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A small diagnostic improvement for dropping_copy_types

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fixes #125189
This commit is contained in:
surechen 2024-05-22 18:25:26 +08:00
parent 9f432d7b44
commit 09c8e39adb
11 changed files with 169 additions and 11 deletions
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1
compiler/rustc_lint/messages.ftl
View File

@ -197,6 +197,7 @@ lint_drop_trait_constraints =
lint_dropping_copy_types = calls to `std::mem::drop` with a value that implements `Copy` does nothing
.label = argument has type `{$arg_ty}`
.note = use `let _ = ...` to ignore the expression or result
.suggestion = use `let _ = ...` to ignore the expression or result
lint_dropping_references = calls to `std::mem::drop` with a reference instead of an owned value does nothing
.label = argument has type `{$arg_ty}`

21
compiler/rustc_lint/src/drop_forget_useless.rs
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@ -1,11 +1,11 @@
use rustc_hir::{Arm, Expr, ExprKind, Node};
use rustc_hir::{Arm, Expr, ExprKind, Node, StmtKind};
use rustc_middle::ty;
use rustc_span::sym;
use crate::{
lints::{
DropCopyDiag, DropRefDiag, ForgetCopyDiag, ForgetRefDiag, UndroppedManuallyDropsDiag,
UndroppedManuallyDropsSuggestion,
DropCopyDiag, DropCopySuggestion, DropRefDiag, ForgetCopyDiag, ForgetRefDiag,
UndroppedManuallyDropsDiag, UndroppedManuallyDropsSuggestion,
},
LateContext, LateLintPass, LintContext,
};
@ -163,10 +163,23 @@ fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>) {
);
}
sym::mem_drop if is_copy && !drop_is_single_call_in_arm => {
let sugg = if let Some((_, node)) = cx.tcx.hir().parent_iter(expr.hir_id).nth(0)
&& let Node::Stmt(stmt) = node
&& let StmtKind::Semi(e) = stmt.kind
&& e.hir_id == expr.hir_id
{
DropCopySuggestion::Suggestion {
start_span: expr.span.shrink_to_lo().until(arg.span),
end_span: arg.span.shrink_to_hi().until(expr.span.shrink_to_hi()),
}
} else {
DropCopySuggestion::Note
};
cx.emit_span_lint(
DROPPING_COPY_TYPES,
expr.span,
DropCopyDiag { arg_ty, label: arg.span },
DropCopyDiag { arg_ty, label: arg.span, sugg },
);
}
sym::mem_forget if is_copy => {

16
compiler/rustc_lint/src/lints.rs
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@ -669,11 +669,25 @@ pub struct DropRefDiag<'a> {
#[derive(LintDiagnostic)]
#[diag(lint_dropping_copy_types)]
#[note]
pub struct DropCopyDiag<'a> {
pub arg_ty: Ty<'a>,
#[label]
pub label: Span,
#[subdiagnostic]
pub sugg: DropCopySuggestion,
}
#[derive(Subdiagnostic)]
pub enum DropCopySuggestion {
#[note(lint_note)]
Note,
#[multipart_suggestion(lint_suggestion, style = "verbose", applicability = "maybe-incorrect")]
Suggestion {
#[suggestion_part(code = "let _ = ")]
start_span: Span,
#[suggestion_part(code = "")]
end_span: Span,
},
}
#[derive(LintDiagnostic)]

6
tests/ui/associated-types/defaults-unsound-62211-1.next.stderr
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@ -6,8 +6,12 @@ LL | drop(origin);
| |
| argument has type `<T as UncheckedCopy>::Output`
|
= note: use `let _ = ...` to ignore the expression or result
= note: `#[warn(dropping_copy_types)]` on by default
help: use `let _ = ...` to ignore the expression or result
|
LL - drop(origin);
LL + let _ = origin;
|
warning: 1 warning emitted

6
tests/ui/associated-types/defaults-unsound-62211-2.next.stderr
View File

@ -6,8 +6,12 @@ LL | drop(origin);
| |
| argument has type `<T as UncheckedCopy>::Output`
|
= note: use `let _ = ...` to ignore the expression or result
= note: `#[warn(dropping_copy_types)]` on by default
help: use `let _ = ...` to ignore the expression or result
|
LL - drop(origin);
LL + let _ = origin;
|
warning: 1 warning emitted

14
tests/ui/lint/dropping_copy_types-issue-125189-can-not-fixed.rs Normal file
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@ -0,0 +1,14 @@
//@ check-fail
#![deny(dropping_copy_types)]
fn main() {
let y = 1;
let z = 2;
match y {
0 => drop(y), //~ ERROR calls to `std::mem::drop`
1 => drop(z), //~ ERROR calls to `std::mem::drop`
2 => drop(3), //~ ERROR calls to `std::mem::drop`
_ => {},
}
}

37
tests/ui/lint/dropping_copy_types-issue-125189-can-not-fixed.stderr Normal file
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@ -0,0 +1,37 @@
error: calls to `std::mem::drop` with a value that implements `Copy` does nothing
--> $DIR/dropping_copy_types-issue-125189-can-not-fixed.rs:9:14
|
LL | 0 => drop(y),
| ^^^^^-^
| |
| argument has type `i32`
|
= note: use `let _ = ...` to ignore the expression or result
note: the lint level is defined here
--> $DIR/dropping_copy_types-issue-125189-can-not-fixed.rs:3:9
|
LL | #![deny(dropping_copy_types)]
| ^^^^^^^^^^^^^^^^^^^
error: calls to `std::mem::drop` with a value that implements `Copy` does nothing
--> $DIR/dropping_copy_types-issue-125189-can-not-fixed.rs:10:14
|
LL | 1 => drop(z),
| ^^^^^-^
| |
| argument has type `i32`
|
= note: use `let _ = ...` to ignore the expression or result
error: calls to `std::mem::drop` with a value that implements `Copy` does nothing
--> $DIR/dropping_copy_types-issue-125189-can-not-fixed.rs:11:14
|
LL | 2 => drop(3),
| ^^^^^-^
| |
| argument has type `i32`
|
= note: use `let _ = ...` to ignore the expression or result
error: aborting due to 3 previous errors

10
tests/ui/lint/dropping_copy_types-issue-125189.fixed Normal file
View File

@ -0,0 +1,10 @@
//@ check-fail
//@ run-rustfix
#![deny(dropping_copy_types)]
fn main() {
let y = 1;
let _ = 3.2; //~ ERROR calls to `std::mem::drop`
let _ = y; //~ ERROR calls to `std::mem::drop`
}

10
tests/ui/lint/dropping_copy_types-issue-125189.rs Normal file
View File

@ -0,0 +1,10 @@
//@ check-fail
//@ run-rustfix
#![deny(dropping_copy_types)]
fn main() {
let y = 1;
drop(3.2); //~ ERROR calls to `std::mem::drop`
drop(y); //~ ERROR calls to `std::mem::drop`
}

35
tests/ui/lint/dropping_copy_types-issue-125189.stderr Normal file
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@ -0,0 +1,35 @@
error: calls to `std::mem::drop` with a value that implements `Copy` does nothing
--> $DIR/dropping_copy_types-issue-125189.rs:8:5
|
LL | drop(3.2);
| ^^^^^---^
| |
| argument has type `f64`
|
note: the lint level is defined here
--> $DIR/dropping_copy_types-issue-125189.rs:4:9
|
LL | #![deny(dropping_copy_types)]
| ^^^^^^^^^^^^^^^^^^^
help: use `let _ = ...` to ignore the expression or result
|
LL - drop(3.2);
LL + let _ = 3.2;
|
error: calls to `std::mem::drop` with a value that implements `Copy` does nothing
--> $DIR/dropping_copy_types-issue-125189.rs:9:5
|
LL | drop(y);
| ^^^^^-^
| |
| argument has type `i32`
|
help: use `let _ = ...` to ignore the expression or result
|
LL - drop(y);
LL + let _ = y;
|
error: aborting due to 2 previous errors

24
tests/ui/lint/dropping_copy_types.stderr
View File

@ -6,12 +6,16 @@ LL | drop(s1);
| |
| argument has type `SomeStruct`
|
= note: use `let _ = ...` to ignore the expression or result
note: the lint level is defined here
--> $DIR/dropping_copy_types.rs:3:9
|
LL | #![warn(dropping_copy_types)]
| ^^^^^^^^^^^^^^^^^^^
help: use `let _ = ...` to ignore the expression or result
|
LL - drop(s1);
LL + let _ = s1;
|
warning: calls to `std::mem::drop` with a value that implements `Copy` does nothing
--> $DIR/dropping_copy_types.rs:35:5
@ -21,7 +25,11 @@ LL | drop(s2);
| |
| argument has type `SomeStruct`
|
= note: use `let _ = ...` to ignore the expression or result
help: use `let _ = ...` to ignore the expression or result
|
LL - drop(s2);
LL + let _ = s2;
|
warning: calls to `std::mem::drop` with a reference instead of an owned value does nothing
--> $DIR/dropping_copy_types.rs:36:5
@ -42,7 +50,11 @@ LL | drop(s4);
| |
| argument has type `SomeStruct`
|
= note: use `let _ = ...` to ignore the expression or result
help: use `let _ = ...` to ignore the expression or result
|
LL - drop(s4);
LL + let _ = s4;
|
warning: calls to `std::mem::drop` with a reference instead of an owned value does nothing
--> $DIR/dropping_copy_types.rs:38:5
@ -82,7 +94,11 @@ LL | drop(println_and(13));
| |
| argument has type `i32`
|
= note: use `let _ = ...` to ignore the expression or result
help: use `let _ = ...` to ignore the expression or result
|
LL - drop(println_and(13));
LL + let _ = println_and(13);
|
warning: calls to `std::mem::drop` with a value that implements `Copy` does nothing
--> $DIR/dropping_copy_types.rs:74:14