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Rollup merge of #50854 - zackmdavis:and_the_case_of_the_unused_field_pattern_3_straight_to_video, r=estebank

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in which the unused shorthand field pattern debacle/saga continues

In e4b1a79 (#47922), we corrected erroneous suggestions for unused
shorthand field pattern bindings, suggesting `field: _` where the
previous suggestion of `_field` wouldn't even have compiled
(#47390). Soon, it was revealed that this was insufficient (#50303), and
the fix was extended to references, slices, &c. (#50327) But even this
proved inadequate, as the erroneous suggestions were still being issued
for patterns in local (`let`) bindings (#50804). Here, we yank the
shorthand-detection and variable/node registration code into a new
common function that can be called while visiting both match arms and
`let` bindings.

Resolves #50804.

r? @estebank
This commit is contained in:
kennytm 2018-05-19 23:41:03 +08:00
commit 907288c73f
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3 changed files with 80 additions and 71 deletions
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9
src/test/ui/lint/issue-47390-unused-variable-in-struct-pattern.rs
View file

@ -20,6 +20,11 @@ struct SoulHistory {
endless_and_singing: bool
}
struct LovelyAmbition {
lips: usize,
fire: usize
}
#[derive(Clone, Copy)]
enum Large {
Suit { case: () }
@ -45,6 +50,10 @@ fn main() {
hours_are_suns = false;
}
let the_spirit = LovelyAmbition { lips: 1, fire: 2 };
let LovelyAmbition { lips, fire } = the_spirit;
println!("{}", lips);
let bag = 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:31:9
--> $DIR/issue-47390-unused-variable-in-struct-pattern.rs:36:9
|
LL | let i_think_continually = 2;
| ^^^^^^^^^^^^^^^^^^^ help: consider using `_i_think_continually` instead
@ -12,31 +12,31 @@ LL | #![warn(unused)] // UI tests pass `-A unused` (#43896)
= note: #[warn(unused_variables)] implied by #[warn(unused)]
warning: unused variable: `mut_unused_var`
--> $DIR/issue-47390-unused-variable-in-struct-pattern.rs:38:13
--> $DIR/issue-47390-unused-variable-in-struct-pattern.rs:43:13
|
LL | let mut mut_unused_var = 1;
| ^^^^^^^^^^^^^^ help: consider using `_mut_unused_var` instead
warning: unused variable: `var`
--> $DIR/issue-47390-unused-variable-in-struct-pattern.rs:40:14
--> $DIR/issue-47390-unused-variable-in-struct-pattern.rs:45:14
|
LL | let (mut var, unused_var) = (1, 2);
| ^^^ help: consider using `_var` instead
warning: unused variable: `unused_var`
--> $DIR/issue-47390-unused-variable-in-struct-pattern.rs:40:19
--> $DIR/issue-47390-unused-variable-in-struct-pattern.rs:45:19
|
LL | let (mut var, unused_var) = (1, 2);
| ^^^^^^^^^^ help: consider using `_unused_var` instead
warning: unused variable: `corridors_of_light`
--> $DIR/issue-47390-unused-variable-in-struct-pattern.rs:42:26
--> $DIR/issue-47390-unused-variable-in-struct-pattern.rs:47:26
|
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:43:30
--> $DIR/issue-47390-unused-variable-in-struct-pattern.rs:48:30
|
LL | mut hours_are_suns,
| ^^^^^^^^^^^^^^
@ -44,7 +44,7 @@ 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:45:9
--> $DIR/issue-47390-unused-variable-in-struct-pattern.rs:50:9
|
LL | hours_are_suns = false;
| ^^^^^^^^^^^^^^
@ -56,44 +56,50 @@ LL | #![warn(unused)] // UI tests pass `-A unused` (#43896)
| ^^^^^^
= note: #[warn(unused_assignments)] implied by #[warn(unused)]
warning: unused variable: `fire`
--> $DIR/issue-47390-unused-variable-in-struct-pattern.rs:54:32
|
LL | let LovelyAmbition { lips, fire } = the_spirit;
| ^^^^ help: try ignoring the field: `fire: _`
warning: unused variable: `case`
--> $DIR/issue-47390-unused-variable-in-struct-pattern.rs:54:23
--> $DIR/issue-47390-unused-variable-in-struct-pattern.rs:63:23
|
LL | Large::Suit { case } => {}
| ^^^^ help: try ignoring the field: `case: _`
warning: unused variable: `case`
--> $DIR/issue-47390-unused-variable-in-struct-pattern.rs:59:24
--> $DIR/issue-47390-unused-variable-in-struct-pattern.rs:68:24
|
LL | &Large::Suit { case } => {}
| ^^^^ help: try ignoring the field: `case: _`
warning: unused variable: `case`
--> $DIR/issue-47390-unused-variable-in-struct-pattern.rs:64:27
--> $DIR/issue-47390-unused-variable-in-struct-pattern.rs:73:27
|
LL | box Large::Suit { case } => {}
| ^^^^ help: try ignoring the field: `case: _`
warning: unused variable: `case`
--> $DIR/issue-47390-unused-variable-in-struct-pattern.rs:69:24
--> $DIR/issue-47390-unused-variable-in-struct-pattern.rs:78:24
|
LL | (Large::Suit { case },) => {}
| ^^^^ help: try ignoring the field: `case: _`
warning: unused variable: `case`
--> $DIR/issue-47390-unused-variable-in-struct-pattern.rs:74:24
--> $DIR/issue-47390-unused-variable-in-struct-pattern.rs:83:24
|
LL | [Large::Suit { case }] => {}
| ^^^^ help: try ignoring the field: `case: _`
warning: unused variable: `case`
--> $DIR/issue-47390-unused-variable-in-struct-pattern.rs:79:29
--> $DIR/issue-47390-unused-variable-in-struct-pattern.rs:88:29
|
LL | Tuple(Large::Suit { case }, ()) => {}
| ^^^^ help: try ignoring the field: `case: _`
warning: variable does not need to be mutable
--> $DIR/issue-47390-unused-variable-in-struct-pattern.rs:38:9
--> $DIR/issue-47390-unused-variable-in-struct-pattern.rs:43:9
|
LL | let mut mut_unused_var = 1;
| ----^^^^^^^^^^^^^^
@ -108,7 +114,7 @@ LL | #![warn(unused)] // UI tests pass `-A unused` (#43896)
= note: #[warn(unused_mut)] implied by #[warn(unused)]
warning: variable does not need to be mutable
--> $DIR/issue-47390-unused-variable-in-struct-pattern.rs:40:10
--> $DIR/issue-47390-unused-variable-in-struct-pattern.rs:45:10
|
LL | let (mut var, unused_var) = (1, 2);
| ----^^^