<code>T</code> is a <a href="#Numeric_types">floating-point type</a> and <code>x</code> can be rounded to <code>T</code>'s
precision without overflow. Rounding uses IEEE 754 round-to-even rules but with an IEEE
negative zero further simplified to an unsigned zero. Note that constant values never result
in an IEEE negative zero, NaN, or infinity.
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<li>
<code>T</code> is a complex type, and <code>x</code>'s