[Diag] [Typechecker] Diagnose throw in defer properly

[theblixguy]

The body of a defer statement is an implicit FuncDecl, but that's implementation detail and it shouldn't leak into diagnostics. For example, we end up emitting an incorrect diagnostic when using a throw in a defer:

defer { throw Foo.bar } // error is not handled because the enclosing function is not declared 'throws'

Treat throw the same way we treat other control flow statements, like return, break & yield when used inside a defer.

[theblixguy]

cc @xedin

[xedin]

LGTM!

[xedin]

@swift-ci please smoke test and merge

[xedin]

@theblixguy Looks like there is a problem in verifier.

[theblixguy]

@xedin Hmm this makes sense since we're backing out of error type checking if we're in a defer body. I have fixed it now. Could you trigger the test again? Should be all good!

[xedin]

@swift-ci please smoke test and merge

[xedin]

@swift-ci please smoke test and merge

[xedin]

@swift-ci please smoke test

[theblixguy]

@xedin Could you trigger the CI again? Had to make a small change! Thank you!

[xedin]

@swift-ci please smoke test

[theblixguy]

Unrelated build failure:

15:10:35 The following build commands failed:
15:10:35 PhaseScriptExecution Install\ Swift\ compiler\ resources /Users/buildnode/jenkins/workspace/swift-PR-osx-smoke-test/branch-master/buildbot_incremental/lldb-macosx-x86_64/lldb.build/CustomSwift-Release/LLDB.build/Script-49DD45051B4EDB4A00DB3579.sh

[xedin]

@swift-ci please smoke test macOS platform

[theblixguy]

Seems like the bots are not working correctly today 😅 Something's wrong with LLDB

[xedin]

We'll just have to wait until that's cleared, unfortunately...

[theblixguy]

No problem!

[theblixguy]

Okay, let's give the tests one more try. @xedin can you invoke the CI?

[xedin]

@swift-ci please smoke test

[theblixguy]

All tests have passed 🙏 🎉

[xedin]

Ok, great! Let's run source compatibility just in case...

[xedin]

@swift-ci please test source compatibility

[theblixguy]

Hmm I don't think the source compat test ran (or maybe the CI screwed up) 🤔

Problem accessing /job/swift-PR-source-compat-suite/2695/. Reason:
Not Found

[xedin]

@swift-ci please test source compatibility