Bug 22351 – extern(C++) function contravariant in D, but not C++

////////////////// test.d //////////////////////// extern(C++) class A { int f() { return 1; } } extern(C++) class B: A { override int f() const { return 2; } } extern(C++) B createB() { return new B; } ////////////////// test.cpp ////////////////////// #include <stdio.h> class A { public: virtual int f(); }; class B: public A { public: virtual int f() const; }; B *createB(); int main() { const B *b = createB(); printf("%d\n", b->f()); return 0; } ////////////////////////////////////////////////// D allows to override the mutable function A.f with const B.f, because they are contravariant. The vtbl for B only contains one entry for f. C++ does not support that and expects a vtbl with two functions f. Calling b->f() results in a segmentation fault, because the vtbl entry for B.f does not exist. There are probably also other differences for covariant/contravariant functions between D and C++.

@ibuclaw created dlang/dmd pull request #14169 "fix Issue 22351 - extern(C++) function contravariant in D, but not C++" fixing this issue: - fix Issue 22351 - extern(C++) function contravariant in D, but not C++ https://github.com/dlang/dmd/pull/14169

dlang/dmd pull request #14169 "fix Issue 22351 - extern(C++) function contravariant in D, but not C++" was merged into master: - 283b1ca4b54d42a9a22a9e2b34a045d69573f445 by Iain Buclaw: fix Issue 22351 - extern(C++) function contravariant in D, but not C++ https://github.com/dlang/dmd/pull/14169