Merge pull request #2187 from dotty-staging/fix-2166

fix #2166: unpickling of shared CaseDef

Author: odersky

compiler/src/dotty/tools/dotc/core/tasty/TreeUnpickler.scala

@@ -1059,7 +1059,13 @@ class TreeUnpickler(reader: TastyReader, tastyName: TastyName.Table, posUnpickle
       }
 
     def readCases(end: Addr)(implicit ctx: Context): List[CaseDef] =
-      collectWhile(nextByte == CASEDEF && currentAddr != end) { readCase()(ctx.fresh.setNewScope) }
+      collectWhile((nextByte == CASEDEF || nextByte == SHARED) && currentAddr != end) {
+        if (nextByte == SHARED) {
+          readByte()
+          forkAt(readAddr()).readCase()(ctx.fresh.setNewScope)
+        }
+        else readCase()(ctx.fresh.setNewScope)
+      }
 
     def readCase()(implicit ctx: Context): CaseDef = {
       val start = currentAddr

tests/pickling/i2166.scala

@@ -0,0 +1,5 @@
+object Test {
+  @inline def f = "" match { case _ => false }
+
+  def main(args: Array[String]): Unit = f
+}