Swift: Remove workaround for LWG/issue3657.

swift/extractor/infra/SwiftLocationExtractor.h

@@ -9,7 +9,6 @@
 #include <filesystem>
 
 #include "swift/extractor/trap/generated/TrapEntries.h"
-#include "swift/extractor/infra/file/PathHash.h"
 
 namespace codeql {
 

swift/extractor/infra/file/BUILD.bazel

@@ -9,26 +9,7 @@ swift_cc_library(
     hdrs = glob(
         ["*.h"],
         exclude = ["FsLogger.h"],
-    ) + [":path_hash_workaround"],
+    ),
     visibility = ["//swift:__subpackages__"],
     deps = ["//swift/logging"],
 )
-
-genrule(
-    name = "path_hash_workaround",
-    srcs = [
-        "PathHash.h.workaround",
-        "PathHash.h.fixed",
-    ],
-    outs = ["PathHash.h"],
-    # see if https://cplusplus.github.io/LWG/issue3657 is fixed with the current compiler or not
-    # if fixed, PathHash.h.workaround will not compile
-    cmd = "\n".join([
-        "if clang -c -x c++ -std=c++20 -Wno-pragma-once-outside-header \\",
-        "    $(rootpath PathHash.h.workaround) -o /dev/null &> /dev/null; then",
-        "  cp $(rootpath PathHash.h.workaround) $@",
-        "else",
-        "  cp $(rootpath PathHash.h.fixed) $@",
-        "fi",
-    ]),
-)

swift/extractor/infra/file/PathHash.h.fixed

@@ -1,4 +0,0 @@
-#pragma once
-
-#include <filesystem>
-#include <functional>

swift/extractor/infra/file/PathHash.h.workaround

@@ -1,17 +0,0 @@
-#pragma once
-
-#include <filesystem>
-#include <functional>
-
-// workaround for https://cplusplus.github.io/LWG/issue3657
-// notice that theoretically by the standard you are not allowed to specialize on std types...
-// but it works, and this is recognized as a defect of the standard.
-// Using a non-standard Hasher type would be a huge pain, as the automatic hash implementation of
-// std::variant would not kick in (we use std::filesystem::path in a variant used as a map key).
-namespace std {
-template <>
-struct hash<filesystem::path> {
-  size_t operator()(const filesystem::path& path) const { return hash_value(path); }
-};
-
-}  // namespace std