Address @agryaznov's comments

frame/contracts/fixtures/reentrant_count_call.wat

@@ -1,6 +1,6 @@
 (module
-	(import "seal0" "seal_input" (func $seal_input (param i32 i32)))
-	(import "seal0" "seal_call" (func $seal_call (param i32 i32 i64 i32 i32 i32 i32 i32 i32) (result i32)))
+	(import "seal1" "seal_input" (func $seal_input (param i32 i32)))
+	(import "seal1" "seal_call" (func $seal_call (param i32 i32 i64 i32 i32 i32 i32 i32 i32) (result i32)))
 	(import "seal0" "seal_delegate_call" (func $seal_delegate_call (param i32 i32 i32 i32 i32 i32) (result i32)))
 	(import "__unstable__" "seal_reentrant_count" (func $seal_reentrant_count (result i32)))
 	(import "env" "memory" (memory 1 1))
@@ -41,7 +41,7 @@
 		        		(i32.const 0)	;; Pointer to "callee" code_hash.
 		        		(i32.const 0)	;; Input is ignored
 		        		(i32.const 0)	;; Length of the input
-		        		(i32.const 4294967295)	;; u32 max sentinel value: do not copy output
+		        		(i32.const 0xffffffff)	;; u32 max sentinel value: do not copy output
 		        		(i32.const 0)	;; Length is ignored in this case
 		        	)
 		        )

frame/contracts/src/exec.rs

@@ -1243,7 +1243,7 @@ where
 	}
 
 	fn account_entrance_count(&self, account_id: &AccountIdOf<Self::T>) -> u32 {
-		self.frames().filter_map(|f| Some(f.delegate_caller.is_none() && &f.account_id == account_id)).count() as u32
+		self.frames().filter_map(|f| (f.delegate_caller.is_none() && &f.account_id == account_id).then(|| true)).count() as u32
 	}
 }
 

frame/contracts/src/tests.rs

@@ -3231,7 +3231,7 @@ fn set_code_hash() {
 
 #[test]
 #[cfg(feature = "unstable-interface")]
-fn reentrant_count() {
+fn reentrant_count_works() {
 	let (wasm1, code_hash1) = compile_module::<Test>("reentrant_count_call").unwrap();
 	let contract_addr1 = Contracts::contract_address(&ALICE, &code_hash1, &[]);
 

frame/contracts/src/wasm/mod.rs

@@ -2599,7 +2599,7 @@ mod tests {
 
 	#[test]
 	#[cfg(feature = "unstable-interface")]
-	fn reentrant_count() {
+	fn reentrant_count_works() {
 		const CODE: &str = r#"
 (module
 	(import "__unstable__" "seal_reentrant_count" (func $seal_reentrant_count (result i32)))

frame/contracts/src/wasm/runtime.rs

@@ -2088,15 +2088,26 @@ define_env!(Env, <E: Ext>,
 	},
 
 	// Returns then number of times currently executing contract exists on the call stack in addition
-	// to the calling instance. A value of 0 means no reentrancy.
+	// to the calling instance.
+	//
+	// # Return Value
+	//
+	// Returns 0 when there is no reentrancy
 	[__unstable__] seal_reentrant_count(ctx) -> u32 => {
 		ctx.charge_gas(RuntimeCosts::ReentrantCount)?;
 		Ok(ctx.ext.reentrant_count() as u32)
 	},
 
 	// Returns the number of times specified contract exists on the call stack. Delegated calls are
 	// not calculated as separate calls.
-	// A value of 0 means it does not exist on the stack.
+	//
+	// # Parameters
+	//
+	// - `account_ptr`: a pointer to the contract address.
+	//
+	// # Return Value
+	//
+	// Returns 0 when the contract does not exist on the call stack.
 	[__unstable__] seal_account_entrance_count(ctx, account_ptr: u32) -> u32 => {
 		ctx.charge_gas(RuntimeCosts::AccountEntranceCount)?;
 		let account_id: <<E as Ext>::T as frame_system::Config>::AccountId = ctx.read_sandbox_memory_as(account_ptr)?;