presto-main/src/main/java/io/prestosql/sql/planner/TranslationMap.java/TranslationMap/put
class TranslationMap:    public void put(Expression expression, Symbol symbol)
    {
        if (expression instanceof FieldReference) {
            int fieldIndex = ((FieldReference) expression).getFieldIndex();
            fieldSymbols[fieldIndex] = symbol;
            expressionToSymbols.put(rewriteBase.getSymbol(fieldIndex).toSymbolReference(), symbol);
            return;
        }

        Expression translated = translateNamesToSymbols(expression);
        expressionToSymbols.put(translated, symbol);

        // also update the field mappings if this expression is a field reference
        rewriteBase.getScope().tryResolveField(expression)
                .filter(ResolvedField::isLocal)
                .ifPresent(field -> fieldSymbols[field.getHierarchyFieldIndex()] = symbol);
    }