[temp.pre] Fix note about uniqueness of a template name in a scope #7284
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There appears to be no implementation divergence on the example between 4 compilers: https://godbolt.org/z/axe9j9eTr |
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Sorry, I don't understand the CI error about comments not being aligned. They seem aligned to me, even in the error message. |
See: Diagnostic could be WAY better there. |
Opened #7285 |
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... and please squash all commits and force-push. |
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Should be good to go now. |
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…clared in the same scope?" (#111446) [P1787R6](https://wg21.link/p1787r6): > [CWG110](https://cplusplus.github.io/CWG/issues/110.html) is resolved by reducing the restriction in [temp.pre] to a note (matching the behavior of GCC, Clang, and ICC). Wording: see changes to [temp.pre]/7 I believe the wording for the questions raised in the issue is now the definition of corresponding declarations that is given in [[basic.scope.scope]/4](https://eel.is/c++draft/basic.scope#scope-4): > Two declarations correspond if they (re)introduce the same name, both declare constructors, or both declare destructors, unless > — either is a using-declarator, or > — one declares a type (not a typedef-name) and the other declares a variable, non-static data member other than of an anonymous union ([class.union.anon]), enumerator, function, or function template, or > — each declares a function or function template and they do not declare corresponding overloads. Then it's used as an input for the definition of potentially conflicting declarations given in [[basic.scope.scope]/6](https://eel.is/c++draft/basic.scope#scope-6). Answering the question in the title: yes, having a function template and a type with the same name that has the same target scope is well-formed. A keen eye might spot that the current [[temp.pre]/7](https://eel.is/c++draft/temp.pre#7) note doesn't reflect all of the exceptions from the definition of corresponding declarations in [basic.scope.scope]/4, namely 4.1 and 4.2. I believe the note is defective, and I opened an editorial PR against the draft to fix that: cplusplus/draft#7284.
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@jensmaurer Do you want me to do any further changes? |
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https://eel.is/c++draft/temp.pre#7 was normative wording that was converted into a note by P1787R6. The first half of it reads:
I think it refers to wording about which declarations correspond (and consequently might conflict, rendering the program ill-formed), but it only reflects [basic.scope.scope]/4.3. The problem is that it's worded in a way that claims completeness, despite omitting 4.1 (using-declarators) and 4.2 (types not conflicting with non-types, including function templates).
This PR makes the note complete, and adds an example that focuses on function templates.