Implicit conversion

A conversion inserted by the language's typing rules rather than an explicit conversion call in source code. Its availability depends on scope and the conversion rules; converting a method receiver and converting an argument are distinct uses. In Scala, an imported implicit conversion can supply a rational-number receiver for an integer expression lacking an applicable multiplication overload.

A language-defined conversion from a numeric type to another admitted numeric type, such as Scala's conversion of an Int argument to Double. It can make an overloaded method applicable even when the argument's static type differs from the parameter type. It does not imply a subtyping relationship between every pair of numeric types or exact representation of every source value; sufficiently large integers can lose precision in a floating-point target. ^[ref]