#### 12.2.51 upgraded-complex-part-type [Function]

`upgraded-complex-part-type` typespec &optional environment ⇒ upgraded-typespec

#### Arguments and Values::

typespec—a type specifier.

environment—an environment object. The default is nil, denoting the null lexical environment and the and current global environment.

upgraded-typespec—a type specifier.

#### Description::

upgraded-complex-part-type returns the part type of the most specialized complex number representation that can hold parts of type typespec.

The typespec is a subtype of (and possibly type equivalent to) the upgraded-typespec.

The purpose of upgraded-complex-part-type is to reveal how an implementation does its upgrading.

#### See Also::

complex (function and type)

#### Notes::