Separate compilation of traits broken when using -optimised

[scabug]

Separate compilation of traits is broken when implementation classes are loaded by the front end. Currently that happens only when -optimised is on. The result is a broken constructor signature in the trait initializer.

$$ bscalac -d build/optimised/classes/compiler/ src/compiler/scala/tools/nsc/symtab/Symbols.scala -optimise
$$ oscalac -help
Exception in thread "main" java.lang.NoSuchMethodError: scala.tools.nsc.symtab.Symbols$$class.$$init$$(Lscala/tools/nsc/symtab/SymbolTable;)V
	at scala.tools.nsc.symtab.SymbolTable.<init>(SymbolTable.scala:12)
	at scala.tools.nsc.Global.<init>(Global.scala:35)
	at scala.tools.nsc.Main$$compiler$$3$$.<init>(Main.scala:57)
	at scala.tools.nsc.Main$$.compiler$$2(Main.scala:57)
	at scala.tools.nsc.Main$$.process(Main.scala:64)
	at scala.tools.nsc.Main$$.main(Main.scala:87)

(bscalac and oscalac are aliases for build/quick/scalac and build/optimised/bin/scalac)

[scabug]

Imported From: https://issues.scala-lang.org/browse/SI-1995?orig=1
Reporter: @dragos

[scabug]

@dragos said:
Fixed in r18643.