Lookup in wrong scope when redeclaring function field in a function

[Martin Sjölund]

Modelica_LinearSystems2.Controller.Examples.DiscretizationSeries has some code with the same error as:

record R
  Real x[:];
end R;
function f
  input Integer n;
  output R r(redeclare Real x[n]);
end f;
model M
  Real x[:] = f(3);
end M;

[Per Östlund]

The issue is that we don't save the scope that the dimension are declared in, so when we later try to instantiate it we don't know it came from a redeclare and should actually be looked up inside f. We need to save the scope in the same way that we currently handle bindings and use that instead when instantiating dimensions.

[Francesco Casella]

I guess after 1.17.0 we can start to use "Frontend" again. At least, let's wait until we are sure that we can transition to the NF safely.

[Per Östlund]

Fixed in ​PR 6938, but it still doesn't work properly.

The lookup now works as it should but the type of the function call will be record R(Real[n]), i.e. we apply the redeclare correctly but don't evaluate n in the return type. The issue is that complex types are represented by an instance node, so we can't currently change a complex output type without also affecting the type of all other calls of that function. We need to either clone the instance nodes in complex types when typing a function call, which I'm not sure is a good idea, or change how we represent types in this situation.

[Francesco Casella]

Retargeted to 1.18.0 because of 1.17.0 timed release.

[Francesco Casella]

Ticket retargeted after milestone closed