Add StaticTypeInfo convenience trait

README.md

@@ -97,7 +97,7 @@ struct Foo<T> {
 
 impl<T> TypeInfo for Foo<T>
 where
-    T: TypeInfo,
+    T: TypeInfo + 'static,
 {
     type Identity = Self;
 
@@ -146,7 +146,7 @@ enum Foo<T>{
 
 impl<T> TypeInfo for Foo<T>
 where
-    T: TypeInfo,
+    T: TypeInfo + 'static,
 {
     type Identity = Self;
 

derive/src/trait_bounds.rs

@@ -31,7 +31,7 @@ use syn::{
 
 use crate::utils;
 
-/// Generates a where clause for a `TypeInfo` impl, adding `TypeInfo` bounds to all
+/// Generates a where clause for a `TypeInfo` impl, adding `TypeInfo + 'static` bounds to all
 /// relevant generic types including associated types (e.g. `T::A: TypeInfo`), correctly dealing
 /// with self-referential types.
 pub fn make_where_clause<'a>(
@@ -66,25 +66,26 @@ pub fn make_where_clause<'a>(
 
     types.into_iter().for_each(|(ty, is_compact)| {
         // Compact types need extra bounds, T: HasCompact and <T as
-        // HasCompact>::Type: TypeInfo
+        // HasCompact>::Type: TypeInfo + 'static
         if is_compact {
             where_clause
                 .predicates
                 .push(parse_quote!(#ty : :: #parity_scale_codec ::HasCompact));
             where_clause
                 .predicates
-                .push(parse_quote!(<#ty as :: #parity_scale_codec ::HasCompact>::Type : :: #scale_info ::TypeInfo));
+                .push(parse_quote!(<#ty as :: #parity_scale_codec ::HasCompact>::Type : :: #scale_info ::TypeInfo + 'static));
         } else {
             where_clause
                 .predicates
-                .push(parse_quote!(#ty : :: #scale_info ::TypeInfo));
+                .push(parse_quote!(#ty : :: #scale_info ::TypeInfo + 'static));
         }
     });
 
     generics.type_params().into_iter().for_each(|type_param| {
         let ident = type_param.ident.clone();
         let mut bounds = type_param.bounds.clone();
         bounds.push(parse_quote!(:: #scale_info ::TypeInfo));
+        bounds.push(parse_quote!('static));
         where_clause
             .predicates
             .push(parse_quote!( #ident : #bounds));

src/build.rs

@@ -30,7 +30,7 @@
 //!
 //! impl<T> TypeInfo for Foo<T>
 //! where
-//!     T: TypeInfo,
+//!     T: TypeInfo + 'static,
 //! {
 //!     type Identity = Self;
 //!
@@ -74,7 +74,7 @@
 //!
 //! impl<T> TypeInfo for Foo<T>
 //! where
-//!     T: TypeInfo,
+//!     T: TypeInfo + 'static,
 //! {
 //!     type Identity = Self;
 //!
@@ -254,7 +254,7 @@ impl FieldsBuilder<NamedFields> {
     /// Add a named field with the type of the type parameter `T`
     pub fn field_of<T>(mut self, name: &'static str, type_name: &'static str) -> Self
     where
-        T: TypeInfo + ?Sized,
+        T: TypeInfo + ?Sized + 'static,
     {
         self.fields.push(Field::named_of::<T>(name, type_name));
         self
@@ -264,7 +264,7 @@ impl FieldsBuilder<NamedFields> {
     pub fn compact_of<T>(mut self, name: &'static str, type_name: &'static str) -> Self
     where
         T: scale::HasCompact,
-        <T as scale::HasCompact>::Type: TypeInfo,
+        <T as scale::HasCompact>::Type: TypeInfo + 'static,
     {
         self.fields
             .push(Field::compact_of::<T>(Some(name), type_name));
@@ -276,7 +276,7 @@ impl FieldsBuilder<UnnamedFields> {
     /// Add an unnamed field with the type of the type parameter `T`
     pub fn field_of<T>(mut self, type_name: &'static str) -> Self
     where
-        T: TypeInfo + ?Sized,
+        T: TypeInfo + ?Sized + 'static,
     {
         self.fields.push(Field::unnamed_of::<T>(type_name));
         self
@@ -286,7 +286,7 @@ impl FieldsBuilder<UnnamedFields> {
     pub fn compact_of<T>(mut self, type_name: &'static str) -> Self
     where
         T: scale::HasCompact,
-        <T as scale::HasCompact>::Type: TypeInfo,
+        <T as scale::HasCompact>::Type: TypeInfo + 'static,
     {
         self.fields.push(Field::compact_of::<T>(None, type_name));
         self

src/impls.rs

@@ -68,7 +68,7 @@ impl_metadata_for_primitives!(
     i128 => TypeDefPrimitive::I128,
 );
 
-impl<T: TypeInfo, const N: usize> TypeInfo for [T; N] {
+impl<T: TypeInfo + 'static, const N: usize> TypeInfo for [T; N] {
     type Identity = Self;
 
     fn type_info() -> Type {
@@ -81,7 +81,7 @@ macro_rules! impl_metadata_for_tuple {
         impl<$($ty),*> TypeInfo for ($($ty,)*)
         where
             $(
-                $ty: TypeInfo,
+                $ty: TypeInfo+ 'static,
             )*
         {
             type Identity = Self;
@@ -113,7 +113,7 @@ impl_metadata_for_tuple!(A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P);
 
 impl<T> TypeInfo for Vec<T>
 where
-    T: TypeInfo,
+    T: TypeInfo + 'static,
 {
     type Identity = [T];
 
@@ -124,7 +124,7 @@ where
 
 impl<T> TypeInfo for Option<T>
 where
-    T: TypeInfo,
+    T: TypeInfo + 'static,
 {
     type Identity = Self;
 
@@ -142,8 +142,8 @@ where
 
 impl<T, E> TypeInfo for Result<T, E>
 where
-    T: TypeInfo,
-    E: TypeInfo,
+    T: TypeInfo + 'static,
+    E: TypeInfo + 'static,
 {
     type Identity = Self;
 
@@ -161,7 +161,7 @@ where
 
 impl<T> TypeInfo for Cow<'static, T>
 where
-    T: ToOwned + TypeInfo + ?Sized,
+    T: ToOwned + TypeInfo + ?Sized + 'static,
 {
     type Identity = Self;
 
@@ -175,8 +175,8 @@ where
 
 impl<K, V> TypeInfo for BTreeMap<K, V>
 where
-    K: TypeInfo,
-    V: TypeInfo,
+    K: TypeInfo + 'static,
+    V: TypeInfo + 'static,
 {
     type Identity = Self;
 
@@ -190,7 +190,7 @@ where
 
 impl<T> TypeInfo for BTreeSet<T>
 where
-    T: TypeInfo,
+    T: TypeInfo + 'static,
 {
     type Identity = Self;
 
@@ -204,7 +204,7 @@ where
 
 impl<T> TypeInfo for Box<T>
 where
-    T: TypeInfo + ?Sized,
+    T: TypeInfo + ?Sized + 'static,
 {
     type Identity = T;
 
@@ -213,9 +213,9 @@ where
     }
 }
 
-impl<T> TypeInfo for &'static T
+impl<T> TypeInfo for &T
 where
-    T: TypeInfo + ?Sized,
+    T: TypeInfo + ?Sized + 'static,
 {
     type Identity = T;
 
@@ -224,9 +224,9 @@ where
     }
 }
 
-impl<T> TypeInfo for &'static mut T
+impl<T> TypeInfo for &mut T
 where
-    T: TypeInfo + ?Sized,
+    T: TypeInfo + ?Sized + 'static,
 {
     type Identity = T;
 
@@ -237,7 +237,7 @@ where
 
 impl<T> TypeInfo for [T]
 where
-    T: TypeInfo,
+    T: TypeInfo + 'static,
 {
     type Identity = Self;
 
@@ -264,7 +264,7 @@ impl TypeInfo for String {
 
 impl<T> TypeInfo for PhantomData<T>
 where
-    T: TypeInfo + ?Sized,
+    T: TypeInfo + ?Sized + 'static,
 {
     type Identity = Self;
 
@@ -275,7 +275,7 @@ where
 
 impl<T> TypeInfo for scale::Compact<T>
 where
-    T: TypeInfo,
+    T: TypeInfo + 'static,
 {
     type Identity = Self;
     fn type_info() -> Type {

src/lib.rs

@@ -129,7 +129,7 @@ pub use self::{
 pub use scale_info_derive::TypeInfo;
 
 /// Implementors return their meta type information.
-pub trait TypeInfo: 'static {
+pub trait TypeInfo {
     /// The type identifying for which type info is provided.
     ///
     /// # Note
@@ -143,10 +143,21 @@ pub trait TypeInfo: 'static {
     fn type_info() -> Type;
 }
 
+/// Convenience trait for implementors, combining `TypeInfo` and `'static` bounds.
+///
+/// # Note
+///
+/// Currently because of the `'static` constraint on [`std::any::TypeId::of`] (see [`MetaType`]),
+/// `TypeInfo` constraints must also be accompanied by a `'static` bound. This trait is useful to
+/// for implementors so only a single constraint is required.
+pub trait StaticTypeInfo: TypeInfo + 'static {}
+
+impl<T> StaticTypeInfo for T where T: TypeInfo + 'static {}
+
 /// Returns the runtime bridge to the types compile-time type information.
 pub fn meta_type<T>() -> MetaType
 where
-    T: ?Sized + TypeInfo,
+    T: ?Sized + TypeInfo + 'static,
 {
     MetaType::new::<T>()
 }

src/meta_type.rs

@@ -88,7 +88,7 @@ impl MetaType {
     /// Creates a new meta type from the given compile-time known type.
     pub fn new<T>() -> Self
     where
-        T: TypeInfo + ?Sized,
+        T: TypeInfo + ?Sized + 'static,
     {
         Self {
             fn_type_info: <T as TypeInfo>::type_info,

src/tests.rs

@@ -154,7 +154,7 @@ fn struct_with_generics() {
 
     impl<T> TypeInfo for MyStruct<T>
     where
-        T: TypeInfo,
+        T: TypeInfo + 'static,
     {
         type Identity = Self;
 
@@ -193,7 +193,7 @@ fn basic_struct_with_phantoms() {
 
     impl<T> TypeInfo for SomeStruct<T>
     where
-        T: TypeInfo,
+        T: TypeInfo + 'static,
     {
         type Identity = Self;
 

src/ty/fields.rs

@@ -115,7 +115,7 @@ impl Field {
     /// compile-time type.
     pub fn named_of<T>(name: &'static str, type_name: &'static str) -> Field
     where
-        T: TypeInfo + ?Sized,
+        T: TypeInfo + ?Sized + 'static,
     {
         Self::new(Some(name), MetaType::new::<T>(), type_name)
     }
@@ -126,7 +126,7 @@ impl Field {
     /// given compile-time type.
     pub fn unnamed_of<T>(type_name: &'static str) -> Field
     where
-        T: TypeInfo + ?Sized,
+        T: TypeInfo + ?Sized + 'static,
     {
         Self::new(None, MetaType::new::<T>(), type_name)
     }
@@ -135,7 +135,7 @@ impl Field {
     pub fn compact_of<T>(name: Option<&'static str>, type_name: &'static str) -> Field
     where
         T: HasCompact,
-        <T as HasCompact>::Type: TypeInfo,
+        <T as HasCompact>::Type: TypeInfo + 'static,
     {
         Self::new(name, MetaType::new::<<T as HasCompact>::Type>(), type_name)
     }

src/ty/mod.rs

@@ -370,7 +370,7 @@ impl TypeDefSequence {
     /// compile-time type.
     pub fn of<T>() -> Self
     where
-        T: TypeInfo,
+        T: TypeInfo + 'static,
     {
         Self::new(MetaType::new::<T>())
     }

test_suite/tests/derive.rs

@@ -231,22 +231,6 @@ fn fields_with_type_alias() {
     assert_type!(S, ty);
 }
 
-#[test]
-fn basic_reference_with_lifetime() {
-    #[allow(unused)]
-    #[derive(TypeInfo)]
-    struct S<'a, T> {
-        f: &'a T,
-    }
-
-    let struct_type = Type::builder()
-        .path(Path::new("S", "derive"))
-        .type_params(tuple_meta_type!(u32))
-        .composite(Fields::named().field_of::<&'static u32>("f", "&'static T"));
-
-    assert_type!(S<u32>, struct_type);
-}
-
 #[test]
 fn associated_types_derive_without_bounds() {
     trait Types {

test_suite/tests/ui/fail_missing_derive.rs

@@ -11,7 +11,7 @@ struct Cat<Tail, Ear, Paw> {
     paws: PawType<Paw>,
 }
 
-fn assert_type_info<T: TypeInfo>() {}
+fn assert_type_info<T: TypeInfo + 'static>() {}
 
 fn main() {
     assert_type_info::<Cat<bool, u8, u16>>();

test_suite/tests/ui/fail_missing_derive.stderr

@@ -1,7 +1,7 @@
 error[E0277]: the trait bound `PawType<u16>: TypeInfo` is not satisfied
   --> $DIR/fail_missing_derive.rs:17:5
    |
-14 | fn assert_type_info<T: TypeInfo>() {}
+14 | fn assert_type_info<T: TypeInfo + 'static>() {}
    |                        -------- required by this bound in `assert_type_info`
 ...
 17 |     assert_type_info::<Cat<bool, u8, u16>>();

test_suite/tests/ui/fail_non_static_lifetime.rs

@@ -5,7 +5,7 @@ struct Me<'a> {
     me: &'a Me<'a>,
 }
 
-fn assert_type_info<T: TypeInfo>() {}
+fn assert_type_info<T: TypeInfo + 'static>() {}
 
 fn main() {
     assert_type_info::<Me>();