OMC oldfrontend vs newfrontend, Error: variable is discrete, but does not appear on the LHS of a when-statement

Question

openmodelica version OpenModelica1.22.1-64bit.

model SimpleTest2 "just a simple model - Compilation etc."
  Modelica.Blocks.Interfaces.RealInput u annotation(Placement(visible = true, transformation(origin = {-100, 40}, extent = {{-10, -10}, {10, 10}}, rotation = 0), iconTransformation(origin = {-80, 40}, extent = {{-10, -10}, {10, 10}}, rotation = 0)));
  Modelica.Blocks.Interfaces.RealOutput y annotation(Placement(visible = true, transformation(origin = {100, 20}, extent = {{-10, -10}, {10, 10}}, rotation = 0), iconTransformation(origin = {100, 20}, extent = {{-10, -10}, {10, 10}}, rotation = 0)));
protected 
  discrete Real x;
algorithm
  x := u;
  when change(x) then
    y := y + 2;
  end when;
  annotation(Icon(coordinateSystem(extent = {{-100, -100}, {100, 100}}, preserveAspectRatio = true, initialScale = 0.1, grid = {2, 2})), Diagram(coordinateSystem(extent = {{-100, -100}, {100, 100}}, preserveAspectRatio = true, initialScale = 0.1, grid = {2, 2}), graphics = {Rectangle(origin = {-6.15, 2.93}, fillColor = {0, 133, 199}, fillPattern = FillPattern.HorizontalCylinder, extent = {{-77.89, 83.75}, {88.14, -92.53}})}));
end SimpleTest2;

the code gives an error Following variable is discrete, but does not appear on the LHS of a when-statement: 'x'. in newfrontend and compiles in the oldfrontend.

How to make the SimpleTest2 to work in Openmodelica newfrontend?

Answer 1

I guess you need to sample u to get a discrete x, then use that:

model SimpleTest2 "just a simple model - Compilation etc."
  Modelica.Blocks.Interfaces.RealInput u annotation(Placement(visible = true, transformation(origin = {-100, 40}, extent = {{-10, -10}, {10, 10}}, rotation = 0), iconTransformation(origin = {-80, 40}, extent = {{-10, -10}, {10, 10}}, rotation = 0)));
  Modelica.Blocks.Interfaces.RealOutput y annotation(Placement(visible = true, transformation(origin = {100, 20}, extent = {{-10, -10}, {10, 10}}, rotation = 0), iconTransformation(origin = {100, 20}, extent = {{-10, -10}, {10, 10}}, rotation = 0)));
protected 
  discrete Real x;
algorithm
  when sample(time, 0.1) then
    x := u;
  end when;
  when change(x) then
    y := y + 2;
  end when;
  annotation(Icon(coordinateSystem(extent = {{-100, -100}, {100, 100}}, preserveAspectRatio = true, initialScale = 0.1, grid = {2, 2})), Diagram(coordinateSystem(extent = {{-100, -100}, {100, 100}}, preserveAspectRatio = true, initialScale = 0.1, grid = {2, 2}), graphics = {Rectangle(origin = {-6.15, 2.93}, fillColor = {0, 133, 199}, fillPattern = FillPattern.HorizontalCylinder, extent = {{-77.89, 83.75}, {88.14, -92.53}})}));
end SimpleTest2;