SI-8609 Fix flattening of definitions and imports in quasiquotes

Quasiquotes allow to unquote trees with ..$ with block flattening
semantics to simplify composition:

  val onetwo = q"1; 2"
  val onetwothree = q"..$onetwo; 3" // same as q"1; 2; 3"

If there is no block it will be equivalent to $ unquoting:

  val one = q"1"
  val onetwo = q"..$one; 2" // same as q"1; 2"

But the inconsistency here is that currently only terms support
this single-element semantics. This commit extends this functionality
to also support definitions and imports. So that following code works:

  val q1 = q"val x = 1"
  val q2 = q"..$q1; val y = 2" // same as q"val x = 1; val y = 2"

1 files changed, 12 insertions, 0 deletions

diff --git a/test/files/scalacheck/quasiquotes/TermConstructionProps.scala b/test/files/scalacheck/quasiquotes/TermConstructionProps.scala
index 45392de582..409f07037e 100644
--- a/test/files/scalacheck/quasiquotes/TermConstructionProps.scala
+++ b/test/files/scalacheck/quasiquotes/TermConstructionProps.scala
@@ -310,4 +310,16 @@ object TermConstructionProps extends QuasiquoteProperties("term construction") {
     val cases = List(cq"a => b", cq"c => d")
     assertEqAst(q"{ case ..$cases }", "{ case a => b case c => d }")
   }
+
+  property("SI-8609 a") = test {
+    val q1 = q"val x = 1"
+    val q2 = q"..$q1; val y = 2"
+    assert(q2 ≈ q"{ val x = 1; val y = 2 }")
+  }
+
+  property("SI-8609 b") = test {
+    val q1 = q"import foo.bar"
+    val q2 = q"..$q1; val y = 2"
+    assert(q2 ≈ q"{ import foo.bar; val y = 2 }")
+  }
 }