diff --git a/src/evalvars.c b/src/evalvars.c
index 3571169..9aa6d65 100644
--- a/src/evalvars.c
+++ b/src/evalvars.c
@@ -558,6 +558,7 @@
     int		text_indent_len = 0;
     char_u	*text_indent = NULL;
     char_u	dot[] = ".";
+    int		comment_char = in_vim9script() ? '#' : '"';
 
     if (eap->getline == NULL)
     {
@@ -585,11 +586,11 @@
     }
 
     // The marker is the next word.
-    if (*cmd != NUL && *cmd != '"')
+    if (*cmd != NUL && *cmd != comment_char)
     {
 	marker = skipwhite(cmd);
 	p = skiptowhite(marker);
-	if (*skipwhite(p) != NUL && *skipwhite(p) != '"')
+	if (*skipwhite(p) != NUL && *skipwhite(p) != comment_char)
 	{
 	    semsg(_(e_trailing_arg), p);
 	    return NULL;
diff --git a/src/testdir/test_vim9_assign.vim b/src/testdir/test_vim9_assign.vim
index 94861e5..0a94734 100644
--- a/src/testdir/test_vim9_assign.vim
+++ b/src/testdir/test_vim9_assign.vim
@@ -732,4 +732,14 @@
   CheckScriptSuccess(lines)
 enddef
 
+def Test_heredoc()
+  var lines =<< trim END # comment
+    text
+  END
+  assert_equal(['text'], lines)
+
+  CheckDefFailure(['var lines =<< trim END X', 'END'], 'E488:')
+  CheckDefFailure(['var lines =<< trim END " comment', 'END'], 'E488:')
+enddef
+
 " vim: ts=8 sw=2 sts=2 expandtab tw=80 fdm=marker
diff --git a/src/version.c b/src/version.c
index 1ee6801..2072b35 100644
--- a/src/version.c
+++ b/src/version.c
@@ -751,6 +751,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1755,
+/**/
     1754,
 /**/
     1753,
diff --git a/src/vim9compile.c b/src/vim9compile.c
index 2d64015..832d7d9 100644
--- a/src/vim9compile.c
+++ b/src/vim9compile.c
@@ -4632,6 +4632,8 @@
 	eap->getline = exarg_getline;
 	eap->cookie = cctx;
 	l = heredoc_get(eap, op + 3, FALSE);
+	if (l == NULL)
+	    return NULL;
 
 	if (cctx->ctx_skip != SKIP_YES)
 	{