[import-main-matcher.cpp] warning if recn_date < trans_date

gnucash/import-export/import-main-matcher.cpp

@@ -41,6 +41,7 @@
 #include <memory>
 #include <algorithm>
 #include <vector>
+#include <optional>
 
 #include "import-main-matcher.h"
 
@@ -1909,6 +1910,20 @@ get_peer_acct_names (Split *split)
     return retval;
 }
 
+static std::optional<time64>
+acct_get_recndate (const Account* acc)
+{
+    time64 recn_date;
+    if (xaccAccountGetReconcileLastDate (acc, &recn_date))
+        return recn_date;
+    else
+        return {};
+}
+
+const char* recn_date_warning = N_("The import date is earlier than reconcile date. \
+Further reconciliation may be difficult");
+
+
 static void
 refresh_model_row (GNCImportMainMatcher *gui,
                    GtkTreeModel *model,
@@ -2028,6 +2043,13 @@ refresh_model_row (GNCImportMainMatcher *gui,
                                      imbalance, acct_full_name);
 
                 }
+                if (auto recn_date = acct_get_recndate (dest_acc);
+                    recn_date && date < *recn_date)
+                {
+                    auto newtext = g_strdup_printf ("%s %s", text, _(recn_date_warning));
+                    g_free (text);
+                    text = newtext;
+                }
 
                 g_free (acct_full_name);
             }