DeadCode: Add MISRA C 2012 Rule 2.7

Adds a shared implementation query for identifying unused parameters.

Author: lcartey

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

@@ -0,0 +1 @@
+| test.c:6:22:6:22 | x | Unused parameter 'x' for function $@. | test.c:6:6:6:16 | test_unused | test_unused |

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

@@ -0,0 +1,2 @@
+// GENERATED FILE - DO NOT MODIFY
+import codingstandards.cpp.rules.unusedparameter.UnusedParameter

c/common/test/rules/unusedparameter/test.c

@@ -0,0 +1,8 @@
+// NOTICE: THE TEST CASES BELOW ARE ALSO INCLUDED IN THE C++ TEST CASE AND
+// CHANGES SHOULD BE REFLECTED THERE AS WELL.
+
+int test_used(int x) { return x; } // COMPLIANT
+
+void test_unused(int x) {} // NON_COMPLIANT
+
+void test_no_def(int x); // COMPLIANT - no definition, so cannot be "unused"

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

@@ -0,0 +1,22 @@
+/**
+ * @id c/misra/unused-parameter
+ * @name RULE-2-7: There should be no unused parameters in 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-2-7
+ *       readability
+ *       maintainability
+ *       external/misra/obligation/advisory
+ */
+
+import cpp
+import codingstandards.c.misra
+import codingstandards.cpp.rules.unusedparameter.UnusedParameter
+
+class UnusedParameterQuery extends UnusedParameterSharedQuery {
+  UnusedParameterQuery() {
+    this = DeadCodePackage::unusedParameterQuery()
+  }
+}

c/misra/test/rules/RULE-2-7/UnusedParameter.testref

@@ -0,0 +1 @@
+c/common/test/rules/unusedparameter/UnusedParameter.ql

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

@@ -1,2 +1,2 @@
-| test.cpp:3:22:3:22 | x | Unused parameter 'x' for function $@. | test.cpp:3:6:3:16 | test_unused | test_unused |
-| test.cpp:11:14:11:14 | x | Unused parameter 'x' for function $@. | test.cpp:11:8:11:8 | b | A::b |
+| test.cpp:6:22:6:22 | x | Unused parameter 'x' for function $@. | test.cpp:6:6:6:16 | test_unused | test_unused |
+| test.cpp:14:14:14:14 | x | Unused parameter 'x' for function $@. | test.cpp:14:8:14:8 | b | A::b |

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

@@ -1,3 +1,6 @@
+// NOTICE: SOME OF THE TEST CASES BELOW ARE ALSO INCLUDED IN THE C TEST CASE AND
+// CHANGES SHOULD BE REFLECTED THERE AS WELL.
+
 int test_used(int x) { return x; } // COMPLIANT
 
 void test_unused(int x) {} // NON_COMPLIANT