diff --git a/examples/hello-world/main.roc b/examples/hello-world/main.roc
index 3ce1117db0..f89cf66391 100644
--- a/examples/hello-world/main.roc
+++ b/examples/hello-world/main.roc
@@ -3,7 +3,9 @@ app "helloWorld"
     imports [Decode, Decode.{Decoder, Decoding, DecoderFormatting}, Json]
     provides [main] to pf
 
+theDecoder : Decoder {first: a, second: b} fmt | a has Decoding, b has Decoding, fmt has DecoderFormatting
 theDecoder =
+    initialState : {f0: Result a [NoField], f1: Result b [NoField]}
     initialState = {f0: Err NoField, f1: Err NoField}
 
     stepField = \state, field ->