Either expand to an IfExpr to special-case the non-numbers or use number() to force explicit conversions and obtain NaN as under 1.0.

或者扩展 IfExpr 引入非数字的特殊情况，或者像 1.0 那样使用 number() 强制显式转换得到 NaN。

youdao

Generics are useful because they provide stronger compile-time type checking, require fewer explicit conversions between data types, and reduce the need for boxing operations and run-time type checks.

泛型相当有用，因为他们提供强制的编译时类型检查，要求更少的数据类型之间的显式转换，并减少装箱拆箱的操作和运行时类型检查。

youdao

Explicit conversion is required by some compilers to support narrowing conversions.

有些编译器需要显式转换来支持收缩转换。

youdao