From 5dd06714b13b375acdc987b9261679d0c331b9ed Mon Sep 17 00:00:00 2001
From: Niels Lohmann <mail@nlohmann.me>
Date: Mon, 28 Dec 2020 11:31:21 +0100
Subject: [PATCH 01/11] :bug: allow parsing from std::byte containers #2546

---
 include/nlohmann/detail/input/lexer.hpp | 6 +++---
 single_include/nlohmann/json.hpp        | 6 +++---
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/include/nlohmann/detail/input/lexer.hpp b/include/nlohmann/detail/input/lexer.hpp
index 0a9601352..eae82eaa3 100644
--- a/include/nlohmann/detail/input/lexer.hpp
+++ b/include/nlohmann/detail/input/lexer.hpp
@@ -1541,17 +1541,17 @@ scan_number_done:
             // literals
             case 't':
             {
-                std::array<char_type, 4> true_literal = {{'t', 'r', 'u', 'e'}};
+                std::array<char_type, 4> true_literal = {{char_type('t'), char_type('r'), char_type('u'), char_type('e')}};
                 return scan_literal(true_literal.data(), true_literal.size(), token_type::literal_true);
             }
             case 'f':
             {
-                std::array<char_type, 5> false_literal = {{'f', 'a', 'l', 's', 'e'}};
+                std::array<char_type, 5> false_literal = {{char_type('f'), char_type('a'), char_type('l'), char_type('s'), char_type('e')}};
                 return scan_literal(false_literal.data(), false_literal.size(), token_type::literal_false);
             }
             case 'n':
             {
-                std::array<char_type, 4> null_literal = {{'n', 'u', 'l', 'l'}};
+                std::array<char_type, 4> null_literal = {{char_type('n'), char_type('u'), char_type('l'), char_type('l')}};
                 return scan_literal(null_literal.data(), null_literal.size(), token_type::literal_null);
             }
 
diff --git a/single_include/nlohmann/json.hpp b/single_include/nlohmann/json.hpp
index 51fe8382b..539ebc7ad 100644
--- a/single_include/nlohmann/json.hpp
+++ b/single_include/nlohmann/json.hpp
@@ -7511,17 +7511,17 @@ scan_number_done:
             // literals
             case 't':
             {
-                std::array<char_type, 4> true_literal = {{'t', 'r', 'u', 'e'}};
+                std::array<char_type, 4> true_literal = {{char_type('t'), char_type('r'), char_type('u'), char_type('e')}};
                 return scan_literal(true_literal.data(), true_literal.size(), token_type::literal_true);
             }
             case 'f':
             {
-                std::array<char_type, 5> false_literal = {{'f', 'a', 'l', 's', 'e'}};
+                std::array<char_type, 5> false_literal = {{char_type('f'), char_type('a'), char_type('l'), char_type('s'), char_type('e')}};
                 return scan_literal(false_literal.data(), false_literal.size(), token_type::literal_false);
             }
             case 'n':
             {
-                std::array<char_type, 4> null_literal = {{'n', 'u', 'l', 'l'}};
+                std::array<char_type, 4> null_literal = {{char_type('n'), char_type('u'), char_type('l'), char_type('l')}};
                 return scan_literal(null_literal.data(), null_literal.size(), token_type::literal_null);
             }
 

From 7b98df515f26058308f1ea5eedb6d1525cd12630 Mon Sep 17 00:00:00 2001
From: Niels Lohmann <mail@nlohmann.me>
Date: Tue, 29 Dec 2020 14:48:18 +0100
Subject: [PATCH 02/11] :white_check_mark: add regression test

---
 .travis.yml                   | 10 ++++++++++
 test/src/unit-regression2.cpp | 14 ++++++++++++++
 2 files changed, 24 insertions(+)

diff --git a/.travis.yml b/.travis.yml
index f48ee1fd6..c671e93f6 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -300,6 +300,16 @@ matrix:
         sources: ['ubuntu-toolchain-r-test', 'llvm-toolchain-trusty-7']
         packages: ['g++-7', 'clang-7', 'ninja-build']
 
+  - os: linux
+    compiler: clang
+    env:
+      - COMPILER=clang++-7
+      - CXX_STANDARD=20
+    addons:
+      apt:
+        sources: ['ubuntu-toolchain-r-test', 'llvm-toolchain-trusty-7']
+        packages: ['g++-7', 'clang-7', 'ninja-build']
+
 ################
 # build script #
 ################
diff --git a/test/src/unit-regression2.cpp b/test/src/unit-regression2.cpp
index ca50cdd41..1171531f6 100644
--- a/test/src/unit-regression2.cpp
+++ b/test/src/unit-regression2.cpp
@@ -51,6 +51,10 @@ using nlohmann::json;
     #include <variant>
 #endif
 
+#ifdef JSON_HAS_CPP_20
+    #include <span>
+#endif
+
 /////////////////////////////////////////////////////////////////////
 // for #1021
 /////////////////////////////////////////////////////////////////////
@@ -484,4 +488,14 @@ TEST_CASE("regression tests 2")
         json j = json::parse(ss, nullptr, true, true);
         CHECK(j.dump() == "{}");
     }
+
+#ifdef JSON_HAS_CPP_20
+    SECTION("issue #2546 - parsing containers of std::byte")
+    {
+        const char DATA[] = R"("Hello, world!")";
+        const auto s = std::as_bytes(std::span(DATA));
+        json j = json::parse(s);
+        CHECK(j.dump == "Hello, world!");
+    }
+#endif
 }

From 433da313341430cf32b26f2bcdadbb67e9465ced Mon Sep 17 00:00:00 2001
From: Niels Lohmann <mail@nlohmann.me>
Date: Tue, 29 Dec 2020 20:16:51 +0100
Subject: [PATCH 03/11] :alembic: try to use GCC 10

---
 .github/workflows/ubuntu.yml                  |  8 ++++++
 .travis.yml                                   | 10 --------
 .../nlohmann/detail/iterators/iter_impl.hpp   | 25 ++++++++++++++++++-
 single_include/nlohmann/json.hpp              | 25 ++++++++++++++++++-
 test/src/unit-class_parser.cpp                |  2 +-
 test/src/unit-items.cpp                       |  8 ++++++
 test/src/unit-regression1.cpp                 |  2 +-
 test/src/unit-udt.cpp                         | 14 +++++------
 8 files changed, 73 insertions(+), 21 deletions(-)

diff --git a/.github/workflows/ubuntu.yml b/.github/workflows/ubuntu.yml
index 1a47a885c..a4742e6a1 100644
--- a/.github/workflows/ubuntu.yml
+++ b/.github/workflows/ubuntu.yml
@@ -8,8 +8,16 @@ jobs:
 
     steps:
     - uses: actions/checkout@v1
+    - name: install_gcc
+      run: |
+           sudo apt update
+           sudo apt install gcc-10 g++-10
+      shell: bash
     - name: cmake
       run: cmake -S . -B build -D CMAKE_BUILD_TYPE=Debug -DJSON_BuildTests=On
+      env:
+        CC:   gcc-10
+        CXX:  g++-10
     - name: build
       run: cmake --build build --parallel 10
     - name: test
diff --git a/.travis.yml b/.travis.yml
index c671e93f6..f48ee1fd6 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -300,16 +300,6 @@ matrix:
         sources: ['ubuntu-toolchain-r-test', 'llvm-toolchain-trusty-7']
         packages: ['g++-7', 'clang-7', 'ninja-build']
 
-  - os: linux
-    compiler: clang
-    env:
-      - COMPILER=clang++-7
-      - CXX_STANDARD=20
-    addons:
-      apt:
-        sources: ['ubuntu-toolchain-r-test', 'llvm-toolchain-trusty-7']
-        packages: ['g++-7', 'clang-7', 'ninja-build']
-
 ################
 # build script #
 ################
diff --git a/include/nlohmann/detail/iterators/iter_impl.hpp b/include/nlohmann/detail/iterators/iter_impl.hpp
index b4faa88a5..6c65c6018 100644
--- a/include/nlohmann/detail/iterators/iter_impl.hpp
+++ b/include/nlohmann/detail/iterators/iter_impl.hpp
@@ -393,7 +393,30 @@ class iter_impl
     @brief  comparison: equal
     @pre The iterator is initialized; i.e. `m_object != nullptr`.
     */
-    bool operator==(const iter_impl& other) const
+    bool operator==(const iter_impl<const BasicJsonType>& other) const
+    {
+        // if objects are not the same, the comparison is undefined
+        if (JSON_HEDLEY_UNLIKELY(m_object != other.m_object))
+        {
+            JSON_THROW(invalid_iterator::create(212, "cannot compare iterators of different containers"));
+        }
+
+        JSON_ASSERT(m_object != nullptr);
+
+        switch (m_object->m_type)
+        {
+            case value_t::object:
+                return (m_it.object_iterator == other.m_it.object_iterator);
+
+            case value_t::array:
+                return (m_it.array_iterator == other.m_it.array_iterator);
+
+            default:
+                return (m_it.primitive_iterator == other.m_it.primitive_iterator);
+        }
+    }
+
+    bool operator==(const iter_impl<typename std::remove_const<BasicJsonType>::type>& other) const
     {
         // if objects are not the same, the comparison is undefined
         if (JSON_HEDLEY_UNLIKELY(m_object != other.m_object))
diff --git a/single_include/nlohmann/json.hpp b/single_include/nlohmann/json.hpp
index 765eac810..ac0568ce9 100644
--- a/single_include/nlohmann/json.hpp
+++ b/single_include/nlohmann/json.hpp
@@ -11279,7 +11279,30 @@ class iter_impl
     @brief  comparison: equal
     @pre The iterator is initialized; i.e. `m_object != nullptr`.
     */
-    bool operator==(const iter_impl& other) const
+    bool operator==(const iter_impl<const BasicJsonType>& other) const
+    {
+        // if objects are not the same, the comparison is undefined
+        if (JSON_HEDLEY_UNLIKELY(m_object != other.m_object))
+        {
+            JSON_THROW(invalid_iterator::create(212, "cannot compare iterators of different containers"));
+        }
+
+        JSON_ASSERT(m_object != nullptr);
+
+        switch (m_object->m_type)
+        {
+            case value_t::object:
+                return (m_it.object_iterator == other.m_it.object_iterator);
+
+            case value_t::array:
+                return (m_it.array_iterator == other.m_it.array_iterator);
+
+            default:
+                return (m_it.primitive_iterator == other.m_it.primitive_iterator);
+        }
+    }
+
+    bool operator==(const iter_impl<typename std::remove_const<BasicJsonType>::type>& other) const
     {
         // if objects are not the same, the comparison is undefined
         if (JSON_HEDLEY_UNLIKELY(m_object != other.m_object))
diff --git a/test/src/unit-class_parser.cpp b/test/src/unit-class_parser.cpp
index d0335c948..c612daabc 100644
--- a/test/src/unit-class_parser.cpp
+++ b/test/src/unit-class_parser.cpp
@@ -509,7 +509,7 @@ TEST_CASE("parser class")
                 CHECK(parser_helper("\"€\"").get<json::string_t>() == "€");
                 CHECK(parser_helper("\"🎈\"").get<json::string_t>() == "🎈");
 
-                CHECK(parser_helper("\"\\ud80c\\udc60\"").get<json::string_t>() == u8"\U00013060");
+                CHECK(parser_helper("\"\\ud80c\\udc60\"").get<json::string_t>() == "\U00013060");
                 CHECK(parser_helper("\"\\ud83c\\udf1e\"").get<json::string_t>() == "🌞");
             }
         }
diff --git a/test/src/unit-items.cpp b/test/src/unit-items.cpp
index 10621ce7e..4caf76f23 100644
--- a/test/src/unit-items.cpp
+++ b/test/src/unit-items.cpp
@@ -1448,3 +1448,11 @@ TEST_CASE("items()")
         }
     }
 }
+
+#ifdef JSON_HAS_CPP_17
+    #undef JSON_HAS_CPP_17
+#endif
+
+#ifdef JSON_HAS_CPP_14
+    #undef JSON_HAS_CPP_14
+#endif
diff --git a/test/src/unit-regression1.cpp b/test/src/unit-regression1.cpp
index 9dcc75b09..f5520056f 100644
--- a/test/src/unit-regression1.cpp
+++ b/test/src/unit-regression1.cpp
@@ -400,7 +400,7 @@ TEST_CASE("regression tests 1")
 
     SECTION("issue #146 - character following a surrogate pair is skipped")
     {
-        CHECK(json::parse("\"\\ud80c\\udc60abc\"").get<json::string_t>() == u8"\U00013060abc");
+        CHECK(json::parse("\"\\ud80c\\udc60abc\"").get<json::string_t>() == "\U00013060abc");
     }
 
     SECTION("issue #171 - Cannot index by key of type static constexpr const char*")
diff --git a/test/src/unit-udt.cpp b/test/src/unit-udt.cpp
index 7f74ac5f8..b23765505 100644
--- a/test/src/unit-udt.cpp
+++ b/test/src/unit-udt.cpp
@@ -112,13 +112,13 @@ static void to_json(BasicJsonType& j, country c)
     switch (c)
     {
         case country::china:
-            j = u8"中华人民共和国";
+            j = "中华人民共和国";
             return;
         case country::france:
             j = "France";
             return;
         case country::russia:
-            j = u8"Российская Федерация";
+            j = "Российская Федерация";
             return;
         default:
             break;
@@ -201,9 +201,9 @@ static void from_json(const BasicJsonType& j, country& c)
     const auto str = j.template get<std::string>();
     static const std::map<std::string, country> m =
     {
-        {u8"中华人民共和国", country::china},
+        {"中华人民共和国", country::china},
         {"France", country::france},
-        {u8"Российская Федерация", country::russia}
+        {"Российская Федерация", country::russia}
     };
 
     const auto it = m.find(str);
@@ -248,7 +248,7 @@ TEST_CASE("basic usage" * doctest::test_suite("udt"))
     const udt::name n{"theo"};
     const udt::country c{udt::country::france};
     const udt::person sfinae_addict{a, n, c};
-    const udt::person senior_programmer{{42}, {u8"王芳"}, udt::country::china};
+    const udt::person senior_programmer{{42}, {"王芳"}, udt::country::china};
     const udt::address addr{"Paris"};
     const udt::contact cpp_programmer{sfinae_addict, addr};
     const udt::contact_book book{{"C++"}, {cpp_programmer, {senior_programmer, addr}}};
@@ -265,14 +265,14 @@ TEST_CASE("basic usage" * doctest::test_suite("udt"))
 
         CHECK(
             json(book) ==
-            u8R"({"name":"C++", "contacts" : [{"person" : {"age":23, "name":"theo", "country":"France"}, "address":"Paris"}, {"person" : {"age":42, "country":"中华人民共和国", "name":"王芳"}, "address":"Paris"}]})"_json);
+            R"({"name":"C++", "contacts" : [{"person" : {"age":23, "name":"theo", "country":"France"}, "address":"Paris"}, {"person" : {"age":42, "country":"中华人民共和国", "name":"王芳"}, "address":"Paris"}]})"_json);
 
     }
 
     SECTION("conversion from json via free-functions")
     {
         const auto big_json =
-            u8R"({"name":"C++", "contacts" : [{"person" : {"age":23, "name":"theo", "country":"France"}, "address":"Paris"}, {"person" : {"age":42, "country":"中华人民共和国", "name":"王芳"}, "address":"Paris"}]})"_json;
+            R"({"name":"C++", "contacts" : [{"person" : {"age":23, "name":"theo", "country":"France"}, "address":"Paris"}, {"person" : {"age":42, "country":"中华人民共和国", "name":"王芳"}, "address":"Paris"}]})"_json;
         SECTION("via explicit calls to get")
         {
             const auto parsed_book = big_json.get<udt::contact_book>();

From ca51dc62f2a37be1a4f54a069850ffb80091a1e4 Mon Sep 17 00:00:00 2001
From: Niels Lohmann <mail@nlohmann.me>
Date: Tue, 29 Dec 2020 20:21:43 +0100
Subject: [PATCH 04/11] :alembic: try to use Clang 10

---
 .github/workflows/ubuntu.yml | 22 +++++++++++++++++++++-
 1 file changed, 21 insertions(+), 1 deletion(-)

diff --git a/.github/workflows/ubuntu.yml b/.github/workflows/ubuntu.yml
index a4742e6a1..9792431ff 100644
--- a/.github/workflows/ubuntu.yml
+++ b/.github/workflows/ubuntu.yml
@@ -3,7 +3,7 @@ name: Ubuntu
 on: [push, pull_request]
 
 jobs:
-  build:
+  gcc_build:
     runs-on: ubuntu-latest
 
     steps:
@@ -22,3 +22,23 @@ jobs:
       run: cmake --build build --parallel 10
     - name: test
       run: cd build ; ctest -j 10 --output-on-failure
+
+  clang_build:
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v1
+    - name: install_gcc
+      run: |
+           sudo apt update
+           sudo apt install clang-10
+      shell: bash
+    - name: cmake
+      run: cmake -S . -B build -D CMAKE_BUILD_TYPE=Debug -DJSON_BuildTests=On
+      env:
+        CC:   clang-10
+        CXX:  clang++-10
+    - name: build
+      run: cmake --build build --parallel 10
+    - name: test
+      run: cd build ; ctest -j 10 --output-on-failure

From 91d7aa571fbeb991813afd327ad005def52e7a0a Mon Sep 17 00:00:00 2001
From: Niels Lohmann <mail@nlohmann.me>
Date: Tue, 29 Dec 2020 20:30:50 +0100
Subject: [PATCH 05/11] :alembic: add C++20 build

---
 .github/workflows/ubuntu.yml | 40 ++++++++++++++++++++++++++++++++++++
 1 file changed, 40 insertions(+)

diff --git a/.github/workflows/ubuntu.yml b/.github/workflows/ubuntu.yml
index 9792431ff..58fdbd88f 100644
--- a/.github/workflows/ubuntu.yml
+++ b/.github/workflows/ubuntu.yml
@@ -42,3 +42,43 @@ jobs:
       run: cmake --build build --parallel 10
     - name: test
       run: cd build ; ctest -j 10 --output-on-failure
+
+  gcc_build_cxx20:
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v1
+      - name: install_gcc
+        run: |
+          sudo apt update
+          sudo apt install gcc-10 g++-10
+        shell: bash
+      - name: cmake
+      run: cmake -S . -B build -D CMAKE_BUILD_TYPE=Debug -DJSON_BuildTests=On -DCMAKE_CXX_STANDARD=20 -DCMAKE_CXX_STANDARD_REQUIRED=ON
+        env:
+          CC:   gcc-10
+          CXX:  g++-10
+      - name: build
+        run: cmake --build build --parallel 10
+      - name: test
+        run: cd build ; ctest -j 10 --output-on-failure
+
+  clang_build_cxx20:
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v1
+    - name: install_gcc
+      run: |
+           sudo apt update
+           sudo apt install clang-10
+      shell: bash
+    - name: cmake
+      run: cmake -S . -B build -D CMAKE_BUILD_TYPE=Debug -DJSON_BuildTests=On -DCMAKE_CXX_STANDARD=20 -DCMAKE_CXX_STANDARD_REQUIRED=ON
+      env:
+        CC:   clang-10
+        CXX:  clang++-10
+    - name: build
+      run: cmake --build build --parallel 10
+    - name: test
+      run: cd build ; ctest -j 10 --output-on-failure

From 77be4f6aaf2b72cf3f3ca16fce8abd3367bdc1e5 Mon Sep 17 00:00:00 2001
From: Niels Lohmann <mail@nlohmann.me>
Date: Tue, 29 Dec 2020 20:32:07 +0100
Subject: [PATCH 06/11] :alembic: add C++20 build

---
 .github/workflows/ubuntu.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/ubuntu.yml b/.github/workflows/ubuntu.yml
index 58fdbd88f..711cf106d 100644
--- a/.github/workflows/ubuntu.yml
+++ b/.github/workflows/ubuntu.yml
@@ -54,7 +54,7 @@ jobs:
           sudo apt install gcc-10 g++-10
         shell: bash
       - name: cmake
-      run: cmake -S . -B build -D CMAKE_BUILD_TYPE=Debug -DJSON_BuildTests=On -DCMAKE_CXX_STANDARD=20 -DCMAKE_CXX_STANDARD_REQUIRED=ON
+        run: cmake -S . -B build -D CMAKE_BUILD_TYPE=Debug -DJSON_BuildTests=On -DCMAKE_CXX_STANDARD=20 -DCMAKE_CXX_STANDARD_REQUIRED=ON
         env:
           CC:   gcc-10
           CXX:  g++-10

From e4fc598466cffa49953f299c4de4a06f1c9a7392 Mon Sep 17 00:00:00 2001
From: Niels Lohmann <mail@nlohmann.me>
Date: Tue, 29 Dec 2020 20:45:56 +0100
Subject: [PATCH 07/11] :alembic: add C++20 build

---
 .github/workflows/ubuntu.yml  | 20 --------------------
 test/src/unit-regression2.cpp |  2 +-
 2 files changed, 1 insertion(+), 21 deletions(-)

diff --git a/.github/workflows/ubuntu.yml b/.github/workflows/ubuntu.yml
index 711cf106d..d6b654077 100644
--- a/.github/workflows/ubuntu.yml
+++ b/.github/workflows/ubuntu.yml
@@ -43,26 +43,6 @@ jobs:
     - name: test
       run: cd build ; ctest -j 10 --output-on-failure
 
-  gcc_build_cxx20:
-    runs-on: ubuntu-latest
-
-    steps:
-      - uses: actions/checkout@v1
-      - name: install_gcc
-        run: |
-          sudo apt update
-          sudo apt install gcc-10 g++-10
-        shell: bash
-      - name: cmake
-        run: cmake -S . -B build -D CMAKE_BUILD_TYPE=Debug -DJSON_BuildTests=On -DCMAKE_CXX_STANDARD=20 -DCMAKE_CXX_STANDARD_REQUIRED=ON
-        env:
-          CC:   gcc-10
-          CXX:  g++-10
-      - name: build
-        run: cmake --build build --parallel 10
-      - name: test
-        run: cd build ; ctest -j 10 --output-on-failure
-
   clang_build_cxx20:
     runs-on: ubuntu-latest
 
diff --git a/test/src/unit-regression2.cpp b/test/src/unit-regression2.cpp
index 1171531f6..86320f039 100644
--- a/test/src/unit-regression2.cpp
+++ b/test/src/unit-regression2.cpp
@@ -495,7 +495,7 @@ TEST_CASE("regression tests 2")
         const char DATA[] = R"("Hello, world!")";
         const auto s = std::as_bytes(std::span(DATA));
         json j = json::parse(s);
-        CHECK(j.dump == "Hello, world!");
+        CHECK(j.dump() == "Hello, world!");
     }
 #endif
 }

From 4402176df5e1aec1c77b19f973b4575c7e526dcd Mon Sep 17 00:00:00 2001
From: Niels Lohmann <mail@nlohmann.me>
Date: Tue, 29 Dec 2020 20:52:57 +0100
Subject: [PATCH 08/11] :white_check_mark: add regression test

---
 test/src/unit-regression2.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/test/src/unit-regression2.cpp b/test/src/unit-regression2.cpp
index 86320f039..1e8c4922a 100644
--- a/test/src/unit-regression2.cpp
+++ b/test/src/unit-regression2.cpp
@@ -495,7 +495,7 @@ TEST_CASE("regression tests 2")
         const char DATA[] = R"("Hello, world!")";
         const auto s = std::as_bytes(std::span(DATA));
         json j = json::parse(s);
-        CHECK(j.dump() == "Hello, world!");
+        CHECK(j.dump() == "\"Hello, world!\"");
     }
 #endif
 }

From c886646707b14e8919216e7d90d5ea6c9ffa6e2b Mon Sep 17 00:00:00 2001
From: Niels Lohmann <mail@nlohmann.me>
Date: Tue, 29 Dec 2020 21:04:41 +0100
Subject: [PATCH 09/11] :rotating_light: fix warning

---
 test/src/unit-udt_macro.cpp | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/test/src/unit-udt_macro.cpp b/test/src/unit-udt_macro.cpp
index b56a5d15e..a13ac006b 100644
--- a/test/src/unit-udt_macro.cpp
+++ b/test/src/unit-udt_macro.cpp
@@ -106,7 +106,7 @@ NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE(person_without_private_data_2, age, name, met
 class person_with_private_alphabet
 {
   public:
-    bool operator==(const person_with_private_alphabet& other)
+    bool operator==(const person_with_private_alphabet& other) const
     {
         return  a == other.a &&
                 b == other.b &&
@@ -169,7 +169,7 @@ class person_with_private_alphabet
 class person_with_public_alphabet
 {
   public:
-    bool operator==(const person_with_public_alphabet& other)
+    bool operator==(const person_with_public_alphabet& other) const
     {
         return  a == other.a &&
                 b == other.b &&

From bdb2469c313cb8b83bfc0de9a1e789e93379ff00 Mon Sep 17 00:00:00 2001
From: Niels Lohmann <mail@nlohmann.me>
Date: Tue, 29 Dec 2020 21:36:30 +0100
Subject: [PATCH 10/11] :rotating_light: fix warnings

---
 Makefile                                      |  2 +
 .../nlohmann/detail/input/input_adapters.hpp  | 19 ++--
 .../nlohmann/detail/iterators/iter_impl.hpp   | 63 +++++---------
 single_include/nlohmann/json.hpp              | 86 ++++++++-----------
 test/src/unit-conversions.cpp                 |  8 ++
 5 files changed, 76 insertions(+), 102 deletions(-)

diff --git a/Makefile b/Makefile
index 0b9aa8213..d3963f503 100644
--- a/Makefile
+++ b/Makefile
@@ -84,6 +84,7 @@ doctest:
 # -Wno-missing-prototypes: for NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE
 # -Wno-padded: padding is nothing to warn about
 # -Wno-range-loop-analysis: items tests "for(const auto i...)"
+# -Wno-extra-semi-stmt: spurious warnings for semicolons after JSON_ASSERT()
 # -Wno-switch-enum -Wno-covered-switch-default: pedantic/contradicting warnings about switches
 # -Wno-weak-vtables: exception class is defined inline, but has virtual method
 pedantic_clang:
@@ -100,6 +101,7 @@ pedantic_clang:
 		-Wno-missing-prototypes \
 		-Wno-padded \
 		-Wno-range-loop-analysis \
+		-Wno-extra-semi-stmt \
 		-Wno-switch-enum -Wno-covered-switch-default \
 		-Wno-weak-vtables" cmake -S . -B cmake-build-pedantic -GNinja -DCMAKE_BUILD_TYPE=Debug -DJSON_MultipleHeaders=ON -DJSON_BuildTests=On
 	cmake --build cmake-build-pedantic
diff --git a/include/nlohmann/detail/input/input_adapters.hpp b/include/nlohmann/detail/input/input_adapters.hpp
index eed370fd2..a78a6ec96 100644
--- a/include/nlohmann/detail/input/input_adapters.hpp
+++ b/include/nlohmann/detail/input/input_adapters.hpp
@@ -374,7 +374,8 @@ typename iterator_input_adapter_factory<IteratorType>::adapter_type input_adapte
 // Enables ADL on begin(container) and end(container)
 // Encloses the using declarations in namespace for not to leak them to outside scope
 
-namespace container_input_adapter_factory_impl {
+namespace container_input_adapter_factory_impl
+{
 
 using std::begin;
 using std::end;
@@ -384,15 +385,15 @@ struct container_input_adapter_factory {};
 
 template<typename ContainerType>
 struct container_input_adapter_factory< ContainerType,
-                                        void_t<decltype(begin(std::declval<ContainerType>()), end(std::declval<ContainerType>()))> >
-{
-    using adapter_type = decltype(input_adapter(begin(std::declval<ContainerType>()), end(std::declval<ContainerType>())));
+       void_t<decltype(begin(std::declval<ContainerType>()), end(std::declval<ContainerType>()))>>
+       {
+           using adapter_type = decltype(input_adapter(begin(std::declval<ContainerType>()), end(std::declval<ContainerType>())));
 
-    static adapter_type create(const ContainerType& container)
-    {
-        return input_adapter(begin(container), end(container));
-    }
-};
+           static adapter_type create(const ContainerType& container)
+{
+    return input_adapter(begin(container), end(container));
+}
+       };
 
 }
 
diff --git a/include/nlohmann/detail/iterators/iter_impl.hpp b/include/nlohmann/detail/iterators/iter_impl.hpp
index 6c65c6018..67134166e 100644
--- a/include/nlohmann/detail/iterators/iter_impl.hpp
+++ b/include/nlohmann/detail/iterators/iter_impl.hpp
@@ -38,8 +38,10 @@ This class implements a both iterators (iterator and const_iterator) for the
 template<typename BasicJsonType>
 class iter_impl
 {
+    /// the iterator with BasicJsonType of different const-ness
+    using other_iter_impl = iter_impl<typename std::conditional<std::is_const<BasicJsonType>::value, typename std::remove_const<BasicJsonType>::type, const BasicJsonType>::type>;
     /// allow basic_json to access private members
-    friend iter_impl<typename std::conditional<std::is_const<BasicJsonType>::value, typename std::remove_const<BasicJsonType>::type, const BasicJsonType>::type>;
+    friend other_iter_impl;
     friend BasicJsonType;
     friend iteration_proxy<iter_impl>;
     friend iteration_proxy_value<iter_impl>;
@@ -390,33 +392,11 @@ class iter_impl
     }
 
     /*!
-    @brief  comparison: equal
+    @brief comparison: equal
     @pre The iterator is initialized; i.e. `m_object != nullptr`.
     */
-    bool operator==(const iter_impl<const BasicJsonType>& other) const
-    {
-        // if objects are not the same, the comparison is undefined
-        if (JSON_HEDLEY_UNLIKELY(m_object != other.m_object))
-        {
-            JSON_THROW(invalid_iterator::create(212, "cannot compare iterators of different containers"));
-        }
-
-        JSON_ASSERT(m_object != nullptr);
-
-        switch (m_object->m_type)
-        {
-            case value_t::object:
-                return (m_it.object_iterator == other.m_it.object_iterator);
-
-            case value_t::array:
-                return (m_it.array_iterator == other.m_it.array_iterator);
-
-            default:
-                return (m_it.primitive_iterator == other.m_it.primitive_iterator);
-        }
-    }
-
-    bool operator==(const iter_impl<typename std::remove_const<BasicJsonType>::type>& other) const
+    template < typename IterImpl, detail::enable_if_t < (std::is_same<IterImpl, iter_impl>::value || std::is_same<IterImpl, other_iter_impl>::value), std::nullptr_t > = nullptr >
+    bool operator==(const IterImpl& other) const
     {
         // if objects are not the same, the comparison is undefined
         if (JSON_HEDLEY_UNLIKELY(m_object != other.m_object))
@@ -440,16 +420,17 @@ class iter_impl
     }
 
     /*!
-    @brief  comparison: not equal
+    @brief comparison: not equal
     @pre The iterator is initialized; i.e. `m_object != nullptr`.
     */
-    bool operator!=(const iter_impl& other) const
+    template < typename IterImpl, detail::enable_if_t < (std::is_same<IterImpl, iter_impl>::value || std::is_same<IterImpl, other_iter_impl>::value), std::nullptr_t > = nullptr >
+    bool operator!=(const IterImpl& other) const
     {
         return !operator==(other);
     }
 
     /*!
-    @brief  comparison: smaller
+    @brief comparison: smaller
     @pre The iterator is initialized; i.e. `m_object != nullptr`.
     */
     bool operator<(const iter_impl& other) const
@@ -476,7 +457,7 @@ class iter_impl
     }
 
     /*!
-    @brief  comparison: less than or equal
+    @brief comparison: less than or equal
     @pre The iterator is initialized; i.e. `m_object != nullptr`.
     */
     bool operator<=(const iter_impl& other) const
@@ -485,7 +466,7 @@ class iter_impl
     }
 
     /*!
-    @brief  comparison: greater than
+    @brief comparison: greater than
     @pre The iterator is initialized; i.e. `m_object != nullptr`.
     */
     bool operator>(const iter_impl& other) const
@@ -494,7 +475,7 @@ class iter_impl
     }
 
     /*!
-    @brief  comparison: greater than or equal
+    @brief comparison: greater than or equal
     @pre The iterator is initialized; i.e. `m_object != nullptr`.
     */
     bool operator>=(const iter_impl& other) const
@@ -503,7 +484,7 @@ class iter_impl
     }
 
     /*!
-    @brief  add to iterator
+    @brief add to iterator
     @pre The iterator is initialized; i.e. `m_object != nullptr`.
     */
     iter_impl& operator+=(difference_type i)
@@ -532,7 +513,7 @@ class iter_impl
     }
 
     /*!
-    @brief  subtract from iterator
+    @brief subtract from iterator
     @pre The iterator is initialized; i.e. `m_object != nullptr`.
     */
     iter_impl& operator-=(difference_type i)
@@ -541,7 +522,7 @@ class iter_impl
     }
 
     /*!
-    @brief  add to iterator
+    @brief add to iterator
     @pre The iterator is initialized; i.e. `m_object != nullptr`.
     */
     iter_impl operator+(difference_type i) const
@@ -552,7 +533,7 @@ class iter_impl
     }
 
     /*!
-    @brief  addition of distance and iterator
+    @brief addition of distance and iterator
     @pre The iterator is initialized; i.e. `m_object != nullptr`.
     */
     friend iter_impl operator+(difference_type i, const iter_impl& it)
@@ -563,7 +544,7 @@ class iter_impl
     }
 
     /*!
-    @brief  subtract from iterator
+    @brief subtract from iterator
     @pre The iterator is initialized; i.e. `m_object != nullptr`.
     */
     iter_impl operator-(difference_type i) const
@@ -574,7 +555,7 @@ class iter_impl
     }
 
     /*!
-    @brief  return difference
+    @brief return difference
     @pre The iterator is initialized; i.e. `m_object != nullptr`.
     */
     difference_type operator-(const iter_impl& other) const
@@ -595,7 +576,7 @@ class iter_impl
     }
 
     /*!
-    @brief  access to successor
+    @brief access to successor
     @pre The iterator is initialized; i.e. `m_object != nullptr`.
     */
     reference operator[](difference_type n) const
@@ -626,7 +607,7 @@ class iter_impl
     }
 
     /*!
-    @brief  return the key of an object iterator
+    @brief return the key of an object iterator
     @pre The iterator is initialized; i.e. `m_object != nullptr`.
     */
     const typename object_t::key_type& key() const
@@ -642,7 +623,7 @@ class iter_impl
     }
 
     /*!
-    @brief  return the value of an iterator
+    @brief return the value of an iterator
     @pre The iterator is initialized; i.e. `m_object != nullptr`.
     */
     reference value() const
diff --git a/single_include/nlohmann/json.hpp b/single_include/nlohmann/json.hpp
index ac0568ce9..8b6344f92 100644
--- a/single_include/nlohmann/json.hpp
+++ b/single_include/nlohmann/json.hpp
@@ -5186,7 +5186,8 @@ typename iterator_input_adapter_factory<IteratorType>::adapter_type input_adapte
 // Enables ADL on begin(container) and end(container)
 // Encloses the using declarations in namespace for not to leak them to outside scope
 
-namespace container_input_adapter_factory_impl {
+namespace container_input_adapter_factory_impl
+{
 
 using std::begin;
 using std::end;
@@ -5196,15 +5197,15 @@ struct container_input_adapter_factory {};
 
 template<typename ContainerType>
 struct container_input_adapter_factory< ContainerType,
-                                        void_t<decltype(begin(std::declval<ContainerType>()), end(std::declval<ContainerType>()))> >
-{
-    using adapter_type = decltype(input_adapter(begin(std::declval<ContainerType>()), end(std::declval<ContainerType>())));
+       void_t<decltype(begin(std::declval<ContainerType>()), end(std::declval<ContainerType>()))>>
+       {
+           using adapter_type = decltype(input_adapter(begin(std::declval<ContainerType>()), end(std::declval<ContainerType>())));
 
-    static adapter_type create(const ContainerType& container)
-    {
-        return input_adapter(begin(container), end(container));
-    }
-};
+           static adapter_type create(const ContainerType& container)
+{
+    return input_adapter(begin(container), end(container));
+}
+       };
 
 }
 
@@ -10924,8 +10925,10 @@ This class implements a both iterators (iterator and const_iterator) for the
 template<typename BasicJsonType>
 class iter_impl
 {
+    /// the iterator with BasicJsonType of different const-ness
+    using other_iter_impl = iter_impl<typename std::conditional<std::is_const<BasicJsonType>::value, typename std::remove_const<BasicJsonType>::type, const BasicJsonType>::type>;
     /// allow basic_json to access private members
-    friend iter_impl<typename std::conditional<std::is_const<BasicJsonType>::value, typename std::remove_const<BasicJsonType>::type, const BasicJsonType>::type>;
+    friend other_iter_impl;
     friend BasicJsonType;
     friend iteration_proxy<iter_impl>;
     friend iteration_proxy_value<iter_impl>;
@@ -11276,33 +11279,11 @@ class iter_impl
     }
 
     /*!
-    @brief  comparison: equal
+    @brief comparison: equal
     @pre The iterator is initialized; i.e. `m_object != nullptr`.
     */
-    bool operator==(const iter_impl<const BasicJsonType>& other) const
-    {
-        // if objects are not the same, the comparison is undefined
-        if (JSON_HEDLEY_UNLIKELY(m_object != other.m_object))
-        {
-            JSON_THROW(invalid_iterator::create(212, "cannot compare iterators of different containers"));
-        }
-
-        JSON_ASSERT(m_object != nullptr);
-
-        switch (m_object->m_type)
-        {
-            case value_t::object:
-                return (m_it.object_iterator == other.m_it.object_iterator);
-
-            case value_t::array:
-                return (m_it.array_iterator == other.m_it.array_iterator);
-
-            default:
-                return (m_it.primitive_iterator == other.m_it.primitive_iterator);
-        }
-    }
-
-    bool operator==(const iter_impl<typename std::remove_const<BasicJsonType>::type>& other) const
+    template < typename IterImpl, detail::enable_if_t < (std::is_same<IterImpl, iter_impl>::value || std::is_same<IterImpl, other_iter_impl>::value), std::nullptr_t > = nullptr >
+    bool operator==(const IterImpl& other) const
     {
         // if objects are not the same, the comparison is undefined
         if (JSON_HEDLEY_UNLIKELY(m_object != other.m_object))
@@ -11326,16 +11307,17 @@ class iter_impl
     }
 
     /*!
-    @brief  comparison: not equal
+    @brief comparison: not equal
     @pre The iterator is initialized; i.e. `m_object != nullptr`.
     */
-    bool operator!=(const iter_impl& other) const
+    template < typename IterImpl, detail::enable_if_t < (std::is_same<IterImpl, iter_impl>::value || std::is_same<IterImpl, other_iter_impl>::value), std::nullptr_t > = nullptr >
+    bool operator!=(const IterImpl& other) const
     {
         return !operator==(other);
     }
 
     /*!
-    @brief  comparison: smaller
+    @brief comparison: smaller
     @pre The iterator is initialized; i.e. `m_object != nullptr`.
     */
     bool operator<(const iter_impl& other) const
@@ -11362,7 +11344,7 @@ class iter_impl
     }
 
     /*!
-    @brief  comparison: less than or equal
+    @brief comparison: less than or equal
     @pre The iterator is initialized; i.e. `m_object != nullptr`.
     */
     bool operator<=(const iter_impl& other) const
@@ -11371,7 +11353,7 @@ class iter_impl
     }
 
     /*!
-    @brief  comparison: greater than
+    @brief comparison: greater than
     @pre The iterator is initialized; i.e. `m_object != nullptr`.
     */
     bool operator>(const iter_impl& other) const
@@ -11380,7 +11362,7 @@ class iter_impl
     }
 
     /*!
-    @brief  comparison: greater than or equal
+    @brief comparison: greater than or equal
     @pre The iterator is initialized; i.e. `m_object != nullptr`.
     */
     bool operator>=(const iter_impl& other) const
@@ -11389,7 +11371,7 @@ class iter_impl
     }
 
     /*!
-    @brief  add to iterator
+    @brief add to iterator
     @pre The iterator is initialized; i.e. `m_object != nullptr`.
     */
     iter_impl& operator+=(difference_type i)
@@ -11418,7 +11400,7 @@ class iter_impl
     }
 
     /*!
-    @brief  subtract from iterator
+    @brief subtract from iterator
     @pre The iterator is initialized; i.e. `m_object != nullptr`.
     */
     iter_impl& operator-=(difference_type i)
@@ -11427,7 +11409,7 @@ class iter_impl
     }
 
     /*!
-    @brief  add to iterator
+    @brief add to iterator
     @pre The iterator is initialized; i.e. `m_object != nullptr`.
     */
     iter_impl operator+(difference_type i) const
@@ -11438,7 +11420,7 @@ class iter_impl
     }
 
     /*!
-    @brief  addition of distance and iterator
+    @brief addition of distance and iterator
     @pre The iterator is initialized; i.e. `m_object != nullptr`.
     */
     friend iter_impl operator+(difference_type i, const iter_impl& it)
@@ -11449,7 +11431,7 @@ class iter_impl
     }
 
     /*!
-    @brief  subtract from iterator
+    @brief subtract from iterator
     @pre The iterator is initialized; i.e. `m_object != nullptr`.
     */
     iter_impl operator-(difference_type i) const
@@ -11460,7 +11442,7 @@ class iter_impl
     }
 
     /*!
-    @brief  return difference
+    @brief return difference
     @pre The iterator is initialized; i.e. `m_object != nullptr`.
     */
     difference_type operator-(const iter_impl& other) const
@@ -11481,7 +11463,7 @@ class iter_impl
     }
 
     /*!
-    @brief  access to successor
+    @brief access to successor
     @pre The iterator is initialized; i.e. `m_object != nullptr`.
     */
     reference operator[](difference_type n) const
@@ -11512,7 +11494,7 @@ class iter_impl
     }
 
     /*!
-    @brief  return the key of an object iterator
+    @brief return the key of an object iterator
     @pre The iterator is initialized; i.e. `m_object != nullptr`.
     */
     const typename object_t::key_type& key() const
@@ -11528,7 +11510,7 @@ class iter_impl
     }
 
     /*!
-    @brief  return the value of an iterator
+    @brief return the value of an iterator
     @pre The iterator is initialized; i.e. `m_object != nullptr`.
     */
     reference value() const
@@ -16845,7 +16827,7 @@ class basic_json
         detail::parser_callback_t<basic_json>cb = nullptr,
         const bool allow_exceptions = true,
         const bool ignore_comments = false
-    )
+                                 )
     {
         return ::nlohmann::detail::parser<basic_json, InputAdapterType>(std::move(adapter),
                 std::move(cb), allow_exceptions, ignore_comments);
@@ -25390,7 +25372,7 @@ template<>
 inline void swap<nlohmann::json>(nlohmann::json& j1, nlohmann::json& j2) noexcept(
     is_nothrow_move_constructible<nlohmann::json>::value&&
     is_nothrow_move_assignable<nlohmann::json>::value
-)
+                              )
 {
     j1.swap(j2);
 }
diff --git a/test/src/unit-conversions.cpp b/test/src/unit-conversions.cpp
index 16c4f798e..7f59c63ec 100644
--- a/test/src/unit-conversions.cpp
+++ b/test/src/unit-conversions.cpp
@@ -1702,3 +1702,11 @@ TEST_CASE("JSON to enum mapping")
         CHECK(TS_INVALID == json("what?").get<TaskState>());
     }
 }
+
+#ifdef JSON_HAS_CPP_17
+    #undef JSON_HAS_CPP_17
+#endif
+
+#ifdef JSON_HAS_CPP_14
+    #undef JSON_HAS_CPP_14
+#endif

From fc7e181cbf38c041b875723a0194626e31c52430 Mon Sep 17 00:00:00 2001
From: Niels Lohmann <mail@nlohmann.me>
Date: Tue, 29 Dec 2020 22:21:31 +0100
Subject: [PATCH 11/11] :alembic: fix string representation

---
 test/src/unit-class_parser.cpp | 2 +-
 test/src/unit-regression1.cpp  | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/test/src/unit-class_parser.cpp b/test/src/unit-class_parser.cpp
index c612daabc..2df07d6d4 100644
--- a/test/src/unit-class_parser.cpp
+++ b/test/src/unit-class_parser.cpp
@@ -509,7 +509,7 @@ TEST_CASE("parser class")
                 CHECK(parser_helper("\"€\"").get<json::string_t>() == "€");
                 CHECK(parser_helper("\"🎈\"").get<json::string_t>() == "🎈");
 
-                CHECK(parser_helper("\"\\ud80c\\udc60\"").get<json::string_t>() == "\U00013060");
+                CHECK(parser_helper("\"\\ud80c\\udc60\"").get<json::string_t>() == "\xf0\x93\x81\xa0");
                 CHECK(parser_helper("\"\\ud83c\\udf1e\"").get<json::string_t>() == "🌞");
             }
         }
diff --git a/test/src/unit-regression1.cpp b/test/src/unit-regression1.cpp
index f5520056f..df660ddb4 100644
--- a/test/src/unit-regression1.cpp
+++ b/test/src/unit-regression1.cpp
@@ -400,7 +400,7 @@ TEST_CASE("regression tests 1")
 
     SECTION("issue #146 - character following a surrogate pair is skipped")
     {
-        CHECK(json::parse("\"\\ud80c\\udc60abc\"").get<json::string_t>() == "\U00013060abc");
+        CHECK(json::parse("\"\\ud80c\\udc60abc\"").get<json::string_t>() == "\xf0\x93\x81\xa0\x61\x62\x63");
     }
 
     SECTION("issue #171 - Cannot index by key of type static constexpr const char*")