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Merged
merged 3 commits into from
May 14, 2018
Merged

Reduce span highlighted code in unused_variables lint #50675

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6c682eb
reduce variable span
csmoe May 11, 2018
a880971
mark applicability
csmoe May 13, 2018
c4e99dd
Revert "mark applicability"
csmoe May 13, 2018
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9 changes: 9 additions & 0 deletions src/librustc/hir/pat_util.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -141,6 +141,15 @@ impl hir::Pat {
}
}

pub fn simple_span(&self) -> Option<Span> {
match self.node {
PatKind::Binding(hir::BindingAnnotation::Unannotated, _, ref path1, None) |
PatKind::Binding(hir::BindingAnnotation::Mutable, _, ref path1, None) =>
Some(path1.span),
_ => None,
}
}

/// Return variants that are necessary to exist for the pattern to match.
pub fn necessary_variants(&self) -> Vec<DefId> {
let mut variants = vec![];
Expand Down
17 changes: 10 additions & 7 deletions src/librustc/middle/liveness.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -453,11 +453,11 @@ fn visit_arm<'a, 'tcx>(ir: &mut IrMaps<'a, 'tcx>, arm: &'tcx hir::Arm) {
}
}

pat.each_binding(|bm, p_id, sp, path1| {
pat.each_binding(|bm, p_id, _sp, path1| {
debug!("adding local variable {} from match with bm {:?}",
p_id, bm);
let name = path1.node;
ir.add_live_node_for_node(p_id, VarDefNode(sp));
ir.add_live_node_for_node(p_id, VarDefNode(path1.span));
ir.add_variable(Local(LocalInfo {
id: p_id,
name: name,
Expand Down Expand Up @@ -628,10 +628,10 @@ impl<'a, 'tcx> Liveness<'a, 'tcx> {
fn pat_bindings<F>(&mut self, pat: &hir::Pat, mut f: F) where
F: FnMut(&mut Liveness<'a, 'tcx>, LiveNode, Variable, Span, NodeId),
{
pat.each_binding(|_bm, p_id, sp, _n| {
pat.each_binding(|_bm, p_id, sp, n| {
let ln = self.live_node(p_id, sp);
let var = self.variable(p_id, sp);
f(self, ln, var, sp, p_id);
let var = self.variable(p_id, n.span);
f(self, ln, var, n.span, p_id);
})
}

Expand Down Expand Up @@ -1398,7 +1398,8 @@ fn check_local<'a, 'tcx>(this: &mut Liveness<'a, 'tcx>, local: &'tcx hir::Local)
},
None => {
this.pat_bindings(&local.pat, |this, ln, var, sp, id| {
this.warn_about_unused(sp, id, ln, var);
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Instead of the if let you could prepend this line with let sp = local.pat.simple_span.unwrap_or(sp);

let span = local.pat.simple_span().unwrap_or(sp);
this.warn_about_unused(span, id, ln, var);
})
}
}
Expand Down Expand Up @@ -1497,7 +1498,8 @@ impl<'a, 'tcx> Liveness<'a, 'tcx> {

fn warn_about_unused_args(&self, body: &hir::Body, entry_ln: LiveNode) {
for arg in &body.arguments {
arg.pat.each_binding(|_bm, p_id, sp, path1| {
arg.pat.each_binding(|_bm, p_id, _, path1| {
let sp = path1.span;
let var = self.variable(p_id, sp);
// Ignore unused self.
let name = path1.node;
Expand Down Expand Up @@ -1541,6 +1543,7 @@ impl<'a, 'tcx> Liveness<'a, 'tcx> {

let suggest_underscore_msg = format!("consider using `_{}` instead",
name);

if is_assigned {
self.ir.tcx
.lint_node_note(lint::builtin::UNUSED_VARIABLES, id, sp,
Expand Down
4 changes: 4 additions & 0 deletions src/test/ui/lint/issue-47390-unused-variable-in-struct-pattern.rs
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Expand Up @@ -35,6 +35,10 @@ fn main() {
endless_and_singing: true
};

let mut mut_unused_var = 1;
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Not sure if that works, but you can try adding a // run-rustfix comment to the top of the file. That'll show us the file after applying the suggestions


let (mut var, unused_var) = (1, 2);

if let SoulHistory { corridors_of_light,
mut hours_are_suns,
endless_and_singing: true } = who_from_the_womb_remembered {
Expand Down
61 changes: 51 additions & 10 deletions src/test/ui/lint/issue-47390-unused-variable-in-struct-pattern.stderr
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Expand Up @@ -11,22 +11,40 @@ 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
|
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
|
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
|
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:38:26
--> $DIR/issue-47390-unused-variable-in-struct-pattern.rs:42:26
|
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:39:26
--> $DIR/issue-47390-unused-variable-in-struct-pattern.rs:43:30
|
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:41:9
--> $DIR/issue-47390-unused-variable-in-struct-pattern.rs:45:9
|
LL | hours_are_suns = false;
| ^^^^^^^^^^^^^^
Expand All @@ -39,38 +57,61 @@ 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:50:23
--> $DIR/issue-47390-unused-variable-in-struct-pattern.rs:54:23
|
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
--> $DIR/issue-47390-unused-variable-in-struct-pattern.rs:59:24
|
LL | &Large::Suit { case } => {}
| ^^^^ help: try ignoring the field: `case: _`

warning: unused variable: `case`
--> $DIR/issue-47390-unused-variable-in-struct-pattern.rs:60:27
--> $DIR/issue-47390-unused-variable-in-struct-pattern.rs:64:27
|
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
--> $DIR/issue-47390-unused-variable-in-struct-pattern.rs:69:24
|
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
--> $DIR/issue-47390-unused-variable-in-struct-pattern.rs:74:24
|
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
--> $DIR/issue-47390-unused-variable-in-struct-pattern.rs:79:29
|
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
|
LL | let mut mut_unused_var = 1;
| ----^^^^^^^^^^^^^^
| |
| help: remove this `mut`
|
note: lint level defined here
--> $DIR/issue-47390-unused-variable-in-struct-pattern.rs:15:9
|
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
|
LL | let (mut var, unused_var) = (1, 2);
| ----^^^
| |
| help: remove this `mut`