mirror of https://github.com/rust-lang/rust
52 lines
1.7 KiB
Rust
52 lines
1.7 KiB
Rust
use std::marker;
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struct A;
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struct B;
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struct C;
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struct Foo<T = A, U = B, V = C>(marker::PhantomData<(T,U,V)>);
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struct Hash<T>(marker::PhantomData<T>);
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struct HashMap<K, V, H = Hash<K>>(marker::PhantomData<(K,V,H)>);
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fn main() {
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// Ensure that the printed type doesn't include the default type params...
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let _: Foo<isize> = ();
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//~^ ERROR mismatched types
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//~| expected `Foo<isize>`, found `()`
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//~| expected struct `Foo<isize>`
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//~| found unit type `()`
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// ...even when they're present, but the same types as the defaults.
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let _: Foo<isize, B, C> = ();
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//~^ ERROR mismatched types
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//~| expected `Foo<isize>`, found `()`
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//~| expected struct `Foo<isize>`
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//~| found unit type `()`
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// Including cases where the default is using previous type params.
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let _: HashMap<String, isize> = ();
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//~^ ERROR mismatched types
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//~| expected `HashMap<String, isize>`, found `()`
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//~| expected struct `HashMap<String, isize>`
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//~| found unit type `()`
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let _: HashMap<String, isize, Hash<String>> = ();
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//~^ ERROR mismatched types
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//~| expected `HashMap<String, isize>`, found `()`
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//~| expected struct `HashMap<String, isize>`
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//~| found unit type `()`
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// But not when there's a different type in between.
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let _: Foo<A, isize, C> = ();
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//~^ ERROR mismatched types
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//~| expected `Foo<A, isize>`, found `()`
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//~| expected struct `Foo<A, isize>`
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//~| found unit type `()`
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// And don't print <> at all when there's just defaults.
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let _: Foo<A, B, C> = ();
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//~^ ERROR mismatched types
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//~| expected `Foo`, found `()`
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//~| expected struct `Foo`
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//~| found unit type `()`
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}
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