From 1bff5703d28a0232dc772769dd6017862114a4a2 Mon Sep 17 00:00:00 2001
From: Paul Phillips <paulp@improving.org>
Date: Thu, 10 May 2012 13:44:29 -0700
Subject: More useful crash reports.

If you can't get your hands on something which crashes
scalac - I know, I know - you can try this ready-made crasher.

  % cat test/pending/pos/t4717.scala
  trait Bounds[@specialized A] {
    // okay without `>: A`
    def x[B >: A]: Unit = new Bounds[B] {
      lazy val it = ???  // def or val okay
      it
    }
  }

  % scalac -d /tmp test/pending/pos/t4717.scala
  error:
       while compiling: test/pending/pos/t4717.scala
          during phase: specialize
       library version: version 2.10.0-20120510-134429-ce1d68ed19
      compiler version: version 2.10.0-20120510-152646-ba4dfd1e63
    reconstructed args: -d /tmp

    last tree to typer: Select(This(trait Bounds$mcZ$sp), x$mcZ$sp)
                symbol: method x$mcZ$sp in trait Bounds$mcZ$sp (flags: override <method> <specialized>)
     symbol definition: override def x$mcZ$sp[B >: Boolean](): Unit
                   tpe: [B >: Boolean]()Unit
         symbol owners: method x$mcZ$sp -> trait Bounds$mcZ$sp -> package <empty>
        context owners: value it -> anonymous class $anon -> method x$mcZ$sp -> trait Bounds$mcZ$sp -> package <empty>

  == Enclosing template or block ==

  Block(
    Assign(
      $anon.this."it "
      Apply( // def ???(): Nothing in object Predef, tree.tpe=Nothing
        scala.this."Predef"."$qmark$qmark$qmark" // def ???(): Nothing in object Predef, tree.tpe=()Nothing
        Nil
      )
    )
    $anon.this."it " // lazy private[this] var it: Nothing, tree.tpe=Nothing
  )

  == Expanded type of tree ==

  PolyType(
    typeParams = List(TypeParam(B >: Boolean))
    resultType = NullaryMethodType(
      resultType = TypeRef(TypeSymbol(final class Unit extends AnyVal))
    )
  )

  // And then the usual stack trace
---
 test/pending/pos/t4717.scala | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

(limited to 'test/pending')

diff --git a/test/pending/pos/t4717.scala b/test/pending/pos/t4717.scala
index 43cf412bc6..7eaa3dd487 100644
--- a/test/pending/pos/t4717.scala
+++ b/test/pending/pos/t4717.scala
@@ -1,7 +1,7 @@
-trait Bug1[@specialized +A] extends TraversableOnce[A] {  
-  def ++[B >: A](that: TraversableOnce[B]): Iterator[B] = new Iterator[B] {
-    lazy val it = that.toIterator
-    def hasNext = it.hasNext
-    def next = it.next
+trait Bounds[@specialized A] {
+  // okay without `>: A`
+  def x[B >: A]: Unit = new Bounds[B] {
+    lazy val it = ???  // def or val okay
+    it
   }
 }
\ No newline at end of file
-- 
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