From 6eec16fab36f0cfbb9ba225ecdb5b45629452e77 Mon Sep 17 00:00:00 2001
From: Eugene Flesselle <eugene@flesselle.net>
Date: Mon, 29 Jan 2024 21:07:29 +0100
Subject: [PATCH] normalize MatchAlias in unrollTupleTypes

---
 compiler/src/dotty/tools/dotc/inlines/Inlines.scala | 3 +++
 tests/pos/i19385.scala                              | 8 ++++++++
 2 files changed, 11 insertions(+)
 create mode 100644 tests/pos/i19385.scala

diff --git a/compiler/src/dotty/tools/dotc/inlines/Inlines.scala b/compiler/src/dotty/tools/dotc/inlines/Inlines.scala
index 4860913bdc63..c6906a0dbf0a 100644
--- a/compiler/src/dotty/tools/dotc/inlines/Inlines.scala
+++ b/compiler/src/dotty/tools/dotc/inlines/Inlines.scala
@@ -443,6 +443,9 @@ object Inlines:
             unrollTupleTypes(tail).map(head :: _)
           case tpe: TermRef if tpe.symbol == defn.EmptyTupleModule =>
             Some(Nil)
+          case tpRef: TypeRef => tpRef.info match
+            case MatchAlias(alias) => unrollTupleTypes(alias.tryNormalize)
+            case _ => None
           case _ =>
             None
 
diff --git a/tests/pos/i19385.scala b/tests/pos/i19385.scala
new file mode 100644
index 000000000000..0f66a15c13bc
--- /dev/null
+++ b/tests/pos/i19385.scala
@@ -0,0 +1,8 @@
+import scala.compiletime.summonAll
+
+inline def f[M <: Tuple]: Unit =
+  type Alias = Tuple.Map[M, [X] =>> Numeric[X]]
+  summonAll[Tuple.Map[M, [X] =>> Numeric[X]]] // compiles
+  summonAll[Alias] // error: Tuple element types must be known at compile time
+
+val y1 = f[(Int, Int)]
\ No newline at end of file