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Boaz Brickner
d6fbe3c663
C++ Interop Demo:
```c++
// my_number.h
namespace MyNamespace {
class MyNumber {
public:
explicit MyNumber(int value) : value_(value) {}
auto value() const -> int { return value_; }
private:
int value_;
};
auto operator+(MyNumber lhs, MyNumber rhs) -> MyNumber;
} // namespace MyNamespace
```
```c++
// my_number.cpp
#include "my_number.h"
namespace MyNamespace {
auto operator+(MyNumber lhs, MyNumber rhs) -> MyNumber {
return MyNumber(lhs.value() + rhs.value());
}
} // namespace MyNamespace
```
```carbon
// main.carbon
library "Main";
import Core library "io";
import Cpp library "my_number.h";
fn Run() -> i32 {
let n1: Cpp.MyNamespace.MyNumber = Cpp.MyNamespace.MyNumber.MyNumber(5);
Core.Print(n1.value());
let n2: Cpp.MyNamespace.MyNumber = Cpp.MyNamespace.MyNumber.MyNumber(7);
Core.Print(n2.value());
let n3: Cpp.MyNamespace.MyNumber = n1 + n2;
Core.Print(n3.value());
return 0;
}
```
Before this change:
```
$ bazel-bin/toolchain/carbon compile main.carbon
main.carbon:13:38: error: cannot access member of interface `Core.AddWith(Cpp.MyNamespace.MyNumber)` in type `Cpp.MyNamespace.MyNumber` that does not implement that interface
let n3: Cpp.MyNamespace.MyNumber = n1 + n2;
^~~~~~~
```
With this change:
```shell
$ clang -c my_number.cpp
$ bazel-bin/toolchain/carbon compile main.carbon
$ bazel-bin/toolchain/carbon link my_number.o main.o --output=demo
$ ./demo
5
7
12
```
Part of https://github.com/carbon-language/carbon-lang/issues/5995.