scala - Why "value.foreach(setValue(_.toInt))" can't be compiled -

scala code:

val value = some("100") value.foreach( println(_.toint) )   // !!! can't compiled 

the error message is:

missing parameter type expanded function ((x$1)=>x$1.toint)

why can't compiled?

ps: , following code valid:

value.foreach( _.toint ) value.foreach( x => println(x.toint) ) 

the compiler message bit misleading, provides hint: tells interpreted _.toint (x$1)=>x$1.toint. so, putting in place, get

value.foreach( println( (x$1)=>x$1.toint ) ) 

which not intended.

here's imo cleanest way solve issue:

value.map( _.toint ).foreach( println )