bug/regression: nested expandable connectors cause error in new release 1.11 not in previous 1.9.7

[sinisi@…]

If I compile the attached toy model using omc v1.11.0 I get the following error:

Error processing file: A.mo
[/mnt/nfs/sinisi/A.mo:43:3-43:27:writable] Error: Failed to instantiate equation 
connect(busB1.y, bus.b1);.
Error: Error occurred while flattening model A

# Error encountered! Exiting...
# Please check the error message and the flags.

Execution failed!

Instead using omc v1.9.7 compilation process ends without any error.

I discovered that inverting the order of connect equation in model A from:

connect(busB1.y, bus.b1);                                                                                                                                                                            
connect(busB2.y, bus.b2);                                                                                                                                                                            
connect(busB1, b1.busB);                                                                                                                                                                             
connect(busB2, b2.busB);                                                                                                                                                                             
connect(bus, b1.bus);                                                                                                                                                                                
connect(bus, b2.bus);                                                                                                                                                                                
connect(const.y, bus.x);

to:

connect(busB1, b1.busB);                                                                                                                                                                             
connect(busB2, b2.busB);                                                                                                                                                                             
connect(bus, b1.bus);                                                                                                                                                                                
connect(bus, b2.bus);                                                                                                                                                                          
connect(const.y, bus.x);
connect(busB1.y, bus.b1);                                                                                                                                                                           
connect(busB2.y, bus.b2);

the problem is solved.

[Francesco Casella]

I tried this model with Dymola, after building a proper package file (attached).

I got this diagnostic message:

Cannot introduce variables in two expandable connectors with
one connect-statements: at least one of them must exist:
connect(busB1.y, bus.b1);

Found in class P.A, D:/Temp/OMEdit/P.mo at line 45.

Cannot introduce variables in two expandable connectors with
one connect-statements: at least one of them must exist:
connect(busB2.y, bus.b2);

Found in class P.A, D:/Temp/OMEdit/P.mo at line 46.

The model contained invalid connect statements.

So, the model seems to be invalid.