q::all exampe in tutorial not compiling on clang 9.0.0 mac os

[deblauwetom]

Hi, my clang version is:

clang++ --version
Apple LLVM version 9.0.0 (clang-900.0.39.2)
Target: x86_64-apple-darwin16.7.0
Thread model: posix
InstalledDir: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin

And so I'm trying to compile this example:

// This is basically a list of promises of floats
std::vector< q::promise< float > > list;

q:all( list, queue )
.then( [ ]( std::vector< q::expect< float > >&& values )
{
    // Now all promises have settled (i.e. are not waiting anymore),
    // but some of them might have failed.
    for ( auto& val : values )
    {
        if ( val.has_exception( ) )
            std::cout << "Failure: " << val.exception( ) << std::endl;
        else
            std::cout << "Value: " << val.get( ) << std::endl;
    }
} );

But first i think the "q:all" should have double colons in the example? But it doesn't complain about it for some reason :) anyway. Also, writing val.exception() to std::cout is not working for me, also gives a compile error. So the first main error I get is:

error: no matching function for call to 'all'
    q::all( list, qq )
    ^~~~~~

I can only fix it by using a move:

q::all( std::move(list), qq )

So then the next error I get is:

6: error: no matching member function for call to 'then'
    .then( [ ]( std::vector< q::expect< float > >&& values )
    ~^~~~
    ....

The rest of the errors list then states what he tries to do, but I don't know what signature it is supposed to be:

/Users/tom/.conan/data/libq/0.0.1/metalmajor/testing/package/f331ba4cb4cf3b345ec2ebc265629b6ee1340312/include/q/promise/promise.hpp:177:3: note: candidate template ignored: disabled by 'enable_if' [with Fn = (lambda at /Users/tom/projects/BackendCommunication/BackendDispatcherImpl.cpp:136:12), Queue = std::__1::shared_ptr<q::queue>]
                is_function_t< Fn >::value
                ^
/Users/tom/.conan/data/libq/0.0.1/metalmajor/testing/package/f331ba4cb4cf3b345ec2ebc265629b6ee1340312/include/q/promise/promise.hpp:197:3: note: candidate template ignored: disabled by 'enable_if' [with Fn = (lambda at /Users/tom/projects/BackendCommunication/BackendDispatcherImpl.cpp:136:12), Queue = std::__1::shared_ptr<q::queue>]
                is_function_t< Fn >::value
                ^
/Users/tom/.conan/data/libq/0.0.1/metalmajor/testing/package/f331ba4cb4cf3b345ec2ebc265629b6ee1340312/include/q/promise/promise.hpp:231:2: note: candidate template ignored: substitution failure [with Fn = (lambda at /Users/tom/projects/BackendCommunication/BackendDispatcherImpl.cpp:136:12), Queue = std::__1::shared_ptr<q::queue>]: type 'result_of_t<(lambda at /Users/tom/projects/BackendCommunication/BackendDispatcherImpl.cpp:136:12)>' (aka 'void') cannot be used prior to '::' because it has no members
        then( Fn&& fn, Queue&& queue = nullptr );
        ^
/Users/tom/.conan/data/libq/0.0.1/metalmajor/testing/package/f331ba4cb4cf3b345ec2ebc265629b6ee1340312/include/q/promise/promise.hpp:252:2: note: candidate template ignored: substitution failure [with Fn = (lambda at /Users/tom/projects/BackendCommunication/BackendDispatcherImpl.cpp:136:12), Queue = std::__1::shared_ptr<q::queue>]: type 'result_of_t<(lambda at /Users/tom/projects/BackendCommunication/BackendDispatcherImpl.cpp:136:12)>' (aka 'void') cannot be used prior to '::' because it has no members
        then( Fn&& fn, Queue&& queue = nullptr );
        ^
/Users/tom/.conan/data/libq/0.0.1/metalmajor/testing/package/f331ba4cb4cf3b345ec2ebc265629b6ee1340312/include/q/promise/promise.hpp:256:3: note: candidate template ignored: disabled by 'enable_if' [with Logger = (lambda at /Users/tom/projects/BackendCommunication/BackendDispatcherImpl.cpp:136:12), Queue = std::__1::shared_ptr<q::queue>]
                is_same_type< Logger, log_chain_generator >::value
                ^
/Users/tom/.conan/data/libq/0.0.1/metalmajor/testing/package/f331ba4cb4cf3b345ec2ebc265629b6ee1340312/include/q/promise/promise.hpp:272:3: note: candidate template ignored: disabled by 'enable_if' [with AsyncTask = (lambda at /Users/tom/projects/BackendCommunication/BackendDispatcherImpl.cpp:136:12)]
                is_same_type< AsyncTask, async_task >::value,

Is it a clang issue on mac os or is something wrong with the example? ps: as you can see from the compiler output, I am busy making a conan package file for libq too, so if you would be interested, it would be cool to have it in the repo.

[deblauwetom]

It works if I change the lamdas type to std::vector<float>&& so removing the expect<>. a bit unexpected or not?