Contexts in which pack expansions can occur

Question

There is a clear and comprehensible list of contexts in which a pack expansion can occur on cppreference.com. What I am trying to do is to derive the same information from the standard, partly to gain experience in using the standard. However, I am unable to derive all pack expansion contexts listed on cppreference.com from the standard.

cppreference.com lists, among others, the following four contexts: function argument lists, template argument lists, function parameter lists and template parameter lists.

On the other hand, the standard says (14.5.3.4):

A pack expansion consists of a pattern and an ellipsis, the instantiation of which produces zero or more instantiations of the pattern in a list (described below). The form of the pattern depends on the context in which the expansion occurs. Pack expansions can occur in the following contexts:

• In a function parameter pack (8.3.5); the pattern is the parameter-declaration without the ellipsis.
• In a template parameter pack that is a pack expansion (14.1):
  • if the template parameter pack is a parameter-declaration; the pattern is the parameter-declaration without the ellipsis;
  • if the template parameter pack is a type-parameter with a template-parameter-list; the pattern is the corresponding type-parameter without the ellipsis.
• ...
• In a template-argument-list (14.3); the pattern is a template-argument.
• ...

I am unable to find out where the standard says that pack expansion can occur in function argument lists. I suppose this context is somehow covered by one of the three bullet points quoted above.

Just in case it is unclear what I mean by pack expansions in function argument lists, consider the following example:

template <typename ...Args> void f(Args ...args) {}
template <typename ...Args> void g(Args ...args) {
  f(args...); // Pack expansion in a function argument list.
}

Answer 1

A function argument list is syntactically an initializer-list¹, so it's covered by [temp.variadic]/(4.4):

In an initializer-list; the pattern is an initializer-clause.

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_{1. The grammar of a function call is postfix-expression ( expression-listopt). And an expression-list is just an initializer-list. ([expr.post])}