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Correct unused field warning on struct match container patterns

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This commit is contained in:
varkor 2018-04-30 01:27:37 +01:00
parent 8e8fe9042c
commit 2eb8343af1
3 changed files with 77 additions and 13 deletions
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29
src/librustc/middle/liveness.rs
View File

@ -111,6 +111,7 @@ use ty::{self, TyCtxt};
use lint;
use util::nodemap::{NodeMap, NodeSet};
use std::collections::VecDeque;
use std::{fmt, usize};
use std::io::prelude::*;
use std::io;
@ -420,21 +421,35 @@ fn visit_arm<'a, 'tcx>(ir: &mut IrMaps<'a, 'tcx>, arm: &'tcx hir::Arm) {
// phased out in favor of `HirId`s; however, we need to match the signature of
// `each_binding`, which uses `NodeIds`.
let mut shorthand_field_ids = NodeSet();
loop {
let mut pats = VecDeque::new();
pats.push_back(pat);
while let Some(pat) = pats.pop_front() {
use hir::PatKind::*;
match pat.node {
hir::PatKind::Struct(_, ref fields, _) => {
Binding(_, _, _, ref inner_pat) => {
pats.extend(inner_pat.iter());
}
Struct(_, ref fields, _) => {
for field in fields {
if field.node.is_shorthand {
shorthand_field_ids.insert(field.node.pat.id);
}
}
break;
}
hir::PatKind::Ref(ref inner_pat, _) |
hir::PatKind::Box(ref inner_pat) => {
pat = inner_pat;
Ref(ref inner_pat, _) |
Box(ref inner_pat) => {
pats.push_back(inner_pat);
}
_ => break
TupleStruct(_, ref inner_pats, _) |
Tuple(ref inner_pats, _) => {
pats.extend(inner_pats.iter());
}
Slice(ref pre_pats, ref inner_pat, ref post_pats) => {
pats.extend(pre_pats.iter());
pats.extend(inner_pat.iter());
pats.extend(post_pats.iter());
}
_ => {}
}
}

25
src/test/ui/lint/issue-47390-unused-variable-in-struct-pattern.rs
View File

@ -20,10 +20,13 @@ struct SoulHistory {
endless_and_singing: bool
}
#[derive(Clone, Copy)]
enum Large {
Suit { case: () }
}
struct Tuple(Large, ());
fn main() {
let i_think_continually = 2;
let who_from_the_womb_remembered = SoulHistory {
@ -42,11 +45,33 @@ fn main() {
case: ()
};
// Plain struct
match bag {
Large::Suit { case } => {}
};
// Referenced struct
match &bag {
&Large::Suit { case } => {}
};
// Boxed struct
match box bag {
box Large::Suit { case } => {}
};
// Tuple with struct
match (bag,) {
(Large::Suit { case },) => {}
};
// Slice with struct
match [bag] {
[Large::Suit { case }] => {}
};
// Tuple struct with struct
match Tuple(bag, ()) {
Tuple(Large::Suit { case }, ()) => {}
};
}

36
src/test/ui/lint/issue-47390-unused-variable-in-struct-pattern.stderr
View File

@ -1,5 +1,5 @@
warning: unused variable: `i_think_continually`
--> $DIR/issue-47390-unused-variable-in-struct-pattern.rs:28:9
--> $DIR/issue-47390-unused-variable-in-struct-pattern.rs:31:9
|
LL | let i_think_continually = 2;
| ^^^^^^^^^^^^^^^^^^^ help: consider using `_i_think_continually` instead
@ -12,13 +12,13 @@ LL | #![warn(unused)] // UI tests pass `-A unused` (#43896)
= note: #[warn(unused_variables)] implied by #[warn(unused)]
warning: unused variable: `corridors_of_light`
--> $DIR/issue-47390-unused-variable-in-struct-pattern.rs:35:26
--> $DIR/issue-47390-unused-variable-in-struct-pattern.rs:38:26
|
LL | if let SoulHistory { corridors_of_light,
| ^^^^^^^^^^^^^^^^^^ help: try ignoring the field: `corridors_of_light: _`
warning: variable `hours_are_suns` is assigned to, but never used
--> $DIR/issue-47390-unused-variable-in-struct-pattern.rs:36:26
--> $DIR/issue-47390-unused-variable-in-struct-pattern.rs:39:26
|
LL | mut hours_are_suns,
| ^^^^^^^^^^^^^^^^^^
@ -26,7 +26,7 @@ LL | mut hours_are_suns,
= note: consider using `_hours_are_suns` instead
warning: value assigned to `hours_are_suns` is never read
--> $DIR/issue-47390-unused-variable-in-struct-pattern.rs:38:9
--> $DIR/issue-47390-unused-variable-in-struct-pattern.rs:41:9
|
LL | hours_are_suns = false;
| ^^^^^^^^^^^^^^
@ -39,14 +39,38 @@ LL | #![warn(unused)] // UI tests pass `-A unused` (#43896)
= note: #[warn(unused_assignments)] implied by #[warn(unused)]
warning: unused variable: `case`
--> $DIR/issue-47390-unused-variable-in-struct-pattern.rs:46:24
--> $DIR/issue-47390-unused-variable-in-struct-pattern.rs:50:23
|
LL | Large::Suit { case } => {}
| ^^^^ help: try ignoring the field: `case: _`
warning: unused variable: `case`
--> $DIR/issue-47390-unused-variable-in-struct-pattern.rs:55:24
|
LL | &Large::Suit { case } => {}
| ^^^^ help: try ignoring the field: `case: _`
warning: unused variable: `case`
--> $DIR/issue-47390-unused-variable-in-struct-pattern.rs:50:27
--> $DIR/issue-47390-unused-variable-in-struct-pattern.rs:60:27
|
LL | box Large::Suit { case } => {}
| ^^^^ help: try ignoring the field: `case: _`
warning: unused variable: `case`
--> $DIR/issue-47390-unused-variable-in-struct-pattern.rs:65:24
|
LL | (Large::Suit { case },) => {}
| ^^^^ help: try ignoring the field: `case: _`
warning: unused variable: `case`
--> $DIR/issue-47390-unused-variable-in-struct-pattern.rs:70:24
|
LL | [Large::Suit { case }] => {}
| ^^^^ help: try ignoring the field: `case: _`
warning: unused variable: `case`
--> $DIR/issue-47390-unused-variable-in-struct-pattern.rs:75:29
|
LL | Tuple(Large::Suit { case }, ()) => {}
| ^^^^ help: try ignoring the field: `case: _`