rust/src/test/compile-fail/indexing-requires-a-uint.rs
Ariel Ben-Yehuda fe6ad097c6 deduplicate trait errors before they are displayed
Because of type inference, duplicate obligations exist and cause duplicate
errors. To avoid this, only display the first error for each (predicate,span).

The inclusion of the span is somewhat bikesheddy, but *is* the more
conservative option (it does not remove some instability, as duplicate
obligations are ignored by `duplicate_set` under some inference conditions).

Fixes #28098
cc #21528 (is it a dupe?)
2015-09-26 21:13:31 +03:00

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Rust

// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
// Make sure that indexing an array is only valid with a `usize`, not any other
// integral type.
fn main() {
fn bar<T>(_: T) {}
[0][0u8]; //~ ERROR: the trait `core::ops::Index<u8>` is not implemented
[0][0]; // should infer to be a usize
let i = 0; // i is an IntVar
[0][i]; // i should be locked to usize
bar::<isize>(i); // i should not be re-coerced back to an isize
//~^ ERROR: mismatched types
}