Merge pull request #2458 from dotty-staging/fix-2396b

Fix #2454: Non-static synthetic case-objects should be initialized early

Author: nicolasstucki

compiler/src/dotty/tools/dotc/transform/Constructors.scala

@@ -252,9 +252,17 @@ class Constructors extends MiniPhaseTransform with IdentityDenotTransformer { th
       case _ => superCalls
     }
 
+    // Lazy Vals may decide to create an eager val instead of a lazy val
+    // this val should be assigned before constructor body code starts running
+
+    val (lazyAssignments, stats) = followConstrStats.partition {
+      case Assign(l, r) if l.symbol.name.is(NameKinds.LazyLocalName) => true
+      case _ => false
+    }
+
     cpy.Template(tree)(
       constr = cpy.DefDef(constr)(
-        rhs = Block(copyParams ::: mappedSuperCalls ::: followConstrStats, unitLiteral)),
+        rhs = Block(copyParams ::: mappedSuperCalls ::: lazyAssignments ::: stats, unitLiteral)),
       body = clsStats.toList)
   }
 }

tests/run/i2396b.scala

@@ -0,0 +1,14 @@
+class Bees {
+  def f: PartialFunction[Bee, Unit] = {  case Bee(_) => ""  }
+
+  f(new Bee("buzz"))
+
+  case class Bee(value: String)
+  //object Bee // With this it works
+}
+
+object Test {
+  def main(args: Array[String]): Unit = {
+    new Bees
+  }
+}