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[BUG] Implicit move before taking address of member #558
Description
Title: Implicit move before taking address of member.
Minimal reproducer (https://cpp2.godbolt.org/z/651rnTT7b):
t: @struct type = {
x: i32;
}
main: () = {
v: t = ();
_ = v.x&;
}
Commands:
cppfront main.cpp2
clang++17 -std=c++23 -stdlib=libc++ -lc++abi -pedantic-errors -Wall -Wextra -Wconversion -fsanitize=undefined -Werror=unused-result -I . main.cppExpected result: No implicit move, like in other problematic cases.
Actual result and error:
main.cpp2:6:10: error: cannot take the address of an rvalue of type 'cpp2::i32' (aka 'int')
6 | (void) &std::move(v).x;
| ^~~~~~~~~~~~~~~
Cpp2 lowered to Cpp1:
//=== Cpp2 type declarations ====================================================
#include "cpp2util.h"
class t;
//=== Cpp2 type definitions and function declarations ===========================
class t {
public: cpp2::i32 x;
};
auto main() -> int;
//=== Cpp2 function definitions =================================================
auto main() -> int{
t v {};
(void) &std::move(v).x;
}
Activity
JohelEGP commentedon Aug 29, 2023
Note that you could say that this is fixed by appending the statement
_ = v;.IIRC there have been exceptions added to not generate a move on last use
in a case like the one in this issue, e.g., moving is statically known to be always ill-formed.
Which is why I opened this issue instead.
JohelEGP commentedon Sep 12, 2023
This is what I'm referring to:
cppfront/source/cppfront.cpp
Lines 3100 to 3109 in ecd3726
It works for variables, but not when accessing a variable's data member.