[clang] [clang] require template arg list after template kw (PR #80801)

[Davis Herring via cfe-commits]

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@@ -1414,7 +1414,7 @@ namespace dr96 { // dr96: no
     // FIXME: This is ill-formed, because 'f' is not a template-id and does not
     // name a class template.
     // FIXME: What about alias templates?
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opensdh wrote:

The alias template case was aligned with the class-template case as part of [CWG1710](https://cplusplus.github.io/CWG/issues/1710.html).

https://github.com/llvm/llvm-project/pull/80801