parse
DECLARE
  x STRING := e'1GW\'';
BEGIN
  INSERT INTO tab SELECT e'1GW\'';
END
----
DECLARE
x STRING := e'1GW\'';
BEGIN
INSERT INTO tab SELECT e'1GW\'';
END;
 -- normalized!
DECLARE
x STRING := (e'1GW\'');
BEGIN
INSERT INTO tab SELECT (e'1GW\'');
END;
 -- fully parenthesized
DECLARE
x STRING := '_';
BEGIN
INSERT INTO tab SELECT '_';
END;
 -- literals removed
DECLARE
_ STRING := e'1GW\'';
BEGIN
INSERT INTO _ SELECT e'1GW\'';
END;
 -- identifiers removed

parse
DECLARE
  x STRING := b'1GW\'';
BEGIN
  INSERT INTO tab SELECT b'1GW\'';
END
----
DECLARE
x STRING := b'1GW\'';
BEGIN
INSERT INTO tab SELECT b'1GW\'';
END;
 -- normalized!
DECLARE
x STRING := (b'1GW\'');
BEGIN
INSERT INTO tab SELECT (b'1GW\'');
END;
 -- fully parenthesized
DECLARE
x STRING := '_';
BEGIN
INSERT INTO tab SELECT '_';
END;
 -- literals removed
DECLARE
_ STRING := b'1GW\'';
BEGIN
INSERT INTO _ SELECT b'1GW\'';
END;
 -- identifiers removed

parse
DECLARE
  x STRING := x'deadbeef';
BEGIN
  INSERT INTO tab SELECT x'deadbeef';
END
----
DECLARE
x STRING := b'\xde\xad\xbe\xef';
BEGIN
INSERT INTO tab SELECT b'\xde\xad\xbe\xef';
END;
 -- normalized!
DECLARE
x STRING := (b'\xde\xad\xbe\xef');
BEGIN
INSERT INTO tab SELECT (b'\xde\xad\xbe\xef');
END;
 -- fully parenthesized
DECLARE
x STRING := '_';
BEGIN
INSERT INTO tab SELECT '_';
END;
 -- literals removed
DECLARE
_ STRING := b'\xde\xad\xbe\xef';
BEGIN
INSERT INTO _ SELECT b'\xde\xad\xbe\xef';
END;
 -- identifiers removed

parse
DECLARE
  x STRING := B'010101';
BEGIN
  INSERT INTO tab SELECT B'010101';
END
----
DECLARE
x STRING := B'010101';
BEGIN
INSERT INTO tab SELECT B'010101';
END;
 -- normalized!
DECLARE
x STRING := (B'010101');
BEGIN
INSERT INTO tab SELECT (B'010101');
END;
 -- fully parenthesized
DECLARE
x STRING := _;
BEGIN
INSERT INTO tab SELECT _;
END;
 -- literals removed
DECLARE
_ STRING := B'010101';
BEGIN
INSERT INTO _ SELECT B'010101';
END;
 -- identifiers removed

error
DECLARE
  x STRING := 'foo;
BEGIN
  RETURN x;
END
----
at or near ":": syntax error: unterminated string
DETAIL: source SQL:
DECLARE
  x STRING := 'foo;
           ^

error
DECLARE
  x STRING := $foo$ foo;
BEGIN
  RETURN x;
END
----
at or near ":": syntax error: unterminated string
DETAIL: source SQL:
DECLARE
  x STRING := $foo$ foo;
           ^
