[BUG] Implicit move on non-last use

[JohelEGP]

Title: Implicit move on non-last use.

Minimal reproducer (https://cpp2.godbolt.org/z/z1nWesaaa):

main: () = {
  x := 0;

  if true { _ = x; }

  {
    { _ = x; }

    _ = x;
  }
}

Commands:

cppfront main.cpp2
clang++18 -std=c++23 -stdlib=libc++ -lc++abi -pedantic-errors -Wall -Wextra -Wconversion -Werror=unused-result -Werror=unused-value -Werror=unused-parameter -Werror=unused-variable -I . main.cpp

Expected result:

    {static_cast<void>(x); }

    static_cast<void>(std::move(x));

Actual result and error:

    {static_cast<void>(std::move(x)); }

    static_cast<void>(std::move(x));

Cpp2 lowered to Cpp1:

//=== Cpp2 type declarations ====================================================


#include "cpp2util.h"

#line 1 "/app/example.cpp2"


//=== Cpp2 type definitions and function declarations ===========================

#line 1 "/app/example.cpp2"
auto main() -> int;

//=== Cpp2 function definitions =================================================

#line 1 "/app/example.cpp2"
auto main() -> int{
#line 2 "/app/example.cpp2"
  auto x {0}; 

  if (true) {static_cast<void>(x); }

  {
    {static_cast<void>(std::move(x)); }

    static_cast<void>(std::move(x));
  }
}

Output:

Program returned: 0

See also:

• [BUG] Analysis of uninitialized local fails at if without else #440.

[JohelEGP]

Same for the test case of #869.

v: @union @print type = {
  i: int;
}

prints

        if that.is_i()
        {
            set_i(that.i());
        }

which generates

if (CPP2_UFCS(is_i)(std::move(that))) {set_i(CPP2_UFCS(i)(std::move(that)));}