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[BUG] clang-cl compiler error with generated c++ code for swap member function with 'that' parameter #1423
Description
Describe the bug
Defining a swap member function with a that parameter causes compiler error with clang-cl. The code emitted by a swap member function with a that parameter looks like the following:
public: auto swap(test&& that) noexcept && -> void;
The compiler is not happy with noexcept followed by &&. It only compiles when && precedes noexcept.
To Reproduce
Steps to reproduce the behavior:
- Sample code - distilled down to minimal essentials please
test: type = {
a: int = 0;
swap: (move this, move that) = {
temp_a: int = this.a;
a = that.a;
that.a = temp_a;
}
}
- Command lines including which C++ compiler you are using
clang version 19.1.5
Target: x86_64-pc-windows-msvc
cppfront compiler v0.8.2 Build A828:0952
.\cppfront\bin\cppfront.exe .\member_func_rvalue_qualifier_bug.cpp2 -p
clang-cl .\member_func_rvalue_qualifier_bug.cpp -std:c++20 -EHsc -I .\cppfront\include\
-
Expected result - what you expected to happen
Either:
A. Thenoexceptand&&function qualifiers are swapped during code generation
B. cppfront compiler error statingthatis not allowed in swap function -
Actual result/error
.\member_func_rvalue_qualifier_bug.cpp2(4,41): error: expected ';' at end of declaration list
4 | public: auto swap(test&& that) noexcept && -> void;
| ^
| ;
.\member_func_rvalue_qualifier_bug.cpp2(4,40): error: expected function body after function declarator
4 | auto test::swap(test&& that) noexcept && -> void{
| ^
Additional context
cpp code emitted by the cppfront compiler
#define CPP2_IMPORT_STD Yes
#include "cpp2util.h"
class test;
class test {
private: int a {0};
public: auto swap(test&& that) noexcept && -> void;
public: test() = default;
public: test(test const&) = delete; /* No 'that' constructor, suppress copy */
public: auto operator=(test const&) -> void = delete;
};
auto test::swap(test&& that) noexcept && -> void{
int temp_a {(*this).a};
a = cpp2::move(that).a;
that.a = cpp2::move(temp_a);
}