Method trySubstitute

fe/src/main/java/org/apache/impala/analysis/Expr.java:1151–1168

Returns an analyzed clone of 'this' with exprs substituted according to smap. Removes implicit casts and analysis state while cloning/substituting exprs within this tree, such that the returned result has minimal implicit casts and types. Throws if analyzing the post-substitution expr tree failed. I

(ExprSubstitutionMap smap, Analyzer analyzer,
      boolean preserveRootType)

   * the type of 'this'.
   */
  public Expr trySubstitute(ExprSubstitutionMap smap, Analyzer analyzer,
      boolean preserveRootType)
      throws AnalysisException {
    Expr result = clone();
    // Return clone to avoid removing casts.
    if (smap == null) return result;
    result = result.substituteImpl(smap, analyzer);
    result.analyze(analyzer);
    if (preserveRootType && !type_.equals(result.getType())) {
      if (this instanceof CastExpr) {
        CastExpr thisCastExpr = (CastExpr) this;
        TypeCompatibility compatibility = thisCastExpr.getCompatibility();
        return result.castTo(type_, compatibility);
      }
      return result.castTo(type_);
    }
    return result;
  }

  /**
   * Returns an analyzed clone of 'this' with exprs substituted according to smap.