[clang] [Clang][Sema] Abbreviated function templates do not append invented parameters to empty template parameter lists (PR #80864)

[Erich Keane via cfe-commits]

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@@ -9759,7 +9759,7 @@ Sema::ActOnFunctionDeclarator(Scope *S, Declarator &D, DeclContext *DC,
   SmallVector<TemplateParameterList *, 4> TemplateParamLists;
   llvm::append_range(TemplateParamLists, TemplateParamListsRef);
   if (TemplateParameterList *Invented = D.getInventedTemplateParameterList()) {
-    if (!TemplateParamLists.empty() &&
+    if (!TemplateParamLists.empty() && TemplateParamLists.back()->size() &&
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erichkeane wrote:

```suggestion
    if (!TemplateParamLists.empty() && !TemplateParamLists.back()->empty() &&
```

https://github.com/llvm/llvm-project/pull/80864