Add @tailrec to avoid regressions.

2 files changed, 7 insertions, 3 deletions

diff --git a/compiler/src/dotty/tools/dotc/transform/ExplicitOuter.scala b/compiler/src/dotty/tools/dotc/transform/ExplicitOuter.scala
index d75c32fcc..44308012e 100644
--- a/compiler/src/dotty/tools/dotc/transform/ExplicitOuter.scala
+++ b/compiler/src/dotty/tools/dotc/transform/ExplicitOuter.scala
@@ -16,7 +16,9 @@ import SymUtils._
 import dotty.tools.dotc.ast.tpd
 import dotty.tools.dotc.core.Phases.Phase
 import util.Property
+
 import collection.mutable
+import scala.annotation.tailrec
 
 /** This phase adds outer accessors to classes and traits that need them.
  *  Compared to Scala 2.x, it tries to minimize the set of classes
@@ -367,7 +369,7 @@ object ExplicitOuter {
     def path(start: Tree = This(ctx.owner.lexicallyEnclosingClass.asClass),
              toCls: Symbol = NoSymbol,
              count: Int = -1): Tree = try {
-      def loop(tree: Tree, count: Int): Tree = {
+      @tailrec def loop(tree: Tree, count: Int): Tree = {
         val treeCls = tree.tpe.widen.classSymbol
         val outerAccessorCtx = ctx.withPhaseNoLater(ctx.lambdaLiftPhase) // lambdalift mangles local class names, which means we cannot reliably find outer acessors anymore
         ctx.log(i"outer to $toCls of $tree: ${tree.tpe}, looking for ${outerAccName(treeCls.asClass)(outerAccessorCtx)} in $treeCls")
diff --git a/compiler/src/dotty/tools/dotc/transform/SymUtils.scala b/compiler/src/dotty/tools/dotc/transform/SymUtils.scala
index 05305575e..105f54d3a 100644
--- a/compiler/src/dotty/tools/dotc/transform/SymUtils.scala
+++ b/compiler/src/dotty/tools/dotc/transform/SymUtils.scala
@@ -12,7 +12,9 @@ import StdNames._
 import NameOps._
 import Flags._
 import Annotations._
+
 import language.implicitConversions
+import scala.annotation.tailrec
 
 object SymUtils {
   implicit def decorateSymbol(sym: Symbol): SymUtils = new SymUtils(sym)
@@ -59,14 +61,14 @@ class SymUtils(val self: Symbol) extends AnyVal {
   }
 
   /** The closest enclosing method or class of this symbol */
-  final def enclosingMethodOrClass(implicit ctx: Context): Symbol =
+  @tailrec final def enclosingMethodOrClass(implicit ctx: Context): Symbol =
     if (self.is(Method, butNot = Label) || self.isClass) self
     else if (self.exists) self.owner.enclosingMethodOrClass
     else NoSymbol
 
   /** Apply symbol/symbol substitution to this symbol */
   def subst(from: List[Symbol], to: List[Symbol]): Symbol = {
-    def loop(from: List[Symbol], to: List[Symbol]): Symbol =
+    @tailrec def loop(from: List[Symbol], to: List[Symbol]): Symbol =
       if (from.isEmpty) self
       else if (self eq from.head) to.head
       else loop(from.tail, to.tail)