First draft of RULE-0-2-2

c/common/test/rules/unusedparameter/UnusedParameter.ql

@@ -1,4 +1,8 @@
 // GENERATED FILE - DO NOT MODIFY
 import codingstandards.cpp.rules.unusedparameter.UnusedParameter
 
-class TestFileQuery extends UnusedParameterSharedQuery, TestQuery { }
+module UnusedParameterTestConfig implements UnusedParameterSharedConfigSig {
+  Query getQuery() { result instanceof TestQuery }
+}
+
+import UnusedParameterShared<UnusedParameterTestConfig>

c/misra/src/rules/RULE-2-7/UnusedParameter.ql

@@ -16,6 +16,8 @@ import cpp
 import codingstandards.c.misra
 import codingstandards.cpp.rules.unusedparameter.UnusedParameter
 
-class UnusedParameterQuery extends UnusedParameterSharedQuery {
-  UnusedParameterQuery() { this = DeadCodePackage::unusedParameterQuery() }
+module UnusedParameterQueryConfig implements UnusedParameterSharedConfigSig {
+  Query getQuery() { result = DeadCodePackage::unusedParameterQuery() }
 }
+
+import UnusedParameterShared<UnusedParameterQueryConfig>

change_notes/2026-02-13-refactor-unused-parameter-queries.md

@@ -0,0 +1,2 @@
+ - `A0-1-4`, `RULE-2-7` - `UnusedParameter.ql`:
+   - Refactored to be able to share most logic between MISRA C, MISRA C++, and AUTOSAR. No visible change in behavior expected.

cpp/autosar/src/rules/A0-1-4/UnusedParameter.ql

@@ -18,6 +18,13 @@ import codingstandards.cpp.autosar
 import codingstandards.cpp.deadcode.UnusedParameters
 import codingstandards.cpp.rules.unusedparameter.UnusedParameter
 
-class UnusedParameterQuery extends UnusedParameterSharedQuery {
-  UnusedParameterQuery() { this = DeadCodePackage::unusedParameterQuery() }
+module UnusedParameterQueryConfig implements UnusedParameterSharedConfigSig {
+  Query getQuery() { result = DeadCodePackage::unusedParameterQuery() }
+
+  predicate excludeParameter(Parameter p) {
+    // Virtual functions are covered by a different rule
+    p.getFunction().isVirtual()
+  }
 }
+
+import UnusedParameterShared<UnusedParameterQueryConfig>

cpp/autosar/test/rules/A0-1-4/UnusedParameter.expected

@@ -0,0 +1 @@
+| test.cpp:2:14:2:14 | x | Unused parameter 'x' for function $@. | test.cpp:2:8:2:8 | b | A::b |

cpp/autosar/test/rules/A0-1-4/UnusedParameter.qlref

@@ -0,0 +1 @@
+rules/A0-1-4/UnusedParameter.ql

cpp/autosar/test/rules/A0-1-4/test.cpp

@@ -0,0 +1,7 @@
+class A {
+  void b(int x) {} // NON_COMPLIANT
+
+  // This is specially excluded from A0-1-4, covered by a different rule,
+  // even though it's non compliant in the shared query.
+  virtual void d(int x, int y) {} // COMPLIANT
+};

cpp/common/src/codingstandards/cpp/exclusions/cpp/DeadCode8.qll

@@ -0,0 +1,26 @@
+//** THIS FILE IS AUTOGENERATED, DO NOT MODIFY DIRECTLY.  **/
+import cpp
+import RuleMetadata
+import codingstandards.cpp.exclusions.RuleMetadata
+
+newtype DeadCode8Query = TUnusedParameterMisraCppQuery()
+
+predicate isDeadCode8QueryMetadata(Query query, string queryId, string ruleId, string category) {
+  query =
+    // `Query` instance for the `unusedParameterMisraCpp` query
+    DeadCode8Package::unusedParameterMisraCppQuery() and
+  queryId =
+    // `@id` for the `unusedParameterMisraCpp` query
+    "cpp/misra/unused-parameter-misra-cpp" and
+  ruleId = "RULE-0-2-2" and
+  category = "required"
+}
+
+module DeadCode8Package {
+  Query unusedParameterMisraCppQuery() {
+    //autogenerate `Query` type
+    result =
+      // `Query` type for `unusedParameterMisraCpp` query
+      TQueryCPP(TDeadCode8PackageQuery(TUnusedParameterMisraCppQuery()))
+  }
+}

cpp/common/src/codingstandards/cpp/exclusions/cpp/RuleMetadata.qll

@@ -19,6 +19,7 @@ import Conversions2
 import DeadCode
 import DeadCode3
 import DeadCode4
+import DeadCode8
 import Declarations
 import ExceptionSafety
 import Exceptions1
@@ -91,6 +92,7 @@ newtype TCPPQuery =
   TDeadCodePackageQuery(DeadCodeQuery q) or
   TDeadCode3PackageQuery(DeadCode3Query q) or
   TDeadCode4PackageQuery(DeadCode4Query q) or
+  TDeadCode8PackageQuery(DeadCode8Query q) or
   TDeclarationsPackageQuery(DeclarationsQuery q) or
   TExceptionSafetyPackageQuery(ExceptionSafetyQuery q) or
   TExceptions1PackageQuery(Exceptions1Query q) or
@@ -163,6 +165,7 @@ predicate isQueryMetadata(Query query, string queryId, string ruleId, string cat
   isDeadCodeQueryMetadata(query, queryId, ruleId, category) or
   isDeadCode3QueryMetadata(query, queryId, ruleId, category) or
   isDeadCode4QueryMetadata(query, queryId, ruleId, category) or
+  isDeadCode8QueryMetadata(query, queryId, ruleId, category) or
   isDeclarationsQueryMetadata(query, queryId, ruleId, category) or
   isExceptionSafetyQueryMetadata(query, queryId, ruleId, category) or
   isExceptions1QueryMetadata(query, queryId, ruleId, category) or

cpp/common/src/codingstandards/cpp/rules/unusedparameter/UnusedParameter.qll

@@ -7,9 +7,11 @@ import codingstandards.cpp.Customizations
 import codingstandards.cpp.Exclusions
 import codingstandards.cpp.deadcode.UnusedParameters
 
-abstract class UnusedParameterSharedQuery extends Query { }
+signature module UnusedParameterSharedConfigSig {
+  Query getQuery();
 
-Query getQuery() { result instanceof UnusedParameterSharedQuery }
+  default predicate excludeParameter(Parameter p) { none() }
+}
 
 predicate isMaybeUnusedParameter(Parameter parameter) {
   parameter.getAnAttribute().toString() = "maybe_unused"
@@ -19,12 +21,13 @@ predicate isLambdaParameter(Parameter parameter) {
   exists(LambdaExpression lambda | lambda.getLambdaFunction().getParameter(_) = parameter)
 }
 
-query predicate problems(UnusedParameter p, string message, Function f, string fName) {
-  not isExcluded(p, getQuery()) and
-  not isMaybeUnusedParameter(p) and
-  (if isLambdaParameter(p) then fName = "lambda expression" else fName = f.getQualifiedName()) and
-  f = p.getFunction() and
-  // Virtual functions are covered by a different rule
-  not f.isVirtual() and
-  message = "Unused parameter '" + p.getName() + "' for function $@."
+module UnusedParameterShared<UnusedParameterSharedConfigSig Config> {
+  query predicate problems(UnusedParameter p, string message, Function f, string fName) {
+    not isExcluded(p, Config::getQuery()) and
+    not isMaybeUnusedParameter(p) and
+    not Config::excludeParameter(p) and
+    (if isLambdaParameter(p) then fName = "lambda expression" else fName = f.getQualifiedName()) and
+    f = p.getFunction() and
+    message = "Unused parameter '" + p.getName() + "' for function $@."
+  }
 }

cpp/common/test/rules/unusedparameter/UnusedParameter.expected

@@ -1,3 +1,5 @@
 | test.cpp:8:22:8:22 | x | Unused parameter 'x' for function $@. | test.cpp:8:6:8:16 | test_unused | test_unused |
 | test.cpp:16:14:16:14 | x | Unused parameter 'x' for function $@. | test.cpp:16:8:16:8 | b | A::b |
-| test.cpp:35:14:35:14 | y | Unused parameter 'y' for function $@. | test.cpp:34:9:34:9 | operator() | lambda expression |
+| test.cpp:21:22:21:22 | x | Unused parameter 'x' for function $@. | test.cpp:21:16:21:16 | d | A::d |
+| test.cpp:21:29:21:29 | y | Unused parameter 'y' for function $@. | test.cpp:21:16:21:16 | d | A::d |
+| test.cpp:38:14:38:14 | y | Unused parameter 'y' for function $@. | test.cpp:37:9:37:9 | operator() | lambda expression |

cpp/common/test/rules/unusedparameter/UnusedParameter.ql

@@ -1,4 +1,8 @@
 // GENERATED FILE - DO NOT MODIFY
 import codingstandards.cpp.rules.unusedparameter.UnusedParameter
 
-class TestFileQuery extends UnusedParameterSharedQuery, TestQuery { }
+module UnusedParameterTestConfig implements UnusedParameterSharedConfigSig {
+  Query getQuery() { result instanceof TestQuery }
+}
+
+import UnusedParameterShared<UnusedParameterTestConfig>

cpp/common/test/rules/unusedparameter/test.cpp

@@ -12,10 +12,13 @@ void test_unnamed(
 }
 
 class A {
-  int a(int x) { return x; }      // COMPLIANT
-  void b(int x) {}                // NON_COMPLIANT
-  void c(int) {}                  // COMPLIANT
-  virtual void d(int x, int y) {} // virtual, not covered by this rule
+  int a(int x) { return x; } // COMPLIANT
+  void b(int x) {}           // NON_COMPLIANT
+  void c(int) {}             // COMPLIANT
+
+  // This is a violation of A0-1-4, but not a violation of Rule 0-0-2, so it's
+  // accepted by the default shared logic. See A0-1-4 tests for coverage.
+  virtual void d(int x, int y) {} // COMPLIANT
 };
 
 void f(

cpp/misra/src/rules/RULE-0-2-2/UnusedParameterMisraCpp.ql

@@ -0,0 +1,29 @@
+/**
+ * @id cpp/misra/unused-parameter-misra-cpp
+ * @name RULE-0-2-2: There shall be no unused named parameters in non-virtual functions
+ * @description Unused parameters can indicate a mistake when implementing the function.
+ * @kind problem
+ * @precision very-high
+ * @problem.severity warning
+ * @tags external/misra/id/rule-0-2-2
+ *       scope/single-translation-unit
+ *       readability
+ *       maintainability
+ *       external/misra/enforcement/decidable
+ *       external/misra/obligation/required
+ */
+
+import cpp
+import codingstandards.cpp.misra as Misra
+import codingstandards.cpp.rules.unusedparameter.UnusedParameter
+
+module UnusedParameterQueryConfig implements UnusedParameterSharedConfigSig {
+  Query getQuery() { result = Misra::DeadCode8Package::unusedParameterMisraCppQuery() }
+
+  predicate excludeParameter(Parameter p) {
+    // Exclude parameters which are unnamed in the definition.
+    not exists(p.getFunction().getDefinition().getParameterDeclarationEntry(p.getIndex()).getName())
+  }
+}
+
+import UnusedParameterShared<UnusedParameterQueryConfig>

cpp/misra/test/rules/RULE-0-2-2/UnusedParameterMisraCpp.expected

@@ -0,0 +1,8 @@
+| test.cpp:1:13:1:13 | x | Unused parameter 'x' for function $@. | test.cpp:1:6:1:7 | f0 | f0 |
+| test.cpp:9:13:9:13 | x | Unused parameter 'x' for function $@. | test.cpp:9:6:9:7 | f4 | f4 |
+| test.cpp:18:13:18:13 | y | Unused parameter 'y' for function $@. | test.cpp:18:6:18:7 | f7 | f7 |
+| test.cpp:21:13:21:13 | y | Unused parameter 'y' for function $@. | test.cpp:21:6:21:7 | f8 | f8 |
+| test.cpp:24:23:24:23 | x | Unused parameter 'x' for function $@. | test.cpp:24:16:24:17 | m0 | C1::m0 |
+| test.cpp:36:15:36:15 | x | Unused parameter 'x' for function $@. | test.cpp:36:8:36:9 | m0 | C3::m0 |
+| test.cpp:37:15:37:15 | x | Unused parameter 'x' for function $@. | test.cpp:37:8:37:9 | m1 | C3::m1 |
+| test.cpp:38:15:38:15 | x | Unused parameter 'x' for function $@. | test.cpp:38:8:38:9 | m2 | C3::m2 |

cpp/misra/test/rules/RULE-0-2-2/UnusedParameterMisraCpp.qlref

@@ -0,0 +1 @@
+rules/RULE-0-2-2/UnusedParameterMisraCpp.ql

cpp/misra/test/rules/RULE-0-2-2/test.cpp

@@ -0,0 +1,45 @@
+void f0(int x) {}     // NON_COMPLIANT
+void f1(int x) { x; } // COMPLIANT
+void f2(int) {}       // COMPLIANT
+
+void f3(int);
+void f3(int) {} // COMPLIANT
+
+void f4(int);
+void f4(int x) {} // NON_COMPLIANT
+
+void f5(int);
+void f5(int x) { x; } // COMPLIANT
+
+void f6(int x);
+void f6(int) {} // COMPLIANT
+
+void f7(int x);
+void f7(int y) {} // NON_COMPLIANT
+
+void f8(int i);
+void f8(int y) {} // NON_COMPLIANT
+
+class C1 {
+  virtual void m0(int x) {}                  // NON_COMPLIANT
+  virtual void m1(int) {}                    // COMPLIANT
+  virtual void m2([[maybe_unused]] int x) {} // COMPLIANT
+};
+
+class C2 : C1 {
+  void m0(int) override {} // COMPLIANT
+  void m1(int) override {} // COMPLIANT
+  void m2(int) override {} // COMPLIANT
+};
+
+class C3 : C1 {
+  void m0(int x) override {} // NON_COMPLIANT
+  void m1(int x) override {} // NON_COMPLIANT
+  void m2(int x) override {} // NON_COMPLIANT
+};
+
+class C4 : C1 {
+  void m0([[maybe_unused]] int x) override {} // COMPLIANT
+  void m1([[maybe_unused]] int x) override {} // COMPLIANT
+  void m2([[maybe_unused]] int x) override {} // COMPLIANT
+};

rule_packages/cpp/DeadCode8.json

@@ -0,0 +1,27 @@
+{
+  "MISRA-C++-2023": {
+    "RULE-0-2-2": {
+      "properties": {
+        "enforcement": "decidable",
+        "obligation": "required"
+      },
+      "queries": [
+        {
+          "description": "Unused parameters can indicate a mistake when implementing the function.",
+          "kind": "problem",
+          "name": "There shall be no unused named parameters in non-virtual functions",
+          "precision": "very-high",
+          "severity": "warning",
+          "short_name": "UnusedParameterMisraCpp",
+          "tags": [
+            "scope/single-translation-unit",
+            "readability",
+            "maintainability"
+          ],
+          "shared_implementation_short_name": "UnusedParameter"
+        }
+      ],
+      "title": "There shall be no unused named parameters in non-virtual functions."
+    }
+  }
+}

rules.csv

@@ -828,7 +828,7 @@ cpp,MISRA-C++-2023,RULE-0-0-2,Yes,Advisory,Undecidable,System,Controlling expres
 cpp,MISRA-C++-2023,RULE-0-1-1,Yes,Advisory,Undecidable,System,A value should not be unnecessarily written to a local object,A0-1-1,DeadCode2,Medium,
 cpp,MISRA-C++-2023,RULE-0-1-2,Yes,Required,Decidable,Single Translation Unit,The value returned by a function shall be used,A0-1-2,DeadCode2,Easy,
 cpp,MISRA-C++-2023,RULE-0-2-1,Yes,Advisory,Decidable,Single Translation Unit,Variables with limited visibility should be used at least once,M0-1-3,DeadCode2,Easy,
-cpp,MISRA-C++-2023,RULE-0-2-2,Yes,Required,Decidable,Single Translation Unit,A named function parameter shall be used at least once,"A0-1-4, A0-1-5",DeadCode2,Easy,
+cpp,MISRA-C++-2023,RULE-0-2-2,Yes,Required,Decidable,Single Translation Unit,A named function parameter shall be used at least once,"A0-1-4, A0-1-5",DeadCode8,Easy,
 cpp,MISRA-C++-2023,RULE-0-2-3,Yes,Advisory,Decidable,Single Translation Unit,Types with limited visibility should be used at least once,A0-1-6,DeadCode2,Easy,
 cpp,MISRA-C++-2023,RULE-0-2-4,Yes,Advisory,Decidable,System,Functions with limited visibility should be used at least once,A0-1-3,DeadCode2,Easy,
 cpp,MISRA-C++-2023,DIR-0-3-1,Yes,Advisory,,,Floating-point arithmetic should be used appropriately,,FloatingPoint,Hard,