Create rule S7461: Conflicting Borrow and Hash implementations should be avoided (#4847)

* Create rule S7461

* Update metadata.json

* Update rule.adoc

---------

Co-authored-by: sallaigy <sallaigy@users.noreply.github.com>
Co-authored-by: Gyula Sallai <gyula.sallai@sonarsource.com>
Co-authored-by: Ghislain Piot <ghislain.piot@sonarsource.com>

Author: 3 people

rules/S7461/metadata.json

@@ -0,0 +1,2 @@
+{
+}

rules/S7461/rust/metadata.json

@@ -0,0 +1,24 @@
+{
+  "title": "Conflicting `Borrow` and `Hash` implementations should be avoided",
+  "type": "BUG",
+  "status": "ready",
+  "remediation": {
+    "func": "Constant\/Issue",
+    "constantCost": "5min"
+  },
+  "tags": [
+    "clippy"
+  ],
+  "defaultSeverity": "Critical",
+  "ruleSpecification": "RSPEC-7461",
+  "sqKey": "S7461",
+  "scope": "All",
+  "defaultQualityProfiles": ["Sonar way"],
+  "quickfix": "unknown",
+  "code": {
+    "impacts": {
+      "RELIABILITY": "HIGH"
+    },
+    "attribute": "LOGICAL"
+  }
+}

rules/S7461/rust/rule.adoc

@@ -0,0 +1,41 @@
+
+== Why is this an issue?
+
+When a type implements `Borrow<T>`, it should provide consistent behavior between the borrowed and owned values, especially regarding `Eq`, `Ord`, and `Hash`. However, `str` and `[u8]` have different Hash implementations, leading to inconsistent hash values for the same underlying data when accessed through different Borrow implementations. This violates the principle that `hash(x) == hash((x as Borrow<[u8]>).borrow()) == hash((x as Borrow<str>).borrow())` must hold, and can cause issues with hash-based collections and comparisons.
+
+=== Code examples
+
+==== Noncompliant code example
+
+[source,rust]
+----
+use std::borrow::Borrow;
+use std::hash::{Hash, Hasher};
+
+struct ExampleType {
+    data: String,
+}
+
+impl Hash for ExampleType {
+    fn hash<H: Hasher>(&self, state: &mut H) {
+        self.data.hash(state); // Noncompliant: Inconsistent Hash
+    }
+}
+
+impl Borrow<str> for ExampleType {
+    fn borrow(&self) -> &str {
+        &self.data
+    }
+}
+
+impl Borrow<[u8]> for ExampleType {
+    fn borrow(&self) -> &[u8] {
+        self.data.as_bytes()
+    }
+}
+----
+
+== Resources
+=== Documentation
+
+* Clippy Lints - https://rust-lang.github.io/rust-clippy/master/index.html#impl_hash_borrow_with_str_and_bytes