Added compiler crash recovery to the repl.

up it will issue some apologies and then replay the session up
to the crash line with a new compiler. If you combine this with
-Yrich-exceptions then you can induce a crash, see the exact path
through the code which led there, and then continue on your merry way as
if nothing happened.

// say ticket #4188 for example
% scala -Yrich-exceptions
scala> class A {
     |   object Ding
     |   class B {
     |     (null: Any) match { case _: Ding.type => () }
     |   }
     | }

assertion failed: Trying to access the this of another class: tree.symbol = class $read$$iw$$iw$A, ctx.clazz.symbol = class $read$$iw$$iw$A$B compilation unit:<console>
[searching for exception contexts...]
[GenICode.scala$tools$nsc$backend$icode$GenICode$ICodePhase$$genLoad]
 958:
 959:         case This(qual) =>
 960:           assert(tree.symbol == ctx.clazz.symbol || tree.symbol.isModuleClass,
*961:                  "Trying to access the this of another class: " +
 962:                  "tree.symbol = " + tree.symbol + ", ctx.clazz.symbol = " + ctx.clazz.symbol + " compilation unit:"+unit)
 963:           if (tree.symbol.isModuleClass && tree.symbol != ctx.clazz.symbol) {
 964:             if (settings.debug.value)

[GenICode.genLoadQualifier]
 1166:       tree match {
 1167:         case Select(qualifier, _) =>
 1168:           genLoad(qualifier, ctx, toTypeKind(qualifier.tpe))
*1169:         case _ =>
 1170:           abort("Unknown qualifier " + tree)
 1171:       }
 1172:
[...]
Attempting session recovery...

scala>

No review.

0 files changed, 0 insertions, 0 deletions