scala - Test if implicit exists -

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is possible on compile time using macros test if exists implicit current type ?

something 

def packone(tpe:c.universe.type,....) = {   if(tpe =:= bytetpe ) makeast1   else if (tpe =:= longtpe ) makeast2   else if (tpe =:= c.typeof[java.lang.string]) makeast3   ....   else exists implicit convention tpe {    q"""   // call function implicit pack[t]    implicitly[packer[$tpe]].pack(...)   """   } else {   // make default conversion   }   }

it should possible use inferimplicitvalue:

val t = c.internal.typeref(noprefix, typeof[packer[_]].typesymbol, list(tpe)) c.inferimplicitvalue(t) match {   case emptytree => … // default conversion   case packer => q"packer.pack(…)" }

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