Fixes @unchecked warnings

Author: allanrenucci

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

@@ -159,7 +159,7 @@ class TreeBuffer extends TastyBuffer(50000) {
       val tree = it.next
       treeAddrs.get(tree) match {
         case addr: Addr => treeAddrs.put(tree, adjusted(addr))
-        case addrs: List[Addr] => treeAddrs.put(tree, addrs.map(adjusted))
+        case addrs: List[Addr @unchecked] => treeAddrs.put(tree, addrs.map(adjusted))
       }
     }
   }

compiler/src/dotty/tools/dotc/transform/PostTyper.scala

@@ -264,9 +264,9 @@ class PostTyper extends MacroTransform with IdentityDenotTransformer  { thisTran
               ctx.error(s"${ident.name} is not a member of ${expr.show}", ident.pos)
           }
           selectors.foreach {
-            case ident: Ident                 => checkIdent(ident)
-            case Thicket((ident: Ident) :: _) => checkIdent(ident)
-            case _                            =>
+            case ident @ Ident(_)                 => checkIdent(ident)
+            case Thicket((ident @ Ident(_)) :: _) => checkIdent(ident)
+            case _                                =>
           }
           super.transform(tree)
         case tree =>

compiler/src/dotty/tools/dotc/transform/TreeChecker.scala

@@ -145,7 +145,7 @@ class TreeChecker extends Phase with SymTransformer {
     override def checkDerivedValueClass(clazz: Symbol, stats: List[Tree])(implicit ctx: Context) = ()
 
     def withDefinedSym[T](tree: untpd.Tree)(op: => T)(implicit ctx: Context): T = tree match {
-      case tree: DefTree =>
+      case tree: DefTree @unchecked =>
         val sym = tree.symbol
         assert(isValidJVMName(sym.name), s"${sym.fullName} name is invalid on jvm")
         everDefinedSyms.get(sym) match {

compiler/src/dotty/tools/dotc/typer/ProtoTypes.scala

@@ -539,7 +539,7 @@ object ProtoTypes {
   /** Dummy tree to be used as an argument of a FunProto or ViewProto type */
   object dummyTreeOfType {
     def apply(tp: Type): Tree = untpd.Literal(Constant(null)) withTypeUnchecked tp
-    def unapply(tree: Tree): Option[Type] = tree match {
+    def unapply(tree: Tree @unchecked): Option[Type] = tree match {
       case Literal(Constant(null)) => Some(tree.typeOpt)
       case _ => None
     }