A2-10-5: id name reuse false positive with template specialization

[fjatWbyT]

Affected rules

• A2-10-5

Description

Variable template defined with an specialization is alerted as identifier reuse.

Example

template<typename T, typename S>
extern constexpr bool x = false;

template<typename T>
extern constexpr bool x<T, int> = true;

Query IdentifierNameOfANonMemberObjectWithExternalOrInternalLinkageIsReused.ql warns about x in lines 2 and 5.

[fjatWbyT]

Fix proposal: I think that template specializations could be added as an exception, although I am unsure how to capture that. I also wondered whether it should be using the template instantiated or instantiation CodeQL classes.

[lcartey]

Thanks! I agree, we should ignore specializations.

The standard library currently does not provide a variable template specialization class, but this can be implemented in CodeQL by looking for uninstantiated templates where one or more template arguments have been provided.