Save few models to match actual v9 state.
MPS-20951 Exceptions in model/module validators ran asynchronously from project pane highlight thread: correctly dispose tree - clear all parent-child relations, unregister tree of nodes from MPSTree.
bl.closures: remove superfluous node cast
MPS-20921 java.lang.AssertionError: provide more information about deficient meta-model element
ModelAccess: replace deprecated method with contemporary call.
MPS-20926 An exception was encountered: java.lang.NullPointerException (no message): add assertion to get reasonable error instead of weird NPE
Avoid NPE when tree is not complete
MPS-12028 Get counter inside LOOP macro