For <code>complex</code>, the two arguments must be of the same
<a href="#Numeric_types">floating-point type</a> and the return type is the
<a href="#Numeric_types">complex type</a>
with the corresponding floating-point constituents:
<code>complex64</code> for <code>float32</code> arguments, and
<code>complex128</code> for <code>float64</code> arguments.
If one of the arguments evaluates to an untyped constant, it is first implicitly