C++: Address false positive results in template instantiations.

cpp/ql/src/Security/CWE/CWE-570/IncorrectAllocationErrorHandling.ql

@@ -232,6 +232,7 @@ predicate nullCheckInThrowingNew(NewOrNewArrayExpr newExpr, GuardCondition guard
 from NewOrNewArrayExpr newExpr, Element element, string msg, string elementString
 where
   not newExpr.isFromUninstantiatedTemplate(_) and
+  not newExpr.isFromTemplateInstantiation(_) and
   (
     noThrowInTryBlock(newExpr, element) and
     msg = "This allocation cannot throw. $@ is unnecessary." and

cpp/ql/test/query-tests/Security/CWE/CWE-570/IncorrectAllocationErrorHandling.expected

@@ -14,7 +14,6 @@
 | test.cpp:93:15:93:41 | new[] | This allocation cannot throw. $@ is unnecessary. | test.cpp:97:36:98:3 | { ... } | This catch block |
 | test.cpp:96:10:96:36 | new[] | This allocation cannot throw. $@ is unnecessary. | test.cpp:97:36:98:3 | { ... } | This catch block |
 | test.cpp:160:9:160:24 | new | This allocation cannot throw. $@ is unnecessary. | test.cpp:161:15:161:18 | { ... } | This catch block |
-| test.cpp:178:12:178:25 | new | This allocation cannot throw. $@ is unnecessary. | test.cpp:179:17:181:3 | { ... } | This catch block |
 | test.cpp:229:15:229:35 | new | This allocation cannot throw. $@ is unnecessary. | test.cpp:231:16:231:19 | { ... } | This catch block |
 | test.cpp:242:14:242:34 | new | This allocation cannot throw. $@ is unnecessary. | test.cpp:243:34:243:36 | { ... } | This catch block |
 | test.cpp:276:17:276:31 | new[] | This allocation cannot return null. $@ is unnecessary. | test.cpp:277:8:277:12 | ! ... | This check |

cpp/ql/test/query-tests/Security/CWE/CWE-570/test.cpp

@@ -175,7 +175,7 @@ template<typename F> F *test_template_platement_new() {
   char buffer[1024];
 
   try {
-    return new (buffer) F; // GOOD: `F` constructor might throw (when `F` is `Foo`) [FALSE POSITIVE]
+    return new (buffer) F; // GOOD: `F` constructor might throw (when `F` is `Bar`)
   } catch (...) {
     return 0;
   }