refactor: Act on TODOs that are unblocked by C++23 (#7990)

src/test/app/Invariants_test.cpp

@@ -437,16 +437,10 @@ class Invariants_test : public beast::unit_test::Suite
             XRPAmount{},
             STTx{ttACCOUNT_DELETE, [](STObject& tx) {}});
 
-        for (auto const& keyletInfo : kDirectAccountKeylets)
+        for (auto const& [keyletfunc, type, includeInTests] : kDirectAccountKeylets)
         {
-            // TODO: Use structured binding once LLVM 16 is the minimum
-            // supported version. See also:
-            // https://github.com/llvm/llvm-project/issues/48582
-            // https://github.com/llvm/llvm-project/commit/127bf44385424891eb04cff8e52d3f157fc2cb7c
-            if (!keyletInfo.includeInTests)
+            if (!includeInTests)
                 continue;
-            auto const& keyletfunc = keyletInfo.function;
-            auto const& type = keyletInfo.expectedLEName;
 
             using namespace std::string_literals;
 

src/test/jtx/TestHelpers.h

@@ -43,6 +43,7 @@
 #include <memory>
 #include <mutex>
 #include <optional>
+#include <ranges>
 #include <source_location>
 #include <string>
 #include <tuple>
@@ -315,19 +316,11 @@ auto const kData = JTxFieldWrapper<BlobField>(sfData);
 
 auto const kAmount = JTxFieldWrapper<StAmountField>(sfAmount);
 
-// TODO We only need this long "requires" clause as polyfill, for C++20
-// implementations which are missing <ranges> header. Replace with
-// `std::ranges::range<Input>`, and accordingly use std::ranges::begin/end
-// when we have moved to better compilers.
-template <typename Input>
+template <std::ranges::range Input>
 auto
 makeVector(Input const& input)
-    requires requires(Input& v) {
-        std::begin(v);
-        std::end(v);
-    }
 {
-    return std::vector(std::begin(input), std::end(input));
+    return std::vector(std::ranges::begin(input), std::ranges::end(input));
 }
 
 // Functions used in debugging