Imported From: https://issues.scala-lang.org/browse/SI-6842?orig=1
Reporter: @xeno-by
Affected Versions: 2.11.0-M4

@xeno-by said:
When closing this bug, update the docs at http://docs.scala-lang.org/overviews/macros/quasiquotes.html

@densh said:
We've discussed this point a few times. IMO type errors here make sense. I would personally love to have more of them, not less.

@xeno-by said:
I agree that it'd be nice to have more static guarantees when assembling trees. However, this particular initiative seems premature to me, because a lot of our tree-related APIs work with raw Tree's, which means that return values of such APIs would require casting just to satisfy the quasiquoting engine.

This seems somewhat related to the situation with methods like Symbol.typeParams in the reflection API. The idea to move typeParams to TypeSymbol was, in principle, a good one. However, the fact that most of our symbol-related APIs return raw Symbol, which resulted in necessity to do mechanical casting.

Here's another angle to view the situation. When we start using quasiquotes inside the compiler, we'll have to live with the fact that most of tree manipulation functions in the compiler return Tree, not specific subclasses of Tree. If quasiquotes are going to be too picky, we're going to have a lot of casting to do in the interim period.

@densh said:
densh/scala@59ee22c

@densh said:
Fixed in scala/scala#3255

@Blaisorblade said (edited on Jan 20, 2014 5:29:21 AM UTC):
Docs (http://docs.scala-lang.org/overviews/macros/quasiquotes.html) haven't been updated yet, and the example in http://docs.scala-lang.org/overviews/macros/quasiquotes.html still has two type errors:

1. the code must use name.toString.capitalize instead of name.capitalize. I guess that's an actual bug in the example code.
2. q"class $name extends AnyRef \{ ..$\{body ++ newdefs} }" is still missing a toList call, which might be an instance of this bug.

Hence, this should be reopened.

@densh said:
This bug has been fixed and works properly in 2.11-M8. It wasn't backported to macro paradise yet.

Documentation revamp is on my short list of things to be done before 2.11-RC1.

@adriaanm said:
Sounds like this can be closed then? Releasing M8, so I'd like everything with fix-by M8 to be closed :-)