A declarator may be parenthesized as described in [dcl.meaning.general] p8.

Therefore, this sentence ensures that parenthesized declarators are allowed.

"A declarator may be parenthesized as described in [dcl.meaning.general] p8."

[dcl.fct.def.general]/2 is about declarator, but [dcl.meaning.general]/8 is about declarator-id not declarator.

"Therefore, this sentence ensures that parenthesized declarators are allowed."

I simply cannot understand the relationship between the alluded sentence and what you wrote above. Could you elaborate?

[dcl.meaning.general] p8 "In a declaration T D where D has the form ..."

Compare with [dcl.meaning.general] p5, which says that "D" is a declarator. Note that p8 talks about the declarator-id (possibly deep) inside D and assumes the understanding of p5.

"Compare with [dcl.meaning.general] p5, which says that "D" is a declarator. Note that p8 talks about the declarator-id (possibly deep) inside D and assumes the understanding of p5."

Ok, I can accept this. But how does the sentence highlighted in my first post ensure that parenthesized declarators are allowed?

Because it says that "T declarator" (with T=void or absent), with the declarator from the constructor grammar, must be a valid function declaration. In order to analyze this, you need to iterate through [dcl.meaning], which (among other things) takes care of "T (declarator)".

In a function-definition, either void declarator ; or declarator ; shall be a well-formed function declaration
as described in [dcl.fct].

It definitely doesn't tell me anything. I'm giving up !