diff --git a/compiler/src/dotty/tools/dotc/typer/RefChecks.scala b/compiler/src/dotty/tools/dotc/typer/RefChecks.scala
index afb5e1a03b41..ba6302f335de 100644
--- a/compiler/src/dotty/tools/dotc/typer/RefChecks.scala
+++ b/compiler/src/dotty/tools/dotc/typer/RefChecks.scala
@@ -762,8 +762,10 @@ object RefChecks {
        */
     def hasMatchingSym(inclazz: Symbol, member: Symbol): Boolean = {
 
-      def isSignatureMatch(sym: Symbol) = !sym.isTerm ||
-        clazz.thisType.memberInfo(sym).matchesLoosely(member.info)
+      def isSignatureMatch(sym: Symbol) = sym.isType || {
+        val self = clazz.thisType
+        sym.asSeenFrom(self).matches(member.asSeenFrom(self))
+      }
 
       /* The rules for accessing members which have an access boundary are more
          * restrictive in java than scala.  Since java has no concept of package nesting,
diff --git a/tests/neg/i9109.scala b/tests/neg/i9109.scala
new file mode 100644
index 000000000000..7f17a24ffd54
--- /dev/null
+++ b/tests/neg/i9109.scala
@@ -0,0 +1,6 @@
+class A {
+  def foo[T <: Cloneable](x: T): Unit = {}
+}
+class B extends A {
+  override def foo[T <: Serializable](x: T): Unit = {} // error: method foo has a different signature than the overridden declaration
+}