fix Issue 14708 - destructor for temporary not called during stack un…

[WalterBright]

…winding

This is working for me, so to be sure this PR adds the test case for it.

[dlang-bot]

Thanks for your pull request, @WalterBright!

Bugzilla references

Auto-close	Bugzilla	Severity	Description
✓	14708	major	destructor for temporary not called during stack unwinding

Testing this PR locally

If you don't have a local development environment setup, you can use Digger to test this PR:

dub run digger -- build "master + dmd#11676"

[WalterBright]

Looks like it ain't working on Win64.

[WalterBright]

So, why does the autotester dmd build of Win64 work, but the Azure dmd builds fail? The object files generated by each build of dmd should be identical. Can someone email one of the failing Azure dmd builds, so I can compare its output?

[WalterBright]

Here's what the various builds are: https://issues.dlang.org/show_bug.cgi?id=21133

[wilzbach]

So, why does the autotester dmd build of Win64 work, but the Azure dmd builds fail? The object files generated by each build of dmd should be identical.

Because we stopped testing on auto-tester and stubbed the output for the windows machines until we get a full replication of all other builds.

Can someone email one of the failing Azure dmd builds, so I can compare its output?

Did it pass locally on your machine?

[rmanthorpe]

This highlights an asymmetry that has been introduced between constructor and destructor calls. Now temporaries have their destructors called but they are never constructed to begin with. This is a disaster for RAII.

[UplinkCoder]

When has the compiler changed happened that made this work?

[WalterBright]

Did it pass locally on your machine?

No. But at least now I know that Win64 is the only platform where it fails. Kenji's assessment of the cause is likely correct. I have my work cut out for me on this one.

[WalterBright]

Why should everything else pass but buildkite/dmd dlang/phobos fail with:

../dmd/generated/linux/release/64/dmd  -conf= -I../druntime/import  -w -de -preview=dip1000 -preview=dtorfields -m64 -fPIC -transition=complex -O -release -unittest -version=StdUnittest -c -ofgenerated/linux/release/64/unittest/std/traits.o std/traits.d
--
  | posix.mak:379: recipe for target 'generated/linux/release/64/unittest/std/traits.o' failed
  | make[1]: *** [generated/linux/release/64/unittest/std/traits.o] Segmentation fault (core dumped)

which is a linux build yet this change is specific to win64?