Function hasSeen

src/compute-engine/boxed-expression/simplify.ts:104–105

(x: Expression)

  // the cheap `unknowns`/operator gates) so it runs only on fold candidates.

  // If purely numeric (no unknowns), evaluate the whole expression.
  if (
    expr.unknowns.length === 0 &&
    BASIC_ARITHMETIC.includes(expr.operator) &&
    !hasAssignedVariable(expr)