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Point at variant on pattern field count mismatch

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This commit is contained in:
Esteban Küber 2019-09-04 19:04:26 -07:00
parent dfd43f0fdd
commit 21e7e3f1e9
5 changed files with 23 additions and 0 deletions
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2
src/librustc_typeck/check/pat.rs
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@ -677,12 +677,14 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
} else {
let subpats_ending = if subpats.len() == 1 { "" } else { "s" };
let fields_ending = if variant.fields.len() == 1 { "" } else { "s" };
let span = tcx.def_span(res.def_id());
struct_span_err!(tcx.sess, pat.span, E0023,
"this pattern has {} field{}, but the corresponding {} has {} field{}",
subpats.len(), subpats_ending, res.descr(),
variant.fields.len(), fields_ending)
.span_label(pat.span, format!("expected {} field{}, found {}",
variant.fields.len(), fields_ending, subpats.len()))
.span_label(span, format!("{} defined here", res.descr()))
.emit();
on_error();
return tcx.types.err;

9
src/test/ui/error-codes/E0023.stderr
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@ -1,18 +1,27 @@
error[E0023]: this pattern has 1 field, but the corresponding tuple variant has 2 fields
--> $DIR/E0023.rs:10:9
|
LL | Apple(String, String),
| --------------------- tuple variant defined here
...
LL | Fruit::Apple(a) => {},
| ^^^^^^^^^^^^^^^ expected 2 fields, found 1
error[E0023]: this pattern has 3 fields, but the corresponding tuple variant has 2 fields
--> $DIR/E0023.rs:11:9
|
LL | Apple(String, String),
| --------------------- tuple variant defined here
...
LL | Fruit::Apple(a, b, c) => {},
| ^^^^^^^^^^^^^^^^^^^^^ expected 2 fields, found 3
error[E0023]: this pattern has 2 fields, but the corresponding tuple variant has 1 field
--> $DIR/E0023.rs:12:9
|
LL | Pear(u32),
| --------- tuple variant defined here
...
LL | Fruit::Pear(1, 2) => {},
| ^^^^^^^^^^^^^^^^^ expected 1 field, found 2

3
src/test/ui/match/match-pattern-field-mismatch.stderr
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@ -1,6 +1,9 @@
error[E0023]: this pattern has 2 fields, but the corresponding tuple variant has 3 fields
--> $DIR/match-pattern-field-mismatch.rs:10:11
|
LL | Rgb(usize, usize, usize),
| ------------------------ tuple variant defined here
...
LL | Color::Rgb(_, _) => { }
| ^^^^^^^^^^^^^^^^ expected 3 fields, found 2

6
src/test/ui/pattern/pat-tuple-overfield.stderr
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@ -19,12 +19,18 @@ LL | (1, 2, .., 3, 4) => {}
error[E0023]: this pattern has 4 fields, but the corresponding tuple struct has 3 fields
--> $DIR/pat-tuple-overfield.rs:10:9
|
LL | struct S(u8, u8, u8);
| --------------------- tuple struct defined here
...
LL | S(1, 2, 3, 4) => {}
| ^^^^^^^^^^^^^ expected 3 fields, found 4
error[E0023]: this pattern has 4 fields, but the corresponding tuple struct has 3 fields
--> $DIR/pat-tuple-overfield.rs:12:9
|
LL | struct S(u8, u8, u8);
| --------------------- tuple struct defined here
...
LL | S(1, 2, .., 3, 4) => {}
| ^^^^^^^^^^^^^^^^^ expected 3 fields, found 4

3
src/test/ui/pattern/pattern-error-continue.stderr
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@ -15,6 +15,9 @@ LL | A::D(_) => (),
error[E0023]: this pattern has 3 fields, but the corresponding tuple variant has 2 fields
--> $DIR/pattern-error-continue.rs:17:9
|
LL | B(isize, isize),
| --------------- tuple variant defined here
...
LL | A::B(_, _, _) => (),
| ^^^^^^^^^^^^^ expected 2 fields, found 3