pybind11 linking error with ICC 18.0 and 19.0 but not 17.0

I report this here and not on the pybind11 issues as it is a problem related to ICC on Windows. The code compiles and links with ICC 17.0 but not with ICC 18.0 (I checked with updates 2 and 4) nor 19.0 (initial release and update 1). It also compiles with MSVC and MinGW-w64.

The problem is that the linker will fail if the the main pybind11 module cpp file calls a function defined in another pybind11 wrapper cpp file. The following code can be used to reproduce the issue, using pybind11 2.2.4.

Main pybind11 module:

#include <pybind11/pybind11.h>
#include <iostream>

namespace py = pybind11;

void my_function() 
{
    std::cout << "my_function()\n";
}

void init_other(py::module& m);

PYBIND11_MODULE(test, m) 
{
    m.def("my_function", &my_function);
    init_other(m);
}

Other pybind11 wrapper file:

#include <pybind11/pybind11.h>
#include <iostream>

namespace py = pybind11;

void my_other_function() 
{
    std::cout << "my_other_function()\n";
}

void init_other(py::module& m) 
{
    m.def("my_other_function", &my_other_function);
}

This produces the following errors:

1>other.obj : : error LNK2005: "public: static void __cdecl `struct pybind11::detail::internals & __cdecl pybind11::detail::get_internals(void)'::`7'::_FUNC<lambda_2>(class std::exception_ptr)" (?_FUNC<lambda_2>@?6??get_internals@detail@pybind11@@YAAEAUinternals@23@XZ@SAXVexception_ptr@std@@@Z) already defined in module.obj
1>other.obj : : error LNK2005: "public: static void __cdecl `struct pybind11::detail::internals & __cdecl pybind11::detail::get_internals(void)'::`9'::_FUNC<lambda_3>(class std::exception_ptr)" (?_FUNC<lambda_3>@?8??get_internals@detail@pybind11@@YAAEAUinternals@23@XZ@SAXVexception_ptr@std@@@Z) already defined in module.obj
1>other.obj : : error LNK2005: "public: static void __cdecl `public: __cdecl pybind11::capsule::capsule(void const *,void (__cdecl*)(void *))'::`2'::_FUNC<lambda_0>(struct _object *)" (?_FUNC<lambda_0>@?1???0capsule@pybind11@@QEAA@PEBXP6AXPEAX@Z@Z@SAXPEAU_object@@@Z) already defined in module.obj
1>other.obj : : error LNK2005: "public: static void __cdecl `protected: void __cdecl pybind11::cpp_function::initialize_generic(struct pybind11::detail::function_record *,char const *,class type_info const * const *,unsigned __int64)'::`80'::_FUNC<lambda_4>(void *)" (?_FUNC<lambda_4>@?FA@??initialize_generic@cpp_function@pybind11@@IEAAXPEAUfunction_record@detail@3@PEBDPEBQEBVtype_info@@_K@Z@SAXPEAX@Z) already defined in module.obj
1>other.obj : : error LNK2005: "public: static class pybind11::handle __cdecl `protected: void __cdecl pybind11::cpp_function::initialize<class `struct std::pair<class std::_List_iterator<class std::_List_val<struct std::_List_simple_types<struct std::pair<struct _typeobject * const,class std::vector<struct pybind11::detail::type_info *,class std::allocator<struct pybind11::detail::type_info *> > > > > >,bool> __cdecl pybind11::detail::all_type_info_get_cache(struct _typeobject *)'::`5'::<lambda_8>,void,class pybind11::handle>(class `struct std::pair<class std::_List_iterator<class std::_List_val<struct std::_List_simple_types<struct std::pair<struct _typeobject * const,class std::vector<struct pybind11::detail::type_info *,class std::allocator<struct pybind11::detail::type_info *> > > > > >,bool> __cdecl pybind11::detail::all_type_info_get_cache(struct _typeobject *)'::`5'::<lambda_8> &&,void (__cdecl*)(class pybind11::handle))'::`2'::_FUNC<lambda_17>(struct pybind11::detail::function_call &)" (?_FUNC<lambda_17>@?1???$initialize@V<lambda_8>@?4??all_type_info_get_cache@detail@pybind11@@YA?AU?$pair@V?$_List_iterator@V?$_List_val@U?$_List_simple_types@U?$pair@QEAU_typeobject@@V?$vector@PEAUtype_info@detail@pybind11@@V?$allocator@PEAUtype_info@detail@pybind11@@@std@@@std@@@std@@@std@@@std@@@std@@_N@std@@PEAU_typeobject@@@Z@XVhandle@4@$$V@cpp_function@pybind11@@IEAAX$$QEAV<lambda_8>@?4??all_type_info_get_cache@detail@2@YA?AU?$pair@V?$_List_iterator@V?$_List_val@U?$_List_simple_types@U?$pair@QEAU_typeobject@@V?$vector@PEAUtype_info@detail@pybind11@@V?$allocator@PEAUtype_info@detail@pybind11@@@std@@@std@@@std@@@std@@@std@@@std@@_N@std@@PEAU_typeobject@@@Z@P6AXVhandle@2@@Z@Z@SA?AV92@AEAUfunction_call@52@@Z) already defined in module.obj
1>other.obj : : error LNK2005: "public: static void __cdecl `protected: void __cdecl pybind11::cpp_function::initialize<class `struct std::pair<class std::_List_iterator<class std::_List_val<struct std::_List_simple_types<struct std::pair<struct _typeobject * const,class std::vector<struct pybind11::detail::type_info *,class std::allocator<struct pybind11::detail::type_info *> > > > > >,bool> __cdecl pybind11::detail::all_type_info_get_cache(struct _typeobject *)'::`5'::<lambda_8>,void,class pybind11::handle>(class `struct std::pair<class std::_List_iterator<class std::_List_val<struct std::_List_simple_types<struct std::pair<struct _typeobject * const,class std::vector<struct pybind11::detail::type_info *,class std::allocator<struct pybind11::detail::type_info *> > > > > >,bool> __cdecl pybind11::detail::all_type_info_get_cache(struct _typeobject *)'::`5'::<lambda_8> &&,void (__cdecl*)(class pybind11::handle))'::`7'::_FUNC<lambda_15>(struct pybind11::detail::function_record *)" (?_FUNC<lambda_15>@?6???$initialize@V<lambda_8>@?4??all_type_info_get_cache@detail@pybind11@@YA?AU?$pair@V?$_List_iterator@V?$_List_val@U?$_List_simple_types@U?$pair@QEAU_typeobject@@V?$vector@PEAUtype_info@detail@pybind11@@V?$allocator@PEAUtype_info@detail@pybind11@@@std@@@std@@@std@@@std@@@std@@@std@@_N@std@@PEAU_typeobject@@@Z@XVhandle@4@$$V@cpp_function@pybind11@@IEAAX$$QEAV<lambda_8>@?4??all_type_info_get_cache@detail@2@YA?AU?$pair@V?$_List_iterator@V?$_List_val@U?$_List_simple_types@U?$pair@QEAU_typeobject@@V?$vector@PEAUtype_info@detail@pybind11@@V?$allocator@PEAUtype_info@detail@pybind11@@@std@@@std@@@std@@@std@@@std@@@std@@_N@std@@PEAU_typeobject@@@Z@P6AXVhandle@2@@Z@Z@SAXPEAUfunction_record@52@@Z) already defined in module.obj
1>other.obj : : error LNK2005: "public: static void __cdecl `protected: void __cdecl pybind11::cpp_function::initialize<class `struct std::pair<class std::_List_iterator<class std::_List_val<struct std::_List_simple_types<struct std::pair<struct _typeobject * const,class std::vector<struct pybind11::detail::type_info *,class std::allocator<struct pybind11::detail::type_info *> > > > > >,bool> __cdecl pybind11::detail::all_type_info_get_cache(struct _typeobject *)'::`5'::<lambda_8>,void,class pybind11::handle>(class `struct std::pair<class std::_List_iterator<class std::_List_val<struct std::_List_simple_types<struct std::pair<struct _typeobject * const,class std::vector<struct pybind11::detail::type_info *,class std::allocator<struct pybind11::detail::type_info *> > > > > >,bool> __cdecl pybind11::detail::all_type_info_get_cache(struct _typeobject *)'::`5'::<lambda_8> &&,void (__cdecl*)(class pybind11::handle))'::`9'::_FUNC<lambda_16>(struct pybind11::detail::function_record *)" (?_FUNC<lambda_16>@?8???$initialize@V<lambda_8>@?4??all_type_info_get_cache@detail@pybind11@@YA?AU?$pair@V?$_List_iterator@V?$_List_val@U?$_List_simple_types@U?$pair@QEAU_typeobject@@V?$vector@PEAUtype_info@detail@pybind11@@V?$allocator@PEAUtype_info@detail@pybind11@@@std@@@std@@@std@@@std@@@std@@@std@@_N@std@@PEAU_typeobject@@@Z@XVhandle@4@$$V@cpp_function@pybind11@@IEAAX$$QEAV<lambda_8>@?4??all_type_info_get_cache@detail@2@YA?AU?$pair@V?$_List_iterator@V?$_List_val@U?$_List_simple_types@U?$pair@QEAU_typeobject@@V?$vector@PEAUtype_info@detail@pybind11@@V?$allocator@PEAUtype_info@detail@pybind11@@@std@@@std@@@std@@@std@@@std@@@std@@_N@std@@PEAU_typeobject@@@Z@P6AXVhandle@2@@Z@Z@SAXPEAUfunction_record@52@@Z) already defined in module.obj
1>other.obj : : error LNK2005: "public: static class pybind11::handle __cdecl `protected: void __cdecl pybind11::cpp_function::initialize<void (__cdecl*&)(void),void,struct pybind11::name,struct pybind11::scope,struct pybind11::sibling>(void (__cdecl*&)(void),void (__cdecl*)(void),struct pybind11::name const &,struct pybind11::scope const &,struct pybind11::sibling const &)'::`2'::_FUNC<lambda_20>(struct pybind11::detail::function_call &)" (?_FUNC<lambda_20>@?1???$initialize@AEAP6AXXZXUname@pybind11@@Uscope@2@Usibling@2@@cpp_function@pybind11@@IEAAXAEAP6AXXZP6AXXZAEBUname@2@AEBUscope@2@AEBUsibling@2@@Z@SA?AVhandle@2@AEAUfunction_call@detail@2@@Z) already defined in module.obj
1>other.obj : : error LNK2005: "public: static void __cdecl `protected: void __cdecl pybind11::cpp_function::initialize<void (__cdecl*&)(void),void,struct pybind11::name,struct pybind11::scope,struct pybind11::sibling>(void (__cdecl*&)(void),void (__cdecl*)(void),struct pybind11::name const &,struct pybind11::scope const &,struct pybind11::sibling const &)'::`7'::_FUNC<lambda_18>(struct pybind11::detail::function_record *)" (?_FUNC<lambda_18>@?6???$initialize@AEAP6AXXZXUname@pybind11@@Uscope@2@Usibling@2@@cpp_function@pybind11@@IEAAXAEAP6AXXZP6AXXZAEBUname@2@AEBUscope@2@AEBUsibling@2@@Z@SAXPEAUfunction_record@detail@2@@Z) already defined in module.obj
1>other.obj : : error LNK2005: "public: static void __cdecl `protected: void __cdecl pybind11::cpp_function::initialize<void (__cdecl*&)(void),void,struct pybind11::name,struct pybind11::scope,struct pybind11::sibling>(void (__cdecl*&)(void),void (__cdecl*)(void),struct pybind11::name const &,struct pybind11::scope const &,struct pybind11::sibling const &)'::`9'::_FUNC<lambda_19>(struct pybind11::detail::function_record *)" (?_FUNC<lambda_19>@?8???$initialize@AEAP6AXXZXUname@pybind11@@Uscope@2@Usibling@2@@cpp_function@pybind11@@IEAAXAEAP6AXXZP6AXXZAEBUname@2@AEBUscope@2@AEBUsibling@2@@Z@SAXPEAUfunction_record@detail@2@@Z) already defined in module.obj