chore(xcm-executor): remove default implementation for AssetExchange

polkadot/xcm/xcm-builder/src/test_utils.rs

@@ -109,6 +109,10 @@ impl AssetExchange for TestAssetExchanger {
 	) -> Result<AssetsInHolding, AssetsInHolding> {
 		Ok(want.clone().into())
 	}
+
+	fn quote_exchange_price(_: &Asset, _: &Asset, _: bool) -> Option<u128> {
+		None
+	}
 }
 
 pub struct TestPalletsInfo;

polkadot/xcm/xcm-builder/src/tests/mock.rs

@@ -695,6 +695,10 @@ impl AssetExchange for TestAssetExchange {
 		EXCHANGE_ASSETS.with(|l| l.replace(have));
 		Ok(get)
 	}
+
+	fn quote_exchange_price(_: &Asset, _: &Asset, _: bool) -> Option<u128> {
+		None
+	}
 }
 
 pub struct SiblingPrefix;

polkadot/xcm/xcm-executor/src/traits/asset_exchange.rs

@@ -43,9 +43,7 @@ pub trait AssetExchange {
 	/// - `asset1` The first asset.
 	/// - `asset2` The second asset.
 	/// - `maximal`: If `true`, then all of `asset1` should be used.
-	fn quote_exchange_price(_asset1: &Asset, _asset2: &Asset, _maximal: bool) -> Option<u128> {
-		None
-	}
+	fn quote_exchange_price(asset1: &Asset, asset2: &Asset, maximal: bool) -> Option<u128>;
 }
 
 #[impl_trait_for_tuples::impl_for_tuples(30)]
@@ -64,4 +62,14 @@ impl AssetExchange for Tuple {
 		)* );
 		Err(give)
 	}
+
+	fn quote_exchange_price(asset1: &Asset, asset2: &Asset, maximal: bool) -> Option<u128> {
+		for_tuples!( #(
+			match Tuple::quote_exchange_price(asset1, asset2, maximal) {
+				Some(amount) => return Some(amount),
+				None => {}
+			}
+		)* );
+		None
+	}
 }