Francesco Casella

#13678 broke some [testsuite models](https://test.openmodelica.org/jenkins/blue/organizations/jenkins/OpenModelica/detail/PR-13678/2/tests).

[Buildings.Templates.Plants.Controls.StagingRotation.Validation.EquipmentEnable](https://libraries.openmodelica.org/branches/master/Buildings_latest/files/Buildings_latest_Buildings.Templates.Plants.Controls.StagingRotation.Validation.EquipmentEnable.sim) now runs fine 🥳 @Pavanrajhr, please update the Building issues spreadsheet.

@kabdelhak `-d=mergeComponents` is a key step for RTE models, because they instantiate models individually, based on netlists. In order to exploit the array-preserving new frontend and new backend features, we...

@kabdelhak reports that indexing issue is fixed by #13234, now the model fails during causalization, probably for similar reasons. @kabdelhak is investigating that now.

@kabdelhak please check this at your earliest convenience. Thanks!

@kabdelhak with recent developments this model now [fails](https://libraries.openmodelica.org/branches/heavy_tests/ScalableTestGrids_NB_SymbolicJacobian/files/ScalableTestGrids_NB_SymbolicJacobian_ScalableTestGrids.Models.Type1.Type1_N_1_M_1.err) during Jacobian generation with: ``` [OpenModelica/OMCompiler/Compiler/NFFrontEnd/NFComponentRef.mo:598:7-601:102:writable] Error: Internal error NFComponentRef.mergeSubscripts failed because the subscripts {$i1} could not be fully merged onto $pDER_ODE_JAC.$DER.$ControlledGenerator6.PSS.firstWashoutVsi1.integrator.y....

Looking at the [latest run of ScalableTestGrids with the NB](https://libraries.openmodelica.org/branches/newInst-newBackend/ScalableTestGrids_noopt/ScalableTestGrids_noopt.html), which started 2025-07-22 02:25:29, the problem seems to be resolved now. The compilation fails because of #13980.

I was mistaken, sorry. The [newInst-newBackend ScalableTestGrids](https://libraries.openmodelica.org/branches/newInst-newBackend/ScalableTestGrids_noopt/ScalableTestGrids_noopt.html) tests **do not use** `-d=mergeComponents`, so they pass the backend phase successfully and fails because of #13980. The [heavy-test ScalableTestGrids](https://libraries.openmodelica.org/branches/heavy_tests/ScalableTestGrids_NB_SymbolicJacobian/ScalableTestGrids_NB_SymbolicJacobian.html) tests instead **do...

Very likely the same issue as #12930. Still [fails](https://libraries.openmodelica.org/branches/heavy_tests/ScalableTestGrids_NB_SymbolicJacobian/files/ScalableTestGrids_NB_SymbolicJacobian_ScalableTestGrids.Models.Type1.Type1_N_1_M_1.err) with ``` [OMCompiler/Compiler/NFFrontEnd/NFComponentRef.mo:683:7-686:102:writable] Error: Internal error NFComponentRef.mergeSubscripts failed because the subscripts {$i1} could not be fully merged onto $pDER_ODE_JAC.$DER.$ControlledGenerator6.PSS.firstWashoutVsi1.integrator.y. Result: $pDER_ODE_JAC.$DER.$ControlledGenerator6.PSS.firstWashoutVsi1.integrator.y...

@perost during compilation the following errors appear in the [compilation log](https://libraries.openmodelica.org/branches/heavy_tests/ScalableTestGrids_NB_SymbolicJacobian/files/ScalableTestGrids_NB_SymbolicJacobian_ScalableTestGrids.Models.Type1.Type1_N_1_M_1.err): ``` [OMCompiler/Compiler/NFFrontEnd/NFExpression.mo:2346:11-2346:118:writable] Error: Internal error NFExpression.toAbsyn got unknown expression '({true, true})[]' [OMCompiler/Compiler/NFFrontEnd/NFExpression.mo:2346:11-2346:118:writable] Error: Internal error NFExpression.toAbsyn got unknown expression...