Error in type inference when using function passed to function

[carlj@…]

Consider the package Test:

package Test
  partial function myFunBase
    input Real u;
    output Real y1;
    output Real y2;
  end myFunBase;

  function myFun
    extends myFunBase;
  algorithm
    y1 := u;
    y2 := 2 * u;
  end myFun;

  function myFun2
    input myFunBase f;
    output Real y;
  protected
    Real x1,x2;
  algorithm
    (x1,x2) := f(2);
    Y := x1 + x2;
  end myFun2;

  model Test
    Real x(start = 1.0);
    Real y;
  equation
    x = -der(x);
    y = myFun2(myFun);
  end Test;

end Test;

when validating Test.Test in OMEdit one gets:

"[<interactive>:21:5-21:20:writable] Error: Type mismatch in assignment in (x1, x2) := f(#(2.0)) of (Real, Real) := (#Real, #Real)
Error: Error occurred while flattening model Test.Test
"

Tested with "OpenModelica 1.9.1+dev (r22423) (Bootstrapping vers".

[Martin Sjölund]

Problem is we cannot cast the results of a function returning multiple arguments to new types, which makes Modelica grammar fail.
This works with MetaModelica grammar because we can make it a "pattern-matching assignment", which is able to perform the type cast.