this.justAfterNull = checkNotNull(justAfterNull);
    }

    @Override
    public int compare(@Nullable String lhs, @Nullable String rhs) {
      if (lhs == rhs) {
        return 0;
      }
      if (lhs == null) {
        // lhs (null) comes just before justAfterNull.
        // If rhs is b, lhs comes first.
        if (rhs.equals(justAfterNull)) {
          return -1;
        }

      this.justAfterNull = checkNotNull(justAfterNull);
    }

    @Override
    public int compare(@Nullable String lhs, @Nullable String rhs) {
      if (lhs == rhs) {
        return 0;
      }
      if (lhs == null) {
        // lhs (null) comes just before justAfterNull.
        // If rhs is b, lhs comes first.
        if (rhs.equals(justAfterNull)) {
          return -1;
        }

	if arr, ok := rhs.ToArray(); ok {
		for _, element := range arr {
			// If we have an array we are on the wrong level.
			if cmp(element, *lhs) {
				return FromBool(true), nil
			}
		}
		return FromBool(false), nil
	}

	return FromBool(cmp(rhs, *lhs)), nil
}

func (e *Operand) evalNode(r Record, tableAlias string) (*Value, error) {
	lval, lerr := e.Left.evalNode(r, tableAlias)

				p.errorf("expected simple register reference")
			}
			a.Type = obj.TYPE_REG
			a.Reg = r1
			if r2 != 0 {
				// Form is R1:R2. It is on RHS and the second register
				// needs to go into the LHS.
				panic("cannot happen (Addr.Reg2)")
			}
		}
		// fmt.Printf("REG %s\n", obj.Dconv(&emptyProg, 0, a))
		p.expectOperandEnd()
		return
	}

	// Constant.
	haveConstant := false

	case *ast.SendStmt:
		f.walk(&n.Chan, ctxExpr, visit)
		f.walk(&n.Value, ctxExpr, visit)
	case *ast.IncDecStmt:
		f.walk(&n.X, ctxExpr, visit)
	case *ast.AssignStmt:
		f.walk(n.Lhs, ctxExpr, visit)
		if len(n.Lhs) == 2 && len(n.Rhs) == 1 {
			f.walk(n.Rhs, ctxAssign2, visit)
		} else {
			f.walk(n.Rhs, ctxExpr, visit)
		}
	case *ast.GoStmt:
		f.walk(n.Call, ctxExpr, visit)
	case *ast.DeferStmt:

pkg go/types, type Info struct, Types map[ast.Expr]TypeAndValue
pkg go/types, type Info struct, Uses map[*ast.Ident]Object
pkg go/types, type Initializer struct
pkg go/types, type Initializer struct, Lhs []*Var
pkg go/types, type Initializer struct, Rhs ast.Expr
pkg go/types, type Interface struct
pkg go/types, type Label struct
pkg go/types, type Map struct
pkg go/types, type MethodSet struct