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Boaz Brickner
ef488f00fa
Multiple overloads for the same operator are now resolved using overload resolution. This change doesn't try to solve all issues with operator lookup. Moved the operator lookup logic from `import` to `operators` and changed it to take the args into account. Use `Sema::LookupOverloadedBinOp()` (with ADL) when looking up operator functions to create an overload set. Verified all demos in #6017, #6020 and #6024 still work. C++ Interop Demo: ```c++ // my_number.h class MyNumber { public: explicit MyNumber(int value) : value_(value) {} auto value() const -> int { return value_; } private: int value_; }; class NotMyNumber {}; auto operator+(MyNumber lhs, MyNumber rhs) -> MyNumber; auto operator+(NotMyNumber lhs, NotMyNumber rhs) -> NotMyNumber; ``` ```c++ // my_number.cpp #include "my_number.h" auto operator+(MyNumber lhs, MyNumber rhs) -> MyNumber { return MyNumber(lhs.value() + rhs.value()); } auto operator+(NotMyNumber lhs, NotMyNumber /*rhs*/) -> NotMyNumber { return lhs; } ``` ```carbon // main.carbon library "Main"; import Core library "io"; import Cpp library "my_number.h"; fn Run() -> i32 { // Arithmetic var num1: Cpp.MyNumber = Cpp.MyNumber.MyNumber(14); var num2: Cpp.MyNumber = Cpp.MyNumber.MyNumber(5); Core.Print(num1.value()); Core.Print(num2.value()); Core.Print((num1 + num2).value()); return 0; } ``` **After 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 14 5 19 ``` **Before this change** ```shell $ bazel-bin/toolchain/carbon compile main.carbon main.carbon:14:15: error: semantics TODO: `Unsupported: Lookup succeeded but couldn't find a single result; LookupResultKind: 3` Core.Print((num1 + num2).value()); ^~~~~~~~~~~ main.carbon:14:15: note: in `Cpp` operator `AddWith` lookup Core.Print((num1 + num2).value()); ^~~~~~~~~~~ ``` Part of https://github.com/carbon-language/carbon-lang/issues/5995.