Feat: add return type assertion

Cargo.toml

@@ -63,7 +63,6 @@ clap = { version = "4.5.4", features = ["derive"] }
 env_logger = { version = "0.11.3" }
 tracing-subscriber = { version = "0.3.18", features = ["env-filter"] }
 
-impl-trait-for-tuples = "0.2"
 fortuples = "0.9"
 
 # proc macros

poc/guests/sum-balance-percent/src/main.rs

@@ -5,9 +5,9 @@ static GLOBAL: polkavm_derive::LeakingAllocator = polkavm_derive::LeakingAllocat
 use alloc::vec::Vec;
 #[xcq_api::program]
 mod sum_balance {
-    #[xcq::call_def]
+    #[xcq::call_def(extension_id = 10588899351449456541u64, call_index = 1)]
     fn balance(asset: u32, who: [u8; 32]) -> u64 {}
-    #[xcq::call_def]
+    #[xcq::call_def(extension_id = 10588899351449456541u64, call_index = 0)]
     fn total_supply(asset: u32) -> u64 {}
 
     #[xcq::entrypoint]

poc/guests/sum-balance/src/main.rs

@@ -3,11 +3,11 @@
 #[global_allocator]
 static GLOBAL: polkavm_derive::LeakingAllocator = polkavm_derive::LeakingAllocator;
 use alloc::vec::Vec;
+// An example instance of xcq program with specific arg types
 #[xcq_api::program]
 mod sum_balance {
-    #[xcq::call_def]
+    #[xcq::call_def(extension_id = 10588899351449456541u64, call_index = 1)]
     fn balance(asset: u32, who: [u8; 32]) -> u64 {}
-
     #[xcq::entrypoint]
     fn sum_balance(calls: Vec<BalanceCall>) -> u64 {
         let mut sum = 0;

poc/guests/total-supply/src/main.rs

@@ -4,7 +4,7 @@
 static GLOBAL: polkavm_derive::LeakingAllocator = polkavm_derive::LeakingAllocator;
 #[xcq_api::program]
 mod query_total_supply {
-    #[xcq::call_def]
+    #[xcq::call_def(extension_id = 10588899351449456541u64, call_index = 0)]
     fn total_supply(asset: u32) -> u64 {}
 
     #[xcq::entrypoint]

xcq-api/procedural/Cargo.toml

@@ -12,3 +12,5 @@ syn = { workspace = true }
 proc-macro2 = { workspace = true }
 proc-macro-crate = { workspace = true }
 Inflector = { workspace = true }
+xcq-types = { workspace = true }
+parity-scale-codec = { workspace = true }

xcq-api/procedural/src/lib.rs

@@ -1,13 +1,14 @@
 /// Declare the calls used in XCQ program
 /// #[xcq::program]
 /// mod query_fungibles {
-///     #[xcq::call(extern_types = [AssetId, AccountId, Balance]])]]
+///     #[xcq::call_def(extension_id = 123456, extern_types = [AssetId, AccountId, Balance])]
 ///     fn balance(asset: AssetId, who: AccountId) -> Balance;
 ///
-///     #[xcq(entrypoint)]
+///     #[xcq::entrypoint]
 ///     fn sum_balance(calls: Vec<Call>) -> u64 {
 ///         let mut sum = 0;
 ///         for call in calls {
+///            // calculation requires a known balance type, we can use assert-type here
 ///             sum += call.call();
 ///         }
 ///         sum