From 89153ca75a962db8f74a2dee6f91e491fae9bb44 Mon Sep 17 00:00:00 2001
From: jean-pierre charras <jp.charras@wanadoo.fr>
Date: Fri, 16 Dec 2022 11:48:26 +0100
Subject: [PATCH] Eeschema: fix incorrect calculation of unit id in reference:
 U1.A was shown as U1A. Fixes #13178
 https://gitlab.com/kicad/code/kicad/issues/13178

---
 eeschema/lib_symbol.cpp | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/eeschema/lib_symbol.cpp b/eeschema/lib_symbol.cpp
index 99c0762eeb..adad526d67 100644
--- a/eeschema/lib_symbol.cpp
+++ b/eeschema/lib_symbol.cpp
@@ -601,14 +601,16 @@ wxString LIB_SYMBOL::SubReference( int aUnit, bool aAddSeparator )
         // use one letter if letter = A .. Z or a ... z, and 2 letters otherwise
         // first letter is expected to be 'A' or 'a' (i.e. 26 letters are available)
         int u;
+        wxString suffix;
 
         do
         {
             u = ( aUnit - 1 ) % 26;
-            subRef = wxChar( m_subpartFirstId + u ) + subRef;
+            suffix = wxChar( m_subpartFirstId + u ) + suffix;
             aUnit = ( aUnit - u ) / 26;
         } while( aUnit > 0 );
 
+        subRef << suffix;
     }
 
     return subRef;