Error while compiling with clang/clang++ [-Werror,-Wrange-loop-constrcut] - c++

Question

I'm trying to build a c++ project. While doing so with g++ the project compiles fine. However if I try to compile with clang I get the error:
ec_read_plan.h:135:19: error: loop variable 'op' creates a copy from type 'const std::pair<ChunkPartType, ReadPlan::ReadOperation>' [-Werror,-Wrange-loop-construct]
for (const auto op : read_operationss_{
ec_read_plan.h:135:8: note: use reference type 'const std:pair<ChunkPartType, ReadPlan::ReadOperation> &' to prevent copying
for (const auto op : read_operations) {
Code is below, I have put a comment next on the line that is giving the error:
protected:
void recoverParts(uint8_t *buffer,
const std::bitset<Goal::Slice::kMaxPartsCount> &available_parts) const {
typedef ReedSolomon<slice_traits::ec::kMaxDataCount, slice_traits::ec::kMaxParityCount> RS;
int k = slice_traits::ec::getNumberOfDataParts(slice_type);
int m = slice_traits::ec::getNumberOfParityParts(slice_type);
int max_parts = k + m;
RS::ConstFragmentMap data_parts{{0}};
RS::FragmentMap result_parts{{0}};
RS::ErasedMap erased;
RS rs(k, m);
int available_count = 0;
for (int i = 0; i < max_parts; ++i) {
if (!available_parts[i] || available_count >= k) {
erased.set(i);
} else {
available_count++;
}
}
for (const auto op : read_operations) { //ERROR appears to be here
data_parts[op.first.getSlicePart()] = buffer + op.second.buffer_offset;
}
for (int i = 0; i < (int)requested_parts.size(); ++i) {
if (!available_parts[requested_parts[i].part]) {
result_parts[requested_parts[i].part] = buffer + i * buffer_part_size;
}
}
rs.recover(data_parts, erased, result_parts, buffer_part_size);
}
Why am I getting such an error with Clang and how can I fix this? Thank you.
For anyone who may want to reproduce the error, the source code is here: https://github.com/lizardfs/lizardfs. Afterwards do:
export CC=/usr/bin/clang
export CC=/usr/bin/clang++
cd lizardfs
mkdir build
cd build
cmake .. -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX=/opt/lizardfs
make

Answer 1

It turns out the error has to do with the clang and clang++ versions. As mentioned gcc had no problems compiling. By default my machine uses clang/clang++ version 10. I tried using version 11 but also had the same problem. I therefore installed version 9 of clang/clang++ and tried compiling again and it worked.
If you happen to have the same problems make sure to run the following commands or have them in the ~/.bashrc file and run source ~/.bashrc after installing version 9 of clang/clang++
export CC=/usr/bin/clang-9
export CC=/usr/bin/clang++-9