diff --git a/src/testdir/Make_all.mak b/src/testdir/Make_all.mak
index db74f05..772c083 100644
--- a/src/testdir/Make_all.mak
+++ b/src/testdir/Make_all.mak
@@ -45,12 +45,14 @@
 
 # Tests for Vim9 script.
 TEST_VIM9 = \
+	test_vim9_cmd \
 	test_vim9_disassemble \
 	test_vim9_expr \
 	test_vim9_func \
 	test_vim9_script
 
 TEST_VIM9_RES = \
+	test_vim9_cmd.res \
 	test_vim9_disassemble.res \
 	test_vim9_expr.res \
 	test_vim9_func.res \
diff --git a/src/testdir/test_vim9_cmd.vim b/src/testdir/test_vim9_cmd.vim
new file mode 100644
index 0000000..7ccd1f7
--- /dev/null
+++ b/src/testdir/test_vim9_cmd.vim
@@ -0,0 +1,23 @@
+" Test commands that are not compiled in a :def function
+
+source vim9.vim
+
+def Test_edit_wildcards()
+  let filename = 'Xtest'
+  edit `=filename`
+  assert_equal('Xtest', bufname())
+
+  let filenr = 123
+  edit Xtest`=filenr`
+  assert_equal('Xtest123', bufname())
+
+  filenr = 77
+  edit `=filename``=filenr`
+  assert_equal('Xtest77', bufname())
+
+  edit X`=filename`xx`=filenr`yy
+  assert_equal('XXtestxx77yy', bufname())
+enddef
+
+
+" vim: ts=8 sw=2 sts=2 expandtab tw=80 fdm=marker
diff --git a/src/testdir/test_vim9_disassemble.vim b/src/testdir/test_vim9_disassemble.vim
index 89ca66f..4e2caf0 100644
--- a/src/testdir/test_vim9_disassemble.vim
+++ b/src/testdir/test_vim9_disassemble.vim
@@ -53,6 +53,32 @@
         res)
 enddef
 
+def s:EditExpand()
+  let filename = "file"
+  let filenr = 123
+  edit the`=filename``=filenr`.txt
+enddef
+
+def Test_disassemble_exec_expr()
+  let res = execute('disass s:EditExpand')
+  assert_match('<SNR>\d*_EditExpand.*' ..
+        ' let filename = "file".*' ..
+        '\d PUSHS "file".*' ..
+        '\d STORE $0.*' ..
+        ' let filenr = 123.*' ..
+        '\d STORE 123 in $1.*' ..
+        ' edit the`=filename``=filenr`.txt.*' ..
+        '\d PUSHS "edit the".*' ..
+        '\d LOAD $0.*' ..
+        '\d LOAD $1.*' ..
+        '\d 2STRING stack\[-1\].*' ..
+        '\d PUSHS ".txt".*' ..
+        '\d EXECCONCAT 4.*' ..
+        '\d PUSHNR 0.*' ..
+        '\d RETURN',
+        res)
+enddef
+
 def s:ScriptFuncPush()
   let localbool = true
   let localspec = v:none
diff --git a/src/testdir/test_vim9_expr.vim b/src/testdir/test_vim9_expr.vim
index fe3752c..42a9926 100644
--- a/src/testdir/test_vim9_expr.vim
+++ b/src/testdir/test_vim9_expr.vim
@@ -1,33 +1,7 @@
 " Tests for Vim9 script expressions
 
 source check.vim
-
-" Check that "line" inside ":def" results in an "error" message.
-func CheckDefFailure(line, error)
-  call writefile(['def! Func()', a:line, 'enddef'], 'Xdef')
-  call assert_fails('so Xdef', a:error, a:line)
-  call delete('Xdef')
-endfunc
-
-func CheckDefFailureMult(lines, error)
-  call writefile(['def! Func()'] + a:lines + ['enddef'], 'Xdef')
-  call assert_fails('so Xdef', a:error, join(a:lines, ' | '))
-  call delete('Xdef')
-endfunc
-
-" Check that "line" inside ":def" results in an "error" message when executed.
-func CheckDefExecFailure(line, error)
-  call writefile(['def! Func()', a:line, 'enddef'], 'Xdef')
-  so Xdef
-  call assert_fails('call Func()', a:error, a:line)
-  call delete('Xdef')
-endfunc
-
-func CheckDefFailureList(lines, error)
-  call writefile(['def! Func()'] + a:lines + ['enddef'], 'Xdef')
-  call assert_fails('so Xdef', a:error, string(a:lines))
-  call delete('Xdef')
-endfunc
+source vim9.vim
 
 " test cond ? expr : expr
 def Test_expr1()
@@ -59,18 +33,18 @@
 enddef
 
 func Test_expr1_fails()
-  call CheckDefFailure("let x = 1 ? 'one'", "Missing ':' after '?'")
-  call CheckDefFailure("let x = 1 ? 'one' : xxx", "E1001:")
+  call CheckDefFailure(["let x = 1 ? 'one'"], "Missing ':' after '?'")
+  call CheckDefFailure(["let x = 1 ? 'one' : xxx"], "E1001:")
 
   let msg = "white space required before and after '?'"
-  call CheckDefFailure("let x = 1? 'one' : 'two'", msg)
-  call CheckDefFailure("let x = 1 ?'one' : 'two'", msg)
-  call CheckDefFailure("let x = 1?'one' : 'two'", msg)
+  call CheckDefFailure(["let x = 1? 'one' : 'two'"], msg)
+  call CheckDefFailure(["let x = 1 ?'one' : 'two'"], msg)
+  call CheckDefFailure(["let x = 1?'one' : 'two'"], msg)
 
   let msg = "white space required before and after ':'"
-  call CheckDefFailure("let x = 1 ? 'one': 'two'", msg)
-  call CheckDefFailure("let x = 1 ? 'one' :'two'", msg)
-  call CheckDefFailure("let x = 1 ? 'one':'two'", msg)
+  call CheckDefFailure(["let x = 1 ? 'one': 'two'"], msg)
+  call CheckDefFailure(["let x = 1 ? 'one' :'two'"], msg)
+  call CheckDefFailure(["let x = 1 ? 'one':'two'"], msg)
 endfunc
 
 " TODO: define inside test function
@@ -107,11 +81,11 @@
 
 func Test_expr2_fails()
   let msg = "white space required before and after '||'"
-  call CheckDefFailure("let x = 1||2", msg)
-  call CheckDefFailure("let x = 1 ||2", msg)
-  call CheckDefFailure("let x = 1|| 2", msg)
+  call CheckDefFailure(["let x = 1||2"], msg)
+  call CheckDefFailure(["let x = 1 ||2"], msg)
+  call CheckDefFailure(["let x = 1|| 2"], msg)
 
-  call CheckDefFailure("let x = 1 || xxx", 'E1001:')
+  call CheckDefFailure(["let x = 1 || xxx"], 'E1001:')
 endfunc
 
 " test &&
@@ -148,9 +122,9 @@
 
 func Test_expr3_fails()
   let msg = "white space required before and after '&&'"
-  call CheckDefFailure("let x = 1&&2", msg)
-  call CheckDefFailure("let x = 1 &&2", msg)
-  call CheckDefFailure("let x = 1&& 2", msg)
+  call CheckDefFailure(["let x = 1&&2"], msg)
+  call CheckDefFailure(["let x = 1 &&2"], msg)
+  call CheckDefFailure(["let x = 1&& 2"], msg)
 endfunc
 
 let atrue = v:true
@@ -212,7 +186,7 @@
   assert_equal(false, 'abc' ==# 'ABC')
   set noignorecase
 
-  call CheckDefFailure("let x = 'a' == xxx", 'E1001:')
+  call CheckDefFailure(["let x = 'a' == xxx"], 'E1001:')
 
   assert_equal(true, 0z3f == 0z3f)
   assert_equal(false, 0z3f == 0z4f)
@@ -413,71 +387,71 @@
 
 func Test_expr4_fails()
   let msg = "white space required before and after '>'"
-  call CheckDefFailure("let x = 1>2", msg)
-  call CheckDefFailure("let x = 1 >2", msg)
-  call CheckDefFailure("let x = 1> 2", msg)
+  call CheckDefFailure(["let x = 1>2"], msg)
+  call CheckDefFailure(["let x = 1 >2"], msg)
+  call CheckDefFailure(["let x = 1> 2"], msg)
 
   let msg = "white space required before and after '=='"
-  call CheckDefFailure("let x = 1==2", msg)
-  call CheckDefFailure("let x = 1 ==2", msg)
-  call CheckDefFailure("let x = 1== 2", msg)
+  call CheckDefFailure(["let x = 1==2"], msg)
+  call CheckDefFailure(["let x = 1 ==2"], msg)
+  call CheckDefFailure(["let x = 1== 2"], msg)
 
   let msg = "white space required before and after 'is'"
-  call CheckDefFailure("let x = '1'is'2'", msg)
-  call CheckDefFailure("let x = '1' is'2'", msg)
-  call CheckDefFailure("let x = '1'is '2'", msg)
+  call CheckDefFailure(["let x = '1'is'2'"], msg)
+  call CheckDefFailure(["let x = '1' is'2'"], msg)
+  call CheckDefFailure(["let x = '1'is '2'"], msg)
 
   let msg = "white space required before and after 'isnot'"
-  call CheckDefFailure("let x = '1'isnot'2'", msg)
-  call CheckDefFailure("let x = '1' isnot'2'", msg)
-  call CheckDefFailure("let x = '1'isnot '2'", msg)
+  call CheckDefFailure(["let x = '1'isnot'2'"], msg)
+  call CheckDefFailure(["let x = '1' isnot'2'"], msg)
+  call CheckDefFailure(["let x = '1'isnot '2'"], msg)
 
-  call CheckDefFailure("let x = 1 is# 2", 'E15:')
-  call CheckDefFailure("let x = 1 is? 2", 'E15:')
-  call CheckDefFailure("let x = 1 isnot# 2", 'E15:')
-  call CheckDefFailure("let x = 1 isnot? 2", 'E15:')
+  call CheckDefFailure(["let x = 1 is# 2"], 'E15:')
+  call CheckDefFailure(["let x = 1 is? 2"], 'E15:')
+  call CheckDefFailure(["let x = 1 isnot# 2"], 'E15:')
+  call CheckDefFailure(["let x = 1 isnot? 2"], 'E15:')
 
-  call CheckDefFailure("let x = 1 == '2'", 'Cannot compare number with string')
-  call CheckDefFailure("let x = '1' == 2", 'Cannot compare string with number')
-  call CheckDefFailure("let x = 1 == RetVoid()", 'Cannot use void value')
-  call CheckDefFailure("let x = RetVoid() == 1", 'Cannot compare void with number')
+  call CheckDefFailure(["let x = 1 == '2'"], 'Cannot compare number with string')
+  call CheckDefFailure(["let x = '1' == 2"], 'Cannot compare string with number')
+  call CheckDefFailure(["let x = 1 == RetVoid()"], 'Cannot use void value')
+  call CheckDefFailure(["let x = RetVoid() == 1"], 'Cannot compare void with number')
 
-  call CheckDefFailure("let x = true > false", 'Cannot compare bool with bool')
-  call CheckDefFailure("let x = true >= false", 'Cannot compare bool with bool')
-  call CheckDefFailure("let x = true < false", 'Cannot compare bool with bool')
-  call CheckDefFailure("let x = true <= false", 'Cannot compare bool with bool')
-  call CheckDefFailure("let x = true =~ false", 'Cannot compare bool with bool')
-  call CheckDefFailure("let x = true !~ false", 'Cannot compare bool with bool')
-  call CheckDefFailure("let x = true is false", 'Cannot use "is" with bool')
-  call CheckDefFailure("let x = true isnot false", 'Cannot use "isnot" with bool')
+  call CheckDefFailure(["let x = true > false"], 'Cannot compare bool with bool')
+  call CheckDefFailure(["let x = true >= false"], 'Cannot compare bool with bool')
+  call CheckDefFailure(["let x = true < false"], 'Cannot compare bool with bool')
+  call CheckDefFailure(["let x = true <= false"], 'Cannot compare bool with bool')
+  call CheckDefFailure(["let x = true =~ false"], 'Cannot compare bool with bool')
+  call CheckDefFailure(["let x = true !~ false"], 'Cannot compare bool with bool')
+  call CheckDefFailure(["let x = true is false"], 'Cannot use "is" with bool')
+  call CheckDefFailure(["let x = true isnot false"], 'Cannot use "isnot" with bool')
 
-  call CheckDefFailure("let x = v:none is v:null", 'Cannot use "is" with special')
-  call CheckDefFailure("let x = v:none isnot v:null", 'Cannot use "isnot" with special')
-  call CheckDefFailure("let x = 123 is 123", 'Cannot use "is" with number')
-  call CheckDefFailure("let x = 123 isnot 123", 'Cannot use "isnot" with number')
+  call CheckDefFailure(["let x = v:none is v:null"], 'Cannot use "is" with special')
+  call CheckDefFailure(["let x = v:none isnot v:null"], 'Cannot use "isnot" with special')
+  call CheckDefFailure(["let x = 123 is 123"], 'Cannot use "is" with number')
+  call CheckDefFailure(["let x = 123 isnot 123"], 'Cannot use "isnot" with number')
   if has('float')
-    call CheckDefFailure("let x = 1.3 is 1.3", 'Cannot use "is" with float')
-    call CheckDefFailure("let x = 1.3 isnot 1.3", 'Cannot use "isnot" with float')
+    call CheckDefFailure(["let x = 1.3 is 1.3"], 'Cannot use "is" with float')
+    call CheckDefFailure(["let x = 1.3 isnot 1.3"], 'Cannot use "isnot" with float')
   endif
 
-  call CheckDefFailure("let x = 0za1 > 0z34", 'Cannot compare blob with blob')
-  call CheckDefFailure("let x = 0za1 >= 0z34", 'Cannot compare blob with blob')
-  call CheckDefFailure("let x = 0za1 < 0z34", 'Cannot compare blob with blob')
-  call CheckDefFailure("let x = 0za1 <= 0z34", 'Cannot compare blob with blob')
-  call CheckDefFailure("let x = 0za1 =~ 0z34", 'Cannot compare blob with blob')
-  call CheckDefFailure("let x = 0za1 !~ 0z34", 'Cannot compare blob with blob')
+  call CheckDefFailure(["let x = 0za1 > 0z34"], 'Cannot compare blob with blob')
+  call CheckDefFailure(["let x = 0za1 >= 0z34"], 'Cannot compare blob with blob')
+  call CheckDefFailure(["let x = 0za1 < 0z34"], 'Cannot compare blob with blob')
+  call CheckDefFailure(["let x = 0za1 <= 0z34"], 'Cannot compare blob with blob')
+  call CheckDefFailure(["let x = 0za1 =~ 0z34"], 'Cannot compare blob with blob')
+  call CheckDefFailure(["let x = 0za1 !~ 0z34"], 'Cannot compare blob with blob')
 
-  call CheckDefFailure("let x = [13] > [88]", 'Cannot compare list with list')
-  call CheckDefFailure("let x = [13] >= [88]", 'Cannot compare list with list')
-  call CheckDefFailure("let x = [13] < [88]", 'Cannot compare list with list')
-  call CheckDefFailure("let x = [13] <= [88]", 'Cannot compare list with list')
-  call CheckDefFailure("let x = [13] =~ [88]", 'Cannot compare list with list')
-  call CheckDefFailure("let x = [13] !~ [88]", 'Cannot compare list with list')
+  call CheckDefFailure(["let x = [13] > [88]"], 'Cannot compare list with list')
+  call CheckDefFailure(["let x = [13] >= [88]"], 'Cannot compare list with list')
+  call CheckDefFailure(["let x = [13] < [88]"], 'Cannot compare list with list')
+  call CheckDefFailure(["let x = [13] <= [88]"], 'Cannot compare list with list')
+  call CheckDefFailure(["let x = [13] =~ [88]"], 'Cannot compare list with list')
+  call CheckDefFailure(["let x = [13] !~ [88]"], 'Cannot compare list with list')
 
-  call CheckDefFailureMult(['let j: job', 'let chan: channel', 'let r = j == chan'], 'Cannot compare job with channel')
-  call CheckDefFailureMult(['let j: job', 'let x: list<any>', 'let r = j == x'], 'Cannot compare job with list')
-  call CheckDefFailureMult(['let j: job', 'let Xx: func', 'let r = j == Xx'], 'Cannot compare job with func')
-  call CheckDefFailureMult(['let j: job', 'let Xx: func', 'let r = j == Xx'], 'Cannot compare job with func')
+  call CheckDefFailure(['let j: job', 'let chan: channel', 'let r = j == chan'], 'Cannot compare job with channel')
+  call CheckDefFailure(['let j: job', 'let x: list<any>', 'let r = j == x'], 'Cannot compare job with list')
+  call CheckDefFailure(['let j: job', 'let Xx: func', 'let r = j == Xx'], 'Cannot compare job with func')
+  call CheckDefFailure(['let j: job', 'let Xx: func', 'let r = j == Xx'], 'Cannot compare job with func')
 endfunc
 
 " test addition, subtraction, concatenation
@@ -532,27 +506,27 @@
 
 func Test_expr5_fails()
   let msg = "white space required before and after '+'"
-  call CheckDefFailure("let x = 1+2", msg)
-  call CheckDefFailure("let x = 1 +2", msg)
-  call CheckDefFailure("let x = 1+ 2", msg)
+  call CheckDefFailure(["let x = 1+2"], msg)
+  call CheckDefFailure(["let x = 1 +2"], msg)
+  call CheckDefFailure(["let x = 1+ 2"], msg)
 
   let msg = "white space required before and after '-'"
-  call CheckDefFailure("let x = 1-2", msg)
-  call CheckDefFailure("let x = 1 -2", msg)
-  call CheckDefFailure("let x = 1- 2", msg)
+  call CheckDefFailure(["let x = 1-2"], msg)
+  call CheckDefFailure(["let x = 1 -2"], msg)
+  call CheckDefFailure(["let x = 1- 2"], msg)
 
   let msg = "white space required before and after '..'"
-  call CheckDefFailure("let x = '1'..'2'", msg)
-  call CheckDefFailure("let x = '1' ..'2'", msg)
-  call CheckDefFailure("let x = '1'.. '2'", msg)
+  call CheckDefFailure(["let x = '1'..'2'"], msg)
+  call CheckDefFailure(["let x = '1' ..'2'"], msg)
+  call CheckDefFailure(["let x = '1'.. '2'"], msg)
 
-  call CheckDefFailure("let x = 0z1122 + 33", 'E1035')
-  call CheckDefFailure("let x = 0z1122 + [3]", 'E1035')
-  call CheckDefFailure("let x = 0z1122 + 'asd'", 'E1035')
-  call CheckDefFailure("let x = 33 + 0z1122", 'E1035')
-  call CheckDefFailure("let x = [3] + 0z1122", 'E1035')
-  call CheckDefFailure("let x = 'asdf' + 0z1122", 'E1035')
-  call CheckDefFailure("let x = 6 + xxx", 'E1001')
+  call CheckDefFailure(["let x = 0z1122 + 33"], 'E1035')
+  call CheckDefFailure(["let x = 0z1122 + [3]"], 'E1035')
+  call CheckDefFailure(["let x = 0z1122 + 'asd'"], 'E1035')
+  call CheckDefFailure(["let x = 33 + 0z1122"], 'E1035')
+  call CheckDefFailure(["let x = [3] + 0z1122"], 'E1035')
+  call CheckDefFailure(["let x = 'asdf' + 0z1122"], 'E1035')
+  call CheckDefFailure(["let x = 6 + xxx"], 'E1001')
 endfunc
 
 " test multiply, divide, modulo
@@ -588,7 +562,7 @@
     assert_equal(6.0, xf[0] * yf[0])
   endif
 
-  call CheckDefFailure("let x = 6 * xxx", 'E1001')
+  call CheckDefFailure(["let x = 6 * xxx"], 'E1001')
 enddef
 
 def Test_expr6_float()
@@ -623,45 +597,45 @@
 
 func Test_expr6_fails()
   let msg = "white space required before and after '*'"
-  call CheckDefFailure("let x = 1*2", msg)
-  call CheckDefFailure("let x = 1 *2", msg)
-  call CheckDefFailure("let x = 1* 2", msg)
+  call CheckDefFailure(["let x = 1*2"], msg)
+  call CheckDefFailure(["let x = 1 *2"], msg)
+  call CheckDefFailure(["let x = 1* 2"], msg)
 
   let msg = "white space required before and after '/'"
-  call CheckDefFailure("let x = 1/2", msg)
-  call CheckDefFailure("let x = 1 /2", msg)
-  call CheckDefFailure("let x = 1/ 2", msg)
+  call CheckDefFailure(["let x = 1/2"], msg)
+  call CheckDefFailure(["let x = 1 /2"], msg)
+  call CheckDefFailure(["let x = 1/ 2"], msg)
 
   let msg = "white space required before and after '%'"
-  call CheckDefFailure("let x = 1%2", msg)
-  call CheckDefFailure("let x = 1 %2", msg)
-  call CheckDefFailure("let x = 1% 2", msg)
+  call CheckDefFailure(["let x = 1%2"], msg)
+  call CheckDefFailure(["let x = 1 %2"], msg)
+  call CheckDefFailure(["let x = 1% 2"], msg)
 
-  call CheckDefFailure("let x = '1' * '2'", 'E1036:')
-  call CheckDefFailure("let x = '1' / '2'", 'E1036:')
-  call CheckDefFailure("let x = '1' % '2'", 'E1035:')
+  call CheckDefFailure(["let x = '1' * '2'"], 'E1036:')
+  call CheckDefFailure(["let x = '1' / '2'"], 'E1036:')
+  call CheckDefFailure(["let x = '1' % '2'"], 'E1035:')
 
-  call CheckDefFailure("let x = 0z01 * 0z12", 'E1036:')
-  call CheckDefFailure("let x = 0z01 / 0z12", 'E1036:')
-  call CheckDefFailure("let x = 0z01 % 0z12", 'E1035:')
+  call CheckDefFailure(["let x = 0z01 * 0z12"], 'E1036:')
+  call CheckDefFailure(["let x = 0z01 / 0z12"], 'E1036:')
+  call CheckDefFailure(["let x = 0z01 % 0z12"], 'E1035:')
 
-  call CheckDefFailure("let x = [1] * [2]", 'E1036:')
-  call CheckDefFailure("let x = [1] / [2]", 'E1036:')
-  call CheckDefFailure("let x = [1] % [2]", 'E1035:')
+  call CheckDefFailure(["let x = [1] * [2]"], 'E1036:')
+  call CheckDefFailure(["let x = [1] / [2]"], 'E1036:')
+  call CheckDefFailure(["let x = [1] % [2]"], 'E1035:')
 
-  call CheckDefFailure("let x = #{one: 1} * #{two: 2}", 'E1036:')
-  call CheckDefFailure("let x = #{one: 1} / #{two: 2}", 'E1036:')
-  call CheckDefFailure("let x = #{one: 1} % #{two: 2}", 'E1035:')
+  call CheckDefFailure(["let x = #{one: 1} * #{two: 2}"], 'E1036:')
+  call CheckDefFailure(["let x = #{one: 1} / #{two: 2}"], 'E1036:')
+  call CheckDefFailure(["let x = #{one: 1} % #{two: 2}"], 'E1035:')
 
-  call CheckDefFailure("let x = 0xff[1]", 'E714:')
+  call CheckDefFailure(["let x = 0xff[1]"], 'E714:')
   if has('float')
-    call CheckDefFailure("let x = 0.7[1]", 'E714:')
+    call CheckDefFailure(["let x = 0.7[1]"], 'E714:')
   endif
 endfunc
 
 func Test_expr6_float_fails()
   CheckFeature float
-  call CheckDefFailure("let x = 1.0 % 2", 'E1035:')
+  call CheckDefFailure(["let x = 1.0 % 2"], 'E1035:')
 endfunc
 
 " define here to use old style parsing
@@ -721,7 +695,7 @@
   assert_equal(g:blob_one, 0z01)
   assert_equal(g:blob_long, 0z0102.0304)
 
-  call CheckDefFailure("let x = 0z123", 'E973:')
+  call CheckDefFailure(["let x = 0z123"], 'E973:')
 enddef
 
 def Test_expr7_string()
@@ -734,16 +708,16 @@
   assert_equal(g:string_long, "abcdefghijklm")
   assert_equal(g:string_special, "ab\ncd\ref\ekk")
 
-  call CheckDefFailure('let x = "abc', 'E114:')
-  call CheckDefFailure("let x = 'abc", 'E115:')
+  call CheckDefFailure(['let x = "abc'], 'E114:')
+  call CheckDefFailure(["let x = 'abc"], 'E115:')
 enddef
 
 def Test_expr7_vimvar()
   let old: list<string> = v:oldfiles
   let compl: dict<any> = v:completed_item
 
-  call CheckDefFailure("let old: list<number> = v:oldfiles", 'E1013: type mismatch, expected list<number> but got list<string>')
-  call CheckDefFailure("let old: dict<number> = v:completed_item", 'E1013: type mismatch, expected dict<number> but got dict<any>')
+  call CheckDefFailure(["let old: list<number> = v:oldfiles"], 'E1013: type mismatch, expected list<number> but got list<string>')
+  call CheckDefFailure(["let old: dict<number> = v:completed_item"], 'E1013: type mismatch, expected dict<number> but got dict<any>')
 enddef
 
 def Test_expr7_special()
@@ -755,11 +729,11 @@
   assert_equal(g:special_null, v:null)
   assert_equal(g:special_none, v:none)
 
-  call CheckDefFailure('v:true = true', 'E46:')
-  call CheckDefFailure('v:true = false', 'E46:')
-  call CheckDefFailure('v:false = true', 'E46:')
-  call CheckDefFailure('v:null = 11', 'E46:')
-  call CheckDefFailure('v:none = 22', 'E46:')
+  call CheckDefFailure(['v:true = true'], 'E46:')
+  call CheckDefFailure(['v:true = false'], 'E46:')
+  call CheckDefFailure(['v:false = true'], 'E46:')
+  call CheckDefFailure(['v:null = 11'], 'E46:')
+  call CheckDefFailure(['v:none = 22'], 'E46:')
 enddef
 
 def Test_expr7_list()
@@ -770,9 +744,9 @@
   assert_equal('b', g:list_mixed[1])
 
   call CheckDefExecFailure("let x = g:anint[3]", 'E714:')
-  call CheckDefFailure("let x = g:list_mixed[xxx]", 'E1001:')
+  call CheckDefFailure(["let x = g:list_mixed[xxx]"], 'E1001:')
   call CheckDefExecFailure("let x = g:list_mixed['xx']", 'E39:')
-  call CheckDefFailure("let x = g:list_mixed[0", 'E111:')
+  call CheckDefFailure(["let x = g:list_mixed[0"], 'E111:')
   call CheckDefExecFailure("let x = g:list_empty[3]", 'E684:')
 enddef
 
@@ -792,16 +766,16 @@
   let val = 1
   assert_equal(g:dict_one, {key: val})
 
-  call CheckDefFailure("let x = #{8: 8}", 'E1014:')
-  call CheckDefFailure("let x = #{xxx}", 'E720:')
-  call CheckDefFailureMult(["let x = #{xxx: 1", "let y = 2"], 'E722:')
-  call CheckDefFailure("let x = #{xxx: 1,", 'E723:')
-  call CheckDefFailure("let x = {'a': xxx}", 'E1001:')
-  call CheckDefFailure("let x = {xxx: 8}", 'E1001:')
-  call CheckDefFailure("let x = #{a: 1, a: 2}", 'E721:')
-  call CheckDefFailure("let x = #", 'E1015:')
-  call CheckDefFailure("let x += 1", 'E1020:')
-  call CheckDefFailure("let x = x + 1", 'E1001:')
+  call CheckDefFailure(["let x = #{8: 8}"], 'E1014:')
+  call CheckDefFailure(["let x = #{xxx}"], 'E720:')
+  call CheckDefFailure(["let x = #{xxx: 1", "let y = 2"], 'E722:')
+  call CheckDefFailure(["let x = #{xxx: 1,"], 'E723:')
+  call CheckDefFailure(["let x = {'a': xxx}"], 'E1001:')
+  call CheckDefFailure(["let x = {xxx: 8}"], 'E1001:')
+  call CheckDefFailure(["let x = #{a: 1, a: 2}"], 'E721:')
+  call CheckDefFailure(["let x = #"], 'E1015:')
+  call CheckDefFailure(["let x += 1"], 'E1020:')
+  call CheckDefFailure(["let x = x + 1"], 'E1001:')
   call CheckDefExecFailure("let x = g:anint.member", 'E715:')
   call CheckDefExecFailure("let x = g:dict_empty.member", 'E716:')
 enddef
@@ -809,7 +783,7 @@
 def Test_expr_member()
   assert_equal(1, g:dict_one.one)
 
-  call CheckDefFailure("let x = g:dict_one.#$!", 'E1002:')
+  call CheckDefFailure(["let x = g:dict_one.#$!"], 'E1002:')
 enddef
 
 def Test_expr7_option()
@@ -831,7 +805,7 @@
   assert_equal('testvar', $TESTVAR)
   assert_equal('', $ASDF_ASD_XXX)
 
-  call CheckDefFailure("let x = $$$", 'E1002:')
+  call CheckDefFailure(["let x = $$$"], 'E1002:')
 enddef
 
 def Test_expr7_register()
@@ -871,7 +845,7 @@
   assert_equal('yes', 'yes'->Echo())
   assert_equal('yes', 'yes'->s:EchoArg())
 
-  call CheckDefFailure("let x = 'yes'->Echo", 'E107:')
+  call CheckDefFailure(["let x = 'yes'->Echo"], 'E107:')
 enddef
 
 
@@ -904,39 +878,39 @@
 enddef
 
 func Test_expr7_fails()
-  call CheckDefFailure("let x = (12", "E110:")
+  call CheckDefFailure(["let x = (12"], "E110:")
 
-  call CheckDefFailure("let x = -'xx'", "E1030:")
-  call CheckDefFailure("let x = +'xx'", "E1030:")
-  call CheckDefFailure("let x = -0z12", "E974:")
+  call CheckDefFailure(["let x = -'xx'"], "E1030:")
+  call CheckDefFailure(["let x = +'xx'"], "E1030:")
+  call CheckDefFailure(["let x = -0z12"], "E974:")
   call CheckDefExecFailure("let x = -[8]", "E39:")
   call CheckDefExecFailure("let x = -{'a': 1}", "E39:")
 
-  call CheckDefFailure("let x = @", "E1002:")
-  call CheckDefFailure("let x = @<", "E354:")
+  call CheckDefFailure(["let x = @"], "E1002:")
+  call CheckDefFailure(["let x = @<"], "E354:")
 
-  call CheckDefFailure("let x = [1, 2", "E697:")
-  call CheckDefFailure("let x = [notfound]", "E1001:")
+  call CheckDefFailure(["let x = [1, 2"], "E697:")
+  call CheckDefFailure(["let x = [notfound]"], "E1001:")
 
-  call CheckDefFailure("let x = { -> 123) }", "E451:")
-  call CheckDefFailure("let x = 123->{x -> x + 5) }", "E451:")
+  call CheckDefFailure(["let x = { -> 123) }"], "E451:")
+  call CheckDefFailure(["let x = 123->{x -> x + 5) }"], "E451:")
 
-  call CheckDefFailure("let x = &notexist", 'E113:')
-  call CheckDefFailure("&grepprg = [343]", 'E1013:')
+  call CheckDefFailure(["let x = &notexist"], 'E113:')
+  call CheckDefFailure(["&grepprg = [343]"], 'E1013:')
 
   call CheckDefExecFailure("echo s:doesnt_exist", 'E121:')
   call CheckDefExecFailure("echo g:doesnt_exist", 'E121:')
 
-  call CheckDefFailure("echo a:somevar", 'E1075:')
-  call CheckDefFailure("echo l:somevar", 'E1075:')
-  call CheckDefFailure("echo x:somevar", 'E1075:')
+  call CheckDefFailure(["echo a:somevar"], 'E1075:')
+  call CheckDefFailure(["echo l:somevar"], 'E1075:')
+  call CheckDefFailure(["echo x:somevar"], 'E1075:')
 
   call CheckDefExecFailure("let x = +g:astring", 'E1030:')
   call CheckDefExecFailure("let x = +g:ablob", 'E974:')
   call CheckDefExecFailure("let x = +g:alist", 'E745:')
   call CheckDefExecFailure("let x = +g:adict", 'E728:')
 
-  call CheckDefFailureMult(["let x = ''", "let y = x.memb"], 'E715:')
+  call CheckDefFailure(["let x = ''", "let y = x.memb"], 'E715:')
 
   call CheckDefExecFailure("[1, 2->len()", 'E492:')
   call CheckDefExecFailure("#{a: 1->len()", 'E488:')
@@ -988,23 +962,23 @@
 
 
 func Test_expr7_trailing_fails()
-  call CheckDefFailureList(['let l = [2]', 'l->{l -> add(l, 8)}'], 'E107')
-  call CheckDefFailureList(['let l = [2]', 'l->{l -> add(l, 8)} ()'], 'E274')
+  call CheckDefFailure(['let l = [2]', 'l->{l -> add(l, 8)}'], 'E107')
+  call CheckDefFailure(['let l = [2]', 'l->{l -> add(l, 8)} ()'], 'E274')
 endfunc
 
 func Test_expr_fails()
-  call CheckDefFailure("let x = '1'is2", 'E488:')
-  call CheckDefFailure("let x = '1'isnot2", 'E488:')
+  call CheckDefFailure(["let x = '1'is2"], 'E488:')
+  call CheckDefFailure(["let x = '1'isnot2"], 'E488:')
 
   call CheckDefExecFailure("CallMe ('yes')", 'E492:')
-  call CheckDefFailure("CallMe2('yes','no')", 'E1069:')
-  call CheckDefFailure("CallMe2('yes' , 'no')", 'E1068:')
+  call CheckDefFailure(["CallMe2('yes','no')"], 'E1069:')
+  call CheckDefFailure(["CallMe2('yes' , 'no')"], 'E1068:')
 
-  call CheckDefFailure("v:nosuch += 3", 'E1001:')
-  call CheckDefFailure("let v:statusmsg = ''", 'E1064:')
-  call CheckDefFailure("let asdf = v:nosuch", 'E1001:')
+  call CheckDefFailure(["v:nosuch += 3"], 'E1001:')
+  call CheckDefFailure(["let v:statusmsg = ''"], 'E1064:')
+  call CheckDefFailure(["let asdf = v:nosuch"], 'E1001:')
 
-  call CheckDefFailure("echo len('asdf'", 'E110:')
-  call CheckDefFailure("echo Func0123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789()", 'E1011:')
-  call CheckDefFailure("echo doesnotexist()", 'E117:')
+  call CheckDefFailure(["echo len('asdf'"], 'E110:')
+  call CheckDefFailure(["echo Func0123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789()"], 'E1011:')
+  call CheckDefFailure(["echo doesnotexist()"], 'E117:')
 endfunc
diff --git a/src/testdir/test_vim9_script.vim b/src/testdir/test_vim9_script.vim
index f06bb73..218ef77 100644
--- a/src/testdir/test_vim9_script.vim
+++ b/src/testdir/test_vim9_script.vim
@@ -2,25 +2,7 @@
 
 source check.vim
 source view_util.vim
-
-" Check that "lines" inside ":def" results in an "error" message.
-func CheckDefFailure(lines, error)
-  call writefile(['def Func()'] + a:lines + ['enddef'], 'Xdef')
-  call assert_fails('so Xdef', a:error, a:lines)
-  call delete('Xdef')
-endfunc
-
-def CheckScriptFailure(lines: list<string>, error: string)
-  writefile(lines, 'Xdef')
-  assert_fails('so Xdef', error, lines)
-  delete('Xdef')
-enddef
-
-def CheckScriptSuccess(lines: list<string>)
-  writefile(lines, 'Xdef')
-  so Xdef
-  delete('Xdef')
-enddef
+source vim9.vim
 
 def Test_syntax()
   let var = 234
diff --git a/src/testdir/vim9.vim b/src/testdir/vim9.vim
new file mode 100644
index 0000000..0e0cd1e
--- /dev/null
+++ b/src/testdir/vim9.vim
@@ -0,0 +1,28 @@
+" Utility functions for testing vim9 script
+
+" Check that "lines" inside ":def" results in an "error" message.
+func CheckDefFailure(lines, error)
+  call writefile(['def Func()'] + a:lines + ['enddef'], 'Xdef')
+  call assert_fails('so Xdef', a:error, a:lines)
+  call delete('Xdef')
+endfunc
+
+def CheckScriptFailure(lines: list<string>, error: string)
+  writefile(lines, 'Xdef')
+  assert_fails('so Xdef', error, lines)
+  delete('Xdef')
+enddef
+
+def CheckScriptSuccess(lines: list<string>)
+  writefile(lines, 'Xdef')
+  so Xdef
+  delete('Xdef')
+enddef
+
+" Check that "line" inside ":def" results in an "error" message when executed.
+func CheckDefExecFailure(line, error)
+  call writefile(['def! Func()', a:line, 'enddef'], 'Xdef')
+  so Xdef
+  call assert_fails('call Func()', a:error, a:line)
+  call delete('Xdef')
+endfunc
diff --git a/src/version.c b/src/version.c
index 70af7b0..233106b 100644
--- a/src/version.c
+++ b/src/version.c
@@ -747,6 +747,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    640,
+/**/
     639,
 /**/
     638,
diff --git a/src/vim9.h b/src/vim9.h
index f1da323..ddc84b1 100644
--- a/src/vim9.h
+++ b/src/vim9.h
@@ -13,6 +13,7 @@
 
 typedef enum {
     ISN_EXEC,	    // execute Ex command line isn_arg.string
+    ISN_EXECCONCAT, // execute Ex command from isn_arg.number items on stack
     ISN_ECHO,	    // echo isn_arg.echo.echo_count items on top of stack
     ISN_EXECUTE,    // execute Ex commands isn_arg.number items on top of stack
     ISN_ECHOMSG,    // echo Ex commands isn_arg.number items on top of stack
diff --git a/src/vim9compile.c b/src/vim9compile.c
index 4d1e3ac..092939e 100644
--- a/src/vim9compile.c
+++ b/src/vim9compile.c
@@ -1427,6 +1427,17 @@
     return OK;
 }
 
+    static int
+generate_EXECCONCAT(cctx_T *cctx, int count)
+{
+    isn_T	*isn;
+
+    if ((isn = generate_instr_drop(cctx, ISN_EXECCONCAT, count)) == NULL)
+	return FAIL;
+    isn->isn_arg.number = count;
+    return OK;
+}
+
 /*
  * Reserve space for a local variable.
  * Return the index or -1 if it failed.
@@ -5805,6 +5816,71 @@
 }
 
 /*
+ * A command that is not compiled, execute with legacy code.
+ */
+    static char_u *
+compile_exec(char_u *line, exarg_T *eap, cctx_T *cctx)
+{
+    char_u *p;
+
+    if (cctx->ctx_skip == TRUE)
+	goto theend;
+
+
+    if ((excmd_get_argt(eap->cmdidx) & EX_XFILE)
+	    && (p = (char_u *)strstr((char *)eap->arg, "`=")) != NULL)
+    {
+	int	count = 0;
+	char_u	*start = skipwhite(line);
+
+	// :cmd xxx`=expr1`yyy`=expr2`zzz
+	// PUSHS ":cmd xxx"
+	// eval expr1
+	// PUSHS "yyy"
+	// eval expr2
+	// PUSHS "zzz"
+	// EXECCONCAT 5
+	for (;;)
+	{
+	    if (p > start)
+	    {
+		generate_PUSHS(cctx, vim_strnsave(start, (int)(p - start)));
+		++count;
+	    }
+	    p += 2;
+	    if (compile_expr1(&p, cctx) == FAIL)
+		return NULL;
+	    may_generate_2STRING(-1, cctx);
+	    ++count;
+	    p = skipwhite(p);
+	    if (*p != '`')
+	    {
+		emsg(_("E1083: missing backtick"));
+		return NULL;
+	    }
+	    start = p + 1;
+
+	    p = (char_u *)strstr((char *)start, "`=");
+	    if (p == NULL)
+	    {
+		if (*skipwhite(start) != NUL)
+		{
+		    generate_PUSHS(cctx, vim_strsave(start));
+		    ++count;
+		}
+		break;
+	    }
+	}
+	generate_EXECCONCAT(cctx, count);
+    }
+    else
+	generate_EXEC(cctx, line);
+
+theend:
+    return (char_u *)"";
+}
+
+/*
  * After ex_function() has collected all the function lines: parse and compile
  * the lines into instructions.
  * Adds the function to "def_functions".
@@ -5818,7 +5894,6 @@
 {
     char_u	*line = NULL;
     char_u	*p;
-    exarg_T	ea;
     char	*errormsg = NULL;	// error message
     int		had_return = FALSE;
     cctx_T	cctx;
@@ -5917,6 +5992,7 @@
      */
     for (;;)
     {
+	exarg_T	ea;
 	int	is_ex_command = FALSE;
 
 	// Bail out on the first error to avoid a flood of errors and report
@@ -5952,7 +6028,7 @@
 	switch (*ea.cmd)
 	{
 	    case '#':
-		// "#" starts a comment, but not "#{".
+		// "#" starts a comment, but "#{" does not.
 		if (ea.cmd[1] != '{')
 		{
 		    line = (char_u *)"";
@@ -6093,7 +6169,7 @@
 		&& ea.cmdidx != CMD_else
 		&& ea.cmdidx != CMD_endif)
 	{
-	    line += STRLEN(line);
+	    line = (char_u *)"";
 	    continue;
 	}
 
@@ -6183,10 +6259,10 @@
 		    break;
 
 	    default:
-		    // Not recognized, execute with do_cmdline_cmd().
 		    // TODO: other commands with an expression argument
-		    generate_EXEC(&cctx, line);
-		    line = (char_u *)"";
+		    // Not recognized, execute with do_cmdline_cmd().
+		    ea.arg = p;
+		    line = compile_exec(line, &ea, &cctx);
 		    break;
 	}
 	if (line == NULL)
@@ -6401,10 +6477,11 @@
 	case ISN_DCALL:
 	case ISN_DROP:
 	case ISN_ECHO:
-	case ISN_EXECUTE:
-	case ISN_ECHOMSG:
 	case ISN_ECHOERR:
+	case ISN_ECHOMSG:
 	case ISN_ENDTRY:
+	case ISN_EXECCONCAT:
+	case ISN_EXECUTE:
 	case ISN_FOR:
 	case ISN_FUNCREF:
 	case ISN_INDEX:
diff --git a/src/vim9execute.c b/src/vim9execute.c
index 8c13696..7172718 100644
--- a/src/vim9execute.c
+++ b/src/vim9execute.c
@@ -648,6 +648,45 @@
 		do_cmdline_cmd(iptr->isn_arg.string);
 		break;
 
+	    // execute Ex command from pieces on the stack
+	    case ISN_EXECCONCAT:
+		{
+		    int	    count = iptr->isn_arg.number;
+		    int	    len = 0;
+		    int	    pass;
+		    int	    i;
+		    char_u  *cmd = NULL;
+		    char_u  *str;
+
+		    for (pass = 1; pass <= 2; ++pass)
+		    {
+			for (i = 0; i < count; ++i)
+			{
+			    tv = STACK_TV_BOT(i - count);
+			    str = tv->vval.v_string;
+			    if (str != NULL && *str != NUL)
+			    {
+				if (pass == 2)
+				    STRCPY(cmd + len, str);
+				len += STRLEN(str);
+			    }
+			    if (pass == 2)
+				clear_tv(tv);
+			}
+			if (pass == 1)
+			{
+			    cmd = alloc(len + 1);
+			    if (cmd == NULL)
+				goto failed;
+			    len = 0;
+			}
+		    }
+
+		    do_cmdline_cmd(cmd);
+		    vim_free(cmd);
+		}
+		break;
+
 	    // execute :echo {string} ...
 	    case ISN_ECHO:
 		{
@@ -1961,6 +2000,10 @@
 	    case ISN_EXEC:
 		smsg("%4d EXEC %s", current, iptr->isn_arg.string);
 		break;
+	    case ISN_EXECCONCAT:
+		smsg("%4d EXECCONCAT %lld", current,
+					      (long long)iptr->isn_arg.number);
+		break;
 	    case ISN_ECHO:
 		{
 		    echo_T *echo = &iptr->isn_arg.echo;