diff --git a/.github/workflows/ubuntu.yml b/.github/workflows/ubuntu.yml
index 10239fedf..8036fba2a 100644
--- a/.github/workflows/ubuntu.yml
+++ b/.github/workflows/ubuntu.yml
@@ -5,7 +5,6 @@ on: [push, pull_request]
 jobs:
   ci_test_clang_cxx20:
     runs-on: ubuntu-latest
-
     steps:
     - uses: actions/checkout@v1
     - name: install_clang
@@ -20,7 +19,6 @@ jobs:
 
   ci_clang_analyze:
     runs-on: ubuntu-latest
-
     steps:
       - uses: actions/checkout@v1
       - name: install_ninja
@@ -42,7 +40,6 @@ jobs:
 
   ci_test_clang:
     runs-on: ubuntu-latest
-
     steps:
       - uses: actions/checkout@v1
       - name: install_ninja
@@ -81,3 +78,22 @@ jobs:
         run: cmake -S . -B build -DJSON_CI=On
       - name: build
         run: cmake --build build --target ci_test_valgrind
+
+  ci_cppcheck:
+    runs-on: ubuntu-latest
+    container: nlohmann/json-ci:latest
+    steps:
+      - uses: actions/checkout@v2
+      - name: cmake
+        run: cmake -S . -B build -DJSON_CI=On
+      - name: build
+        run: cmake --build build --target ci_cppcheck
+
+  ci_cpplint:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v1
+      - name: cmake
+        run: cmake -S . -B build -DJSON_CI=On
+      - name: build
+        run: cmake --build build --target ci_cpplint
diff --git a/Makefile b/Makefile
index d3963f503..655bb6c4a 100644
--- a/Makefile
+++ b/Makefile
@@ -641,4 +641,6 @@ update_hedley:
 	curl https://raw.githubusercontent.com/nemequ/hedley/master/hedley.h -o include/nlohmann/thirdparty/hedley/hedley.hpp
 	$(SED) -i 's/HEDLEY_/JSON_HEDLEY_/g' include/nlohmann/thirdparty/hedley/hedley.hpp
 	grep "[[:blank:]]*#[[:blank:]]*undef" include/nlohmann/thirdparty/hedley/hedley.hpp | grep -v "__" | sort | uniq | $(SED) 's/ //g' | $(SED) 's/undef/undef /g' > include/nlohmann/thirdparty/hedley/hedley_undef.hpp
+	$(SED) -i '1s/^/#pragma once\n\n/' include/nlohmann/thirdparty/hedley/hedley.hpp
+	$(SED) -i '1s/^/#pragma once\n\n/' include/nlohmann/thirdparty/hedley/hedley_undef.hpp
 	$(MAKE) amalgamate
diff --git a/cmake/ci.cmake b/cmake/ci.cmake
index 0134328a5..bf276da99 100644
--- a/cmake/ci.cmake
+++ b/cmake/ci.cmake
@@ -463,7 +463,7 @@ add_custom_target(ci_cppcheck
 ###############################################################################
 
 add_custom_target(ci_cpplint
-    COMMAND ${Python3_EXECUTABLE} ${CMAKE_SOURCE_DIR}/third_party/cpplint/cpplint.py --filter=-whitespace,-legal,-runtime/references,-runtime/explicit --quiet --recursive ${SRC_FILES}
+    COMMAND ${Python3_EXECUTABLE} ${CMAKE_SOURCE_DIR}/third_party/cpplint/cpplint.py --filter=-whitespace,-legal,-runtime/references,-runtime/explicit,-runtime/indentation_namespace,-readability/casting --quiet --recursive ${SRC_FILES}
     COMMENT "Check code with cpplint"
 )
 
diff --git a/include/nlohmann/detail/json_pointer.hpp b/include/nlohmann/detail/json_pointer.hpp
index 8c6bda140..4209e676a 100644
--- a/include/nlohmann/detail/json_pointer.hpp
+++ b/include/nlohmann/detail/json_pointer.hpp
@@ -349,7 +349,7 @@ class json_pointer
         }
 
         std::size_t processed_chars = 0;
-        unsigned long long res = 0;
+        unsigned long long res = 0;  // NOLINT(runtime/int)
         JSON_TRY
         {
             res = std::stoull(s, &processed_chars);
@@ -367,7 +367,7 @@ class json_pointer
 
         // only triggered on special platforms (like 32bit), see also
         // https://github.com/nlohmann/json/pull/2203
-        if (res >= static_cast<unsigned long long>((std::numeric_limits<size_type>::max)()))
+        if (res >= static_cast<unsigned long long>((std::numeric_limits<size_type>::max)()))  // NOLINT(runtime/int)
         {
             JSON_THROW(detail::out_of_range::create(410, "array index " + s + " exceeds size_type")); // LCOV_EXCL_LINE
         }
diff --git a/include/nlohmann/thirdparty/hedley/hedley.hpp b/include/nlohmann/thirdparty/hedley/hedley.hpp
index c1fa16dbb..9bc7630a6 100644
--- a/include/nlohmann/thirdparty/hedley/hedley.hpp
+++ b/include/nlohmann/thirdparty/hedley/hedley.hpp
@@ -1,3 +1,5 @@
+#pragma once
+
 /* Hedley - https://nemequ.github.io/hedley
  * Created by Evan Nemerson <evan@nemerson.com>
  *
diff --git a/single_include/nlohmann/json.hpp b/single_include/nlohmann/json.hpp
index a2507ff63..ff669b424 100644
--- a/single_include/nlohmann/json.hpp
+++ b/single_include/nlohmann/json.hpp
@@ -107,6 +107,8 @@ struct position_t
 
 #include <utility> // pair
 // #include <nlohmann/thirdparty/hedley/hedley.hpp>
+
+
 /* Hedley - https://nemequ.github.io/hedley
  * Created by Evan Nemerson <evan@nemerson.com>
  *
@@ -12003,7 +12005,7 @@ class json_pointer
         }
 
         std::size_t processed_chars = 0;
-        unsigned long long res = 0;
+        unsigned long long res = 0;  // NOLINT(runtime/int)
         JSON_TRY
         {
             res = std::stoull(s, &processed_chars);
@@ -12021,7 +12023,7 @@ class json_pointer
 
         // only triggered on special platforms (like 32bit), see also
         // https://github.com/nlohmann/json/pull/2203
-        if (res >= static_cast<unsigned long long>((std::numeric_limits<size_type>::max)()))
+        if (res >= static_cast<unsigned long long>((std::numeric_limits<size_type>::max)()))  // NOLINT(runtime/int)
         {
             JSON_THROW(detail::out_of_range::create(410, "array index " + s + " exceeds size_type")); // LCOV_EXCL_LINE
         }