fix clangcl toolset in latest VS18 (#19289)

Author: memsharded

conan/internal/default_settings.py

@@ -146,7 +146,7 @@
         cppstd: [null, 98, gnu98, 11, gnu11, 14, gnu14, 17, gnu17, 20, gnu20, 23, gnu23, 26, gnu26]
         runtime: [null, static, dynamic]
         runtime_type: [null, Debug, Release]
-        runtime_version: [null, v140, v141, v142, v143, v144]
+        runtime_version: [null, v140, v141, v142, v143, v144, v145]
         cstd: [null, 99, gnu99, 11, gnu11, 17, gnu17, 23, gnu23]
     apple-clang:
         version: ["5.0", "5.1", "6.0", "6.1", "7.0", "7.3", "8.0", "8.1", "9.0", "9.1",

conan/tools/cmake/toolchain/blocks.py

@@ -13,7 +13,7 @@
 from conan.tools.build.flags import architecture_flag, architecture_link_flag, libcxx_flags, threads_flags
 from conan.tools.build.cross_building import cross_building
 from conan.tools.cmake.toolchain import CONAN_TOOLCHAIN_FILENAME
-from conan.tools.cmake.utils import is_multi_configuration, parse_extra_variable
+from conan.tools.cmake.utils import is_multi_configuration
 from conan.tools.intel import IntelCC
 from conan.tools.microsoft.visual import msvc_version_to_toolset_version, msvc_platform_from_arch
 from conan.internal.api.install.generators import relativize_path
@@ -1005,11 +1005,11 @@ def get_toolset(generator, conanfile):
                     toolset += ",version=14.{}{}".format(compiler_version[-1], compiler_update)
         elif compiler == "clang":
             if generator and "Visual" in generator:
-                if "Visual Studio 16" in generator or "Visual Studio 17" in generator:
+                if any(f"Visual Studio {v}" in generator for v in ("16", "17", "18")):
                     toolset = "ClangCL"
                 else:
                     raise ConanException("CMakeToolchain with compiler=clang and a CMake "
-                                         "'Visual Studio' generator requires VS16 or VS17")
+                                         "'Visual Studio' generator requires VS16, VS17 or VS18")
         toolset_arch = conanfile.conf.get("tools.cmake.cmaketoolchain:toolset_arch")
         if toolset_arch is not None:
             toolset_arch = "host={}".format(toolset_arch)

test/unittests/tools/cmake/test_cmaketoolchain.py

@@ -351,6 +351,34 @@ def test_older_msvc_toolset():
     assert 'CMAKE_CXX_STANDARD 98' in content
 
 
+def test_vs_clangcl():
+    c = ConanFile(None)
+    c.settings = Settings({"os": ["Windows"],
+                           "compiler": {"clang": {"version": ["20"], "runtime": ["v145"],
+                                                  "cppstd": ["14"]}},
+                           "build_type": ["Release"],
+                           "arch": ["x86_64"]})
+    c.settings.build_type = "Release"
+    c.settings.arch = "x86_64"
+    c.settings.compiler = "clang"
+    c.settings.compiler.runtime = "v145"
+    c.settings.compiler.version = "20"
+    c.settings.compiler.cppstd = "14"
+    c.settings.os = "Windows"
+    c.settings_build = c.settings
+    c.conf = Conf()
+    c.conf.define("tools.cmake.cmaketoolchain:generator", "Visual Studio 18")
+    c.folders.set_base_generators(".")
+    c._conan_node = Mock()
+    c._conan_node.dependencies = []
+    c._conan_node.transitive_deps = {}
+    c._conan_node.replaced_requires = {}
+    toolchain = CMakeToolchain(c)
+    content = toolchain.content
+    assert 'CMAKE_GENERATOR_TOOLSET "ClangCL"' in content
+    assert 'CMAKE_CXX_STANDARD 14' in content
+
+
 def test_older_msvc_toolset_update():
     # https://github.com/conan-io/conan/issues/15787
     c = ConanFile(None)