[cfe-dev] Endless recursion due to return type deduction of mutually-recursive templates

[Yaron Keren]

Hello,

The following code causes endless recursion leading to seg fault with the
latest SVN.

clang tries to deduce g return type, which requires f return type, which
requires g return type, repeats endlessly.

If the templates are modified to regular functions taking double, clang
correctly errors upon parse:
error: function 'g' with deduced return type cannot be used before it is
defined
    return x*g(x-1);

but with templates there is no error parsing, just seg fault running.

Yaron


// Endless recursion with revision 190992.

template <class T>
auto g(T x);

template <class T>
auto f(T x) {
  if (x>0)
    return x*g(x-1);
  else
    return 1.0;
}

template <class T>
auto g(T x) {
  if (x>0)
    return x*f(x-1);
  else
    return 1.0;
}

int main() {
  f(9.0);
}
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/cfe-dev/attachments/20130919/a8cffa4d/attachment.html>