On 8th of November, Tom Lane committed patch, which doesn't provide any new features, but removes one of the more annoying footguns in PostgreSQL:
Prevent invoking I/O conversion casts via functional/attribute notation. PG 8.4 added a built-in feature for casting pretty much any data type to string types (text, varchar, etc). We allowed this to work in any of the historically-allowed syntaxes: CAST(x AS text), x::text, text(x), or x.text. However, multiple complaints have shown that it's too easy to invoke such casts unintentionally in the latter two styles, particularly field selection. To cure the problem with the narrowest possible change of behavior, disallow use of I/O conversion casts from composite types to string types via functional/attribute syntax. The new functionality is still available via cast syntax. In passing, document the equivalence of functional and attribute syntax in a more visible place.