Merge branch 'wip/bring-forward': Incremental compilation

1) Make definitions load symbols in current run
2) Change handling of invalid parents. Instead of a copied denotation, we now invalidate the caches of the existing one. (Copying was not enough, as old versions of denotations kept leaking in).

1 files changed, 17 insertions, 4 deletions

diff --git a/src/dotty/tools/dotc/typer/Typer.scala b/src/dotty/tools/dotc/typer/Typer.scala
index f48dfa09b..697441ca1 100644
--- a/src/dotty/tools/dotc/typer/Typer.scala
+++ b/src/dotty/tools/dotc/typer/Typer.scala
@@ -63,12 +63,25 @@ class Typer extends Namer with Applications with Implicits {
    */
   private var importedFromRoot: Set[Symbol] = Set()
 
+ /** A denotation exists really if it exists and does not point to a stale symbol.
+  def reallyExists(denot: Denotation)(implicit ctx: Context): Boolean = denot match {
+    case denot: SymDenotation =>
+      denot.ensureCompleted
+      denot.exists && !denot.isAbsent
+    case _ =>
+      true
+  }*/
+
   /** A denotation exists really if it exists and does not point to a stale symbol. */
   def reallyExists(denot: Denotation)(implicit ctx: Context): Boolean =
-    denot.exists && {
-      val sym = denot.symbol
-      sym.ensureCompleted
-      (sym eq NoSymbol) || !sym.isAbsent
+    try
+      denot.exists && {
+        val sym = denot.symbol
+            sym.ensureCompleted
+            (sym eq NoSymbol) || !sym.isAbsent
+      }
+    catch {
+      case ex: StaleSymbol => false
     }
 
   /** The type of a selection with `name` of a tree with type `site`.