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Rollup merge of rust-lang#63111 - Centril:rest-pat-tests, r=estebank
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Add syntactic and semantic tests for rest patterns, i.e. `..`

As per my first note in rust-lang#62254 (comment) this adds syntactic and semantic tests for `..` ("rest") patterns which were implemented in rust-lang#62550.

r? @estebank
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Centril authored Jul 30, 2019
2 parents 2becb62 + 6c7613b commit 91c10f8
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82 changes: 82 additions & 0 deletions src/test/ui/pattern/rest-pat-semantic-disallowed.rs
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// Here we test that rest patterns, i.e. `..`, are not allowed
// outside of slice (+ ident patterns witin those), tuple,
// and tuple struct patterns and that duplicates are caught in these contexts.

#![feature(slice_patterns, box_patterns)]

fn main() {}

macro_rules! mk_pat {
() => { .. } //~ ERROR `..` patterns are not allowed here
}

fn rest_patterns() {
let mk_pat!();

// Top level:
fn foo(..: u8) {} //~ ERROR `..` patterns are not allowed here
let ..; //~ ERROR `..` patterns are not allowed here

// Box patterns:
let box ..; //~ ERROR `..` patterns are not allowed here

// In or-patterns:
match 1 {
1 | .. => {} //~ ERROR `..` patterns are not allowed here
}

// Ref patterns:
let &..; //~ ERROR `..` patterns are not allowed here
let &mut ..; //~ ERROR `..` patterns are not allowed here

// Ident patterns:
let x @ ..; //~ ERROR `..` patterns are not allowed here
let ref x @ ..; //~ ERROR `..` patterns are not allowed here
let ref mut x @ ..; //~ ERROR `..` patterns are not allowed here

// Tuple:
let (..): (u8,); // OK.
let (..,): (u8,); // OK.
let (
..,
.., //~ ERROR `..` can only be used once per tuple pattern
.. //~ ERROR `..` can only be used once per tuple pattern
): (u8, u8, u8);
let (
..,
x,
.. //~ ERROR `..` can only be used once per tuple pattern
): (u8, u8, u8);

struct A(u8, u8, u8);

// Tuple struct (same idea as for tuple patterns):
let A(..); // OK.
let A(..,); // OK.
let A(
..,
.., //~ ERROR `..` can only be used once per tuple struct pattern
.. //~ ERROR `..` can only be used once per tuple struct pattern
);
let A(
..,
x,
.. //~ ERROR `..` can only be used once per tuple struct pattern
);

// Array/Slice:
let [..]: &[u8]; // OK.
let [..,]: &[u8]; // OK.
let [
..,
.., //~ ERROR `..` can only be used once per slice pattern
.. //~ ERROR `..` can only be used once per slice pattern
]: &[u8];
let [
..,
ref x @ .., //~ ERROR `..` can only be used once per slice pattern
ref mut y @ .., //~ ERROR `..` can only be used once per slice pattern
(ref z @ ..), //~ ERROR `..` patterns are not allowed here
.. //~ ERROR `..` can only be used once per slice pattern
]: &[u8];
}
188 changes: 188 additions & 0 deletions src/test/ui/pattern/rest-pat-semantic-disallowed.stderr
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error: `..` patterns are not allowed here
--> $DIR/rest-pat-semantic-disallowed.rs:10:13
|
LL | () => { .. }
| ^^
...
LL | let mk_pat!();
| --------- in this macro invocation
|
= note: only allowed in tuple, tuple struct, and slice patterns

error: `..` patterns are not allowed here
--> $DIR/rest-pat-semantic-disallowed.rs:18:9
|
LL | let ..;
| ^^
|
= note: only allowed in tuple, tuple struct, and slice patterns

error: `..` patterns are not allowed here
--> $DIR/rest-pat-semantic-disallowed.rs:21:13
|
LL | let box ..;
| ^^
|
= note: only allowed in tuple, tuple struct, and slice patterns

error: `..` patterns are not allowed here
--> $DIR/rest-pat-semantic-disallowed.rs:25:13
|
LL | 1 | .. => {}
| ^^
|
= note: only allowed in tuple, tuple struct, and slice patterns

error: `..` patterns are not allowed here
--> $DIR/rest-pat-semantic-disallowed.rs:29:10
|
LL | let &..;
| ^^
|
= note: only allowed in tuple, tuple struct, and slice patterns

error: `..` patterns are not allowed here
--> $DIR/rest-pat-semantic-disallowed.rs:30:14
|
LL | let &mut ..;
| ^^
|
= note: only allowed in tuple, tuple struct, and slice patterns

error: `..` patterns are not allowed here
--> $DIR/rest-pat-semantic-disallowed.rs:33:13
|
LL | let x @ ..;
| ^^
|
= note: only allowed in tuple, tuple struct, and slice patterns

error: `..` patterns are not allowed here
--> $DIR/rest-pat-semantic-disallowed.rs:34:17
|
LL | let ref x @ ..;
| ^^
|
= note: only allowed in tuple, tuple struct, and slice patterns

error: `..` patterns are not allowed here
--> $DIR/rest-pat-semantic-disallowed.rs:35:21
|
LL | let ref mut x @ ..;
| ^^
|
= note: only allowed in tuple, tuple struct, and slice patterns

error: `..` can only be used once per tuple pattern
--> $DIR/rest-pat-semantic-disallowed.rs:42:9
|
LL | ..,
| -- previously used here
LL | ..,
| ^^ can only be used once per tuple pattern

error: `..` can only be used once per tuple pattern
--> $DIR/rest-pat-semantic-disallowed.rs:43:9
|
LL | ..,
| -- previously used here
LL | ..,
LL | ..
| ^^ can only be used once per tuple pattern

error: `..` can only be used once per tuple pattern
--> $DIR/rest-pat-semantic-disallowed.rs:48:9
|
LL | ..,
| -- previously used here
LL | x,
LL | ..
| ^^ can only be used once per tuple pattern

error: `..` can only be used once per tuple struct pattern
--> $DIR/rest-pat-semantic-disallowed.rs:58:9
|
LL | ..,
| -- previously used here
LL | ..,
| ^^ can only be used once per tuple struct pattern

error: `..` can only be used once per tuple struct pattern
--> $DIR/rest-pat-semantic-disallowed.rs:59:9
|
LL | ..,
| -- previously used here
LL | ..,
LL | ..
| ^^ can only be used once per tuple struct pattern

error: `..` can only be used once per tuple struct pattern
--> $DIR/rest-pat-semantic-disallowed.rs:64:9
|
LL | ..,
| -- previously used here
LL | x,
LL | ..
| ^^ can only be used once per tuple struct pattern

error: `..` can only be used once per slice pattern
--> $DIR/rest-pat-semantic-disallowed.rs:72:9
|
LL | ..,
| -- previously used here
LL | ..,
| ^^ can only be used once per slice pattern

error: `..` can only be used once per slice pattern
--> $DIR/rest-pat-semantic-disallowed.rs:73:9
|
LL | ..,
| -- previously used here
LL | ..,
LL | ..
| ^^ can only be used once per slice pattern

error: `..` can only be used once per slice pattern
--> $DIR/rest-pat-semantic-disallowed.rs:77:17
|
LL | ..,
| -- previously used here
LL | ref x @ ..,
| ^^ can only be used once per slice pattern

error: `..` can only be used once per slice pattern
--> $DIR/rest-pat-semantic-disallowed.rs:78:21
|
LL | ..,
| -- previously used here
LL | ref x @ ..,
LL | ref mut y @ ..,
| ^^ can only be used once per slice pattern

error: `..` patterns are not allowed here
--> $DIR/rest-pat-semantic-disallowed.rs:79:18
|
LL | (ref z @ ..),
| ^^
|
= note: only allowed in tuple, tuple struct, and slice patterns

error: `..` can only be used once per slice pattern
--> $DIR/rest-pat-semantic-disallowed.rs:80:9
|
LL | ..,
| -- previously used here
...
LL | ..
| ^^ can only be used once per slice pattern

error: `..` patterns are not allowed here
--> $DIR/rest-pat-semantic-disallowed.rs:17:12
|
LL | fn foo(..: u8) {}
| ^^
|
= note: only allowed in tuple, tuple struct, and slice patterns

error: aborting due to 22 previous errors

70 changes: 70 additions & 0 deletions src/test/ui/pattern/rest-pat-syntactic.rs
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// Here we test that `..` is allowed in all pattern locations *syntactically*.
// The semantic test is in `rest-pat-semantic-disallowed.rs`.

// check-pass

fn main() {}

macro_rules! accept_pat {
($p:pat) => {}
}

accept_pat!(..);

#[cfg(FALSE)]
fn rest_patterns() {
// Top level:
fn foo(..: u8) {}
let ..;

// Box patterns:
let box ..;

// In or-patterns:
match x {
.. | .. => {}
}

// Ref patterns:
let &..;
let &mut ..;

// Ident patterns:
let x @ ..;
let ref x @ ..;
let ref mut x @ ..;

// Tuple:
let (..); // This is interpreted as a tuple pattern, not a parenthesis one.
let (..,); // Allowing trailing comma.
let (.., .., ..); // Duplicates also.
let (.., P, ..); // Including with things in between.

// Tuple struct (same idea as for tuple patterns):
let A(..);
let A(..,);
let A(.., .., ..);
let A(.., P, ..);

// Array/Slice (like with tuple patterns):
let [..];
let [..,];
let [.., .., ..];
let [.., P, ..];

// Random walk to guard against special casing:
match x {
.. |
[
(
box ..,
&(..),
&mut ..,
x @ ..
),
ref x @ ..,
] |
ref mut x @ ..
=> {}
}
}

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