// Test type causality propagation
// Mimics MSL's Modelica.Blocks.Interfaces pattern
package Interfaces
connector RealInput = input Real;
connector RealOutput = output Real;
block SISO "Single input single output"
RealInput u "Input";
RealOutput y "Output";
end SISO;
end Interfaces;
block Der "Derivative block"
extends Interfaces.SISO;
equation
y = der(u);
end Der;