scala - Implicit conversion not working -

why following implicit method not applied? , how can achieve automatically convert instance of x instance of y while having implicit conversion[x,y] in scope.

trait conversion[x, y] {   def apply(x: x): y } implicit object str2intconversion extends conversion[string, int] {   def apply(s: string): int = s.size } implicit def convert[x, y](x: x)(implicit c: conversion[x, y]): y = c(x)  val s = "hello" val i1: int = convert(s) val i2: int = s // type mismatch; found: string  required: int 

make conversion extend function1, don't need helper method anymore:

trait conversion[x, y] extends (x => y) {   def apply(x: x): y }  // unchanged implicit object str2intconversion extends conversion[string, int] {   def apply(s: string): int = s.size }  // removed convert  // unchanged val s = "hello" val i1: int = convert(s) val i2: int = s