problem with isMoreVisible for functions and point of instantiation

[mppf]

Related to #19167.

Here is another program showing incorrect behavior of isMoreVisible for functions. This one shows that isMoreVisible is leading to incorrect behavior with the point of instantiation. In particular, this should fail to compile should fail due to ambiguity between the two N.helper calls but it does not. I think this is because isMoreVisible cannot find any of the helper1 candidates since they all come from POI and so returns true. We stopped using POI in isMoreVisible in PR #8079 but I think that as of PR #16158, we should already be preferring a candidate in a closer POI, so isMoreVisible now just needs to handle differentiating between visibility levels at a given point of instantiation.

module G {
  proc genericfunc(param p) {
    helper1();
  }
}

module M {
  use G;
  proc mCallFunc() {
    writeln("mCallFunc");
    genericfunc(1);
  }
  proc helper1() { writeln("M.helper1"); }
}

module N {
  use G,M;
  proc helper1() { writeln("N.helper1"); }
  proc helper1() { writeln("N.helper1 mark two"); }
  proc nCallFunc() {
    writeln("nCallFunc");
    genericfunc(1);
  }

  proc main() {
    nCallFunc();
    mCallFunc();
  }
}

Removing module M makes the bug go away.

[skaller]

In this case, I think you have the wrong idea for params. A param is not generic. It should be replaced in the AST by whatever the user specified on the command line or configuration script or wherever params come from: its basically the same as a macro in C, macros are replaced by the pre-processor. I think Brad mentioned this in reference to using them for conditional compilation. However, the original problem would still exist if you replace param p with p:?1.

So here's what should happen in the example assuming p:?1: the compilation should fail immediately in module G, genericfunc on seeing the call helper1 because that function is not dependent on the generic type parameter, and it is not in scope.

POI lookup rules ONLY apply to dependent names.