fix issue #868

[swiftomkar]

This PR intends to fix issue #868
Seems like it was a deleted copy constructor that was getting called.
May be an issue with some compilers.
Here is some more detail from the build toolchain:

-- The C compiler identification is GNU 9.3.0
-- The CXX compiler identification is GNU 9.3.0
-- Check for working C compiler: /usr/bin/cc
-- Check for working C compiler: /usr/bin/cc -- works
...

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[swiftomkar]

@googlebot I signed it!