diff --git a/core/src/main/scala/nz/co/bottech/scala2plantuml/DiagramModifications.scala b/core/src/main/scala/nz/co/bottech/scala2plantuml/DiagramModifications.scala
index f3209ba..6260229 100644
--- a/core/src/main/scala/nz/co/bottech/scala2plantuml/DiagramModifications.scala
+++ b/core/src/main/scala/nz/co/bottech/scala2plantuml/DiagramModifications.scala
@@ -144,7 +144,6 @@ private[scala2plantuml] object DiagramModifications {
       assert(names.isEmpty)
       def typeParameterSymbols(parameters: Seq[TypeParameter]): Seq[String] =
         parameters.flatMap(parameter => parameter.symbol +: parameter.parentSymbols)
-      // TODO: This might be overkill. All the symbols we care about should be types.
       def elementSymbols(element: ClassDiagramElement): Seq[String] =
         element match {
           case typ: Type                => typ.symbol +: typ.parentSymbols ++: typeParameterSymbols(typ.typeParameters)
@@ -161,8 +160,8 @@ private[scala2plantuml] object DiagramModifications {
               symbolName(parameter.symbol) +: parameter.parentSymbols.map(symbolName)
             }
             elementName +: typeParameterNames
-          case member: Member => Seq(member.symbol -> member.displayName)
-          case _: Aggregation => Seq.empty
+          case member: Member           => Seq(member.symbol -> member.displayName)
+          case aggregation: Aggregation => Seq(symbolName(aggregation.aggregator), symbolName(aggregation.aggregated))
         }
       }
       val newNames = options.naming match {
diff --git a/core/src/test/scala/nz/co/bottech/scala2plantuml/MethodParameterTests.scala b/core/src/test/scala/nz/co/bottech/scala2plantuml/MethodParameterTests.scala
new file mode 100644
index 0000000..bf552d8
--- /dev/null
+++ b/core/src/test/scala/nz/co/bottech/scala2plantuml/MethodParameterTests.scala
@@ -0,0 +1,20 @@
+package nz.co.bottech.scala2plantuml
+
+import utest.{test, TestSuite, Tests}
+
+object MethodParameterTests extends TestSuite with ClassDiagramTests {
+
+  override protected val exampleDir: String = "methodparameters"
+
+  val tests: Tests = Tests {
+    test("parameter with type alias") {
+      success(
+        "Foo.",
+        """class Foo {
+          |  + {static} {method} foo
+          |}
+          |Foo o-- "package$Bar"""".stripMargin
+      )
+    }
+  }
+}
diff --git a/core/src/test/scala/nz/co/bottech/scala2plantuml/examples/methodparameters/Foo.scala b/core/src/test/scala/nz/co/bottech/scala2plantuml/examples/methodparameters/Foo.scala
new file mode 100644
index 0000000..7582738
--- /dev/null
+++ b/core/src/test/scala/nz/co/bottech/scala2plantuml/examples/methodparameters/Foo.scala
@@ -0,0 +1,6 @@
+package nz.co.bottech.scala2plantuml.examples.methodparameters
+
+object Foo {
+
+  def foo(bar: Bar): String = bar
+}
diff --git a/core/src/test/scala/nz/co/bottech/scala2plantuml/examples/methodparameters/package.scala b/core/src/test/scala/nz/co/bottech/scala2plantuml/examples/methodparameters/package.scala
new file mode 100644
index 0000000..8f7b091
--- /dev/null
+++ b/core/src/test/scala/nz/co/bottech/scala2plantuml/examples/methodparameters/package.scala
@@ -0,0 +1,6 @@
+package nz.co.bottech.scala2plantuml.examples
+
+package object methodparameters {
+
+  type Bar = String
+}