Refine unit requirement

byg/src/DependencyGenerator.hs

@@ -104,7 +104,7 @@ runFunction f input = genDependency (makeDependency input (Function f))
 runFunctionIO :: IsFunctionIO f a b => f -> Token a -> DepGenM' b
 runFunctionIO f input = genDependency (makeDependency input (FunctionIO f))
 
-runFunctionIO_ :: IsFunctionIO f a b => f -> Token a -> DepGenM ()
+runFunctionIO_ :: IsFunctionIO f a () => f -> Token a -> DepGenM ()
 runFunctionIO_ f input = tellDep $ makeDependency input (FunctionIO f) NoToken
 
 class TokenableTo t s | s -> t where