Fix display of HasCallStack backtraces when a test throws an error

[Bodigrim]

Closes #469. There are two parts:

• Catch and rethrow exceptions with context in our vendored-in fork of async. This is inspired by upstream PR feat: support for exception context propagation simonmar/async#165.
• Bridge over multiple changes to displayException in base to ensure that at least some stack trace is shown.

[Bodigrim]

How to test this patch? Create a test, which throws an error, and observe tasty output. Here is a sample:

With GHC < 9.10:

    Foo: FAIL
      Exception: foo
      CallStack (from HasCallStack):
        error, called at Dependencies.hs:27:10 in core-tests-0.1-inplace-tasty-core-tests:Dependencies
        myTest, called at Dependencies.hs:20:20 in core-tests-0.1-inplace-tasty-core-tests:Dependencies

With GHC 9.10 (lots of garbage, but at least the first stack trace is relevant):

    Foo: FAIL
      Exception: foo
      CallStack (from HasCallStack):
        error, called at Dependencies.hs:27:10 in core-tests-0.1-inplace-tasty-core-tests:Dependencies
        myTest, called at Dependencies.hs:20:20 in core-tests-0.1-inplace-tasty-core-tests:Dependencies
      HasCallStack backtrace:
        collectBacktraces, called at libraries/ghc-internal/src/GHC/Internal/Exception.hs:169:13 in ghc-internal:GHC.Internal.Exception
        toExceptionWithBacktrace, called at libraries/ghc-internal/src/GHC/Internal/IO.hs:260:11 in ghc-internal:GHC.Internal.IO
        throwIO, called at ./Control/Concurrent/Async.hs:122:7 in tasty-1.5.3-inplace:Control.Concurrent.Async

With GHC 9.12:

    Foo: FAIL
      Exception: foo

      HasCallStack backtrace:
        error, called at Dependencies.hs:27:10 in core-tests-0.1-inplace-tasty-core-tests:Dependencies
        myTest, called at Dependencies.hs:20:20 in core-tests-0.1-inplace-tasty-core-tests:Dependencies

With GHC 9.14:

    Foo: FAIL
      Exception: ghc-internal:GHC.Internal.Exception.ErrorCall:

      foo

      HasCallStack backtrace:
        error, called at Dependencies.hs:27:10 in core-tests-0.1-inplace-tasty-core-tests:Dependencies
        myTest, called at Dependencies.hs:20:20 in core-tests-0.1-inplace-tasty-core-tests:Dependencies

I was not aiming to match the whole message between GHCs, because it would require much more CPP. But at least all of versions point to myTest instead of omitting stack traces entirely or interrupting them inside of Control.Concurrent.Async.

[andreasabel]

Is it possible to add a golden value test for this fix?

[Bodigrim]

Is it possible to add a golden value test for this fix?

It's hard to do so: we are testing Tasty's output, so a golden test would have to run another instance of Tasty to collect its output. Then, as demonstated above, the output somewhat varies from version to version of GHC and contains highly volatile data (like exact line and column numbers).