Synthesize SAM from match-defined function literal

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Under -Xexperimental i get the following compilation error.

public interface Must {
  void musta(String str, int i);
}

object Mustare {
  def takesM(m: Must) = ???
  takesM{ (a, b) => println } // compiles 
  takesM{  
     case (a: String, b: Int) => println("")
  }
}

error: missing parameter type for expanded function
The argument types of an anonymous function must be fully known. (SLS 8.5)
Expected type was: Must
takesM{
^
one error found

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Imported From: https://issues.scala-lang.org/browse/SI-8429?orig=1
Reporter: Raul Bache (arneball)
Affected Versions: 2.11.0-RC1

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@retronym said:
Adriaan: I'm not sure whether we should support this or not. I can see the utility, but I think our SAM impl is approaching its complexity budget. Whatever you decide, we should mention patmat anon funs explicitly in the SIP

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@retronym said:
Reassinging to 2.11.5, 2.11.4 has already been released.

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@adriaanm said:
I think we should support this. It's an easy fix (both code & spec). WIP: https://github.com/scala/scala/compare/2.11.x...adriaanm:t8429?expand=1

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@lrytz said:
scala/scala#4945