fix Issue 11216 - Make synchronized statement nothrow

[MartinNowak]

• require Object.Monitor lock and unlock functions to be nothrow
• change methods of all core.sync classes to nothrow

Requires dmd pull dlang/dmd#4115
Issue 11216

[MartinNowak]

As this changes the API of the Object.Monitor interface it can potentially break client code that implements this interface. I couldn't come up with an idea how to avoid this, but it will only affect very few people and it will be simple to fulfill the nothrow requirement.

[MartinNowak]

requires dlang/phobos#2704 which in turn requires #1021

[MartinNowak]

Need to nothrow the osx semaphore headers.

[MartinNowak]

Updated

[DmitryOlshansky]

LGTM

[MartinNowak]

Well, the compiler change for _d_monitorenter and _d_monitorexit is already in.
Classes implementing Object.Monitor should be scarce outside of core.sync.

it will be simple to fulfill the nothrow requirement

At worse, scope (failure) assert(0); can be used to turn any function into a nothrow function, useful for practical nothrow functions that aren't nothrow because of missing annotations. Credit for that idiom goes to Kenji.

So unless there are any further objections, I'll merge this soon.

[DmitryOlshansky]

Auto-merge toggled on

[DmitryOlshansky]

Since we already march in this way and opposition is rather weak I'm merging it.

[MartinNowak]

Thx

[MartinNowak]

scope (failure) assert(0);

Even better because it checks nothrow in 2.067.

static if (__VERSION__ <= 2066)
    scope (failure) assert(0, "should be nothrow");