Function mir_borrowck 

pub(crate) fn mir_borrowck(
    tcx: TyCtxt<'_>,
    def: LocalDefId,
) -> Result<&FxIndexMap<LocalDefId, DefinitionSiteHiddenType<'_>>, ErrorGuaranteed>

Provider for query mir_borrowck. Unlike typeck, this must only be called for typeck roots which similar to typeck will then borrowck all nested bodies as well.