From c50d0a3bca6e6a75d71608aa068e21df7e2cae5d Mon Sep 17 00:00:00 2001
From: Lucy Martin <lucy.martin@nttdata.com>
Date: Wed, 19 Jun 2024 16:56:34 +0100
Subject: [PATCH 1/2] #20145 - bugfix when a return tail recurse is called
 inside a val definition, previously this would neither optimise nor fail.

---
 .../src/dotty/tools/dotc/transform/TailRec.scala  |  4 ++--
 tests/run/i20145.check                            |  1 +
 tests/run/i20145.scala                            | 15 +++++++++++++++
 3 files changed, 18 insertions(+), 2 deletions(-)
 create mode 100644 tests/run/i20145.check
 create mode 100644 tests/run/i20145.scala

diff --git a/compiler/src/dotty/tools/dotc/transform/TailRec.scala b/compiler/src/dotty/tools/dotc/transform/TailRec.scala
index d054c5aa6232..0235aba32635 100644
--- a/compiler/src/dotty/tools/dotc/transform/TailRec.scala
+++ b/compiler/src/dotty/tools/dotc/transform/TailRec.scala
@@ -430,8 +430,8 @@ class TailRec extends MiniPhase {
           tree
 
         case tree: ValDef =>
-          if (isMandatory) noTailTransform(tree.rhs)
-          tree
+          // This could contain a return statement in a code block, so we do have to go into it.
+          noTailTransform(tree)
 
         case tree: DefDef =>
           if (isMandatory)
diff --git a/tests/run/i20145.check b/tests/run/i20145.check
new file mode 100644
index 000000000000..f6af6debe594
--- /dev/null
+++ b/tests/run/i20145.check
@@ -0,0 +1 @@
+10000001
diff --git a/tests/run/i20145.scala b/tests/run/i20145.scala
new file mode 100644
index 000000000000..ea26f00e2c89
--- /dev/null
+++ b/tests/run/i20145.scala
@@ -0,0 +1,15 @@
+import scala.annotation.tailrec
+@tailrec
+def foo(i: Int): Int = {
+  if (i > 10000000) {
+    i
+  } else {
+    val bar: String = {
+      return foo(i + 1)
+      "foo"
+    }
+    -1
+  }
+}
+@main def Test =
+  println(foo(0))
\ No newline at end of file

From 8215d011b76527601a53d0fed3c75a3000a8af46 Mon Sep 17 00:00:00 2001
From: Lucy Martin <lucy.martin@nttdata.com>
Date: Wed, 19 Jun 2024 17:33:11 +0100
Subject: [PATCH 2/2] #20145 - bugfix when a return tail recurse is called
 inside a val definition, previously this would neither optimise nor fail.

---
 compiler/src/dotty/tools/dotc/transform/TailRec.scala | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/compiler/src/dotty/tools/dotc/transform/TailRec.scala b/compiler/src/dotty/tools/dotc/transform/TailRec.scala
index 0235aba32635..5cc50f220eaf 100644
--- a/compiler/src/dotty/tools/dotc/transform/TailRec.scala
+++ b/compiler/src/dotty/tools/dotc/transform/TailRec.scala
@@ -431,7 +431,10 @@ class TailRec extends MiniPhase {
 
         case tree: ValDef =>
           // This could contain a return statement in a code block, so we do have to go into it.
-          noTailTransform(tree)
+          cpy.ValDef(tree)(
+            tree.name,
+            noTailTransform(tree.rhs)
+          )
 
         case tree: DefDef =>
           if (isMandatory)