Related: tdf#118073 SbiScanner::NextSym: no symbol is no symbol

Whatever may or may not advance or put back nLineIdx, if there's
no progress at the end return false so we don't end up in an
endless loop with the next NextSym() starting at the same
position.

Change-Id: I7084fea073490c15b8ff5abb3781ac82cdccd6d6
Reviewed-on: https://gerrit.libreoffice.org/56029
Reviewed-by: Eike Rathke <erack@redhat.com>
Tested-by: Jenkins

basic/source/comp/scanner.cxx

@@ -226,6 +226,8 @@ bool SbiScanner::NextSym()
         nOldCol1 = nOldCol2 = 0;
     }
 
+    const sal_Int32 nLineIdxScanStart = nLineIdx;
+
     if(nCol < aLine.getLength() && BasicCharClass::isWhitespace(aLine[nCol]))
     {
         bSpaces = true;
@@ -632,6 +634,13 @@ PrevLineCommentLbl:
         nCol2 = nCol2 + nLen;
         nLineIdx = -1;
     }
+
+    if (nLineIdx == nLineIdxScanStart)
+    {
+        GenError( ERRCODE_BASIC_SYMBOL_EXPECTED );
+        return false;
+    }
+
     return true;