Possibly address unused parameter/variable warnings

[gorakhargosh]

Hi!

Thank you for creating this wonderful library. I have a small request.
Could you please turn on -Wall -Wpedantic -Wextra -Wunused and
try to minimize the unused variables/parameters? We see a flurry of
warnings when we build code that uses immer.

INFO: From Compiling codelab/cc/containers/immutable/vector_test.cc:
In file included from codelab/cc/containers/immutable/vector_test.cc:1:
In file included from bazel-out/darwin-fastbuild/bin/external/com_github_arximboldi_immer/_virtual_includes/immer/immer/vector.hpp:11:
In file included from bazel-out/darwin-fastbuild/bin/external/com_github_arximboldi_immer/_virtual_includes/immer/immer/detail/rbts/rbtree.hpp:11:
In file included from bazel-out/darwin-fastbuild/bin/external/com_github_arximboldi_immer/_virtual_includes/immer/immer/detail/rbts/node.hpp:13:
bazel-out/darwin-fastbuild/bin/external/com_github_arximboldi_immer/_virtual_includes/immer/immer/detail/util.hpp:132:20: warning: unused parameter 'f' [-Wunused-parameter]
auto static_if(F&& f) -> std::enable_if_t<!b>
                   ^
bazel-out/darwin-fastbuild/bin/external/com_github_arximboldi_immer/_virtual_includes/immer/immer/detail/util.hpp:136:30: warning: unused parameter 'f2' [-Wunused-parameter]
auto static_if(F1&& f1, F2&& f2) -> std::enable_if_t<b, R>
                             ^
bazel-out/darwin-fastbuild/bin/external/com_github_arximboldi_immer/_virtual_includes/immer/immer/detail/util.hpp:141:21: warning: unused parameter 'f1' [-Wunused-parameter]
auto static_if(F1&& f1, F2&& f2) -> std::enable_if_t<!b, R>
                    ^
In file included from codelab/cc/containers/immutable/vector_test.cc:1:
In file included from bazel-out/darwin-fastbuild/bin/external/com_github_arximboldi_immer/_virtual_includes/immer/immer/vector.hpp:11:
In file included from bazel-out/darwin-fastbuild/bin/external/com_github_arximboldi_immer/_virtual_includes/immer/immer/detail/rbts/rbtree.hpp:11:
bazel-out/darwin-fastbuild/bin/external/com_github_arximboldi_immer/_virtual_includes/immer/immer/detail/rbts/node.hpp:874:24: warning: unused parameter 'shift' [-Wunused-parameter]
    bool check(shift_t shift, size_t size)
                       ^
bazel-out/darwin-fastbuild/bin/external/com_github_arximboldi_immer/_virtual_includes/immer/immer/detail/rbts/node.hpp:874:38: warning: unused parameter 'size' [-Wunused-parameter]
    bool check(shift_t shift, size_t size)
                                     ^
In file included from codelab/cc/containers/immutable/vector_test.cc:1:
In file included from bazel-out/darwin-fastbuild/bin/external/com_github_arximboldi_immer/_virtual_includes/immer/immer/vector.hpp:11:
In file included from bazel-out/darwin-fastbuild/bin/external/com_github_arximboldi_immer/_virtual_includes/immer/immer/detail/rbts/rbtree.hpp:12:
In file included from bazel-out/darwin-fastbuild/bin/external/com_github_arximboldi_immer/_virtual_includes/immer/immer/detail/rbts/operations.hpp:17:
bazel-out/darwin-fastbuild/bin/external/com_github_arximboldi_immer/_virtual_includes/immer/immer/detail/rbts/position.hpp:55:34: warning: unused parameter 'v' [-Wunused-parameter]
    decltype(auto) visit(Visitor v, Args&&... args)
                                 ^
bazel-out/darwin-fastbuild/bin/external/com_github_arximboldi_immer/_virtual_includes/immer/immer/detail/rbts/position.hpp:79:34: warning: unused parameter 'v' [-Wunused-parameter]
    decltype(auto) visit(Visitor v, Args&&... args)
                                 ^
bazel-out/darwin-fastbuild/bin/external/com_github_arximboldi_immer/_virtual_includes/immer/immer/detail/rbts/position.hpp:110:34: warning: unused parameter 'v' [-Wunused-parameter]
    decltype(auto) visit(Visitor v, Args&&... args)
                                 ^
bazel-out/darwin-fastbuild/bin/external/com_github_arximboldi_immer/_virtual_includes/immer/immer/detail/rbts/position.hpp:142:34: warning: unused parameter 'v' [-Wunused-parameter]
    decltype(auto) visit(Visitor v, Args&&... args)
                                 ^
bazel-out/darwin-fastbuild/bin/external/com_github_arximboldi_immer/_virtual_includes/immer/immer/detail/rbts/position.hpp:174:34: warning: unused parameter 'v' [-Wunused-parameter]
    decltype(auto) visit(Visitor v, Args&&... args)
                                 ^
bazel-out/darwin-fastbuild/bin/external/com_github_arximboldi_immer/_virtual_includes/immer/immer/detail/rbts/position.hpp:204:34: warning: unused parameter 'v' [-Wunused-parameter]
    decltype(auto) visit(Visitor v, Args&&... args)
                                 ^
bazel-out/darwin-fastbuild/bin/external/com_github_arximboldi_immer/_virtual_includes/immer/immer/detail/rbts/position.hpp:312:42: warning: unused parameter 'count_hint' [-Wunused-parameter]
                                 count_t count_hint,
                                         ^
bazel-out/darwin-fastbuild/bin/external/com_github_arximboldi_immer/_virtual_includes/immer/immer/detail/rbts/position.hpp:333:34: warning: unused parameter 'v' [-Wunused-parameter]
    decltype(auto) visit(Visitor v, Args&&... args)
                                 ^
bazel-out/darwin-fastbuild/bin/external/com_github_arximboldi_immer/_virtual_includes/immer/immer/detail/rbts/position.hpp:730:26: warning: unused parameter 'idx' [-Wunused-parameter]
    count_t index(size_t idx) const { return 0; }
                         ^
bazel-out/darwin-fastbuild/bin/external/com_github_arximboldi_immer/_virtual_includes/immer/immer/detail/rbts/position.hpp:731:29: warning: unused parameter 'idx' [-Wunused-parameter]
    count_t subindex(size_t idx) const { return 0; }
                            ^
bazel-out/darwin-fastbuild/bin/external/com_github_arximboldi_immer/_virtual_includes/immer/immer/detail/rbts/position.hpp:732:32: warning: unused parameter 'offset' [-Wunused-parameter]
    size_t size_before(count_t offset) const { return 0; }
                               ^
bazel-out/darwin-fastbuild/bin/external/com_github_arximboldi_immer/_virtual_includes/immer/immer/detail/rbts/position.hpp:734:25: warning: unused parameter 'offset' [-Wunused-parameter]
    size_t size(count_t offset) { return count_; }
                        ^
bazel-out/darwin-fastbuild/bin/external/com_github_arximboldi_immer/_virtual_includes/immer/immer/detail/rbts/position.hpp:737:32: warning: unused parameter 'v' [-Wunused-parameter]
    void each_left_sub(Visitor v, Args&&... args)
                               ^
bazel-out/darwin-fastbuild/bin/external/com_github_arximboldi_immer/_virtual_includes/immer/immer/detail/rbts/position.hpp:737:45: warning: unused parameter 'args' [-Wunused-parameter]
    void each_left_sub(Visitor v, Args&&... args)
                                            ^
bazel-out/darwin-fastbuild/bin/external/com_github_arximboldi_immer/_virtual_includes/immer/immer/detail/rbts/position.hpp:740:23: warning: unused parameter 'v' [-Wunused-parameter]
    void each(Visitor v, Args&&... args)
                      ^
bazel-out/darwin-fastbuild/bin/external/com_github_arximboldi_immer/_virtual_includes/immer/immer/detail/rbts/position.hpp:740:36: warning: unused parameter 'args' [-Wunused-parameter]
    void each(Visitor v, Args&&... args)
                                   ^
bazel-out/darwin-fastbuild/bin/external/com_github_arximboldi_immer/_virtual_includes/immer/immer/detail/rbts/position.hpp:750:34: warning: unused parameter 'v' [-Wunused-parameter]
    decltype(auto) visit(Visitor v, Args&&... args)
                                 ^
bazel-out/darwin-fastbuild/bin/external/com_github_arximboldi_immer/_virtual_includes/immer/immer/detail/rbts/position.hpp:922:42: warning: unused parameter 'count_hint' [-Wunused-parameter]
                                 count_t count_hint,
                                         ^
bazel-out/darwin-fastbuild/bin/external/com_github_arximboldi_immer/_virtual_includes/immer/immer/detail/rbts/position.hpp:1021:34: warning: unused parameter 'v' [-Wunused-parameter]
    decltype(auto) visit(Visitor v, Args&&... args)
                                 ^
bazel-out/darwin-fastbuild/bin/external/com_github_arximboldi_immer/_virtual_includes/immer/immer/detail/rbts/position.hpp:1072:34: warning: unused parameter 'v' [-Wunused-parameter]
    decltype(auto) visit(Visitor v, Args&&... args)
                                 ^
bazel-out/darwin-fastbuild/bin/external/com_github_arximboldi_immer/_virtual_includes/immer/immer/detail/rbts/position.hpp:1097:34: warning: unused parameter 'v' [-Wunused-parameter]
    decltype(auto) visit(Visitor v, Args&&... args)
                                 ^
bazel-out/darwin-fastbuild/bin/external/com_github_arximboldi_immer/_virtual_includes/immer/immer/detail/rbts/position.hpp:1150:25: warning: unused parameter 'offset' [-Wunused-parameter]
    size_t size(count_t offset) const { return size_t{1} << shift_; }
                        ^
bazel-out/darwin-fastbuild/bin/external/com_github_arximboldi_immer/_virtual_includes/immer/immer/detail/rbts/position.hpp:1151:29: warning: unused parameter 'offset' [-Wunused-parameter]
    size_t size_sbh(count_t offset, size_t) const
                            ^
bazel-out/darwin-fastbuild/bin/external/com_github_arximboldi_immer/_virtual_includes/immer/immer/detail/rbts/position.hpp:1157:29: warning: unused parameter 'offset' [-Wunused-parameter]
    void copy_sizes(count_t offset, count_t n, size_t init, size_t* sizes)
                            ^
bazel-out/darwin-fastbuild/bin/external/com_github_arximboldi_immer/_virtual_includes/immer/immer/detail/rbts/position.hpp:1385:34: warning: unused parameter 'v' [-Wunused-parameter]
    decltype(auto) visit(Visitor v, Args&&... args)
                                 ^
bazel-out/darwin-fastbuild/bin/external/com_github_arximboldi_immer/_virtual_includes/immer/immer/detail/rbts/position.hpp:1787:34: warning: unused parameter 'v' [-Wunused-parameter]
    decltype(auto) visit(Visitor v, Args&&... args)
                                 ^
bazel-out/darwin-fastbuild/bin/external/com_github_arximboldi_immer/_virtual_includes/immer/immer/detail/rbts/position.hpp:1875:34: warning: unused parameter 'v' [-Wunused-parameter]
    decltype(auto) visit(Visitor v, Args&&... args)
                                 ^
bazel-out/darwin-fastbuild/bin/external/com_github_arximboldi_immer/_virtual_includes/immer/immer/detail/rbts/position.hpp:1913:34: warning: unused parameter 'v' [-Wunused-parameter]
    decltype(auto) visit(Visitor v, Args&&... args)
                                 ^
In file included from codelab/cc/containers/immutable/vector_test.cc:1:
In file included from bazel-out/darwin-fastbuild/bin/external/com_github_arximboldi_immer/_virtual_includes/immer/immer/vector.hpp:11:
In file included from bazel-out/darwin-fastbuild/bin/external/com_github_arximboldi_immer/_virtual_includes/immer/immer/detail/rbts/rbtree.hpp:12:
In file included from bazel-out/darwin-fastbuild/bin/external/com_github_arximboldi_immer/_virtual_includes/immer/immer/detail/rbts/operations.hpp:18:
bazel-out/darwin-fastbuild/bin/external/com_github_arximboldi_immer/_virtual_includes/immer/immer/detail/rbts/visitor.hpp:24:48: warning: unused parameter 'args' [-Wunused-parameter]
    static decltype(auto) visit_node(Args&&... args)
                                               ^
In file included from codelab/cc/containers/immutable/vector_test.cc:1:
In file included from bazel-out/darwin-fastbuild/bin/external/com_github_arximboldi_immer/_virtual_includes/immer/immer/vector.hpp:11:
In file included from bazel-out/darwin-fastbuild/bin/external/com_github_arximboldi_immer/_virtual_includes/immer/immer/detail/rbts/rbtree.hpp:12:
bazel-out/darwin-fastbuild/bin/external/com_github_arximboldi_immer/_virtual_includes/immer/immer/detail/rbts/operations.hpp:417:52: warning: unused parameter 'first' [-Wunused-parameter]
    visit_regular(PosL&& posl, PosR&& posr, Iter&& first, size_t idx)
                                                   ^
bazel-out/darwin-fastbuild/bin/external/com_github_arximboldi_immer/_virtual_includes/immer/immer/detail/rbts/operations.hpp:417:66: warning: unused parameter 'idx' [-Wunused-parameter]
    visit_regular(PosL&& posl, PosR&& posr, Iter&& first, size_t idx)
                                                                 ^
bazel-out/darwin-fastbuild/bin/external/com_github_arximboldi_immer/_virtual_includes/immer/immer/detail/rbts/operations.hpp:766:37: warning: unused parameter 'pos' [-Wunused-parameter]
    static node_t* visit_leaf(Pos&& pos, edit_t e, node_t* tail, Args&&...)
                                    ^
bazel-out/darwin-fastbuild/bin/external/com_github_arximboldi_immer/_virtual_includes/immer/immer/detail/rbts/operations.hpp:766:49: warning: unused parameter 'e' [-Wunused-parameter]
    static node_t* visit_leaf(Pos&& pos, edit_t e, node_t* tail, Args&&...)
                                                ^
bazel-out/darwin-fastbuild/bin/external/com_github_arximboldi_immer/_virtual_includes/immer/immer/detail/rbts/operations.hpp:766:60: warning: unused parameter 'tail' [-Wunused-parameter]
    static node_t* visit_leaf(Pos&& pos, edit_t e, node_t* tail, Args&&...)
                                                           ^
bazel-out/darwin-fastbuild/bin/external/com_github_arximboldi_immer/_virtual_includes/immer/immer/detail/rbts/operations.hpp:843:37: warning: unused parameter 'pos' [-Wunused-parameter]
    static node_t* visit_leaf(Pos&& pos, node_t* tail, Args&&...)
                                    ^
bazel-out/darwin-fastbuild/bin/external/com_github_arximboldi_immer/_virtual_includes/immer/immer/detail/rbts/operations.hpp:843:50: warning: unused parameter 'tail' [-Wunused-parameter]
    static node_t* visit_leaf(Pos&& pos, node_t* tail, Args&&...)
                                                 ^
bazel-out/darwin-fastbuild/bin/external/com_github_arximboldi_immer/_virtual_includes/immer/immer/detail/rbts/operations.hpp:877:34: warning: unused parameter 'p' [-Wunused-parameter]
    static void visit_leaf(Pos&& p, count_t idx)
                                 ^
bazel-out/darwin-fastbuild/bin/external/com_github_arximboldi_immer/_virtual_includes/immer/immer/detail/rbts/operations.hpp:877:45: warning: unused parameter 'idx' [-Wunused-parameter]
    static void visit_leaf(Pos&& p, count_t idx)
                                            ^
bazel-out/darwin-fastbuild/bin/external/com_github_arximboldi_immer/_virtual_includes/immer/immer/detail/rbts/operations.hpp:1201:34: warning: unused parameter 'p' [-Wunused-parameter]
    static void visit_leaf(Pos&& p, count_t idx)
                                 ^
bazel-out/darwin-fastbuild/bin/external/com_github_arximboldi_immer/_virtual_includes/immer/immer/detail/rbts/operations.hpp:1201:45: warning: unused parameter 'idx' [-Wunused-parameter]
    static void visit_leaf(Pos&& p, count_t idx)
                                            ^
bazel-out/darwin-fastbuild/bin/external/com_github_arximboldi_immer/_virtual_includes/immer/immer/detail/rbts/operations.hpp:1858:23: warning: unused parameter 'lpos' [-Wunused-parameter]
    visit_leaf(LPos&& lpos, TPos&& tpos, RPos&& rpos)
                      ^
bazel-out/darwin-fastbuild/bin/external/com_github_arximboldi_immer/_virtual_includes/immer/immer/detail/rbts/operations.hpp:1858:36: warning: unused parameter 'tpos' [-Wunused-parameter]
    visit_leaf(LPos&& lpos, TPos&& tpos, RPos&& rpos)
                                   ^
bazel-out/darwin-fastbuild/bin/external/com_github_arximboldi_immer/_virtual_includes/immer/immer/detail/rbts/operations.hpp:1858:49: warning: unused parameter 'rpos' [-Wunused-parameter]
    visit_leaf(LPos&& lpos, TPos&& tpos, RPos&& rpos)
                                                ^
bazel-out/darwin-fastbuild/bin/external/com_github_arximboldi_immer/_virtual_includes/immer/immer/detail/rbts/operations.hpp:2236:62: warning: unused parameter 'ec' [-Wunused-parameter]
concat_center_mut_pos<Node> concat_leafs_mut(edit_type<Node> ec,
                                                             ^
bazel-out/darwin-fastbuild/bin/external/com_github_arximboldi_immer/_virtual_includes/immer/immer/detail/rbts/operations.hpp:2237:62: warning: unused parameter 'el' [-Wunused-parameter]
                                             edit_type<Node> el,
                                                             ^
bazel-out/darwin-fastbuild/bin/external/com_github_arximboldi_immer/_virtual_includes/immer/immer/detail/rbts/operations.hpp:2240:62: warning: unused parameter 'er' [-Wunused-parameter]
                                             edit_type<Node> er,
                                                             ^
bazel-out/darwin-fastbuild/bin/external/com_github_arximboldi_immer/_virtual_includes/immer/immer/detail/rbts/operations.hpp:2320:16: warning: unused parameter 'lpos' [-Wunused-parameter]
        LPos&& lpos, edit_t ec, edit_t el, TPos&& tpos, edit_t er, RPos&& rpos)
               ^
bazel-out/darwin-fastbuild/bin/external/com_github_arximboldi_immer/_virtual_includes/immer/immer/detail/rbts/operations.hpp:2320:29: warning: unused parameter 'ec' [-Wunused-parameter]
        LPos&& lpos, edit_t ec, edit_t el, TPos&& tpos, edit_t er, RPos&& rpos)
                            ^
bazel-out/darwin-fastbuild/bin/external/com_github_arximboldi_immer/_virtual_includes/immer/immer/detail/rbts/operations.hpp:2320:40: warning: unused parameter 'el' [-Wunused-parameter]
        LPos&& lpos, edit_t ec, edit_t el, TPos&& tpos, edit_t er, RPos&& rpos)
                                       ^
bazel-out/darwin-fastbuild/bin/external/com_github_arximboldi_immer/_virtual_includes/immer/immer/detail/rbts/operations.hpp:2320:51: warning: unused parameter 'tpos' [-Wunused-parameter]
        LPos&& lpos, edit_t ec, edit_t el, TPos&& tpos, edit_t er, RPos&& rpos)
                                                  ^
bazel-out/darwin-fastbuild/bin/external/com_github_arximboldi_immer/_virtual_includes/immer/immer/detail/rbts/operations.hpp:2320:64: warning: unused parameter 'er' [-Wunused-parameter]
        LPos&& lpos, edit_t ec, edit_t el, TPos&& tpos, edit_t er, RPos&& rpos)
                                                               ^
bazel-out/darwin-fastbuild/bin/external/com_github_arximboldi_immer/_virtual_includes/immer/immer/detail/rbts/operations.hpp:2320:75: warning: unused parameter 'rpos' [-Wunused-parameter]
        LPos&& lpos, edit_t ec, edit_t el, TPos&& tpos, edit_t er, RPos&& rpos)
                                                                          ^
In file included from codelab/cc/containers/immutable/vector_test.cc:1:
In file included from bazel-out/darwin-fastbuild/bin/external/com_github_arximboldi_immer/_virtual_includes/immer/immer/vector.hpp:13:
In file included from bazel-out/darwin-fastbuild/bin/external/com_github_arximboldi_immer/_virtual_includes/immer/immer/memory_policy.hpp:11:
bazel-out/darwin-fastbuild/bin/external/com_github_arximboldi_immer/_virtual_includes/immer/immer/heap/cpp_heap.hpp:35:40: warning: unused parameter 'size' [-Wunused-parameter]
    static void deallocate(std::size_t size, void* data)
                                       ^
58 warnings generated.

[arximboldi]

Makes sense, but this is low priority, since unused parameter warnings provide not much value in my opinion. You can work around it by including the library in path with -isystem.

If this is part of some commercial work, consider supporting the project here: https://github.com/sponsors/arximboldi
The higher sponsorship tiers help prioritizing issues 🙂