to_regtype() Raises Error

The docs for `to_regtype()` say, “this function will return NULL rather than throwing an error if the name is not
found.”And it’s true most of the time: 

david=# select to_regtype('foo'), to_regtype('clam');
 to_regtype | to_regtype
------------+------------
 [null]     | [null]

But not others:

david=# select to_regtype('inteval second');
ERROR:  syntax error at or near "second"
LINE 1: select to_regtype('inteval second');
                ^
CONTEXT:  invalid type name "inteval second”

I presume this has something to do with not catching errors from the parser?

david=# select to_regtype('clam bake');
ERROR:  syntax error at or near "bake"
LINE 1: select to_regtype('clam bake');
             ^
CONTEXT:  invalid type name "clam bake"

Best,

David