compiling error when using BiCGSTAB with a SparseMatrix of std::complex<mpreal>

I get a compiling error when using Eigen::BiCGSTAB with a Eigen::SparseMatrix of std::complex< mpfr::mpreal >

 /nobackup/Build/eigen/include/eigen3/Eigen/src/IterativeLinearSolvers/BiCGSTAB.h:54:19: error: conversion from ‘int’ to non-scalar type ‘Scalar’ {aka ‘std::complex<mpfr::mpreal>’} requested
   54 |   Scalar rho    = 1;
      |                   ^
/nobackup/Build/eigen/include/eigen3/Eigen/src/IterativeLinearSolvers/BiCGSTAB.h:55:19: error: conversion from ‘int’ to non-scalar type ‘Scalar’ {aka ‘std::complex<mpfr::mpreal>’} requested
   55 |   Scalar alpha  = 1;
      |                   ^
/nobackup/Build/eigen/include/eigen3/Eigen/src/IterativeLinearSolvers/BiCGSTAB.h:56:19: error: conversion from ‘int’ to non-scalar type ‘Scalar’ {aka ‘std::complex<mpfr::mpreal>’} requested
   56 |   Scalar w      = 1;
      |                   ^

This can be fixed by rewriting the above mentioned lines as such:

Scalar rho (1);
Scalar alpha(1);
Scalar w(1);