Move reporting logic into Reporting trait

Move code from Global/SymbolTable to separate Reporting traits to
start carving out an interface in scala.reflect.internal.Reporting,
with internals in scala.tools.nsc. Reporting is mixed into the cake.
It contains a nested class PerRunReporting.

Should do the same for debugging/logging.

The idea is that CompilationUnit and Global forward all reporting
to Reporter. The Reporting trait contains these forwarders, and
PerRunReporting, which accumulates warning state during a run.

In the process, I slightly changed the behavior of `globalError`
in reflect.internal.SymbolTable: it used to abort, weirdly.
I assume that was dummy behavior to avoid introducing an abstract method.
It's immediately overridden in Global, and I couldn't find any other subclasses,
so I don't think the behavior in SymbolTable was ever observed.

Provide necessary hooks for scala.reflect.macros.Parsers#parse.
See scala/reflect/macros/contexts/Parsers.scala's parse method,
which overrides the reporter to detect when parsing goes wrong.
This should be refactored, but that goes beyond the scope of this PR.

Don't pop empty macro context stack.
(Ran into this while reworking -Xfatal-warnings logic.)

Fix -Xfatal-warnings behavior (and check files): it wasn't meant to
influence warning reporting, except for emitting one final error;
if necessary to fail the compile (when warnings but no errors were reported).
Warnings should stay warnings.

This was refactored in fbbbb22946, but we soon seem to have relapsed.
An hour of gitfu did not lead to where it went wrong. Must've been a merge.

1 files changed, 2 insertions, 2 deletions

diff --git a/src/compiler/scala/tools/nsc/typechecker/Macros.scala b/src/compiler/scala/tools/nsc/typechecker/Macros.scala
index ef74beec62..9c22688581 100644
--- a/src/compiler/scala/tools/nsc/typechecker/Macros.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/Macros.scala
@@ -714,7 +714,7 @@ trait Macros extends MacroRuntimes with Traces with Helpers {
 
   sealed abstract class MacroStatus(val result: Tree)
   case class Success(expanded: Tree) extends MacroStatus(expanded)
-  case class Fallback(fallback: Tree) extends MacroStatus(fallback) { currentRun.seenMacroExpansionsFallingBack = true }
+  case class Fallback(fallback: Tree) extends MacroStatus(fallback) { currentRun.reporting.seenMacroExpansionsFallingBack = true }
   case class Delayed(delayed: Tree) extends MacroStatus(delayed)
   case class Skipped(skipped: Tree) extends MacroStatus(skipped)
   case class Failure(failure: Tree) extends MacroStatus(failure)
@@ -788,7 +788,7 @@ trait Macros extends MacroRuntimes with Traces with Helpers {
           }
         } catch {
           case ex: Throwable =>
-            popMacroContext()
+            if (openMacros.nonEmpty) popMacroContext() // weirdly we started popping on an empty stack when refactoring fatalWarnings logic
             val realex = ReflectionUtils.unwrapThrowable(ex)
             realex match {
               case ex: AbortMacroException => MacroGeneratedAbort(expandee, ex)