External Issue: Behaviour of the compiler affected by trivial 'else'

Notifications Issues
1

18597, "rj-jesus", "Behaviour of the compiler affected by trivial 'else'", "2021-10-20T10:04:04Z"

Summary of Problem

This is a very minor issue (actually, it's mostly just "unexpected behaviour"), but I was trying to use Chapel's polymorphic features to create and initialise arrays from an integer or from a domain in the same function, e.g.

proc foo(len_or_domain) where isDomain(len_or_domain) || isIntegralValue(len_or_domain)
{
  if isIntegralValue(len_or_domain) then
    return foo({0..<len_or_domain});
  //else {  // works if I uncomment this else
  var a: [len_or_domain] real = 123;
  return a;
  //}
}

writeln(foo(10));
writeln();
writeln(foo({0..9, 0..9}));

If I uncomment the explicit else, the code above works. However, if I leave it commented the compiler complains that it can't resolve the function's return type. Since the else in the code is quite obvious, I was surprised that its presence altered the behaviour of the compiler.