How do I get the type from an Ident() in a macro?

Question

I'm trying to write a generic macro in which I can grab any trees that match foo.bar, but only where foo is a Foo. I only need to look inside the enclosing class where the macro is called. So far I have this:

def getFooTrees[T](): Unit = macro getFooTrees_impl[T]

def getFooTrees_impl[T: c.WeakTypeTag](c: Context)(): c.Expr[Unit] = {
  import c.universe._

  val receiverType = implicitly[c.WeakTypeTag[T]].tpe
  val terms = c.enclosingClass  
    .filter { t =>
      t match {
        case Select(ident: Ident, name: TermName) if (??? == receiverType) =>
          true
        case _ =>
          false
      }
    }

  ...etc

}

How do I check the type of what ident refers to? Sorry if I'm totally lost in the woods here.

Huh - that seems right, but it's also null sometimes. I can update the code with the enclosing class I'm using to test, if that's helpful. — colinmarc, Aug 05 '14 at 07:47
Also, if I `showRaw(ident.tpe)`, it looks like `SingleType(NoPrefix, newTermName("bar"))`. I'm not quite sure what to do with that — colinmarc, Aug 05 '14 at 08:06
tpe is null if the tree isn't typechecked yet (see http://stackoverflow.com/questions/20936509/scala-macros-what-is-the-difference-between-typed-aka-typechecked-an-untyped for more information). — Eugene Burmako, Aug 05 '14 at 09:48
If you elaborate on what you need the tpe for, I could help you with that as well. — Eugene Burmako, Aug 05 '14 at 09:48

score 0 · Answer 1 · answered Apr 29 '21 at 09:34

0

Question probably long dormant but I had same problem

val ident: Ident = ... 
ident.tpe  // is null

val tree2 = c.typecheck(tree = ident,mode = c.TYPEmode)
tree2.tpe  // not null

answered Apr 29 '21 at 09:34

Friggles

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How do I get the type from an Ident() in a macro?

1 Answers1