diff --git a/src/testdir/test_vim9_expr.vim b/src/testdir/test_vim9_expr.vim
index 3c16fa4..8cf5bc0 100644
--- a/src/testdir/test_vim9_expr.vim
+++ b/src/testdir/test_vim9_expr.vim
@@ -2382,7 +2382,7 @@
 
   call CheckDefFailure(["CallMe ('yes')"], 'E476:', 1)
   call CheckScriptFailure(["CallMe ('yes')"], 'E492:', 1)
-  call CheckScriptAndDefFailure(["CallMe2('yes','no')"], 'E1069:', 1)
+  call CheckDefAndScriptFailure(["CallMe2('yes','no')"], 'E1069:', 1)
   call CheckDefFailure(["CallMe2('yes' , 'no')"], 'E1068:', 1)
 
   call CheckDefFailure(["v:nosuch += 3"], 'E1001:', 1)
diff --git a/src/testdir/test_vim9_script.vim b/src/testdir/test_vim9_script.vim
index 5712e38..36e39eb 100644
--- a/src/testdir/test_vim9_script.vim
+++ b/src/testdir/test_vim9_script.vim
@@ -39,7 +39,7 @@
 let g:astring = 'text'
 let g:anumber = 123
 
-def Test_assignment()
+def Test_assignment_bool()
   let bool1: bool = true
   assert_equal(v:true, bool1)
   let bool2: bool = false
@@ -50,6 +50,25 @@
   let bool4: bool = 1
   assert_equal(1, bool4)
 
+  let lines =<< trim END
+    vim9script
+    def GetFlag(): bool
+      let flag: bool = 1
+      return flag
+    enddef
+    let flag: bool = GetFlag()
+    flag = 0
+    flag = 1
+  END
+  CheckScriptSuccess(lines)
+  CheckDefAndScriptFailure(['let x: bool = 2'], 'E1012:')
+  CheckDefAndScriptFailure(['let x: bool = -1'], 'E1012:')
+  CheckDefAndScriptFailure(['let x: bool = [1]'], 'E1012:')
+  CheckDefAndScriptFailure(['let x: bool = {}'], 'E1012:')
+  CheckDefAndScriptFailure(['let x: bool = "x"'], 'E1012:')
+enddef
+
+def Test_assignment()
   CheckDefFailure(['let x:string'], 'E1069:')
   CheckDefFailure(['let x:string = "x"'], 'E1069:')
   CheckDefFailure(['let a:string = "x"'], 'E1069:')
@@ -164,8 +183,7 @@
     assert_equal('xxx', &t_TI)
     &t_TI = save_TI
   END
-  CheckDefSuccess(lines)
-  CheckScriptSuccess(['vim9script'] + lines)
+  CheckDefAndScriptSuccess(lines)
 
   CheckDefFailure(['&t_TI = 123'], 'E1012:')
   CheckScriptFailure(['vim9script', '&t_TI = 123'], 'E928:')
diff --git a/src/testdir/vim9.vim b/src/testdir/vim9.vim
index 7fbe4a5..2e4b03f 100644
--- a/src/testdir/vim9.vim
+++ b/src/testdir/vim9.vim
@@ -48,7 +48,7 @@
 
 " Check that a command fails both when used in a :def function and when used
 " in Vim9 script.
-def CheckScriptAndDefFailure(lines: list<string>, error: string, lnum = -3)
+def CheckDefAndScriptFailure(lines: list<string>, error: string, lnum = -3)
   CheckDefFailure(lines, error, lnum)
   CheckScriptFailure(['vim9script'] + lines, error, lnum + 1)
 enddef