build: explicit_this enabled for AppleClang 17 and MSVC 19.32

Both compilers do not implement the feature test macro, but they do
implement `explicit_this`, as mentioned in their corresponding release
notes:
- https://developer.apple.com/documentation/xcode-release-notes/xcode-16_3-release-notes
- https://learn.microsoft.com/en-us/visualstudio/releases/2022/release-notes-v17.2

Resolves #722.

Author: alex-tee

conanfile.py

@@ -119,8 +119,8 @@ def _feature_compatibility(self):
                 "compiler": {
                     "gcc": "14",
                     "clang": "18",
-                    "apple-clang": "",
-                    "msvc": "195",
+                    "apple-clang": "17",
+                    "msvc": "194",
                 },
             },
         }

docs/getting_started/cpp_compiler_support.md

@@ -19,7 +19,7 @@ C++ feature:
 | **`std::format`**             |     20      | 13+  |    17+     |     16+     |                    194+                    |
 | **C++ modules**               |     20      | None |    17+     |    None     |                    None                    |
 | **`import std;`**             |     23      | None |    18+     |    None     |                    None                    |
-| **Explicit `this` parameter** |     23      | 14+  |    18+     |    None     |                    195+                    |
+| **Explicit `this` parameter** |     23      | 14+  |    18+     |    17+      |                    194+                    |
 
 ??? note "clang-19 unfixable bug"
 
@@ -97,6 +97,8 @@ C++ feature:
 - To write code with wide compatibility
   a [dedicated macro may be used](../users_guide/use_cases/wide_compatibility.md#QUANTITY_SPEC).
 - Tested with `__cpp_explicit_this_parameter` [feature test macro](https://en.cppreference.com/w/cpp/feature_test).
+    - Note that some compiler versions do not implement this macro even though they do support the
+      feature well enough. In such cases, compilation with explicit `this` is enforced.
 - Related build options:
     - Conan: [no_crtp](installation_and_usage.md#no_crtp)
     - CMake: [MP_UNITS_API_NO_CRTP](installation_and_usage.md#MP_UNITS_API_NO_CRTP)

src/CMakeLists.txt

@@ -67,13 +67,21 @@ endif()
 
 # clang++-18 supports explicit `this` parameter
 # https://github.com/llvm/llvm-project/issues/82780
-if(NOT ${projectPrefix}EXPLICIT_THIS_PARAMETER_SUPPORTED
-   AND CMAKE_CXX_STANDARD GREATER_EQUAL 23
-   AND CMAKE_CXX_COMPILER_ID STREQUAL "Clang"
-   AND CMAKE_CXX_COMPILER_VERSION VERSION_GREATER_EQUAL "18"
-)
-    message(STATUS "Clang 18+ detected, overriding `no CRTP` support")
-    set(${projectPrefix}EXPLICIT_THIS_PARAMETER_SUPPORTED ON)
+# AppleClang 17 also supports explicit `this` parameter (feature check macro unimplemented)
+# https://developer.apple.com/documentation/xcode-release-notes/xcode-16_3-release-notes
+# MSVC 19.32 also supports explicit `this` parameter (feature check macro unimplemented in this version)
+# https://learn.microsoft.com/en-us/visualstudio/releases/2022/release-notes-v17.2
+if(NOT ${projectPrefix}EXPLICIT_THIS_PARAMETER_SUPPORTED AND CMAKE_CXX_STANDARD GREATER_EQUAL 23)
+    if(CMAKE_CXX_COMPILER_ID STREQUAL "Clang" AND CMAKE_CXX_COMPILER_VERSION VERSION_GREATER_EQUAL "18")
+        message(STATUS "Clang 18+ detected, overriding `no CRTP` support")
+        set(${projectPrefix}EXPLICIT_THIS_PARAMETER_SUPPORTED ON)
+    elseif(CMAKE_CXX_COMPILER_ID STREQUAL "AppleClang" AND CMAKE_CXX_COMPILER_VERSION VERSION_GREATER_EQUAL "17")
+        message(STATUS "AppleClang 17+ detected, overriding `no CRTP` support")
+        set(${projectPrefix}EXPLICIT_THIS_PARAMETER_SUPPORTED ON)
+    elseif(CMAKE_CXX_COMPILER_ID MATCHES "MSVC" AND CMAKE_CXX_COMPILER_VERSION VERSION_GREATER_EQUAL "19.32")
+        message(STATUS "MSVC 19.32+ detected, overriding `no CRTP` support")
+        set(${projectPrefix}EXPLICIT_THIS_PARAMETER_SUPPORTED ON)
+    endif()
 endif()
 
 # project API settings