[contracts] define_env! re-write as a proc macro (#11888)

* define_env proc macro basics + can_satisfy part ready

* expand_impls part done

* fix of the &FunctionType bug

* pallet is compiled

* updated host fn definition syntax

* docs comments allowed to host fn definitions

* all 53 host funcs re-defined by the new macro

* unstable feat fix

* cleanup

* legacy mbe macros cleaned up

* Added Env ident to macro attribute; all tests pass!

* \#[v(..)] -> \#[version(..)]

* some tiny corrections

* save

* builds with non-magic rt; tests fail

* tests pass

* refactored errors + added docs

* merge err fixed

* fixes on @ascjones review, all except moving away from `pub mod env` syntax

* debug printing cleared

* clippy fix

substrate/frame/contracts/src/wasm/prepare.rs

@@ -517,6 +517,7 @@ mod tests {
 		schedule::Limits,
 		tests::{Test, ALICE},
 	};
+	use pallet_contracts_proc_macro::define_env;
 	use std::fmt;
 
 	impl fmt::Debug for PrefabWasmModule<Test> {
@@ -532,17 +533,27 @@ mod tests {
 
 		// Define test environment for tests. We need ImportSatisfyCheck
 		// implementation from it. So actual implementations doesn't matter.
-		define_env!(Test, <E: Ext>,
-			[seal0] panic(_ctx) => { unreachable!(); },
+		#[define_env]
+		pub mod test_env {
+			fn panic(_ctx: crate::wasm::Runtime<E>) -> Result<(), TrapReason> {
+				Ok(())
+			}
 
 			// gas is an implementation defined function and a contract can't import it.
-			[seal0] gas(_ctx, _amount: u32) => { unreachable!(); },
+			fn gas(_ctx: crate::wasm::Runtime<E>, _amount: u32) -> Result<(), TrapReason> {
+				Ok(())
+			}
 
-			[seal0] nop(_ctx, _unused: u64) => { unreachable!(); },
+			fn nop(_ctx: crate::wasm::Runtime<E>, _unused: u64) -> Result<(), TrapReason> {
+				Ok(())
+			}
 
-			// new version of nop with other data type for argument
-			[seal1] nop(_ctx, _unused: i32) => { unreachable!(); },
-		);
+			// new version of nop with other data type for argumebt
+			#[version(1)]
+			fn nop(_ctx: crate::wasm::Runtime<E>, _unused: i32) -> Result<(), TrapReason> {
+				Ok(())
+			}
+		}
 	}
 
 	macro_rules! prepare_test {
@@ -561,7 +572,7 @@ mod tests {
 					},
 					.. Default::default()
 				};
-				let r = do_preparation::<env::Test, Test>(wasm, &schedule, ALICE);
+				let r = do_preparation::<env::Env, Test>(wasm, &schedule, ALICE);
 				assert_matches::assert_matches!(r.map_err(|(_, msg)| msg), $($expected)*);
 			}
 		};