test case closes SI-6047

The bug is not reproducible both in M4 and in M5.

Author: xeno-by

test/files/pos/t6047.flags

@@ -0,0 +1 @@
+-language:experimental.macros

test/files/pos/t6047.scala

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+import scala.reflect.makro.Context
+import java.io.InputStream
+
+object Macros {
+   def unpack[A](input: InputStream): A = macro unpack_impl[A]
+
+   def unpack_impl[A: c.TypeTag](c: Context)(input: c.Expr[InputStream]): c.Expr[A] = {
+     import c.universe._
+
+     def unpackcode(tpe: c.Type): c.Expr[_] = {
+       if (tpe <:< implicitly[c.AbsTypeTag[Traversable[_]]].tpe) {
+
+       }
+       ???
+     }
+
+     unpackcode(c.typeOf[A])
+     ???
+   }
+ }