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Change to give a help message

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This commit is contained in:
John Ginger 2018-12-07 14:15:36 +00:00
parent 70536d4b4c
commit c0e3f4b8bb
4 changed files with 19 additions and 13 deletions
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14
src/librustc/middle/liveness.rs
View file

@ -1657,13 +1657,15 @@ impl<'a, 'tcx> Liveness<'a, 'tcx> {
fn report_dead_assign(&self, hir_id: HirId, sp: Span, var: Variable, is_argument: bool) {
if let Some(name) = self.should_warn(var) {
if is_argument {
self.ir.tcx.lint_hir(lint::builtin::UNUSED_ASSIGNMENTS, hir_id, sp,
&format!("value passed to `{}` is never read
(maybe it is overwritten before being read)", name));
self.ir.tcx.struct_span_lint_hir(lint::builtin::UNUSED_ASSIGNMENTS, hir_id, sp,
&format!("value passed to `{}` is never read", name))
.help("maybe it is overwritten before being read?")
.emit();
} else {
self.ir.tcx.lint_hir(lint::builtin::UNUSED_ASSIGNMENTS, hir_id, sp,
&format!("value assigned to `{}` is never read
(maybe it is overwritten before being read)", name));
self.ir.tcx.struct_span_lint_hir(lint::builtin::UNUSED_ASSIGNMENTS, hir_id, sp,
&format!("value assigned to `{}` is never read", name))
.help("maybe it is overwritten before being read?")
.emit();
}
}
}

2
src/test/ui/lint/issue-47390-unused-variable-in-struct-pattern.stderr
View file

@ -44,7 +44,6 @@ LL | mut hours_are_suns,
= note: consider using `_hours_are_suns` instead
warning: value assigned to `hours_are_suns` is never read
(maybe it is overwritten before being read)
--> $DIR/issue-47390-unused-variable-in-struct-pattern.rs:50:9
|
LL | hours_are_suns = false;
@ -56,6 +55,7 @@ note: lint level defined here
LL | #![warn(unused)] // UI tests pass `-A unused` (#43896)
| ^^^^^^
= note: #[warn(unused_assignments)] implied by #[warn(unused)]
= help: maybe it is overwritten before being read?
warning: unused variable: `fire`
--> $DIR/issue-47390-unused-variable-in-struct-pattern.rs:54:32

11
src/test/ui/liveness/liveness-dead.stderr
View file

@ -1,5 +1,4 @@
error: value assigned to `x` is never read
(maybe it is overwritten before being read)
--> $DIR/liveness-dead.rs:19:13
|
LL | let mut x: isize = 3; //~ ERROR: value assigned to `x` is never read
@ -10,27 +9,31 @@ note: lint level defined here
|
LL | #![deny(unused_assignments)]
| ^^^^^^^^^^^^^^^^^^
= help: maybe it is overwritten before being read?
error: value assigned to `x` is never read
(maybe it is overwritten before being read)
--> $DIR/liveness-dead.rs:27:5
|
LL | x = 4; //~ ERROR: value assigned to `x` is never read
| ^
|
= help: maybe it is overwritten before being read?
error: value passed to `x` is never read
(maybe it is overwritten before being read)
--> $DIR/liveness-dead.rs:30:11
|
LL | fn f4(mut x: i32) { //~ ERROR: value passed to `x` is never read
| ^
|
= help: maybe it is overwritten before being read?
error: value assigned to `x` is never read
(maybe it is overwritten before being read)
--> $DIR/liveness-dead.rs:37:5
|
LL | x = 4; //~ ERROR: value assigned to `x` is never read
| ^
|
= help: maybe it is overwritten before being read?
error: aborting due to 4 previous errors

5
src/test/ui/liveness/liveness-unused.stderr
View file

@ -50,7 +50,6 @@ LL | let mut x = 3;
= note: consider using `_x` instead
error: value assigned to `x` is never read
(maybe it is overwritten before being read)
--> $DIR/liveness-unused.rs:42:5
|
LL | x += 4;
@ -61,6 +60,7 @@ note: lint level defined here
|
LL | #![deny(unused_assignments)]
| ^^^^^^^^^^^^^^^^^^
= help: maybe it is overwritten before being read?
error: variable `z` is assigned to, but never used
--> $DIR/liveness-unused.rs:47:13
@ -103,11 +103,12 @@ LL | let x;
= note: consider using `_x` instead
error: value assigned to `x` is never read
(maybe it is overwritten before being read)
--> $DIR/liveness-unused.rs:126:9
|
LL | x = 0; //~ ERROR value assigned to `x` is never read
| ^
|
= help: maybe it is overwritten before being read?
error: aborting due to 13 previous errors