Merge pull request github#1965 from jbj/bitfield-template

C++: Ignore templates in AmbiguouslySignedBitField.ql

Author: rdmarsh2

cpp/ql/src/Likely Bugs/AmbiguouslySignedBitField.ql

@@ -28,7 +28,8 @@ where
   not bf.getType().hasName("BOOL") and
   // If this is true, then there cannot be unsigned sign extension or overflow.
   not bf.getDeclaredNumBits() = bf.getType().getSize() * 8 and
-  not bf.isAnonymous()
+  not bf.isAnonymous() and
+  not bf.isFromUninstantiatedTemplate(_)
 select bf,
   "Bit field " + bf.getName() + " of type " + bf.getUnderlyingType().getName() +
     " should have explicitly unsigned integral, explicitly signed integral, or enumeration type."

cpp/ql/test/query-tests/Likely Bugs/AmbiguouslySignedBitField/test.cpp

@@ -25,3 +25,10 @@ struct {
     myEnum nosignenum : 2;
     const myEnum constnosignenum : 2;
 };
+
+template<typename T>
+struct TemplateWithBitfield {
+  T templatesign : 2; // GOOD
+};
+
+TemplateWithBitfield<signed int> twb;