diff --git a/CMakeLists.txt b/CMakeLists.txt
index 933b9a235..5500eabc3 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -231,7 +231,7 @@ set(rules_index_parts_dir ${CMAKE_BINARY_DIR}/rules_index/parts)
 set(RULES_IR_DIR "${CMAKE_BINARY_DIR}/rules")
 set(rust_rules_ir_outputs)
 foreach(_rule_dir IN LISTS rule_subdirs)
-  file(GLOB _cpp_srcs ${_rule_dir}/src.c ${_rule_dir}/src.cpp ${_rule_dir}/src_cxx*.cpp)
+  file(GLOB _cpp_srcs ${_rule_dir}/src.c ${_rule_dir}/src.cpp ${_rule_dir}/src_*.cpp)
   if(NOT _cpp_srcs)
     continue()
   endif()
diff --git a/cpp2rust/converter/rules/rules_loader.cpp b/cpp2rust/converter/rules/rules_loader.cpp
index 73f5c1bfe..7f12147d8 100644
--- a/cpp2rust/converter/rules/rules_loader.cpp
+++ b/cpp2rust/converter/rules/rules_loader.cpp
@@ -320,6 +320,9 @@ std::string BuildRulesEpilogue(const std::unordered_set<std::string> &keys,
       if (auto since = rule->getInteger("since"); since && *since > standard) {
         continue;
       }
+      if (auto until = rule->getInteger("until"); until && *until <= standard) {
+        continue;
+      }
       if (auto required = rule->getArray("requires");
           required &&
           !llvm::all_of(*required, [&](const llvm::json::Value &key) {
diff --git a/cpp2rust/rule_preprocessing/cpp_rule_indexer.cpp b/cpp2rust/rule_preprocessing/cpp_rule_indexer.cpp
index 2478d6f2c..240431c17 100644
--- a/cpp2rust/rule_preprocessing/cpp_rule_indexer.cpp
+++ b/cpp2rust/rule_preprocessing/cpp_rule_indexer.cpp
@@ -335,15 +335,27 @@ llvm::json::Object ReadJson(const fs::path &path) {
   return std::move(*parsed->getAsObject());
 }
 
-unsigned SinceStandard(const fs::path &src_path) {
+struct StandardRange {
+  unsigned since = 11;
+  unsigned until = 0;
+};
+
+StandardRange RuleFileStandards(const fs::path &src_path) {
   auto stem_string = src_path.stem().string();
   llvm::StringRef stem = stem_string;
-  unsigned standard = 11;
-  if (stem.consume_front("src_cxx") && stem.getAsInteger(10, standard)) {
+  StandardRange range;
+  bool valid = stem.consume_front("src");
+  if (valid && stem.consume_front("_cxx")) {
+    valid = !stem.consumeInteger(10, range.since);
+  }
+  if (valid && stem.consume_front("_until_cxx")) {
+    valid = !stem.consumeInteger(10, range.until);
+  }
+  if (!valid || !stem.empty()) {
     llvm::errs() << "ERROR: unexpected rule file " << src_path.string() << '\n';
     std::exit(EXIT_FAILURE);
   }
-  return standard;
+  return range;
 }
 
 void MergeRules(llvm::json::Object &into, llvm::json::Object &&from) {
@@ -364,20 +376,24 @@ void IndexDir(const fs::path &rule_dir, const fs::path &out) {
   for (const auto &entry : fs::directory_iterator(rule_dir)) {
     auto name = entry.path().filename().string();
     if (name == "src.c" || name == "src.cpp" ||
-        (name.starts_with("src_cxx") && name.ends_with(".cpp"))) {
+        (name.starts_with("src_") && name.ends_with(".cpp"))) {
       cxx_srcs.push_back(entry.path());
     }
   }
   std::ranges::sort(cxx_srcs);
   llvm::json::Object cxx_rules;
   for (const auto &src_path : cxx_srcs) {
-    auto standard = SinceStandard(src_path);
+    auto range = RuleFileStandards(src_path);
     llvm::json::Object rules;
     Index(src_path, /*is_c=*/false, dir_name,
-          {std::format("-std=c++{}", standard)}, rules);
+          {std::format("-std=c++{}", range.since)}, rules);
     for (auto &[key, entries] : rules) {
       for (auto &entry : *entries.getAsArray()) {
-        (*entry.getAsObject())["since"] = standard;
+        auto &rule = *entry.getAsObject();
+        rule["since"] = range.since;
+        if (range.until) {
+          rule["until"] = range.until;
+        }
       }
     }
     MergeRules(cxx_rules, std::move(rules));
diff --git a/rules/algorithm/src_until_cxx17.cpp b/rules/algorithm/src_until_cxx17.cpp
new file mode 100644
index 000000000..09eb27554
--- /dev/null
+++ b/rules/algorithm/src_until_cxx17.cpp
@@ -0,0 +1,8 @@
+// Copyright (c) 2022-present INESC-ID.
+// Distributed under the MIT license that can be found in the LICENSE file.
+
+#include <algorithm>
+
+template <typename T1> void f18(T1 first, T1 last) {
+  return std::random_shuffle(first, last);
+}
diff --git a/rules/algorithm/tgt_refcount.rs b/rules/algorithm/tgt_refcount.rs
index 52a96393e..fb5d275e3 100644
--- a/rules/algorithm/tgt_refcount.rs
+++ b/rules/algorithm/tgt_refcount.rs
@@ -117,3 +117,16 @@ fn f16<T1: PartialOrd + Clone + ByteRepr>(a0: Ptr<T1>, a1: Ptr<T1>) -> Ptr<T1> {
 fn f17<T1: PartialOrd + Clone + ByteRepr>(a0: Ptr<T1>, a1: Ptr<T1>) -> Ptr<T1> {
     if a0.read() >= a1.read() { a0 } else { a1 }
 }
+
+fn f18<T1: Clone + ByteRepr>(a0: Ptr<T1>, a1: Ptr<T1>) {
+    let count = a1.get_offset() - a0.get_offset();
+    let random = std::hash::RandomState::new();
+    for i in (1..count).rev() {
+        let j = std::hash::BuildHasher::hash_one(&random, i) as usize % (i + 1);
+        let x = a0.offset(i);
+        let y = a0.offset(j);
+        let tmp = x.read();
+        x.write(y.read());
+        y.write(tmp);
+    }
+}
diff --git a/rules/algorithm/tgt_unsafe.rs b/rules/algorithm/tgt_unsafe.rs
index 6257589a5..ffec814fc 100644
--- a/rules/algorithm/tgt_unsafe.rs
+++ b/rules/algorithm/tgt_unsafe.rs
@@ -133,3 +133,11 @@ unsafe fn f17<T1: PartialOrd>(a0: *const T1, a1: *const T1) -> *const T1 {
         (a1) as *const _
     }
 }
+
+unsafe fn f18<T1>(a0: *mut T1, a1: *mut T1) {
+    let len = a1.offset_from(a0) as usize;
+    let slice = ::std::slice::from_raw_parts_mut(a0, len);
+    for i in (1..len).rev() {
+        slice.swap(i, libc::rand() as usize % (i + 1));
+    }
+}
diff --git a/rules/string/src_until_cxx20.cpp b/rules/string/src_until_cxx20.cpp
new file mode 100644
index 000000000..1e763b1fe
--- /dev/null
+++ b/rules/string/src_until_cxx20.cpp
@@ -0,0 +1,6 @@
+// Copyright (c) 2022-present INESC-ID.
+// Distributed under the MIT license that can be found in the LICENSE file.
+
+#include <string>
+
+bool f31(const std::string &a, const char *b) { return a != b; }
diff --git a/rules/string/tgt_refcount.rs b/rules/string/tgt_refcount.rs
index 96b9cb6ed..4d96960d2 100644
--- a/rules/string/tgt_refcount.rs
+++ b/rules/string/tgt_refcount.rs
@@ -190,3 +190,7 @@ fn f29(a0: Ptr<Vec<i8>>, a1: Vec<i8>) {
 fn f30(a0: Ptr<Vec<i8>>, a1: &mut Vec<i8>) {
     a0.write(std::mem::take(&mut *a1))
 }
+
+fn f31(a0: Vec<i8>, a1: Ptr<i8>) -> bool {
+    a1.with_c_str(|__s| a0[..a0.len().saturating_sub(1)] != *__s)
+}
diff --git a/rules/string/tgt_unsafe.rs b/rules/string/tgt_unsafe.rs
index a31efb208..a7b7966de 100644
--- a/rules/string/tgt_unsafe.rs
+++ b/rules/string/tgt_unsafe.rs
@@ -184,3 +184,10 @@ unsafe fn f29(a0: &mut Vec<libc::c_char>, a1: Vec<libc::c_char>) {
 unsafe fn f30(a0: &mut Vec<libc::c_char>, a1: &mut Vec<libc::c_char>) {
     *a0 = std::mem::take(&mut *a1)
 }
+
+unsafe fn f31(a0: Vec<libc::c_char>, a1: *const libc::c_char) -> bool {
+    a0 != {
+        let s = a1;
+        std::slice::from_raw_parts(s, (0..).take_while(|&i| *s.add(i) != 0).count() + 1).to_vec()
+    }
+}
diff --git a/tests/unit/elidable_iterator_copy_cxx11.cpp b/tests/unit/elidable_iterator_copy_cxx11.cpp
index 6b8fad741..fbb30febd 100644
--- a/tests/unit/elidable_iterator_copy_cxx11.cpp
+++ b/tests/unit/elidable_iterator_copy_cxx11.cpp
@@ -10,5 +10,8 @@ int main() {
   std::vector<int>::iterator it = std::find(v.begin(), v.end(), 7);
   assert(it != v.end());
   assert(*it == 7);
+  std::random_shuffle(v.begin(), v.end());
+  std::sort(v.begin(), v.end());
+  assert(v[0] == 4 && v[1] == 7);
   return 0;
 }
diff --git a/tests/unit/out/refcount/elidable_iterator_copy_cxx11.rs b/tests/unit/out/refcount/elidable_iterator_copy_cxx11.rs
index cda73dcf7..adc8e2314 100644
--- a/tests/unit/out/refcount/elidable_iterator_copy_cxx11.rs
+++ b/tests/unit/out/refcount/elidable_iterator_copy_cxx11.rs
@@ -34,6 +34,21 @@ fn main_0() -> i32 {
     };
     assert!(it != (v.as_pointer() as Ptr<i32>).to_end());
     assert!(((it.read()) == 7));
+    {
+        let count = (v.as_pointer() as Ptr<i32>).to_end().get_offset()
+            - (v.as_pointer() as Ptr<i32>).get_offset();
+        let random = std::hash::RandomState::new();
+        for i in (1..count).rev() {
+            let j = std::hash::BuildHasher::hash_one(&random, i) as usize % (i + 1);
+            let x = (v.as_pointer() as Ptr<i32>).offset(i);
+            let y = (v.as_pointer() as Ptr<i32>).offset(j);
+            let tmp = x.read();
+            x.write(y.read());
+            y.write(tmp);
+        }
+    };
+    (v.as_pointer() as Ptr<i32>).sort((v.as_pointer() as Ptr<i32>).to_end().get_offset());
+    assert!(({ (*v.borrow())[0_usize] } == 4) && ({ (*v.borrow())[1_usize] } == 7));
     return 0;
 }
 pub fn __cpp2rust_init_globals() {}
diff --git a/tests/unit/out/refcount/string.rs b/tests/unit/out/refcount/string.rs
index 1f4e13a22..69da8da79 100644
--- a/tests/unit/out/refcount/string.rs
+++ b/tests/unit/out/refcount/string.rs
@@ -29,6 +29,14 @@ fn main_0() -> i32 {
         Ptr::<i8>::from_string_literal(b"hello")
             .with_c_str(|__s| (*s1.borrow())[..(*s1.borrow()).len().saturating_sub(1)] == *__s)
     );
+    assert!(
+        Ptr::<i8>::from_string_literal(b"world")
+            .with_c_str(|__s| (*s1.borrow())[..(*s1.borrow()).len().saturating_sub(1)] != *__s)
+    );
+    assert!(
+        !(Ptr::<i8>::from_string_literal(b"hello")
+            .with_c_str(|__s| (*s1.borrow())[..(*s1.borrow()).len().saturating_sub(1)] != *__s))
+    );
     let mut p1: Ptr<i8> = (s1.as_pointer() as Ptr<i8>);
     assert!((((elem!(p1, 0).read()) as i32) == (('h' as i8) as i32)));
     assert!((((elem!(p1, 1).read()) as i32) == (('e' as i8) as i32)));
diff --git a/tests/unit/out/unsafe/elidable_iterator_copy_cxx11.rs b/tests/unit/out/unsafe/elidable_iterator_copy_cxx11.rs
index ddbf28195..e53770a75 100644
--- a/tests/unit/out/unsafe/elidable_iterator_copy_cxx11.rs
+++ b/tests/unit/out/unsafe/elidable_iterator_copy_cxx11.rs
@@ -31,6 +31,18 @@ unsafe fn main_0() -> i32 {
     };
     assert!(it != v.as_mut_ptr().add(v.len()));
     assert!(((*it) == (7)));
+    {
+        let len = v.as_mut_ptr().add(v.len()).offset_from(v.as_mut_ptr()) as usize;
+        let slice = ::std::slice::from_raw_parts_mut(v.as_mut_ptr(), len);
+        for i in (1..len).rev() {
+            slice.swap(i, libc::rand() as usize % (i + 1));
+        }
+    };
+    {
+        let len = v.as_mut_ptr().add(v.len()).offset_from(v.as_mut_ptr()) as usize;
+        ::std::slice::from_raw_parts_mut(v.as_mut_ptr(), len).sort()
+    };
+    assert!(((v[(0_usize)]) == (4)) && ((v[(1_usize)]) == (7)));
     return 0;
 }
 pub unsafe fn __cpp2rust_init_globals() {}
diff --git a/tests/unit/out/unsafe/string.rs b/tests/unit/out/unsafe/string.rs
index 71432816b..eb2fe255e 100644
--- a/tests/unit/out/unsafe/string.rs
+++ b/tests/unit/out/unsafe/string.rs
@@ -33,6 +33,20 @@ unsafe fn main_0() -> i32 {
                 .to_vec()
         }
     );
+    assert!(
+        s1 != {
+            let s = c"world".as_ptr();
+            std::slice::from_raw_parts(s, (0..).take_while(|&i| *s.add(i) != 0).count() + 1)
+                .to_vec()
+        }
+    );
+    assert!(
+        !(s1 != {
+            let s = c"hello".as_ptr();
+            std::slice::from_raw_parts(s, (0..).take_while(|&i| *s.add(i) != 0).count() + 1)
+                .to_vec()
+        })
+    );
     let mut p1: *const libc::c_char = (s1.as_mut_ptr()).cast_const();
     assert!((((*p1.offset((0) as isize)) as i32) == (('h' as libc::c_char) as i32)));
     assert!((((*p1.offset((1) as isize)) as i32) == (('e' as libc::c_char) as i32)));
diff --git a/tests/unit/string.cpp b/tests/unit/string.cpp
index 560531bce..41ba4d0ee 100644
--- a/tests/unit/string.cpp
+++ b/tests/unit/string.cpp
@@ -1,3 +1,4 @@
+// ADDITIONAL_COMPILE_FLAGS: -std=c++17
 #include <cassert>
 #include <cstdint>
 #include <string>
@@ -14,6 +15,8 @@ int main() {
   assert(s1[3] == 'l');
   assert(s1[4] == 'o');
   assert(s1 == "hello");
+  assert(s1 != "world");
+  assert(!(s1 != "hello"));
   const char *p1 = s1.data();
   assert(p1[0] == 'h');
   assert(p1[1] == 'e');