69 lines
1.9 KiB
Rust
69 lines
1.9 KiB
Rust
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#![warn(clippy::implied_bounds_in_impls)]
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#![allow(dead_code)]
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#![feature(return_position_impl_trait_in_trait)]
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use std::ops::{Deref, DerefMut};
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// Only one bound, nothing to lint.
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fn normal_deref<T>(x: T) -> impl Deref<Target = T> {
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Box::new(x)
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}
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// Deref implied by DerefMut
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fn deref_derefmut<T>(x: T) -> impl DerefMut<Target = T> {
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Box::new(x)
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}
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trait GenericTrait<T> {}
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trait GenericTrait2<V> {}
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// U is intentionally at a different "index" in GenericSubtrait than `T` is in GenericTrait,
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// so this can be a good test to make sure that the calculations are right (no off-by-one errors,
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// ...)
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trait GenericSubtrait<T, U, V>: GenericTrait<U> + GenericTrait2<V> {}
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impl GenericTrait<i32> for () {}
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impl GenericTrait<i64> for () {}
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impl<V> GenericTrait2<V> for () {}
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impl<V> GenericSubtrait<(), i32, V> for () {}
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impl<V> GenericSubtrait<(), i64, V> for () {}
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fn generics_implied<U, W>() -> impl GenericSubtrait<U, W, U>
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where
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(): GenericSubtrait<U, W, U>,
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{
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}
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fn generics_implied_multi<V>() -> impl GenericSubtrait<(), i32, V> {}
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fn generics_implied_multi2<T, V>() -> impl GenericSubtrait<(), T, V>
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where
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(): GenericSubtrait<(), T, V> + GenericTrait<T>,
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{
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}
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// i32 != i64, GenericSubtrait<_, i64, _> does not imply GenericTrait<i32>, don't lint
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fn generics_different() -> impl GenericTrait<i32> + GenericSubtrait<(), i64, ()> {}
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// i32 == i32, GenericSubtrait<_, i32, _> does imply GenericTrait<i32>, lint
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fn generics_same() -> impl GenericSubtrait<(), i32, ()> {}
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trait SomeTrait {
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// Check that it works in trait declarations.
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fn f() -> impl DerefMut<Target = u8>;
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}
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struct SomeStruct;
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impl SomeStruct {
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// Check that it works in inherent impl blocks.
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fn f() -> impl DerefMut<Target = u8> {
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Box::new(123)
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}
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}
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impl SomeTrait for SomeStruct {
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// Check that it works in trait impls.
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fn f() -> impl DerefMut<Target = u8> {
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Box::new(42)
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}
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}
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fn main() {}
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