From 611cea8fbd994eb957c981f0de0877cde9754317 Mon Sep 17 00:00:00 2001
From: kenji yoshida <6b656e6a69@gmail.com>
Date: Mon, 23 Feb 2026 12:20:46 +0900
Subject: [PATCH] Add tailrec annotations (#8785)

---
 .../src/main/scala/sbt/internal/EvaluateConfigurations.scala   | 2 ++
 .../src/main/scala/sbt/internal/parser/SbtRefactorings.scala   | 2 ++
 .../src/main/scala/sbt/internal/util/complete/Parser.scala     | 3 +++
 .../src/main/scala/sbt/internal/util/Settings.scala            | 2 ++
 4 files changed, 9 insertions(+)

diff --git a/buildfile/src/main/scala/sbt/internal/EvaluateConfigurations.scala b/buildfile/src/main/scala/sbt/internal/EvaluateConfigurations.scala
index 3458877cf..668901dcc 100644
--- a/buildfile/src/main/scala/sbt/internal/EvaluateConfigurations.scala
+++ b/buildfile/src/main/scala/sbt/internal/EvaluateConfigurations.scala
@@ -17,6 +17,7 @@ import Def.{ ScopedKey, Setting, Settings }
 import Scope.GlobalScope
 import sbt.internal.parser.SbtParser
 import sbt.io.IO
+import scala.annotation.tailrec
 import scala.jdk.CollectionConverters.*
 import xsbti.PathBasedFile
 import xsbti.VirtualFile
@@ -299,6 +300,7 @@ private[sbt] object EvaluateConfigurations {
   ): (Seq[(String, Tree, LineRange)], Seq[(String, Tree, LineRange)]) =
     lines partition { case (_, tree, _) => isDefinition(tree) }
 
+  @tailrec
   private def isDefinition(tree: Tree): Boolean = {
     tree match {
       case Annotated(arg, annot) => isDefinition(arg)
diff --git a/buildfile/src/main/scala/sbt/internal/parser/SbtRefactorings.scala b/buildfile/src/main/scala/sbt/internal/parser/SbtRefactorings.scala
index 13ccc9b2b..36d67a9cd 100644
--- a/buildfile/src/main/scala/sbt/internal/parser/SbtRefactorings.scala
+++ b/buildfile/src/main/scala/sbt/internal/parser/SbtRefactorings.scala
@@ -11,6 +11,7 @@ package parser
 
 import dotty.tools.dotc.ast.untpd
 import dotty.tools.dotc.core.Contexts.Context
+import scala.annotation.tailrec
 
 private[sbt] object SbtRefactorings:
 
@@ -91,6 +92,7 @@ private[sbt] object SbtRefactorings:
     seq.toMap
   }
 
+  @tailrec
   private def extractSettingName(tree: untpd.Tree): String = tree match
     case untpd.Ident(name)        => name.toString
     case untpd.InfixOp(lhs, _, _) => extractSettingName(lhs)
diff --git a/internal/util-complete/src/main/scala/sbt/internal/util/complete/Parser.scala b/internal/util-complete/src/main/scala/sbt/internal/util/complete/Parser.scala
index 5549de44a..9bb7781a9 100644
--- a/internal/util-complete/src/main/scala/sbt/internal/util/complete/Parser.scala
+++ b/internal/util-complete/src/main/scala/sbt/internal/util/complete/Parser.scala
@@ -12,6 +12,7 @@ package complete
 import Parser.*
 import sbt.internal.util.Types.{ left, right, some }
 import sbt.internal.util.Util.{ makeList, separate }
+import scala.annotation.tailrec
 
 /**
  * A String parser that provides semi-automatic tab completion. A successful parse results in a
@@ -505,6 +506,7 @@ trait ParserMain {
 
   // intended to be temporary pending proper error feedback
   def result[T](p: Parser[T], s: String): Either[() => (Seq[String], Int), T] = {
+    @tailrec
     def loop(i: Int, a: Parser[T]): Either[() => (Seq[String], Int), T] =
       a match {
         case Invalid(f) => Left(() => (f.errors, i))
@@ -1003,6 +1005,7 @@ private final class Repeat[T](
     repeat(Some(repeated.derive(c)), repeated, scala.math.max(0, min - 1), max.decrement, accRev)
 
   def completions(level: Int) = {
+    @tailrec
     def pow(comp: Completions, exp: Completions, n: Int): Completions =
       if (n == 1) comp else pow(comp.x(exp), exp, n - 1)
 
diff --git a/util-collection/src/main/scala/sbt/internal/util/Settings.scala b/util-collection/src/main/scala/sbt/internal/util/Settings.scala
index 6295f5a04..e75031531 100644
--- a/util-collection/src/main/scala/sbt/internal/util/Settings.scala
+++ b/util-collection/src/main/scala/sbt/internal/util/Settings.scala
@@ -10,6 +10,7 @@ package sbt.internal.util
 import Types.*
 import sbt.util.Show
 import Util.{ nil, nilSeq }
+import scala.annotation.tailrec
 import scala.jdk.CollectionConverters.*
 
 // delegates should contain the input ScopeType as the first entry
@@ -590,6 +591,7 @@ trait Init:
     val processed = new mutable.HashSet[ScopedKey[?]]
 
     // derives settings, transitively so that a derived setting can trigger another
+    @tailrec
     def process(rem: List[Setting[?]]): Unit = rem match {
       case s :: ss =>
         val sk = s.key