Function Error Response Is Not Clear

Some functions if they are missing the correct arguments give vague error messages while others give specific ones.

Specific error message example query 1:

SELECT sum();

Specific error message example output 1:
ERROR:  function sum() does not exist
LINE 1: SELECT sum();
                            ^
HINT:  No function matches the given name and argument types. You might need to add explicit type casts.

ERROR:  function lower() does not exist
LINE 1: SELECT lower();
                            ^
HINT:  No function matches the given name and argument types. You might need to add explicit type casts.

Vague error message example query 1:

SELECT nullif();

Vague error message example output 1:

ERROR:  syntax error at or near ")"
LINE 1: SELECT nullif();
                                    ^

These examples it is clear the function is the issue, but in my actual query there were many parentheses nearby so I thought I had mismatched parentheses for a while and it sent me hunting for the wrong thing wasting precious time on a production bugfix mid-crisis. I do not know if any other function besides NULLIF and COALESCE are affected by this. They are just the two I happened to test.

Best,

Luke