Merge branch 'master' into mary/update-rule

Author: mary-georgiou-sonarsource

rules/S7475/java/metadata.json

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+{
+  "title": "Types of unused record components should be removed from pattern matching",
+  "type": "CODE_SMELL",
+  "status": "ready",
+  "remediation": {
+    "func": "Constant\/Issue",
+    "constantCost": "5min"
+  },
+  "tags": [
+    "java22",
+    "unused"
+  ],
+  "defaultSeverity": "Info",
+  "ruleSpecification": "RSPEC-7475",
+  "sqKey": "S7475",
+  "scope": "All",
+  "defaultQualityProfiles": ["Sonar way"],
+  "quickfix": "targeted",
+  "code": {
+    "impacts": {
+      "MAINTAINABILITY": "INFO"
+    },
+    "attribute": "CLEAR"
+  }
+}

rules/S7475/java/rule.adoc

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+== Why is this an issue?
+
+When using pattern matching on records, matching is done against the canonical constructor of the record.
+This implies listing all the components in the canonical constructor even if some are unused.
+To make the intent of not using the component clear, Java 22 introduced the unnamed variable pattern `_`.
+
+Because we can only pattern match against the canonical constructor, there is no need to disambiguate by specifying the types of its parameters.
+Therefore, the type of unused variables in pattern matching should be omitted, as it does not bring additional value.
+
+== How to fix it
+Remove the type of the unused component.
+
+=== Code examples
+
+==== Noncompliant code example
+
+[source,java,diff-id=1,diff-type=noncompliant]
+----
+record Guest(String name, String email, String phoneNumber) {}
+
+String greet(Object o) {
+    if (o instanceof Guest(String name, String _, String _)) { // Noncompliant
+        return "Hello " + name + "!";
+    }
+    return "Hello!";
+}
+
+String switchToGreet(Object o) {
+    return switch (o) {
+        case Guest(String name, String _, String _) -> "Hello " + name + "!"; // Noncompliant
+        default -> "Hello!";
+    };
+}
+----
+
+==== Compliant solution
+
+[source,java,diff-id=1,diff-type=compliant]
+----
+record Guest(String name, String email, String phoneNumber) {}
+
+String greet(Object o) {
+    if (o instanceof Guest(String name, _, _)) {
+        return "Hello " + name + "!";
+    }
+    return "Hello!";
+}
+
+String switchToGreet(Object o) {
+    return switch (o) {
+        case Guest(String name, _, _) -> "Hello " + name + "!";
+        default -> "Hello!";
+    };
+}
+----
+
+== Resources
+=== Documentation
+* https://openjdk.org/jeps/456[JEP 456: Unnamed Variables & Patterns]

rules/S7475/metadata.json

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+{
+}