diff --git a/effekt/shared/src/main/scala/effekt/core/PrettyPrinter.scala b/effekt/shared/src/main/scala/effekt/core/PrettyPrinter.scala
index 928de274a..8f75f943e 100644
--- a/effekt/shared/src/main/scala/effekt/core/PrettyPrinter.scala
+++ b/effekt/shared/src/main/scala/effekt/core/PrettyPrinter.scala
@@ -108,13 +108,15 @@ object PrettyPrinter extends ParenPrettyPrinter {
   def argsToDoc(targs: List[core.ValueType], vargs: List[core.Pure], bargs: List[core.Block]): Doc =
     val targsDoc = if targs.isEmpty then emptyDoc else brackets(targs.map(toDoc))
     //val cargsDoc = if cargs.isEmpty then emptyDoc else brackets(cargs.map(toDoc))
-    val vargsDoc = if vargs.isEmpty && !bargs.isEmpty then emptyDoc else vargs.map(toDoc)
-    val bargsDoc = bargs.map(toDoc)
-    targsDoc <> parens(vargsDoc) <> braces(bargsDoc)
+    val vargsDoc = if vargs.isEmpty && !bargs.isEmpty then emptyDoc else parens(vargs.map(toDoc))
+    val bargsDoc = if bargs.isEmpty then emptyDoc else braces(bargs.map(toDoc))
+    targsDoc <> vargsDoc <> bargsDoc
 
   def paramsToDoc(tps: List[symbols.Symbol], vps: List[ValueParam], bps: List[BlockParam]): Doc = {
-    val tpsDoc = if (tps.isEmpty) emptyDoc else brackets(tps.map(toDoc))
-    tpsDoc <> parens(hsep(vps map toDoc, comma)) <> hcat(bps map toDoc)
+    val tpsDoc = if tps.isEmpty then emptyDoc else brackets(tps.map(toDoc))
+    val vpsDoc = if vps.isEmpty && !bps.isEmpty then emptyDoc else parens(vps.map(toDoc))
+    val bpsDoc = if bps.isEmpty then emptyDoc else hcat(bps.map(toDoc)) // already are in braces!
+    tpsDoc <> vpsDoc <> bpsDoc
   }
 
   def toDoc(instance: Implementation): Doc = {