A refinement context associated with refinement ref, specifying that variable var
is assumed to have abstract value val.
Each context keeps track of its associated AnalyzedRefinement node so that we can
restrict the RefinementCandidate expressions that it applies to: it should only
apply to those expressions that are syntactically nested inside the AnalyzedRefinement.
Import path
import semmle.javascript.dataflow.Refinements