https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111728
--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> --- [apinski@xeond2 upstream-gcc-git]$ ~/upstream-gcc/bin/gcc main.cpp.ii -std=gnu++20 /home/yunus/Projects/terraqtt/examples/main.cpp: In instantiation of ‘write_fields(write_fields()::_Z12write_fieldsv.Frame*)::<lambda(auto:50)> [with auto:50 = int]’: /home/yunus/Projects/terraqtt/examples/main.cpp:12:4: required from here /home/yunus/Projects/terraqtt/examples/main.cpp:12:3: internal compiler error: in rewrite_param_uses, at cp/coroutines.cc:3798 0x792564 rewrite_param_uses /home/apinski/src/upstream-gcc-git/gcc/gcc/cp/coroutines.cc:3798 0x1613da4 walk_tree_1(tree_node**, tree_node* (*)(tree_node**, int*, void*), void*, hash_set<tree_node*, false, default_hash_traits<tree_node*> >*, tree_node* (*)(tree_node**, int*, tree_node* (*)(tree_node**, int*, void*), void*, hash_set<tree_node*, false, default_hash_traits<tree_node*> >*)) /home/apinski/src/upstream-gcc-git/gcc/gcc/tree.cc:11400 0x1613ef8 walk_tree_1(tree_node**, tree_node* (*)(tree_node**, int*, void*), void*, hash_set<tree_node*, false, default_hash_traits<tree_node*> >*, tree_node* (*)(tree_node**, int*, tree_node* (*)(tree_node**, int*, void*), void*, hash_set<tree_node*, false, default_hash_traits<tree_node*> >*)) /home/apinski/src/upstream-gcc-git/gcc/gcc/tree.cc:11634 0xad2426 rewrite_param_uses /home/apinski/src/upstream-gcc-git/gcc/gcc/cp/coroutines.cc:3786 0x1613da4 walk_tree_1(tree_node**, tree_node* (*)(tree_node**, int*, void*), void*, hash_set<tree_node*, false, default_hash_traits<tree_node*> >*, tree_node* (*)(tree_node**, int*, tree_node* (*)(tree_node**, int*, void*), void*, hash_set<tree_node*, false, default_hash_traits<tree_node*> >*)) /home/apinski/src/upstream-gcc-git/gcc/gcc/tree.cc:11400 0xccfdcc cp_walk_subtrees(tree_node**, int*, tree_node* (*)(tree_node**, int*, void*), void*, hash_set<tree_node*, false, default_hash_traits<tree_node*> >*) /home/apinski/src/upstream-gcc-git/gcc/gcc/cp/tree.cc:5591 0x1613e13 walk_tree_1(tree_node**, tree_node* (*)(tree_node**, int*, void*), void*, hash_set<tree_node*, false, default_hash_traits<tree_node*> >*, tree_node* (*)(tree_node**, int*, tree_node* (*)(tree_node**, int*, void*), void*, hash_set<tree_node*, false, default_hash_traits<tree_node*> >*)) /home/apinski/src/upstream-gcc-git/gcc/gcc/tree.cc:11424 0x1613ef8 walk_tree_1(tree_node**, tree_node* (*)(tree_node**, int*, void*), void*, hash_set<tree_node*, false, default_hash_traits<tree_node*> >*, tree_node* (*)(tree_node**, int*, tree_node* (*)(tree_node**, int*, void*), void*, hash_set<tree_node*, false, default_hash_traits<tree_node*> >*)) /home/apinski/src/upstream-gcc-git/gcc/gcc/tree.cc:11634 0x16144a3 walk_tree_1(tree_node**, tree_node* (*)(tree_node**, int*, void*), void*, hash_set<tree_node*, false, default_hash_traits<tree_node*> >*, tree_node* (*)(tree_node**, int*, tree_node* (*)(tree_node**, int*, void*), void*, hash_set<tree_node*, false, default_hash_traits<tree_node*> >*)) /home/apinski/src/upstream-gcc-git/gcc/gcc/tree.cc:11516 0xaca338 coro_rewrite_function_body /home/apinski/src/upstream-gcc-git/gcc/gcc/cp/coroutines.cc:4205 0xacf3f5 morph_fn_to_coro(tree_node*, tree_node**, tree_node**) /home/apinski/src/upstream-gcc-git/gcc/gcc/cp/coroutines.cc:4485 0xb24b59 finish_function(bool) /home/apinski/src/upstream-gcc-git/gcc/gcc/cp/decl.cc:18168 0xc700a6 instantiate_body /home/apinski/src/upstream-gcc-git/gcc/gcc/cp/pt.cc:27110 0xc81bcb instantiate_decl(tree_node*, bool, bool) /home/apinski/src/upstream-gcc-git/gcc/gcc/cp/pt.cc:27379 0xc92d5b instantiate_pending_templates(int) /home/apinski/src/upstream-gcc-git/gcc/gcc/cp/pt.cc:27457 0xb3b2d1 c_parse_final_cleanups() /home/apinski/src/upstream-gcc-git/gcc/gcc/cp/decl2.cc:5060 0xd7bfc0 c_common_parse_file() /home/apinski/src/upstream-gcc-git/gcc/gcc/c-family/c-opts.cc:1296 Please submit a full bug report, with preprocessed source (by using -freport-bug). Please include the complete backtrace with any bug report. See <https://gcc.gnu.org/bugs/> for instructions.