[BUG] Double move when passing by move

Title: Double move when passing by move.

Minimal reproducer (https://cpp2.godbolt.org/z/31sPe9xMj):

main: () = {
  x := 0;
  :(y) = 0;
  (move x);
}

Commands:

cppfront -clean-cpp1 main.cpp2

Expected result:

  [](auto const& y) -> void { 0;  }
  (std::move(x));

Actual result and error:

  [](auto const& y) -> void { 0;  }
  (std::move(std::move(x)));

I fixed it locally, I don't know if it breaks something else in the process.
In cppfront.h, line under 1628:

line 1624          //  For an explicit 'forward' apply forwarding to correct identifier
                           assert (!current_args.empty());
                           if (current_args.back().pass == passing_style::forward) {
                                        add_forward = current_args.back().ptoken == n.identifier;
line 1628              }

I have added :

  // If explicit 'move' is used then don't add move
   if (current_args.back().pass == passing_style::move) {
            add_move = false;
    }

Let me know if this works or not, I look forward to contributing more actively, but for the time being I'm familiarizing my self with the compiler code.

Let me know if this works or not, I look forward to contributing more actively, but for the time being I'm familiarizing my self with the compiler code.

I can't know, as I don't have working code.
Just lots of snippets compliant to the grammar.

My apologies, I was referring to the contributors.

Now I can confirm that it works,
and there's just one change to existing tests:

-    v = X<19>(); std::cout << "move(v) as X<19> = " + cpp2::to_string(int(cpp2::as_<X<19>>((std::move(std::move(v)))))) << std::endl;
+    v = X<19>(); std::cout << "move(v) as X<19> = " + cpp2::to_string(int(cpp2::as_<X<19>>((std::move(v))))) << std::endl;

An alternative Expected result
is a diagnostic saying that x will be moved,
and thus the explicit move is redundant.

An alternative Expected result
is a diagnostic saying that x will be moved,
and thus the explicit move is redundant.

This isn't true in a generic context.
So I expect move x to always work in a generic context.

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[BUG] Double move when passing by move #413

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[BUG] Double move when passing by move #413

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HALL9kv0 commented on May 4, 2023

JohelEGP commented on May 4, 2023

HALL9kv0 commented on May 4, 2023

JohelEGP commented on May 31, 2023

JohelEGP commented on Jul 26, 2023

JohelEGP commented on Dec 14, 2023

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