Don't try to copy a null item.

Fixes: lp:1836126
* https://bugs.launchpad.net/kicad/+bug/1836126

eeschema/sch_edit_frame.cpp

@@ -359,11 +359,14 @@ void SCH_EDIT_FRAME::SaveCopyForRepeatItem( SCH_ITEM* aItem )
     // that item may be deleted, such as part of a line concatenation or other.
     // So simply always keep a copy of the object which is to be repeated.
 
-    delete m_item_to_repeat;
+    if( aItem )
+    {
+        delete m_item_to_repeat;
 
-    m_item_to_repeat = (SCH_ITEM*) aItem->Clone();
-    // Clone() preserves the flags, we want 'em cleared.
-    m_item_to_repeat->ClearFlags();
+        m_item_to_repeat = (SCH_ITEM*) aItem->Clone();
+        // Clone() preserves the flags, we want 'em cleared.
+        m_item_to_repeat->ClearFlags();
+    }
 }
 
 

eeschema/tools/sch_line_wire_bus_tool.cpp

@@ -797,7 +797,7 @@ void SCH_LINE_WIRE_BUS_TOOL::finishSegments()
     }
 
     // Get the last non-null wire (this is the last created segment).
-    m_frame->SaveCopyForRepeatItem( s_wires.GetLast());
+    m_frame->SaveCopyForRepeatItem( s_wires.GetLast() );
 
     // Add the new wires
     while( s_wires.GetFirst() )