Repository navigation
[BUG] 1 as std::string errors #717
Description
Title: 1 as std::string errors.
Minimal reproducer (https://cpp2.godbolt.org/z/qdh9vWzod):
main: () = {
_ = 1 as std::string;
}
Commands:
cppfront main.cpp2
clang++18 -std=c++23 -stdlib=libc++ -lc++abi -pedantic-errors -Wall -Wextra -Wconversion -Werror=unused-result -I . main.cppExpected result: Program returned: 0
Actual result and error:
Cpp2 lowered to Cpp1:
//=== Cpp2 type declarations ====================================================
#include "cpp2util.h"
//=== Cpp2 type definitions and function declarations ===========================
auto main() -> int;
//=== Cpp2 function definitions =================================================
auto main() -> int{
static_cast<void>(cpp2::as_<std::string, 1>());
}Output:
In file included from /app/build/main.cpp:6:
In file included from /app/cpp2util.h:1:
raw.githubusercontent.com/hsutter/cppfront/main/include/cpp2util.h:1825:13: error: static assertion failed due to requirement 'program_violates_type_safety_guarantee<std::string, int>': No safe 'as' cast available - please check your cast
1825 | program_violates_type_safety_guarantee<C, CPP2_TYPEOF(x)>,
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
build/main.cpp:18:27: note: in instantiation of function template specialization 'cpp2::as_<std::string, 1>' requested here
18 | static_cast<void>(cpp2::as_<std::string, 1>());
| ^
In file included from /app/build/main.cpp:6:
In file included from /app/cpp2util.h:1:
raw.githubusercontent.com/hsutter/cppfront/main/include/cpp2util.h:1830:12: error: no matching function for call to 'as'
1830 | return as<C,x>();
| ^~~~~~~
raw.githubusercontent.com/hsutter/cppfront/main/include/cpp2util.h:1104:23: note: candidate template ignored: constraints not satisfied [with C = std::string, x = 1]
1104 | inline constexpr auto as() -> auto
| ^
raw.githubusercontent.com/hsutter/cppfront/main/include/cpp2util.h:1103:15: note: because 'std::is_arithmetic_v<std::string>' evaluated to false
1103 | requires (std::is_arithmetic_v<C> && std::is_arithmetic_v<CPP2_TYPEOF(x)>)
| ^
raw.githubusercontent.com/hsutter/cppfront/main/include/cpp2util.h:1520:16: note: candidate function template not viable: requires single argument 'x', but no arguments were provided
1520 | constexpr auto as( X const& x ) -> decltype(auto)
| ^ ~~~~~~~~~~
raw.githubusercontent.com/hsutter/cppfront/main/include/cpp2util.h:1474:16: note: candidate function template not viable: requires single argument 'x', but no arguments were provided
1474 | constexpr auto as( X const& x ) -> T
| ^ ~~~~~~~~~~
raw.githubusercontent.com/hsutter/cppfront/main/include/cpp2util.h:1406:6: note: candidate function template not viable: requires single argument 'x', but no arguments were provided
1406 | auto as( std::variant<Ts...> const& x ) -> decltype(auto) {
| ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
raw.githubusercontent.com/hsutter/cppfront/main/include/cpp2util.h:1381:6: note: candidate function template not viable: requires single argument 'x', but no arguments were provided
1381 | auto as( std::variant<Ts...> & x ) -> decltype(auto) {
| ^ ~~~~~~~~~~~~~~~~~~~~~~~
raw.githubusercontent.com/hsutter/cppfront/main/include/cpp2util.h:1356:6: note: candidate function template not viable: requires single argument 'x', but no arguments were provided
1356 | auto as( std::variant<Ts...> && x ) -> decltype(auto) {
| ^ ~~~~~~~~~~~~~~~~~~~~~~~~
raw.githubusercontent.com/hsutter/cppfront/main/include/cpp2util.h:1213:6: note: candidate function template not viable: requires single argument 'x', but no arguments were provided
1213 | auto as( X x ) -> C {
| ^ ~~~
raw.githubusercontent.com/hsutter/cppfront/main/include/cpp2util.h:1202:6: note: candidate function template not viable: requires single argument 'x', but no arguments were provided
1202 | auto as( X const& x ) -> C const& {
| ^ ~~~~~~~~~~
raw.githubusercontent.com/hsutter/cppfront/main/include/cpp2util.h:1196:6: note: candidate function template not viable: requires single argument 'x', but no arguments were provided
1196 | auto as( X& x ) -> C& {
| ^ ~~~~
raw.githubusercontent.com/hsutter/cppfront/main/include/cpp2util.h:1190:6: note: candidate function template not viable: requires single argument 'x', but no arguments were provided
1190 | auto as( X const& x ) -> C const& {
| ^ ~~~~~~~~~~
raw.githubusercontent.com/hsutter/cppfront/main/include/cpp2util.h:1184:6: note: candidate function template not viable: requires single argument 'x', but no arguments were provided
1184 | auto as( X& x ) -> C& {
| ^ ~~~~
raw.githubusercontent.com/hsutter/cppfront/main/include/cpp2util.h:1166:6: note: candidate function template not viable: requires single argument 'x', but no arguments were provided
1166 | auto as( X const& x ) -> auto
| ^ ~~~~~~~~~~
raw.githubusercontent.com/hsutter/cppfront/main/include/cpp2util.h:1158:6: note: candidate function template not viable: requires single argument 'x', but no arguments were provided
1158 | auto as(X const& x) -> C
| ^ ~~~~~~~~~~
raw.githubusercontent.com/hsutter/cppfront/main/include/cpp2util.h:1152:6: note: candidate function template not viable: requires single argument 'x', but no arguments were provided
1152 | auto as( X& x ) -> decltype(auto) {
| ^ ~~~~
raw.githubusercontent.com/hsutter/cppfront/main/include/cpp2util.h:1146:6: note: candidate function template not viable: requires single argument 'x', but no arguments were provided
1146 | auto as( X const& x ) -> decltype(auto) {
| ^ ~~~~~~~~~~
raw.githubusercontent.com/hsutter/cppfront/main/include/cpp2util.h:1128:23: note: candidate function template not viable: requires single argument 'x', but no arguments were provided
1128 | inline constexpr auto as(auto const& x CPP2_SOURCE_LOCATION_PARAM_WITH_DEFAULT) -> auto
| ^ ~~~~~~~~~~~~~
raw.githubusercontent.com/hsutter/cppfront/main/include/cpp2util.h:1114:23: note: candidate function template not viable: requires single argument 'x', but no arguments were provided
1114 | inline constexpr auto as(auto const& x) -> auto
| ^ ~~~~~~~~~~~~~
raw.githubusercontent.com/hsutter/cppfront/main/include/cpp2util.h:1098:6: note: candidate function template not viable: requires 1 argument, but 0 were provided
1098 | auto as(auto const&) -> auto {
| ^ ~~~~~~~~~~~
2 errors generated.
Activity
leejy12 commentedon Oct 2, 2023
What is the expected value of
1 as std::string?JohelEGP commentedon Oct 2, 2023
Like this: https://cpp2.godbolt.org/z/E7ebY9GYW.
filipsajdak commentedon Oct 3, 2023
It was already fixed in #701
JohelEGP commentedon Oct 3, 2023
Then you may add that to its opening comment so that this is automatically closed when that is merged.
JohelEGP commentedon Oct 4, 2024
Now it works in the
mainbranch.