Proposed resolution (approved by CWG 2022-09-23):

Change in 9.3.3 [dcl.ambig.res] paragraph 1 as follows:

The ambiguity arising from the similarity between a function-style cast and a declaration mentioned in 8.9 [stmt.ambig] can also occur in the context of a declaration. In that context, the choice is between a function declaration with a redundant set of parentheses around a parameter name and an object declaration with a function-style cast as the initializer and a declaration involving a function declarator with a redundant set of parentheses around a parameter name. Just as for the ambiguities mentioned in 8.9 [stmt.ambig], the resolution is to consider any construct, such as the potential parameter declaration, that could possibly be a declaration to be a declaration.

Proposed resolution (2022-09-09) [SUPERSEDED]:

Change in 9.3.3 [dcl.ambig.res] paragraph 1 as follows:

... Just as for the ambiguities mentioned in 8.9 [stmt.ambig], the The resolution is to consider any construct that could possibly be a function declaration a function declaration.

[Accepted as a DR at the November, 2022 meeting.]

Subclause 9.3.3 [dcl.ambig.res] paragraph 1 specifies:

The ambiguity arising from the similarity between a function-style cast and a declaration mentioned in 8.9 [stmt.ambig] can also occur in the context of a declaration. In that context, the choice is between a function declaration with a redundant set of parentheses around a parameter name and an object declaration with a function-style cast as the initializer. Just as for the ambiguities mentioned in 8.9 [stmt.ambig], the resolution is to consider any construct that could possibly be a declaration a declaration.

The specification correctly describes an ambiguity between a function declaration and an object declaration, but resolves the ambiguity to a "declaration", which does not offer any insight.