From 7bbed2b0a73e9c4aef9fedf6473a319431a7df7f Mon Sep 17 00:00:00 2001
From: odersky <odersky@gmail.com>
Date: Tue, 1 Oct 2024 15:24:46 +0200
Subject: [PATCH] Revert SAM condition to what it was before

Fixes #21676
---
 .../src/dotty/tools/dotc/typer/Typer.scala     |  4 +++-
 tests/pos/i21676.scala                         | 18 ++++++++++++++++++
 2 files changed, 21 insertions(+), 1 deletion(-)
 create mode 100644 tests/pos/i21676.scala

diff --git a/compiler/src/dotty/tools/dotc/typer/Typer.scala b/compiler/src/dotty/tools/dotc/typer/Typer.scala
index 159ce8354a30..c4c3f6b2d439 100644
--- a/compiler/src/dotty/tools/dotc/typer/Typer.scala
+++ b/compiler/src/dotty/tools/dotc/typer/Typer.scala
@@ -4569,7 +4569,7 @@ class Typer(@constructorOnly nestingLevel: Int = 0) extends Namer
 
       // convert function literal to SAM closure
       tree match {
-        case closure(Nil, id @ Ident(nme.ANON_FUN), _)
+        case blockEndingInClosure(Nil, id @ Ident(nme.ANON_FUN), _)
         if defn.isFunctionNType(wtp) && !defn.isFunctionNType(pt) =>
           pt match {
             case SAMType(samMeth, samParent)
@@ -4578,6 +4578,8 @@ class Typer(@constructorOnly nestingLevel: Int = 0) extends Namer
               // but this prevents case blocks from implementing polymorphic partial functions,
               // since we do not know the result parameter a priori. Have to wait until the
               // body is typechecked.
+	          // Note: Need to come back to this when we clean up SAMs/PartialFunctions
+    	      // These conditions would most likely be affected by a precise spec.
               return toSAM(tree, samParent)
             case _ =>
           }
diff --git a/tests/pos/i21676.scala b/tests/pos/i21676.scala
new file mode 100644
index 000000000000..2f94fda47be5
--- /dev/null
+++ b/tests/pos/i21676.scala
@@ -0,0 +1,18 @@
+def Test =
+  val members = collection.immutable.SortedSet.empty[String]
+  members.collect {
+    var upNumber = 0
+    {
+      case m =>
+        // upNumber += 1
+        m
+    }
+  }
+
+  members.collect {
+    var upNumber = 0
+    {
+      m => m
+    }
+  }
+