Fix feeless_if in pallet section (#6032)

fixes #5981 

Could confirm the issue with the added tests:

```
test tests/split_ui/pass/split_call.rs [should pass] ... error
┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
error[E0423]: expected value, found attribute macro `origin`
  --> tests/split_ui/pass/split_call.rs:23:1
   |
23 | #[frame_support::pallet(dev_mode)]
   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ not a value
   |
   = note: this error originates in the attribute macro `frame_support::pallet` (in Nightly builds, run with -Z macro-backtrace for more info)
```

# Description

`origin` unexpectedly resolved to a macro, which is available at the
span of invocation. The solution here is to use the expansion as a
function instead of a call and pass in the desired values to avoid
ambiguities.

prdoc/pr_6032.prdoc

@@ -0,0 +1,11 @@
+title: Fix `feeless_if` in pallet section
+
+doc:
+  - audience: Runtime Dev
+    description: |
+      Fix compilation with `pallet::feeless_if` in a pallet section: a local binding unexpectely
+      resolved to a macro definition.
+
+crates:
+  - name: frame-support-procedural
+    bump: patch

substrate/frame/support/procedural/src/pallet/expand/call.rs

@@ -253,13 +253,13 @@ pub fn expand_call(def: &mut Def) -> proc_macro2::TokenStream {
 		})
 		.collect::<Vec<_>>();
 
-	let feeless_check = methods.iter().map(|method| &method.feeless_check).collect::<Vec<_>>();
-	let feeless_check_result =
-		feeless_check.iter().zip(args_name.iter()).map(|(feeless_check, arg_name)| {
-			if let Some(feeless_check) = feeless_check {
-				quote::quote!(#feeless_check(origin, #( #arg_name, )*))
+	let feeless_checks = methods.iter().map(|method| &method.feeless_check).collect::<Vec<_>>();
+	let feeless_check =
+		feeless_checks.iter().zip(args_name.iter()).map(|(feeless_check, arg_name)| {
+			if let Some(check) = feeless_check {
+				quote::quote_spanned!(span => #check)
 			} else {
-				quote::quote!(false)
+				quote::quote_spanned!(span => |_origin, #( #arg_name, )*| { false })
 			}
 		});
 
@@ -393,7 +393,8 @@ pub fn expand_call(def: &mut Def) -> proc_macro2::TokenStream {
 					#(
 						#cfg_attrs
 						Self::#fn_name { #( #args_name_pattern_ref, )* } => {
-							#feeless_check_result
+							let feeless_check = #feeless_check;
+							feeless_check(origin, #( #args_name, )*)
 						},
 					)*
 					Self::__Ignore(_, _) => unreachable!("__Ignore cannot be used"),

substrate/frame/support/test/tests/split_ui/pass/call/mod.rs

@@ -0,0 +1,63 @@
+// This file is part of Substrate.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: Apache-2.0
+
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+use frame_support::pallet_macros::pallet_section;
+
+#[pallet_section]
+mod call {
+	#[pallet::call]
+	impl<T: Config> Pallet<T> {
+        #[pallet::call_index(0)]
+        pub fn noop0(origin: OriginFor<T>) -> DispatchResult {
+            ensure_signed(origin)?;
+            Ok(())
+        }
+
+        #[pallet::call_index(1)]
+        pub fn noop1(origin: OriginFor<T>, _x: u64) -> DispatchResult {
+            ensure_signed(origin)?;
+            Ok(())
+        }
+
+        #[pallet::call_index(2)]
+        pub fn noop2(origin: OriginFor<T>, _x: u64, _y: u64) -> DispatchResult {
+            ensure_signed(origin)?;
+            Ok(())
+        }
+
+        #[pallet::call_index(3)]
+        #[pallet::feeless_if(|_origin: &OriginFor<T>| -> bool { true })]
+        pub fn noop_feeless0(origin: OriginFor<T>) -> DispatchResult {
+            ensure_signed(origin)?;
+            Ok(())
+        }
+
+        #[pallet::call_index(4)]
+        #[pallet::feeless_if(|_origin: &OriginFor<T>, x: &u64| -> bool { *x == 1 })]
+        pub fn noop_feeless1(origin: OriginFor<T>, _x: u64) -> DispatchResult {
+            ensure_signed(origin)?;
+            Ok(())
+        }
+
+        #[pallet::call_index(5)]
+        #[pallet::feeless_if(|_origin: &OriginFor<T>, x: &u64, y: &u64| -> bool { *x == *y })]
+        pub fn noop_feeless2(origin: OriginFor<T>, _x: u64, _y: u64) -> DispatchResult {
+            ensure_signed(origin)?;
+            Ok(())
+        }
+	}
+}

substrate/frame/support/test/tests/split_ui/pass/split_call.rs

@@ -0,0 +1,36 @@
+// This file is part of Substrate.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: Apache-2.0
+
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+use frame_support::pallet_macros::import_section;
+
+mod call;
+
+#[import_section(call::call)]
+#[frame_support::pallet(dev_mode)]
+pub mod pallet {
+    use frame_support::pallet_prelude::*;
+    use frame_system::pallet_prelude::*;
+
+    #[pallet::pallet]
+    pub struct Pallet<T>(_);
+
+    #[pallet::config]
+    pub trait Config: frame_system::Config {}
+}
+
+fn main() {
+}