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cdc3d701cb
Having multiple relaxed bounds like `?Sized + ?Iterator` is actually *fine*. We actually want to reject *duplicate* relaxed bounds like `?Sized + ?Sized` because these most certainly represent a user error. Note that this doesn't mean that we accept more code because a bound like `?Iterator` is still invalid as it's not relaxing a *default* trait and the only way to define / use more default bounds is under the experimental and internal feature `more_maybe_bounds` plus `lang_items` plus unstable flag `-Zexperimental-default-bounds` (historical context: for the longest time, bounds like `?Iterator` were actually allowed and lead to a hard warning). Ultimately, this simply *reframes* the diagnostic. The scope of `more_maybe_bounds` / `-Zexperimental-default-bounds` remains unchanged as well.
39 lines
1.6 KiB
Rust
39 lines
1.6 KiB
Rust
// Test that we emit a correct structured suggestions for dynamically sized ("maybe unsized")
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// function parameters.
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// We used to emit a butchered suggestion if duplicate relaxed `Sized` bounds were present.
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// issue: <https://github.com/rust-lang/rust/issues/127441>.
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use std::fmt::Debug;
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fn foo1<T: ?Sized>(a: T) {}
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//~^ ERROR the size for values of type `T` cannot be known at compilation time
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fn foo2<T: ?Sized + ?Sized>(a: T) {}
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//~^ ERROR duplicate relaxed `Sized` bounds
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//~| ERROR the size for values of type `T` cannot be known at compilation time
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fn foo3<T: ?Sized + ?Sized + Debug>(a: T) {}
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//~^ ERROR duplicate relaxed `Sized` bounds
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//~| ERROR the size for values of type `T` cannot be known at compilation time
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fn foo4<T: ?Sized + Debug + ?Sized >(a: T) {}
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//~^ ERROR duplicate relaxed `Sized` bounds
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//~| ERROR the size for values of type `T` cannot be known at compilation time
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fn foo5(_: impl ?Sized) {}
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//~^ ERROR the size for values of type `impl ?Sized` cannot be known at compilation time
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fn foo6(_: impl ?Sized + ?Sized) {}
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//~^ ERROR duplicate relaxed `Sized` bounds
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//~| ERROR the size for values of type `impl ?Sized + ?Sized` cannot be known at compilation tim
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fn foo7(_: impl ?Sized + ?Sized + Debug) {}
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//~^ ERROR duplicate relaxed `Sized` bounds
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//~| ERROR the size for values of type `impl ?Sized + ?Sized + Debug` cannot be known at compilation time
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fn foo8(_: impl ?Sized + Debug + ?Sized ) {}
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//~^ ERROR duplicate relaxed `Sized` bounds
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//~| ERROR the size for values of type `impl ?Sized + Debug + ?Sized` cannot be known at compilation time
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fn main() {}
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