Struct syn::parse::Nothing [−][src]
An empty syntax tree node that consumes no tokens when parsed.
This is useful for attribute macros that want to ensure they are not provided any attribute args.
use proc_macro::TokenStream; use syn::parse_macro_input; use syn::parse::Nothing; #[proc_macro_attribute] pub fn my_attr(args: TokenStream, input: TokenStream) -> TokenStream { parse_macro_input!(args as Nothing); /* ... */ }
error: unexpected token
--> src/main.rs:3:19
|
3 | #[my_attr(asdf)]
| ^^^^
Trait Implementations
Auto Trait Implementations
impl RefUnwindSafe for Nothing
impl Send for Nothing
impl Sync for Nothing
impl Unpin for Nothing
impl UnwindSafe for Nothing
Blanket Implementations
impl<T> Any for T where
T: 'static + ?Sized,
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T: 'static + ?Sized,
impl<T> Borrow<T> for T where
T: ?Sized,
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T: ?Sized,
impl<T> BorrowMut<T> for T where
T: ?Sized,
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T: ?Sized,
pub fn borrow_mut(&mut self) -> &mut T
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impl<T> From<T> for T
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impl<T, U> Into<U> for T where
U: From<T>,
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U: From<T>,
impl<T, U> TryFrom<U> for T where
U: Into<T>,
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U: Into<T>,
type Error = Infallible
The type returned in the event of a conversion error.
pub fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>
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impl<T, U> TryInto<U> for T where
U: TryFrom<T>,
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U: TryFrom<T>,