diff --git a/src/build/roc/Builtin.roc b/src/build/roc/Builtin.roc
index 91c0b98684..c550332013 100644
--- a/src/build/roc/Builtin.roc
+++ b/src/build/roc/Builtin.roc
@@ -4,8 +4,6 @@ Builtin := [].{
 
 		contains : Str, Str -> Bool
 		contains = |_str, _other| True
-
-		concat : Str, Str -> Str
 	}
 
 	List := [ProvidedByCompiler].{