Decimal.fromFixedDecimal

Decimal fromFixedDecimal(
          I,  int  Scale)(
          const  FixedDecimal!(
          I,  Scale)  fd,  ref  DecimalContext ctx)

static @safe

Construction from any FixedDecimal form via its exact text (18/38-digit fixed versus 16/34-digit IEEE boundaries resolve through the context; no fixed-arithmetic coupling).