Bug 18954 – extern(C++) ICE when `cppmangle` is used

test.d: -------------------------------------------------------------- extern (C++, std) { extern (C++, class) struct allocator(T) { } extern (C++, struct) struct char_traits(Char) { } extern (C++, class) struct basic_string(T, Traits, Alloc) { } alias string = basic_string!(char, char_traits!char, allocator!char); } extern (C++) void test(ref const(std.string) str) {} -------------------------------------------------------------- The problem is instantiating basic_string!(...) `basic_string` is mangled as a class, but char_traits is mangled as a struct. When instantiating basic_string with char_traits as an argument, it triggers an assert in a weird bit of code insisting that the mangle types be the same (but they're not)

I don't understand the intent of the code that asserts. Walter might want to have a look, since he probably understands what the logic is intended to do?

I cannot reproduce this on Linux or Windows with 2.081.

I'm pretty sure nobody attempted to fix it...?

I attempted to fix it, but couldn't reproduce it, so I don't know what needs to be fixed.

I just tried to repro with 2.081.1b, this issue as logged above seems to be resolved. This variant persists though: test.d: -------------------------------------------------------------- extern (C++, std) { extern (C++, class) struct allocator(T) { } struct char_traits(Char) { } extern (C++, class) struct basic_string(T, Traits, Alloc) { } alias string = basic_string!(char, char_traits!char, allocator!char); } extern (C++) void test(ref const(std.string) str) {} -------------------------------------------------------------- I just removed the explicit `extern(C++, struct)` from the struct. It's declared as a struct, no need to override a struct as struct! In this code, it gets mangled as a class instead of as a struct, which is incorrect. This is only relevant on windows, this issue doesn't affect linux (posix mangling doesn't distinguish class/struct).

That still-broken variant is logged as another bug: https://issues.dlang.org/show_bug.cgi?id=18955 This particular one seems to have been fixed... perhaps by accident? O_o I can't find a recent patch that looks like it should have fixed this. Marking as resolved...