From 9b060ec20aabe0f74934050a2be5a91799a1ce20 Mon Sep 17 00:00:00 2001
From: Dolphin von Chips <td2505052@gmail.com>
Date: Wed, 7 May 2025 09:11:45 +0300
Subject: [PATCH] Handle comparing with TypeVar in mergeRefinedOrApplied

Closes #23032
---
 compiler/src/dotty/tools/dotc/core/TypeOps.scala | 10 +++++++++-
 tests/pos/i23032.scala                           |  2 ++
 2 files changed, 11 insertions(+), 1 deletion(-)
 create mode 100644 tests/pos/i23032.scala

diff --git a/compiler/src/dotty/tools/dotc/core/TypeOps.scala b/compiler/src/dotty/tools/dotc/core/TypeOps.scala
index a1e26c20fdbb..efd4c6e83cd2 100644
--- a/compiler/src/dotty/tools/dotc/core/TypeOps.scala
+++ b/compiler/src/dotty/tools/dotc/core/TypeOps.scala
@@ -278,7 +278,15 @@ object TypeOps:
           }
         case AndType(tp11, tp12) =>
           mergeRefinedOrApplied(tp11, tp2) & mergeRefinedOrApplied(tp12, tp2)
-        case tp1: TypeParamRef if tp1 == tp2 => tp1
+        case tp1: TypeParamRef =>
+          tp2.stripTypeVar match
+            case tp2: TypeParamRef if tp1 == tp2 => tp1
+            case _ => fail
+        case tp1: TypeVar =>
+          tp2 match
+            case tp2: TypeVar if tp1 == tp2 => tp1
+            case tp2: TypeParamRef if tp1.stripTypeVar == tp2 => tp2
+            case _ => fail
         case _ => fail
       }
     }
diff --git a/tests/pos/i23032.scala b/tests/pos/i23032.scala
new file mode 100644
index 000000000000..7e56d0f8b153
--- /dev/null
+++ b/tests/pos/i23032.scala
@@ -0,0 +1,2 @@
+def f[F[_], T, U]: F[T] | F[U] = ???
+def x = f.toString