PsiExpression (PsiExpression qualifier) { while (true) { if (ExpressionUtils.isImplicitToStringCall(qualifier)) { return qualifier; } final PsiMethodCallExpression call = ExpressionUtils.getCallForQualifier(qualifier); if (call == null) return null; if (isToStringCall(call)) { return call; } if (!isAppendCall(call)) return null; qualifier = call; } }