diff --git a/compiler/src/dotty/tools/dotc/typer/TypeAssigner.scala b/compiler/src/dotty/tools/dotc/typer/TypeAssigner.scala
index 2b5e7dd6f17c..1b1d55322bbb 100644
--- a/compiler/src/dotty/tools/dotc/typer/TypeAssigner.scala
+++ b/compiler/src/dotty/tools/dotc/typer/TypeAssigner.scala
@@ -401,15 +401,19 @@ trait TypeAssigner {
   def assignType(tree: untpd.CaseDef, pat: Tree, body: Tree)(using Context): CaseDef = {
     val ownType =
       if (body.isType) {
-        val params = new TreeAccumulator[mutable.ListBuffer[TypeSymbol]] {
+        val getParams = new TreeAccumulator[mutable.ListBuffer[TypeSymbol]] {
           def apply(ps: mutable.ListBuffer[TypeSymbol], t: Tree)(using Context) = t match {
             case t: Bind if t.symbol.isType => foldOver(ps += t.symbol.asType, t)
             case _ => foldOver(ps, t)
           }
         }
-        HKTypeLambda.fromParams(
-          params(new mutable.ListBuffer[TypeSymbol](), pat).toList,
-          defn.MatchCase(pat.tpe, body.tpe))
+        val params = getParams(new mutable.ListBuffer[TypeSymbol](), pat).toList
+        pat.tpe match
+          case AppliedType(tycon, args) =>
+            val tparams = tycon.typeParamSymbols
+            for param <- params do param.info = param.info.subst(tparams, args))
+          case _ =>
+        HKTypeLambda.fromParams(params, defn.MatchCase(pat.tpe, body.tpe))
       }
       else body.tpe
     tree.withType(ownType)
diff --git a/tests/neg/6697.check b/tests/neg/6697.check
deleted file mode 100644
index 3249ad7aa4af..000000000000
--- a/tests/neg/6697.check
+++ /dev/null
@@ -1,13 +0,0 @@
--- [E057] Type Mismatch Error: tests/neg/6697.scala:6:35 ---------------------------------------------------------------
-6 |  type Copy[O <: Off] = Of[Sup[O], Sub[O]]  // error
-  |                                   ^
-  |                                   Type argument Test.Sub[O] does not conform to upper bound Test.Sup[O]
-  |
-  |                                   Note: a match type could not be fully reduced:
-  |
-  |                                     trying to reduce  Test.Sub[O]
-  |                                     failed since selector  O
-  |                                     does not match  case Test.Of[sup, sub] => sub
-  |                                     and cannot be shown to be disjoint from it either.
-  |
-  | longer explanation available when compiling with `-explain`
diff --git a/tests/neg/6697.scala b/tests/pos/6697.scala
similarity index 100%
rename from tests/neg/6697.scala
rename to tests/pos/6697.scala
diff --git a/tests/pos/i14477.scala b/tests/pos/i14477.scala
new file mode 100644
index 000000000000..1647cb3432d4
--- /dev/null
+++ b/tests/pos/i14477.scala
@@ -0,0 +1,9 @@
+sealed trait Foo[A, X <: A]
+
+type FooX[F] = F match {
+  case Foo[a, x] => x
+}
+
+type MyFoo = Foo[String, "hello"]
+
+val hello: FooX[MyFoo] = "hello"