Fixed SI-6092. Fixed leaky annotations, and relaxed the conditions under which a try-catch is lifted

out to an inner method.

Less known fact: lazy values null-out their dependent values is their accessed only from
their initializer. The analysis is not context-dependent (meaning the owner where a reference
happens needs to be exactly that lazy value).

* Removed no-op code around positions in `LazyAnnotationInfo`
* Don't lift expressions that have no `catch` clause

The two changes combined fix a memory leak that's been plaguing the IDE: an annotation
(even when forced) would hang on to a namer, through the outer field of its call-by-name
parameter.

The test for the memory leak is in the IDE project (couldn't find a simple way to reproduce it outside
the IDE), but there's a test checking that the field is null after initialization.

1 files changed, 1 insertions, 6 deletions

diff --git a/src/reflect/scala/reflect/internal/AnnotationInfos.scala b/src/reflect/scala/reflect/internal/AnnotationInfos.scala
index c283ae408e..2bcc95b9a8 100644
--- a/src/reflect/scala/reflect/internal/AnnotationInfos.scala
+++ b/src/reflect/scala/reflect/internal/AnnotationInfos.scala
@@ -160,12 +160,7 @@ trait AnnotationInfos extends api.AnnotationInfos { self: SymbolTable =>
    */
   final class LazyAnnotationInfo(lazyInfo: => AnnotationInfo) extends AnnotationInfo {
     private var forced = false
-    private lazy val forcedInfo =
-      try {
-        val result = lazyInfo
-        if (result.pos == NoPosition) result setPos pos
-        result
-      } finally forced = true
+    private lazy val forcedInfo = try lazyInfo finally forced = true
 
     def atp: Type                               = forcedInfo.atp
     def args: List[Tree]                        = forcedInfo.args