptFailure(lines, 'E15:')
+
+  " skipped heredoc
+  if 0
+    let msg =<< trim eval END
+        n is: {n}
+    END
+  endif
+
+  " Test for sourcing a script containing a heredoc with invalid expression.
+  " Variable assignment should fail, if expression evaluation fails
+  new
+  let g:Xvar = 'test'
+  let g:b = 10
+  let lines =<< trim END
+    let Xvar =<< eval CODE
+    let a = 1
+    let b = {5+}
+    let c = 2
+    CODE
+    let g:Count += 1
+  END
+  call setline(1, lines)
+  let g:Count = 0
+  call assert_fails('source', 'E15:')
+  call assert_equal(1, g:Count)
+  call setline(3, 'let b = {abc}')
+  call assert_fails('source', 'E121:')
+  call assert_equal(2, g:Count)
+  call setline(3, 'let b = {abc} + {min([9, 4])} + 2')
+  call assert_fails('source', 'E121:')
+  call assert_equal(3, g:Count)
+  call assert_equal('test', g:Xvar)
+  call assert_equal(10, g:b)
+  bw!
+endfunc
+
+" vim: shiftwidth=2 sts=2 expandtab