diff --git a/compiler/src/dotty/tools/dotc/typer/Implicits.scala b/compiler/src/dotty/tools/dotc/typer/Implicits.scala
index 2bf9f176028b..1a2260c2a9cf 100644
--- a/compiler/src/dotty/tools/dotc/typer/Implicits.scala
+++ b/compiler/src/dotty/tools/dotc/typer/Implicits.scala
@@ -1167,7 +1167,7 @@ trait Implicits { self: Typer =>
           err.userDefinedErrorString(
             raw,
             pt.typeSymbol.typeParams.map(_.name.unexpandedName.toString),
-            pt.argInfos))
+            pt.widenExpr.argInfos))
 
         def hiddenImplicitsAddendum: String = arg.tpe match {
           case fail: SearchFailureType =>
diff --git a/tests/neg/i6826.scala b/tests/neg/i6826.scala
new file mode 100644
index 000000000000..0adb73d1ed6f
--- /dev/null
+++ b/tests/neg/i6826.scala
@@ -0,0 +1,5 @@
+class Foo {
+  inline def foo[T](implicit ct: =>scala.reflect.ClassTag[T]): Unit = Unit
+  type U
+  foo[U] // error
+}
\ No newline at end of file