v0.20.1

What's Changed

• Bug fix to stop important error messages disappearing (thanks to @testforvln for the report) - in #1021
• Slightly more flexibility when storing C++ objects in Rust boxes:
  • Cease to need MakeCppStorage to put something in a Box by @adetaylor in #1022
  • impl ValueParam for Pin<Box<T>> by @adetaylor in #1024

Various internal tidyings.

• Outdent a test. by @adetaylor in #1023
• Fix destructor trait safety. by @adetaylor in #1025
• Unsafe dialect by @adetaylor in #1026
• Upgrade to 0.20.1. by @adetaylor in #1027

The next release is likely to be a significant compatibility break as we land a major part of #379.

Full Changelog: v0.20.0...v0.20.1