ERROR: null value cannot be assigned to variable "x" declared NOT NULL

CONTEXT: PL/pgSQL function inline_code_block line 3 during statement block local variable initialization

-- Check that variables are reinitialized on block re-entry.

\set VERBOSITY terse \\ -- needed for output stability

do $$

begin

for i in 1..3 loop

NOTICE: y = 3

NOTICE: r = <NULL>

NOTICE: c = <NULL>

\set VERBOSITY default

-- Check enforcement of domain constraints during initialization

do $$

declare x int_nn; -- fail

\set VERBOSITY terse \\-- needed for output stability

do $$

for iin1..3 loop

end;

end loop;

end$$;

\set VERBOSITY default