Add with_pays_fee for conversion to DispatchErrorWithPostInfo

frame/support/src/dispatch.rs

@@ -328,7 +328,7 @@ impl sp_runtime::traits::Printable for PostDispatchInfo {
 }
 
 /// Allows easy conversion from `DispatchError` to `DispatchErrorWithPostInfo` for dispatchables
-/// that want to return a custom a posterior weight on error.
+/// that want to return a custom posterior weight or fee payment decision on error.
 pub trait WithPostDispatchInfo {
 	/// Call this on your modules custom errors type in order to return a custom weight on error.
 	///
@@ -339,6 +339,14 @@ pub trait WithPostDispatchInfo {
 	/// ensure!(who == me, Error::<T>::NotMe.with_weight(200_000));
 	/// ```
 	fn with_weight(self, actual_weight: Weight) -> DispatchErrorWithPostInfo;
+	/// Call this on your modules custom errors type in order to decide fee payment on error.
+	///
+	/// # Example
+	///
+	/// ```ignore
+	/// ensure!(validate(params), Error::<T>::InvalidParameters.with_pays_fee(Pays::No));
+	/// ```
+	fn with_pays_fee(self, pays_fee: Pays) -> DispatchErrorWithPostInfo;
 }
 
 impl<T> WithPostDispatchInfo for T
@@ -354,6 +362,12 @@ where
 			error: self.into(),
 		}
 	}
+	fn with_pays_fee(self, pays_fee: Pays) -> DispatchErrorWithPostInfo {
+		DispatchErrorWithPostInfo {
+			post_info: PostDispatchInfo { actual_weight: None, pays_fee },
+			error: self.into(),
+		}
+	}
 }
 
 /// Implementation for unchecked extrinsic.