mirror of https://github.com/rust-lang/rust
60 lines
2.3 KiB
Rust
60 lines
2.3 KiB
Rust
// Test `ignored_generic_bounds` lint warning about bounds in type aliases.
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//@ check-pass
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#![allow(dead_code)]
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use std::rc::Rc;
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type SVec<T: Send + Send> = Vec<T>;
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//~^ WARN bounds on generic parameters are not enforced in type aliases [type_alias_bounds]
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type S2Vec<T> where T: Send = Vec<T>;
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//~^ WARN where clauses are not enforced in type aliases [type_alias_bounds]
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type VVec<'b, 'a: 'b + 'b> = (&'b u32, Vec<&'a i32>);
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//~^ WARN bounds on generic parameters are not enforced in type aliases [type_alias_bounds]
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type WVec<'b, T: 'b + 'b> = (&'b u32, Vec<T>);
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//~^ WARN bounds on generic parameters are not enforced in type aliases [type_alias_bounds]
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type W2Vec<'b, T> where T: 'b, T: 'b = (&'b u32, Vec<T>);
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//~^ WARN where clauses are not enforced in type aliases [type_alias_bounds]
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static STATIC: u32 = 0;
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fn foo<'a>(y: &'a i32) {
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// If any of the bounds above would matter, the code below would be rejected.
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// This can be seen when replacing the type aliases above by newtype structs.
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// (The type aliases have no unused parameters to make that a valid transformation.)
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let mut x: SVec<_> = Vec::new();
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x.push(Rc::new(42)); // is not send
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let mut x: S2Vec<_> = Vec::new();
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x.push(Rc::new(42)); // is not `Send`
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let mut x: VVec<'static, 'a> = (&STATIC, Vec::new());
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x.1.push(y); // `'a: 'static` does not hold
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let mut x: WVec<'static, &'a i32> = (&STATIC, Vec::new());
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x.1.push(y); // `&'a i32: 'static` does not hold
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let mut x: W2Vec<'static, &'a i32> = (&STATIC, Vec::new());
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x.1.push(y); // `&'a i32: 'static` does not hold
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}
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// Bounds are not checked either; i.e., the definition is not necessarily well-formed.
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struct Sendable<T: Send>(T);
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type MySendable<T> = Sendable<T>; // no error here!
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// However, bounds *are* taken into account when accessing associated types
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trait Bound { type Assoc; }
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type T1<U: Bound> = U::Assoc; //~ WARN not enforced in type aliases
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type T2<U> where U: Bound = U::Assoc; //~ WARN not enforced in type aliases
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// This errors:
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// `type T3<U> = U::Assoc;`
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// Do this instead:
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type T4<U> = <U as Bound>::Assoc;
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// Make sure the help about associated types is not shown incorrectly
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type T5<U: Bound> = <U as Bound>::Assoc; //~ WARN not enforced in type aliases
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type T6<U: Bound> = ::std::vec::Vec<U>; //~ WARN not enforced in type aliases
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fn main() {}
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