From a57f6bbe6a7d115c9c9db1c83e1cf9f5507f64b9 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bastian=20K=C3=B6cher?= <bkchr@users.noreply.github.com>
Date: Thu, 14 Mar 2019 21:53:05 +0100
Subject: [PATCH] Remove warning and make `__PhantomItem` unconstructable
(#2000)
* Remove warning and make `__PhantomItem` unconstructable
* Switch to unreachable
---
substrate/srml/support/src/dispatch.rs | 12 +++++++-----
1 file changed, 7 insertions(+), 5 deletions(-)
diff --git a/substrate/srml/support/src/dispatch.rs b/substrate/srml/support/src/dispatch.rs
index 9f30f6195b0..166b545171a 100644
--- a/substrate/srml/support/src/dispatch.rs
+++ b/substrate/srml/support/src/dispatch.rs
@@ -27,6 +27,9 @@ pub use srml_metadata::{
FunctionArgumentMetadata, OuterDispatchMetadata, OuterDispatchCall
};
+/// A type that can not be instantiated.
+pub enum Never {}
+
/// Result of a module function call; either nothing (functions are only called for "side efeects")
/// or an error message.
pub type Result = result::Result<(), &'static str>;
@@ -615,7 +618,7 @@ macro_rules! decl_module {
$(#[$attr])*
pub enum $call_type<$trait_instance: $trait_name> {
#[doc(hidden)]
- __PhantomItem(::std::marker::PhantomData<$trait_instance>),
+ __PhantomItem(::std::marker::PhantomData<$trait_instance>, $crate::dispatch::Never),
$(
#[allow(non_camel_case_types)]
$(#[doc = $doc_attr])*
@@ -627,7 +630,7 @@ macro_rules! decl_module {
$(#[$attr])*
pub enum $call_type<$trait_instance: $trait_name> {
#[doc(hidden)]
- __PhantomItem(::core::marker::PhantomData<$trait_instance>),
+ __PhantomItem(::core::marker::PhantomData<$trait_instance>, $crate::dispatch::Never),
$(
#[allow(non_camel_case_types)]
$(#[doc = $doc_attr])*
@@ -662,7 +665,7 @@ macro_rules! decl_module {
self_params == ( $( $param_name, )* )
} else {
match *_other {
- $call_type::__PhantomItem(_) => unreachable!(),
+ $call_type::__PhantomItem(_, _) => unreachable!(),
_ => false,
}
}
@@ -704,7 +707,6 @@ macro_rules! decl_module {
impl<$trait_instance: $trait_name> $crate::dispatch::Encode for $call_type<$trait_instance> {
fn encode_to<W: $crate::dispatch::Output>(&self, _dest: &mut W) {
$crate::__impl_encode!(_dest; *self; 0; $call_type; $( fn $fn_name( $( $(#[$codec_attr on type $param])* $param_name ),* ); )*);
- if let $call_type::__PhantomItem(_) = *self { unreachable!() }
}
}
impl<$trait_instance: $trait_name> $crate::dispatch::Dispatchable
@@ -723,7 +725,7 @@ macro_rules! decl_module {
)
},
)*
- $call_type::__PhantomItem(_) => { panic!("__PhantomItem should never be used.") },
+ $call_type::__PhantomItem(_, _) => { unreachable!("__PhantomItem should never be used.") },
}
}
}
--
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