Merge pull request #64 from lcartey/lcartey/a2-10-5-templates

`A2-10-5`: Exclude variables in template instantiations

Author: lcartey

change_notes/2022-08-18-variable-templates-reused-name.md

@@ -0,0 +1,2 @@
+ - `A2-10-5` - `IdentifierNameOfANonMemberObjectWithExternalOrInternalLinkageIsReused.ql`
+   - Reduce false positives by excluding variable template instantiations.

cpp/autosar/src/rules/A2-10-5/IdentifierNameOfANonMemberObjectWithExternalOrInternalLinkageIsReused.ql

@@ -32,7 +32,11 @@ where
   not isExcluded(o2,
     NamingPackage::identifierNameOfANonMemberObjectWithExternalOrInternalLinkageIsReusedQuery()) and
   not o1 = o2 and
-  o1.getName() = o2.getName()
+  o1.getName() = o2.getName() and
+  // Only consider variables from uninstantiated templates, to avoid false positives where o1 and
+  // o2 are the same object across different template instantiations
+  not o1.isFromTemplateInstantiation(_) and
+  not o2.isFromTemplateInstantiation(_)
 select o2,
   "Identifier name of non-member object $@ reuses the identifier name of non-member object $@.", o2,
   o2.getName(), o1, o1.getName()

cpp/autosar/test/rules/A2-10-5/IdentifierNameOfANonMemberObjectWithExternalOrInternalLinkageIsReused.expected

@@ -1,2 +1,4 @@
 | test1a.cpp:6:12:6:13 | g3 | Identifier name of non-member object $@ reuses the identifier name of non-member object $@. | test1a.cpp:6:12:6:13 | g3 | g3 | test1b.cpp:7:12:7:13 | g3 | g3 |
+| test1a.cpp:17:43:17:43 | number_two | Identifier name of non-member object $@ reuses the identifier name of non-member object $@. | test1a.cpp:17:43:17:43 | number_two | number_two | test1b.cpp:12:43:12:43 | number_two | number_two |
 | test1b.cpp:7:12:7:13 | g3 | Identifier name of non-member object $@ reuses the identifier name of non-member object $@. | test1b.cpp:7:12:7:13 | g3 | g3 | test1a.cpp:6:12:6:13 | g3 | g3 |
+| test1b.cpp:12:43:12:43 | number_two | Identifier name of non-member object $@ reuses the identifier name of non-member object $@. | test1b.cpp:12:43:12:43 | number_two | number_two | test1a.cpp:17:43:17:43 | number_two | number_two |

cpp/autosar/test/rules/A2-10-5/test1a.cpp

@@ -5,3 +5,17 @@ static int g1 = 0;
 static int g2;      // COMPLIANT
 static int g3 = 1;  // NON_COMPLIANT
 static void f1(){}; // NON_COMPLIANT
+
+// Variable template has multiple declarations: one for the uninstantiated
+// template and one for each instantiation
+template <class T> constexpr T number_one = T(1); // COMPLIANT
+
+int test() { return number_one<int>; }
+
+long test2() { return number_one<long>; }
+
+template <class T> constexpr T number_two = T(1); // NON_COMPLIANT
+
+int test3() { return number_two<int>; }
+
+long test4() { return number_two<long>; }

cpp/autosar/test/rules/A2-10-5/test1b.cpp

@@ -8,3 +8,9 @@ static int g3 = 0; // NON_COMPLIANT
 }
 
 static void f1() {} // NON_COMPLIANT
+
+template <class T> constexpr T number_two = T(1); // NON_COMPLIANT
+
+int test3() { return number_two<int>; }
+
+long test4() { return number_two<long>; }