From: Tom Lane <tgl@sss.pgh.pa.us>
To: "Delaney, Ed" <Ed.Delaney@ellucian.com>
cc: "pgsql-bugs@lists.postgresql.org" <pgsql-bugs@lists.postgresql.org>
Subject: Re: Postgres 13.5 out parameter argument with explicit cast fails
 with argument is not writable
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Comments: In-reply-to "Delaney, Ed" <Ed.Delaney@ellucian.com>
	message dated "Tue, 15 Feb 2022 18:12:29 +0000"
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Date: Tue, 15 Feb 2022 13:17:57 -0500
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"Delaney, Ed" <Ed.Delaney@ellucian.com> writes:
> I could not find a reference to this change in the release notes, but si=
nce it is a breaking change, perhaps it should be noted?

The 2021-11-11 release notes all say

  * Don't discard a cast to the same type with unspecified type modifier (=
Tom Lane)

    For example, if column f1 is of type numeric(18,3), the parser used to
    simply discard a cast like f1::numeric, on the grounds that it would
    have no run-time effect. That's true, but the exposed type of the
    expression should still be considered to be plain numeric, not
    numeric(18,3). This is important for correctly resolving the type of
    larger constructs, such as recursive UNIONs.

			regards, tom lane