New catalog doesn't resolve pg_catalog arguments properly

[maxhawkins]

CREATE FUNCTION f(x TIMESTAMPTZ) RETURNS void AS '' LANGUAGE sql;
CREATE FUNCTION f(x timestamp with time zone) RETURNS void AS '' LANGUAGE sql;

-- name: F :one
SELECT f(1);

Using the experimental parser, this SQL should return an error about a duplicate function. Instead it compiles with no issue.

The problem is TIMESTAMPTZ resolves to type timestamptz and timestamp with time zone resolves to pg_catalog.timestamptz. The catalog doesn't recognize that these refer to the same type, so it allows both functions to be created.

[maxhawkins]

Thanks for the fix!