Improve scope.qll library to handle global classes and align severity tag on RULE-6-2-4 with A3-1-1

Author: knewbury01

cpp/common/src/codingstandards/cpp/Scope.qll

@@ -369,6 +369,9 @@ predicate hidesStrict(UserVariable v1, UserVariable v2) {
 predicate hasNamespaceScope(Declaration decl) {
   // getNamespace always returns a namespace (e.g. the global namespace).
   exists(Namespace n | namespacembrs(unresolveElement(n), underlyingElement(decl)))
+  or
+  decl.isTopLevel() and
+  not namespacembrs(_, decl)
 }
 
 /** Holds if `decl` has class scope. */

cpp/common/test/rules/violationsofonedefinitionrule/ViolationsOfOneDefinitionRule.expected

@@ -1,3 +1,5 @@
 | test.hpp:3:6:3:7 | definition of f1 | Header file $@ contains function f1 that lead to One Definition Rule violation. | test.hpp:0:0:0:0 | test.hpp | test.hpp |
 | test.hpp:8:5:8:5 | definition of i | Header file $@ contains object i that lead to One Definition Rule violation. | test.hpp:0:0:0:0 | test.hpp | test.hpp |
 | test.hpp:9:12:9:13 | definition of i1 | Header file $@ contains object i1 that lead to One Definition Rule violation. | test.hpp:0:0:0:0 | test.hpp | test.hpp |
+| test.hpp:23:5:23:8 | definition of m | Header file $@ contains function m that lead to One Definition Rule violation. | test.hpp:0:0:0:0 | test.hpp | test.hpp |
+| test.hpp:25:5:25:9 | definition of m1 | Header file $@ contains function m1 that lead to One Definition Rule violation. | test.hpp:0:0:0:0 | test.hpp | test.hpp |

cpp/common/test/rules/violationsofonedefinitionrule/test.hpp

@@ -20,7 +20,5 @@ class C {
   int m1();       // COMPLIANT
 };
 
-int C::m() {}  // NON_COMPLIANT[FALSE_NEGATIVE] - external linkage library
-               // issue/namespace of class not found
-int C::m1() {} // NON_COMPLIANT[FALSE_NEGATIVE] - external linkage library
-               // issue/namespace of class not found
+int C::m() {}  // NON_COMPLIANT
+int C::m1() {} // NON_COMPLIANT

cpp/misra/src/rules/RULE-6-2-4/ViolationsOfOneDefinitionRuleMisra.ql

@@ -6,7 +6,7 @@
  *              behaviour.
  * @kind problem
  * @precision very-high
- * @problem.severity error
+ * @problem.severity warning
  * @tags external/misra/id/rule-6-2-4
  *       correctness
  *       maintainability

rule_packages/cpp/Linkage2.json

@@ -11,7 +11,7 @@
           "kind": "problem",
           "name": "A header file shall not contain definitions of functions or objects that are non-inline and have external linkage",
           "precision": "very-high",
-          "severity": "error",
+          "severity": "warning",
           "short_name": "ViolationsOfOneDefinitionRuleMisra",
           "shared_implementation_short_name": "ViolationsOfOneDefinitionRule",
           "tags": [