tests/infra: move to C++23 (std pins, g++-14 in CI, deducing this in test code) (#228)

* tests/infra: move to c++23 (std pins, g++-14 in CI, deducing this in tests)

* [auto-verifier] verify commit d4f4327

* revert deducing this in member-function lambdas (gcc 14/15 bug PR118291)

* [auto-verifier] verify commit 1e06376

* ci: drop installs of preinstalled packages (g++-14, shellcheck, nodejs, npm)

---------

Co-authored-by: Cameron Custer <cam@augmentcode.com>
Co-authored-by: GitHub <noreply@github.com>

Author: 3 people

.github/actions/setup/action.yml

@@ -8,8 +8,9 @@ runs:
         wget https://apt.llvm.org/llvm.sh
         chmod +x llvm.sh
         sudo ./llvm.sh 22
-        sudo apt-get update
         sudo apt-get install -y clang-format-22 clang-tidy-22
+        sudo update-alternatives --install /usr/bin/g++ g++ /usr/bin/g++-14 100
         clang-22 --version
         clang-format-22 --version
         clang-tidy-22 --version
+        g++ --version

.github/workflows/programming_team_code_ci.yml

@@ -12,6 +12,10 @@ jobs:
     - uses: actions/checkout@v1
     - name: Set up Python
       uses: actions/setup-python@v1
+    - name: Make preinstalled g++-14 the default g++
+      run: |
+        sudo update-alternatives --install /usr/bin/g++ g++ /usr/bin/g++-14 100
+        g++ --version
     - name: Install dependencies
       run: |
         pip install "setuptools<81"
@@ -53,6 +57,10 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v4
+    - name: Make preinstalled g++-14 the default g++
+      run: |
+        sudo update-alternatives --install /usr/bin/g++ g++ /usr/bin/g++-14 100
+        g++ --version
     - name: g++ with gcc
       run: make --directory=tests/ compile_gcc
 
@@ -76,8 +84,8 @@ jobs:
     steps:
     - uses: actions/checkout@v4
     - uses: ./.github/actions/setup
-    - name: Install texlive, rename, nodejs, npm
-      run: sudo apt install texlive texlive-latex-extra rename nodejs npm
+    - name: Install texlive, rename
+      run: sudo apt install texlive texlive-latex-extra rename
     - name: build pdf
       run: make --directory=tests/ build_pdf
     - uses: actions/upload-artifact@v4
@@ -127,6 +135,6 @@ jobs:
     steps:
     - uses: actions/checkout@v4
     - name: Install dependencies
-      run: sudo apt install shfmt shellcheck
+      run: sudo apt install shfmt
     - name: shellcheck, shfmt
       run: make --directory=tests/ shellcheck_shfmt

.verify-helper/config.toml

@@ -2,7 +2,7 @@
 CXX = "g++"
 CXXFLAGS = [
 	"-O2",
-	"-std=c++20",
+	"-std=c++23",
 	"-fsanitize=address,undefined",
 	"-fno-sanitize-recover=all",
 	"-fstack-protector",

.verify-helper/timestamps.remote.json

@@ -30,7 +30,7 @@
 "tests/library_checker_aizu_tests/data_structures/lazy_segment_tree_inc_constructor.test.cpp": "2026-07-06 13:10:16 -0700",
 "tests/library_checker_aizu_tests/data_structures/merge_sort_tree.test.cpp": "2026-07-06 13:10:16 -0700",
 "tests/library_checker_aizu_tests/data_structures/mode_query.test.cpp": "2026-07-06 13:10:16 -0700",
-"tests/library_checker_aizu_tests/data_structures/permutation_tree.test.cpp": "2026-07-06 13:10:16 -0700",
+"tests/library_checker_aizu_tests/data_structures/permutation_tree.test.cpp": "2026-07-06 22:18:09 -0700",
 "tests/library_checker_aizu_tests/data_structures/persistent_queue_tree.test.cpp": "2026-07-06 13:10:16 -0700",
 "tests/library_checker_aizu_tests/data_structures/persistent_seg_tree.test.cpp": "2026-07-06 13:10:16 -0700",
 "tests/library_checker_aizu_tests/data_structures/pq_ds_undo_sliding_window.test.cpp": "2026-07-06 13:10:16 -0700",
@@ -49,7 +49,7 @@
 "tests/library_checker_aizu_tests/dsu/dsu_bipartite.test.cpp": "2026-07-06 13:10:16 -0700",
 "tests/library_checker_aizu_tests/dsu/dsu_weighted_aizu.test.cpp": "2026-07-06 13:49:19 -0700",
 "tests/library_checker_aizu_tests/dsu/dsu_weighted_lib_checker.test.cpp": "2026-07-06 13:49:19 -0700",
-"tests/library_checker_aizu_tests/dsu/kruskal_tree_aizu.test.cpp": "2026-07-06 13:10:16 -0700",
+"tests/library_checker_aizu_tests/dsu/kruskal_tree_aizu.test.cpp": "2026-07-06 22:18:09 -0700",
 "tests/library_checker_aizu_tests/dsu/line_tree_aizu.test.cpp": "2026-07-06 13:10:16 -0700",
 "tests/library_checker_aizu_tests/dsu/line_tree_lib_checker.test.cpp": "2026-07-06 13:10:16 -0700",
 "tests/library_checker_aizu_tests/dsu/range_parallel_dsu.test.cpp": "2026-07-06 13:10:16 -0700",
@@ -62,7 +62,7 @@
 "tests/library_checker_aizu_tests/graphs/biconnected_components.test.cpp": "2026-07-06 13:10:16 -0700",
 "tests/library_checker_aizu_tests/graphs/connected_components_of_complement_graph.test.cpp": "2026-07-06 13:10:16 -0700",
 "tests/library_checker_aizu_tests/graphs/dijkstra_aizu.test.cpp": "2026-07-06 13:10:16 -0700",
-"tests/library_checker_aizu_tests/graphs/dijkstra_lib_checker.test.cpp": "2026-07-06 13:10:16 -0700",
+"tests/library_checker_aizu_tests/graphs/dijkstra_lib_checker.test.cpp": "2026-07-06 22:18:09 -0700",
 "tests/library_checker_aizu_tests/graphs/directed_cycle.test.cpp": "2026-07-06 13:10:16 -0700",
 "tests/library_checker_aizu_tests/graphs/enumerate_triangles.test.cpp": "2026-07-06 13:10:16 -0700",
 "tests/library_checker_aizu_tests/graphs/euler_walk_directed.test.cpp": "2026-07-06 13:10:16 -0700",
@@ -74,11 +74,11 @@
 "tests/library_checker_aizu_tests/graphs/strongly_connected_components_aizu.test.cpp": "2026-07-06 13:10:16 -0700",
 "tests/library_checker_aizu_tests/graphs/strongly_connected_components_lib_checker.test.cpp": "2026-07-06 13:10:16 -0700",
 "tests/library_checker_aizu_tests/graphs/two_edge_components.test.cpp": "2026-07-06 13:10:16 -0700",
-"tests/library_checker_aizu_tests/handmade_tests/count_paths.test.cpp": "2026-07-06 13:10:16 -0700",
-"tests/library_checker_aizu_tests/handmade_tests/dsu.test.cpp": "2026-07-06 13:10:16 -0700",
-"tests/library_checker_aizu_tests/handmade_tests/edge_cd_small_trees.test.cpp": "2026-07-06 13:10:16 -0700",
+"tests/library_checker_aizu_tests/handmade_tests/count_paths.test.cpp": "2026-07-06 22:18:09 -0700",
+"tests/library_checker_aizu_tests/handmade_tests/dsu.test.cpp": "2026-07-06 22:18:09 -0700",
+"tests/library_checker_aizu_tests/handmade_tests/edge_cd_small_trees.test.cpp": "2026-07-06 22:18:09 -0700",
 "tests/library_checker_aizu_tests/handmade_tests/fib_matrix_expo.test.cpp": "2026-07-06 13:10:16 -0700",
-"tests/library_checker_aizu_tests/handmade_tests/functional_graph.test.cpp": "2026-07-06 13:10:16 -0700",
+"tests/library_checker_aizu_tests/handmade_tests/functional_graph.test.cpp": "2026-07-06 22:43:37 -0700",
 "tests/library_checker_aizu_tests/handmade_tests/hilbert_mos.test.cpp": "2026-07-06 13:10:16 -0700",
 "tests/library_checker_aizu_tests/handmade_tests/kd_bit.test.cpp": "2026-07-06 13:10:16 -0700",
 "tests/library_checker_aizu_tests/handmade_tests/kth_par.test.cpp": "2026-07-06 13:10:16 -0700",
@@ -92,7 +92,7 @@
 "tests/library_checker_aizu_tests/handmade_tests/sa_find_subarray.test.cpp": "2026-07-06 13:10:16 -0700",
 "tests/library_checker_aizu_tests/handmade_tests/seg_tree_find.test.cpp": "2026-07-06 13:10:16 -0700",
 "tests/library_checker_aizu_tests/handmade_tests/seg_tree_find_small.test.cpp": "2026-07-06 13:10:16 -0700",
-"tests/library_checker_aizu_tests/handmade_tests/seg_tree_midpoint.test.cpp": "2026-07-06 13:10:16 -0700",
+"tests/library_checker_aizu_tests/handmade_tests/seg_tree_midpoint.test.cpp": "2026-07-06 22:18:09 -0700",
 "tests/library_checker_aizu_tests/handmade_tests/xor_basis_walk.test.cpp": "2026-07-06 13:10:16 -0700",
 "tests/library_checker_aizu_tests/loops/chooses.test.cpp": "2026-07-06 13:10:16 -0700",
 "tests/library_checker_aizu_tests/loops/quotients.test.cpp": "2026-07-06 13:10:16 -0700",
@@ -132,11 +132,11 @@
 "tests/library_checker_aizu_tests/strings/suffix_array_short.test.cpp": "2026-04-12 06:15:25 -0600",
 "tests/library_checker_aizu_tests/strings/trie.test.cpp": "2026-07-06 13:10:16 -0700",
 "tests/library_checker_aizu_tests/strings/wildcard_pattern_matching.test.cpp": "2026-07-06 13:10:16 -0700",
-"tests/library_checker_aizu_tests/trees/cd_count_paths_per_length.test.cpp": "2026-07-06 13:10:16 -0700",
-"tests/library_checker_aizu_tests/trees/edge_cd_contour_range_query.test.cpp": "2026-07-06 13:10:16 -0700",
-"tests/library_checker_aizu_tests/trees/edge_cd_contour_range_update.test.cpp": "2026-07-06 13:10:16 -0700",
-"tests/library_checker_aizu_tests/trees/edge_cd_count_paths_per_length.test.cpp": "2026-07-06 13:10:16 -0700",
-"tests/library_checker_aizu_tests/trees/edge_cd_reroot_dp.test.cpp": "2026-07-06 13:10:16 -0700",
+"tests/library_checker_aizu_tests/trees/cd_count_paths_per_length.test.cpp": "2026-07-06 22:18:09 -0700",
+"tests/library_checker_aizu_tests/trees/edge_cd_contour_range_query.test.cpp": "2026-07-06 22:43:37 -0700",
+"tests/library_checker_aizu_tests/trees/edge_cd_contour_range_update.test.cpp": "2026-07-06 22:43:37 -0700",
+"tests/library_checker_aizu_tests/trees/edge_cd_count_paths_per_length.test.cpp": "2026-07-06 22:18:09 -0700",
+"tests/library_checker_aizu_tests/trees/edge_cd_reroot_dp.test.cpp": "2026-07-06 22:18:09 -0700",
 "tests/library_checker_aizu_tests/trees/hld_aizu1.test.cpp": "2026-07-06 13:10:16 -0700",
 "tests/library_checker_aizu_tests/trees/hld_aizu2.test.cpp": "2026-07-06 13:10:16 -0700",
 "tests/library_checker_aizu_tests/trees/hld_lib_checker_path.test.cpp": "2026-07-06 13:10:16 -0700",
@@ -148,7 +148,7 @@
 "tests/library_checker_aizu_tests/trees/kth_path_tree_lift.test.cpp": "2026-07-06 13:10:16 -0700",
 "tests/library_checker_aizu_tests/trees/lca_all_methods_aizu.test.cpp": "2026-07-06 13:10:16 -0700",
 "tests/library_checker_aizu_tests/trees/lca_all_methods_lib_checker.test.cpp": "2026-07-06 13:10:16 -0700",
-"tests/library_checker_aizu_tests/trees/shallowest_aizu_tree_height.test.cpp": "2026-07-06 13:10:16 -0700",
-"tests/library_checker_aizu_tests/trees/shallowest_lib_checker_tree_path_composite.test.cpp": "2026-07-06 13:10:16 -0700",
+"tests/library_checker_aizu_tests/trees/shallowest_aizu_tree_height.test.cpp": "2026-07-06 22:18:09 -0700",
+"tests/library_checker_aizu_tests/trees/shallowest_lib_checker_tree_path_composite.test.cpp": "2026-07-06 22:18:09 -0700",
 "tests/library_checker_aizu_tests/trees/subtree_isomorphism.test.cpp": "2026-07-06 13:10:16 -0700"
 }

tests/.config/.clang-format

@@ -88,5 +88,5 @@ SpacesInCStyleCastParentheses: false
 SpacesInContainerLiterals: false
 SpacesInParentheses: false
 SpacesInSquareBrackets: false
-Standard: c++20
+Standard: Latest
 ...

tests/.config/.gcc_compile_flags

@@ -10,4 +10,4 @@
 -Wduplicated-cond
 -Werror
 -O2
--std=c++20
+-std=c++23

tests/Makefile

@@ -1,9 +1,9 @@
 help:
 	@echo "command                              | explanation"
 	@echo "------------------------------------ | -----------"
-	@echo "make compile_gcc                     | compile all tests with -std=c++20 for warnings"
+	@echo "make compile_gcc                     | compile all tests with -std=c++23 for warnings"
 	@echo "                                     |"
-	@echo "make compile_clang                   | compile all tests with clang, -std=c++20 for warnings"
+	@echo "make compile_clang                   | compile all tests with clang, -std=c++23 for warnings"
 	@echo "                                     |"
 	@echo "make grep_clangformat_cppcheck       | various greps to catch certain things, clang-format, cppcheck"
 	@echo "                                     |"

tests/library_checker_aizu_tests/cd_asserts.hpp

@@ -5,16 +5,16 @@ void cd_asserts(vector<vi> adj) {
   vi naive_par_decomp(sz(adj), -1);
   vi par = cd(adj, [&](int cent) -> void {
     assert(decomp_size[cent] == -1);
-    auto dfs = [&](auto&& self, int u, int p) -> int {
+    auto dfs = [&](this auto&& self, int u, int p) -> int {
       if (p != -1) naive_par_decomp[u] = cent;
       int sub_size = 1;
       for (int v : adj[u])
-        if (v != p) sub_size += self(self, v, u);
+        if (v != p) sub_size += self(v, u);
       return sub_size;
     };
-    decomp_size[cent] = dfs(dfs, cent, -1);
+    decomp_size[cent] = dfs(cent, -1);
     for (int u : adj[cent]) {
-      int sz_subtree = dfs(dfs, u, cent);
+      int sz_subtree = dfs(u, cent);
       assert(1 <= sz_subtree &&
              2 * sz_subtree <= decomp_size[cent]);
     }

tests/library_checker_aizu_tests/data_structures/permutation_tree.test.cpp

@@ -15,16 +15,16 @@ int main() {
   cout << sz(ch) << '\n';
   int curr_time = 0;
   vi node_to_time(sz(ch), -1);
-  auto dfs = [&](auto&& self, int u, int p) -> void {
+  auto dfs = [&](this auto&& self, int u, int p) -> void {
     node_to_time[u] = curr_time++;
     cout << (p == -1 ? p : node_to_time[p]) << " "
          << pt.p[u].mn_idx << " "
          << pt.p[u].mn_idx + pt.p[u].len - 1 << " "
          << (pt.p[u].is_join || empty(ch[u]) ? "linear"
                                              : "prime")
          << '\n';
-    for (int v : ch[u]) self(self, v, u);
+    for (int v : ch[u]) self(v, u);
   };
-  dfs(dfs, root, -1);
+  dfs(root, -1);
   return 0;
 }

tests/library_checker_aizu_tests/dsu/kruskal_tree_aizu.test.cpp

@@ -30,14 +30,14 @@ int main() {
   rep(i, n, kt.id) mst_sum += weight[i];
   vi depth(2 * n);
   vi actual_par(2 * n, -1);
-  auto dfs = [&](auto&& self, int v) -> void {
+  auto dfs = [&](this auto&& self, int v) -> void {
     for (int u : kt.g[v]) {
       depth[u] = 1 + depth[v];
       actual_par[u] = v;
-      self(self, u);
+      self(u);
     }
   };
-  dfs(dfs, kt.id - 1);
+  dfs(kt.id - 1);
   rep(i, 0, n) rep(j, i + 1, n) {
     int u = i, v = j;
     while (u != v)