Avoid mismatched symbols in fields phase

The info of the var that stores a trait's lazy val's computed value
is expressed in terms of symbols that exist before the fields phase.
When we're implementing the lazy val in a subclass of that trait,
we now see symbols created by the fields phase, which results
in mismatches between the types of the lhs and rhs in the assignment
of `lazyVar = super.lazyImpl`.

So, type check the super-call to the trait's lazy accessor before our
own phase. If the lazy var's info depends on a val that is now
implemented by an accessor synthesize by our info transformer,
we'll get a mismatch when assigning `rhs` to `lazyVarOf(getter)`,
unless we also run before our own phase (like when we were
creating the info for the lazy var).

This was revealed by Hanns Holger Rutz's efforts in compiling
scala-refactoring's test suite (reported on scala-internals).

Fixes scala/scala-dev#219

1 files changed, 11 insertions, 0 deletions

diff --git a/test/files/pos/sd219.scala b/test/files/pos/sd219.scala
new file mode 100644
index 0000000000..3c3f4962f0
--- /dev/null
+++ b/test/files/pos/sd219.scala
@@ -0,0 +1,11 @@
+class Global { class Name }
+
+trait CommonPrintUtils {
+  val global: Global 
+  
+  lazy val precedence: global.Name => Int = ???
+}
+
+trait CompilerProvider {  val global: Global = ??? }
+    
+class AbstractPrinter extends CommonPrintUtils with CompilerProvider 
\ No newline at end of file