diff --git a/src/testdir/test_vim9_script.vim b/src/testdir/test_vim9_script.vim
index d25bb47..72e1274 100644
--- a/src/testdir/test_vim9_script.vim
+++ b/src/testdir/test_vim9_script.vim
@@ -1743,6 +1743,21 @@
   CheckDefFailure(['endif'], 'E580:')
   CheckDefFailure(['if g:abool', 'elseif xxx'], 'E1001:')
   CheckDefFailure(['if true', 'echo 1'], 'E171:')
+
+  var lines =<< trim END
+      var s = ''
+      if s = ''
+      endif
+  END
+  CheckDefFailure(lines, 'E488:')
+
+  lines =<< trim END
+      var s = ''
+      if s == ''
+      elseif s = ''
+      endif
+  END
+  CheckDefFailure(lines, 'E488:')
 enddef
 
 let g:bool_true = v:true
@@ -2200,6 +2215,13 @@
   CheckDefFailure(['break'], 'E587:')
   CheckDefFailure(['if true', 'break'], 'E587:')
   CheckDefFailure(['while 1', 'echo 3'], 'E170:')
+
+  var lines =<< trim END
+      var s = ''
+      while s = ''
+      endwhile
+  END
+  CheckDefFailure(lines, 'E488:')
 enddef
 
 def Test_interrupt_loop()
diff --git a/src/version.c b/src/version.c
index 17ab64a..4c53107 100644
--- a/src/version.c
+++ b/src/version.c
@@ -751,6 +751,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    2483,
+/**/
     2482,
 /**/
     2481,
diff --git a/src/vim9compile.c b/src/vim9compile.c
index 3c24fdb..7a220a8 100644
--- a/src/vim9compile.c
+++ b/src/vim9compile.c
@@ -6701,6 +6701,11 @@
 	clear_ppconst(&ppconst);
 	return NULL;
     }
+    if (!ends_excmd2(arg, skipwhite(p)))
+    {
+	semsg(_(e_trailing_arg), p);
+	return NULL;
+    }
     if (cctx->ctx_skip == SKIP_YES)
 	clear_ppconst(&ppconst);
     else if (instr->ga_len == instr_count && ppconst.pp_used == 1)
@@ -6825,6 +6830,11 @@
 	return NULL;
     }
     cctx->ctx_skip = save_skip;
+    if (!ends_excmd2(arg, skipwhite(p)))
+    {
+	semsg(_(e_trailing_arg), p);
+	return NULL;
+    }
     if (scope->se_skip_save == SKIP_YES)
 	clear_ppconst(&ppconst);
     else if (instr->ga_len == instr_count && ppconst.pp_used == 1)
@@ -7237,6 +7247,11 @@
     // compile "expr"
     if (compile_expr0(&p, cctx) == FAIL)
 	return NULL;
+    if (!ends_excmd2(arg, skipwhite(p)))
+    {
+	semsg(_(e_trailing_arg), p);
+	return NULL;
+    }
 
     if (bool_on_stack(cctx) == FAIL)
 	return FAIL;