patch 8.2.2755: Vim9: no error for using a number in a condition

Problem:    Vim9: no error for using a number in a condition.
Solution:   Also use ISN_COND2BOOL if the type is t_number_bool.
            (closes #7644)

src/testdir/test_vim9_disassemble.vim

@@ -770,7 +770,7 @@ def Test_disassemble_const_expr()
             'if has("gui_running")\_s*' ..
             '\d PUSHS "gui_running"\_s*' ..
             '\d BCALL has(argc 1)\_s*' ..
-            '\d 2BOOL (!!val)\_s*' ..
+            '\d COND2BOOL\_s*' ..
             '\d JUMP_IF_FALSE -> \d\_s*' ..
             '  echo "yes"\_s*' ..
             '\d PUSHS "yes"\_s*' ..
@@ -1537,13 +1537,13 @@ def Test_disassemble_return_bool()
   assert_match('ReturnBool\_s*' ..
         'var name: bool = 1 && 0 || 1\_s*' ..
         '0 PUSHNR 1\_s*' ..
-        '1 2BOOL (!!val)\_s*' ..
+        '1 COND2BOOL\_s*' ..
         '2 JUMP_IF_COND_FALSE -> 5\_s*' ..
         '3 PUSHNR 0\_s*' ..
-        '4 2BOOL (!!val)\_s*' ..
+        '4 COND2BOOL\_s*' ..
         '5 JUMP_IF_COND_TRUE -> 8\_s*' ..
         '6 PUSHNR 1\_s*' ..
-        '7 2BOOL (!!val)\_s*' ..
+        '7 COND2BOOL\_s*' ..
         '\d STORE $0\_s*' ..
         'return name\_s*' ..
         '\d\+ LOAD $0\_s*' ..   

src/testdir/test_vim9_expr.vim

@@ -282,6 +282,20 @@ def Test_expr2()
       g:vals = []
       assert_equal(false, Record(0) || Record(false) || Record(0))
       assert_equal([0, false, 0], g:vals)
+
+      g:vals = []
+      var x = 1
+      if x || true
+        g:vals = [1]
+      endif
+      assert_equal([1], g:vals)
+
+      g:vals = []
+      x = 3
+      if true || x
+        g:vals = [1]
+      endif
+      assert_equal([1], g:vals)
   END
   CheckDefAndScriptSuccess(lines)
 enddef
@@ -357,6 +371,9 @@ def Test_expr2_fails()
   # TODO: should fail at compile time
   call CheckDefExecAndScriptFailure(["var x = 3 || 7"], 'E1023:', 1)
 
+  call CheckDefAndScriptFailure(["if 3"], 'E1023:', 1)
+  call CheckDefExecAndScriptFailure(['var x = 3', 'if x', 'endif'], 'E1023:', 2)
+
   call CheckDefAndScriptFailure2(["var x = [] || false"], 'E1012: Type mismatch; expected bool but got list<unknown>', 'E745:', 1)
 
 enddef

src/version.c

@@ -750,6 +750,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    2755,
 /**/
     2754,
 /**/

src/vim9compile.c

@@ -990,7 +990,7 @@ bool_on_stack(cctx_T *cctx)
     if (type == &t_bool)
 	return OK;
 
-    if (type == &t_any || type == &t_number)
+    if (type == &t_any || type == &t_number || type == &t_number_bool)
 	// Number 0 and 1 are OK to use as a bool.  "any" could also be a bool.
 	// This requires a runtime type check.
 	return generate_COND2BOOL(cctx);