diff --git a/src/vim9compile.c b/src/vim9compile.c
index cb00f034..c6a2965 100644
--- a/src/vim9compile.c
+++ b/src/vim9compile.c
@@ -6875,7 +6875,15 @@
 	if (compile_assign_lhs(var_start, &lhs, cmdidx,
 					is_decl, heredoc, oplen, cctx) == FAIL)
 	    goto theend;
-	if (!heredoc)
+	if (heredoc)
+	{
+	    SOURCING_LNUM = start_lnum;
+	    if (lhs.lhs_has_type
+		    && need_type(&t_list_string, lhs.lhs_type,
+					    -1, 0, cctx, FALSE, FALSE) == FAIL)
+		goto theend;
+	}
+	else
 	{
 	    if (cctx->ctx_skip == SKIP_YES)
 	    {