diff --git a/src/testdir/test_vim9_assign.vim b/src/testdir/test_vim9_assign.vim
index 7d32912..189ff4d 100644
--- a/src/testdir/test_vim9_assign.vim
+++ b/src/testdir/test_vim9_assign.vim
@@ -22,11 +22,11 @@
   var bool4: bool = 1
   assert_equal(true, bool4)
 
-  var bool5: bool = 'yes' && 'no'
+  var bool5: bool = 1 && true
   assert_equal(true, bool5)
-  var bool6: bool = [] && 99
+  var bool6: bool = 0 && 1
   assert_equal(false, bool6)
-  var bool7: bool = [] || #{a: 1} && 99
+  var bool7: bool = 0 || 1 && true
   assert_equal(true, bool7)
 
   var lines =<< trim END
@@ -41,9 +41,9 @@
     assert_equal(false, flag)
     flag = 1
     assert_equal(true, flag)
-    flag = 99 || 123
+    flag = 1 || true
     assert_equal(true, flag)
-    flag = 'yes' && []
+    flag = 1 && false
     assert_equal(false, flag)
   END
   CheckScriptSuccess(lines)
diff --git a/src/testdir/test_vim9_cmd.vim b/src/testdir/test_vim9_cmd.vim
index 060b083..82d5f32 100644
--- a/src/testdir/test_vim9_cmd.vim
+++ b/src/testdir/test_vim9_cmd.vim
@@ -72,8 +72,8 @@
   var lines =<< trim END
       vim9script
       if 1 &&
-            2
-            || 3
+            true
+            || 1
         g:res = 42
       endif
       assert_equal(42, g:res)
diff --git a/src/testdir/test_vim9_disassemble.vim b/src/testdir/test_vim9_disassemble.vim
index a8dbe1a..ceeae0d 100644
--- a/src/testdir/test_vim9_disassemble.vim
+++ b/src/testdir/test_vim9_disassemble.vim
@@ -766,11 +766,11 @@
         '\d LOAD arg\[-1]\_s*' ..
         '\d PUSHNR 1\_s*' ..
         '\d COMPAREANY ==\_s*' ..
-        '\d JUMP_AND_KEEP_IF_FALSE -> \d\+\_s*' ..
+        '\d JUMP_IF_COND_FALSE -> \d\+\_s*' ..
         '\d LOAD arg\[-1]\_s*' ..
         '\d PUSHNR 2\_s*' ..
         '\d COMPAREANY !=\_s*' ..
-        '\d JUMP_AND_KEEP_IF_TRUE -> \d\+\_s*' ..
+        '\d JUMP_IF_COND_TRUE -> \d\+\_s*' ..
         '\d LOAD arg\[-1]\_s*' ..
         '\d\+ PUSHNR 4\_s*' ..
         '\d\+ COMPAREANY ==\_s*' ..
@@ -1200,22 +1200,23 @@
 enddef
 
 def ReturnBool(): bool
-  var var: bool = "no" && [] || 123
-  return var
+  var name: bool = 1 && 0 || 1
+  return name
 enddef
 
 def Test_disassemble_return_bool()
   var instr = execute('disassemble ReturnBool')
   assert_match('ReturnBool\_s*' ..
-        'var var: bool = "no" && \[\] || 123\_s*' ..
-        '0 PUSHS "no"\_s*' ..
-        '1 JUMP_AND_KEEP_IF_FALSE -> 3\_s*' ..
-        '2 NEWLIST size 0\_s*' ..
-        '3 JUMP_AND_KEEP_IF_TRUE -> 5\_s*' ..
-        '4 PUSHNR 123\_s*' ..
-        '5 2BOOL (!!val)\_s*' ..
+        'var name: bool = 1 && 0 || 1\_s*' ..
+        '0 PUSHNR 1\_s*' ..
+        '1 JUMP_IF_COND_FALSE -> 3\_s*' ..
+        '2 PUSHNR 0\_s*' ..
+        '3 COND2BOOL\_s*' ..
+        '4 JUMP_IF_COND_TRUE -> 6\_s*' ..
+        '5 PUSHNR 1\_s*' ..
+        '6 2BOOL (!!val)\_s*' ..
         '\d STORE $0\_s*' ..
-        'return var\_s*' ..
+        'return name\_s*' ..
         '\d LOAD $0\_s*' ..   
         '\d RETURN',
         instr)
diff --git a/src/testdir/test_vim9_expr.vim b/src/testdir/test_vim9_expr.vim
index 253e469..5158e10 100644
--- a/src/testdir/test_vim9_expr.vim
+++ b/src/testdir/test_vim9_expr.vim
@@ -196,32 +196,32 @@
 
 " test ||
 def Test_expr2()
-  assert_equal(2, 2 || 0)
-  assert_equal(7, 0 ||
+  assert_equal(true, 1 || 0)
+  assert_equal(true, 0 ||
 		    0 ||
-		    7)
-  assert_equal(0, 0 || 0)
-  assert_equal(0, 0
+		    1)
+  assert_equal(false, 0 || 0)
+  assert_equal(false, 0
   		    || 0)
-  assert_equal('', 0 || '')
+  assert_equal(false, 0 || false)
 
   g:vals = []
-  assert_equal(3, Record(3) || Record(1))
-  assert_equal([3], g:vals)
+  assert_equal(true, Record(1) || Record(3))
+  assert_equal([1], g:vals)
 
   g:vals = []
-  assert_equal(5, Record(0) || Record(5))
-  assert_equal([0, 5], g:vals)
+  assert_equal(true, Record(0) || Record(1))
+  assert_equal([0, 1], g:vals)
 
   g:vals = []
-  assert_equal(4, Record(0)
-		      || Record(4)
+  assert_equal(true, Record(0)
+		      || Record(1)
 		      || Record(0))
-  assert_equal([0, 4], g:vals)
+  assert_equal([0, 1], g:vals)
 
   g:vals = []
-  assert_equal(0, Record([]) || Record('') || Record(0))
-  assert_equal([[], '', 0], g:vals)
+  assert_equal(false, Record(0) || Record(false) || Record(0))
+  assert_equal([0, false, 0], g:vals)
 enddef
 
 def Test_expr2_vimscript()
@@ -230,7 +230,7 @@
       vim9script
       var name = 0
       		|| 1
-      assert_equal(1, name)
+      assert_equal(true, name)
   END
   CheckScriptSuccess(lines)
 
@@ -269,80 +269,85 @@
   END
   CheckScriptFailure(lines, 'E1004:', 2)
 
-  # check keeping the value
+  # check evaluating to bool
   lines =<< trim END
-      vim9script
-      assert_equal(2, 2 || 0)
-      assert_equal(7, 0 ||
+      assert_equal(true, 1 || 0)
+      assert_equal(true, 0 ||
 			0 ||
-			7)
-      assert_equal(0, 0 || 0)
-      assert_equal(0, 0
+			!!7)
+      assert_equal(false, 0 || 0)
+      assert_equal(false, 0
 			|| 0)
-      assert_equal('', 0 || '')
+      assert_equal(false, 0 || false)
 
       g:vals = []
-      assert_equal(3, Record(3) || Record(1))
-      assert_equal([3], g:vals)
+      assert_equal(true, Record(true) || Record(false))
+      assert_equal([true], g:vals)
 
       g:vals = []
-      assert_equal(5, Record(0) || Record(5))
-      assert_equal([0, 5], g:vals)
+      assert_equal(true, Record(0) || Record(true))
+      assert_equal([0, true], g:vals)
 
       g:vals = []
-      assert_equal(4, Record(0)
-			  || Record(4)
+      assert_equal(true, Record(0)
+			  || Record(true)
 			  || Record(0))
-      assert_equal([0, 4], g:vals)
+      assert_equal([0, true], g:vals)
 
       g:vals = []
-      assert_equal(0, Record([]) || Record('') || Record(0))
-      assert_equal([[], '', 0], g:vals)
+      assert_equal(false, Record(0) || Record(false) || Record(0))
+      assert_equal([0, false, 0], g:vals)
   END
-  CheckScriptSuccess(lines)
+  CheckDefAndScriptSuccess(lines)
 enddef
 
-func Test_expr2_fails()
-  let msg = "White space required before and after '||'"
+def Test_expr2_fails()
+  var msg = "White space required before and after '||'"
   call CheckDefFailure(["var x = 1||2"], msg, 1)
   call CheckDefFailure(["var x = 1 ||2"], msg, 1)
   call CheckDefFailure(["var x = 1|| 2"], msg, 1)
 
   call CheckDefFailure(["var x = 1 || xxx"], 'E1001:', 1)
-endfunc
+
+  # TODO: should fail at compile time
+  call CheckDefExecFailure(["var x = 3 || 7"], 'E1023:', 1)
+  call CheckScriptFailure(["vim9script", "var x = 3 || 7"], 'E1023:', 2)
+  call CheckDefExecFailure(["var x = [] || false"], 'E745:', 1)
+  call CheckScriptFailure(["vim9script", "var x = [] || false"], 'E745:', 2)
+enddef
 
 " test &&
 def Test_expr3()
-  assert_equal(0, 2 && 0)
-  assert_equal(0, 0 &&
+  assert_equal(false, 1 && 0)
+  assert_equal(false, 0 &&
 		0 &&
-		7)
-  assert_equal(7, 2
-  		    && 3
-		    && 7)
-  assert_equal(0, 0 && 0)
-  assert_equal(0, 0 && '')
-  assert_equal('', 8 && '')
+		1)
+  assert_equal(true, 1
+  		    && true
+		    && 1)
+  assert_equal(false, 0 && 0)
+  assert_equal(false, 0 && false)
+  assert_equal(true, 1 && true)
 
   g:vals = []
-  assert_equal(1, Record(3) && Record(1))
-  assert_equal([3, 1], g:vals)
+  assert_equal(true, Record(true) && Record(1))
+  assert_equal([true, 1], g:vals)
 
   g:vals = []
-  assert_equal(0, Record(0) && Record(5))
+  assert_equal(false, Record(0) && Record(1))
   assert_equal([0], g:vals)
 
   g:vals = []
-  assert_equal(0, Record(0) && Record(4) && Record(0))
+  assert_equal(false, Record(0) && Record(4) && Record(0))
   assert_equal([0], g:vals)
 
   g:vals = []
-  assert_equal(0, Record(8) && Record(4) && Record(0))
-  assert_equal([8, 4, 0], g:vals)
+  assert_equal(false, Record(1) && Record(true) && Record(0))
+  assert_equal([1, true, 0], g:vals)
 
   g:vals = []
-  assert_equal(0, Record([1]) && Record('z') && Record(0))
-  assert_equal([[1], 'z', 0], g:vals)
+  assert_equal(false, Record(1) && Record(true) && Record(0))
+  assert_equal([1, true, 0], g:vals)
 enddef
 
 def Test_expr3_vimscript()
@@ -351,7 +356,7 @@
       vim9script
       var name = 0
       		&& 1
-      assert_equal(0, name)
+      assert_equal(false, name)
   END
   CheckScriptSuccess(lines)
 
@@ -393,36 +398,32 @@
   # check keeping the value
   lines =<< trim END
       vim9script
-      assert_equal(0, 2 && 0)
-      assert_equal(0, 0 &&
+      assert_equal(false, 1 && 0)
+      assert_equal(false, 0 &&
 		    0 &&
-		    7)
-      assert_equal(7, 2
-			&& 3
-			&& 7)
-      assert_equal(0, 0 && 0)
-      assert_equal(0, 0 && '')
-      assert_equal('', 8 && '')
+		    1)
+      assert_equal(true, 1
+			&& true
+			&& 1)
+      assert_equal(false, 0 && 0)
+      assert_equal(false, 0 && false)
+      assert_equal(false, 1 && 0)
 
       g:vals = []
-      assert_equal(1, Record(3) && Record(1))
-      assert_equal([3, 1], g:vals)
+      assert_equal(true, Record(1) && Record(true))
+      assert_equal([1, true], g:vals)
 
       g:vals = []
-      assert_equal(0, Record(0) && Record(5))
+      assert_equal(false, Record(0) && Record(1))
       assert_equal([0], g:vals)
 
       g:vals = []
-      assert_equal(0, Record(0) && Record(4) && Record(0))
+      assert_equal(false, Record(0) && Record(1) && Record(0))
       assert_equal([0], g:vals)
 
       g:vals = []
-      assert_equal(0, Record(8) && Record(4) && Record(0))
-      assert_equal([8, 4, 0], g:vals)
-
-      g:vals = []
-      assert_equal(0, Record([1]) && Record('z') && Record(0))
-      assert_equal([[1], 'z', 0], g:vals)
+      assert_equal(false, Record(1) && Record(true) && Record(0))
+      assert_equal([1, true, 0], g:vals)
   END
   CheckScriptSuccess(lines)
 enddef