diff --git a/compiler/src/dotty/tools/dotc/typer/Applications.scala b/compiler/src/dotty/tools/dotc/typer/Applications.scala
index 8dad9247a6e9..20ae81a74655 100644
--- a/compiler/src/dotty/tools/dotc/typer/Applications.scala
+++ b/compiler/src/dotty/tools/dotc/typer/Applications.scala
@@ -2166,7 +2166,7 @@ trait Applications extends Compatibility {
     val reverseMapping = alts.flatMap { alt =>
       val t = f(alt)
       if t.exists then
-        val (trimmed, skipped) = trimParamss(t, alt.symbol.rawParamss)
+        val (trimmed, skipped) = trimParamss(t.stripPoly, alt.symbol.rawParamss)
         val mappedSym = alt.symbol.asTerm.copy(info = t)
         mappedSym.rawParamss = trimmed
         val (pre, totalSkipped) = mappedAltInfo(alt.symbol) match
diff --git a/tests/pos/i16484.scala b/tests/pos/i16484.scala
new file mode 100644
index 000000000000..b0a5bf1f8a17
--- /dev/null
+++ b/tests/pos/i16484.scala
@@ -0,0 +1,3 @@
+trait JWTEncoder:
+  def encode[P](arg: String)(opt: Option[String] = None): String
+  def encode[P](arg: String): String = encode(arg)()