Refactor whe way TypecheckingResultsCache is updated:
all mutatiting methods extracted to Update subclass, which is
only available to the updater.
Make TypecheckingState a regular container for (unit) caches.
Make TypecheckingService responsible for managing caches.
Extract TypeModuleOwner and TypeModelHandler classes.
Get rid of QueryResultsCache, merge into TypecheckingResultsCache.
TypeModuleOwner to manage "repository" cache.
Now whether unchecked conversion is allowed is controlled
by ConvertsContext.Options of convertsTo relation.
Introduce 'erased()' term to be used in raw type params.
Drop 'uncheckedConversion' parameter in all macros.
Classifier kind:"raw" is now used only for Recover.
Allow unchecked conversions by default. Forbid for sequences.
This lang doesn't depend on collections lang and extracts
common dependencies of closures and collections langs:
sequence term and its basic typing rules.