Build fails under clang++ 10

Description

Bulild fails under clang++ 10 which comes with Ubuntu 20.04 LTS which is to be released on April 23.

There are many implicit conversion errors like this:
```
error: implicit conversion from 'size_t' (aka 'unsigned long') to 'double' may lose precision
```

```
$ clang++ --version
clang version 10.0.0-2ubuntu2
Target: x86_64-pc-linux-gnu
Thread model: posix
InstalledDir: /usr/bin
```

```
$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu Focal Fossa (development branch)
Release: 20.04
Codename: focal
```

Environment

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Assignee

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Reporter

Andrei Pavel

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Priority

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