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Let lint_forgetting_references give the suggestion if possible

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This commit is contained in:
surechen 2024-05-25 11:44:14 +08:00
parent d7f0d1f564
commit ac736d6d88
10 changed files with 383 additions and 45 deletions
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7
compiler/rustc_lint/messages.ftl
View File

@ -237,8 +237,6 @@ lint_dropping_copy_types = calls to `std::mem::drop` with a value that implement
lint_dropping_references = calls to `std::mem::drop` with a reference instead of an owned value does nothing
.label = argument has type `{$arg_ty}`
.note = use `let _ = ...` to ignore the expression or result
.suggestion = use `let _ = ...` to ignore the expression or result
lint_duplicate_macro_attribute =
duplicated attribute
@ -273,12 +271,9 @@ lint_for_loops_over_fallibles =
lint_forgetting_copy_types = calls to `std::mem::forget` with a value that implements `Copy` does nothing
.label = argument has type `{$arg_ty}`
.note = use `let _ = ...` to ignore the expression or result
.suggestion = use `let _ = ...` to ignore the expression or result
lint_forgetting_references = calls to `std::mem::forget` with a reference instead of an owned value does nothing
.label = argument has type `{$arg_ty}`
.note = use `let _ = ...` to ignore the expression or result
lint_hidden_glob_reexport = private item shadows public glob re-export
.note_glob_reexport = the name `{$name}` in the {$namespace} namespace is supposed to be publicly re-exported here
@ -897,6 +892,8 @@ lint_unused_op = unused {$op} that must be used
lint_unused_result = unused result of type `{$ty}`
lint_use_let_underscore_ignore_suggestion = use `let _ = ...` to ignore the expression or result
lint_variant_size_differences =
enum variant is more than three times larger ({$largest} bytes) than the next largest

39
compiler/rustc_lint/src/drop_forget_useless.rs
View File

@ -5,8 +5,9 @@
use crate::{
lints::{
DropCopyDiag, DropRefDiag, ForgetCopyDiag, ForgetRefDiag, IgnoreDropSuggestion,
DropCopyDiag, DropCopySuggestion, DropRefDiag, ForgetCopyDiag, ForgetRefDiag,
UndroppedManuallyDropsDiag, UndroppedManuallyDropsSuggestion,
UseLetUnderscoreIgnoreSuggestion,
},
LateContext, LateLintPass, LintContext,
};
@ -148,31 +149,37 @@ fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>) {
let arg_ty = cx.typeck_results().expr_ty(arg);
let is_copy = arg_ty.is_copy_modulo_regions(cx.tcx, cx.param_env);
let drop_is_single_call_in_arm = is_single_call_in_arm(cx, arg, expr);
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
{
IgnoreDropSuggestion::Suggestion {
start_span: expr.span.shrink_to_lo().until(arg.span),
end_span: arg.span.shrink_to_hi().until(expr.span.shrink_to_hi()),
let let_underscore_ignore_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
{
UseLetUnderscoreIgnoreSuggestion::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 {
UseLetUnderscoreIgnoreSuggestion::Note
}
} else {
IgnoreDropSuggestion::Note
};
match fn_name {
sym::mem_drop if arg_ty.is_ref() && !drop_is_single_call_in_arm => {
cx.emit_span_lint(
DROPPING_REFERENCES,
expr.span,
DropRefDiag { arg_ty, label: arg.span, sugg },
DropRefDiag { arg_ty, label: arg.span, sugg: let_underscore_ignore_sugg() },
);
}
sym::mem_forget if arg_ty.is_ref() => {
cx.emit_span_lint(
FORGETTING_REFERENCES,
expr.span,
ForgetRefDiag { arg_ty, label: arg.span },
ForgetRefDiag {
arg_ty,
label: arg.span,
sugg: let_underscore_ignore_sugg(),
},
);
}
sym::mem_drop if is_copy && !drop_is_single_call_in_arm => {
@ -199,7 +206,11 @@ fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>) {
cx.emit_span_lint(
FORGETTING_COPY_TYPES,
expr.span,
ForgetCopyDiag { arg_ty, label: arg.span, sugg },
ForgetCopyDiag {
arg_ty,
label: arg.span,
sugg: let_underscore_ignore_sugg(),
},
);
}
sym::mem_drop

17
compiler/rustc_lint/src/lints.rs
View File

@ -657,10 +657,14 @@ pub struct ForLoopsOverFalliblesSuggestion<'a> {
}
#[derive(Subdiagnostic)]
pub enum IgnoreDropSuggestion {
#[note(lint_note)]
pub enum UseLetUnderscoreIgnoreSuggestion {
#[note(lint_use_let_underscore_ignore_suggestion)]
Note,
#[multipart_suggestion(lint_suggestion, style = "verbose", applicability = "maybe-incorrect")]
#[multipart_suggestion(
lint_use_let_underscore_ignore_suggestion,
style = "verbose",
applicability = "maybe-incorrect"
)]
Suggestion {
#[suggestion_part(code = "let _ = ")]
start_span: Span,
@ -677,7 +681,7 @@ pub struct DropRefDiag<'a> {
#[label]
pub label: Span,
#[subdiagnostic]
pub sugg: IgnoreDropSuggestion,
pub sugg: UseLetUnderscoreIgnoreSuggestion,
}
#[derive(LintDiagnostic)]
@ -705,11 +709,12 @@ pub enum DropCopySuggestion {
#[derive(LintDiagnostic)]
#[diag(lint_forgetting_references)]
#[note]
pub struct ForgetRefDiag<'a> {
pub arg_ty: Ty<'a>,
#[label]
pub label: Span,
#[subdiagnostic]
pub sugg: UseLetUnderscoreIgnoreSuggestion,
}
#[derive(LintDiagnostic)]
@ -719,7 +724,7 @@ pub struct ForgetCopyDiag<'a> {
#[label]
pub label: Span,
#[subdiagnostic]
pub sugg: IgnoreDropSuggestion,
pub sugg: UseLetUnderscoreIgnoreSuggestion,
}
#[derive(LintDiagnostic)]

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

@ -39,8 +39,12 @@ LL | drop(s3);
| |
| argument has type `&SomeStruct`
|
= note: use `let _ = ...` to ignore the expression or result
= note: `#[warn(dropping_references)]` on by default
help: use `let _ = ...` to ignore the expression or result
|
LL - drop(s3);
LL + let _ = s3;
|
warning: calls to `std::mem::drop` with a value that implements `Copy` does nothing
--> $DIR/dropping_copy_types.rs:37:5
@ -64,7 +68,11 @@ LL | drop(s5);
| |
| argument has type `&SomeStruct`
|
= note: use `let _ = ...` to ignore the expression or result
help: use `let _ = ...` to ignore the expression or result
|
LL - drop(s5);
LL + let _ = s5;
|
warning: calls to `std::mem::drop` with a reference instead of an owned value does nothing
--> $DIR/dropping_copy_types.rs:50:5
@ -74,7 +82,11 @@ LL | drop(a2);
| |
| argument has type `&AnotherStruct`
|
= note: use `let _ = ...` to ignore the expression or result
help: use `let _ = ...` to ignore the expression or result
|
LL - drop(a2);
LL + let _ = a2;
|
warning: calls to `std::mem::drop` with a reference instead of an owned value does nothing
--> $DIR/dropping_copy_types.rs:52:5
@ -84,7 +96,11 @@ LL | drop(a4);
| |
| argument has type `&AnotherStruct`
|
= note: use `let _ = ...` to ignore the expression or result
help: use `let _ = ...` to ignore the expression or result
|
LL - drop(a4);
LL + let _ = a4;
|
warning: calls to `std::mem::drop` with a value that implements `Copy` does nothing
--> $DIR/dropping_copy_types.rs:71:13

30
tests/ui/lint/forgetting_copy_types.stderr
View File

@ -39,8 +39,12 @@ LL | forget(s3);
| |
| argument has type `&SomeStruct`
|
= note: use `let _ = ...` to ignore the expression or result
= note: `#[warn(forgetting_references)]` on by default
help: use `let _ = ...` to ignore the expression or result
|
LL - forget(s3);
LL + let _ = s3;
|
warning: calls to `std::mem::forget` with a value that implements `Copy` does nothing
--> $DIR/forgetting_copy_types.rs:37:5
@ -64,7 +68,11 @@ LL | forget(s5);
| |
| argument has type `&SomeStruct`
|
= note: use `let _ = ...` to ignore the expression or result
help: use `let _ = ...` to ignore the expression or result
|
LL - forget(s5);
LL + let _ = s5;
|
warning: calls to `std::mem::forget` with a reference instead of an owned value does nothing
--> $DIR/forgetting_copy_types.rs:50:5
@ -74,7 +82,11 @@ LL | forget(a2);
| |
| argument has type `&AnotherStruct`
|
= note: use `let _ = ...` to ignore the expression or result
help: use `let _ = ...` to ignore the expression or result
|
LL - forget(a2);
LL + let _ = a2;
|
warning: calls to `std::mem::forget` with a reference instead of an owned value does nothing
--> $DIR/forgetting_copy_types.rs:52:5
@ -84,7 +96,11 @@ LL | forget(a3);
| |
| argument has type `&AnotherStruct`
|
= note: use `let _ = ...` to ignore the expression or result
help: use `let _ = ...` to ignore the expression or result
|
LL - forget(a3);
LL + let _ = a3;
|
warning: calls to `std::mem::forget` with a reference instead of an owned value does nothing
--> $DIR/forgetting_copy_types.rs:53:5
@ -94,7 +110,11 @@ LL | forget(a4);
| |
| argument has type `&AnotherStruct`
|
= note: use `let _ = ...` to ignore the expression or result
help: use `let _ = ...` to ignore the expression or result
|
LL - forget(a4);
LL + let _ = a4;
|
warning: 8 warnings emitted

40
tests/ui/lint/forgetting_references-can-fixed.fixed Normal file
View File

@ -0,0 +1,40 @@
//@ check-fail
//@ run-rustfix
#![deny(forgetting_references)]
use std::mem::forget;
struct SomeStruct;
fn main() {
let _ = &SomeStruct; //~ ERROR calls to `std::mem::forget`
let mut owned = SomeStruct;
let _ = &owned; //~ ERROR calls to `std::mem::forget`
let _ = &&owned; //~ ERROR calls to `std::mem::forget`
let _ = &mut owned; //~ ERROR calls to `std::mem::forget`
forget(owned);
let reference1 = &SomeStruct;
let _ = &*reference1; //~ ERROR calls to `std::mem::forget`
let reference2 = &mut SomeStruct;
let _ = reference2; //~ ERROR calls to `std::mem::forget`
let ref reference3 = SomeStruct;
let _ = reference3; //~ ERROR calls to `std::mem::forget`
}
#[allow(dead_code)]
fn test_generic_fn_forget<T>(val: T) {
let _ = &val; //~ ERROR calls to `std::mem::forget`
forget(val);
}
#[allow(dead_code)]
fn test_similarly_named_function() {
fn forget<T>(_val: T) {}
forget(&SomeStruct); //OK; call to unrelated function which happens to have the same name
let _ = &SomeStruct; //~ ERROR calls to `std::mem::forget`
}

40
tests/ui/lint/forgetting_references-can-fixed.rs Normal file
View File

@ -0,0 +1,40 @@
//@ check-fail
//@ run-rustfix
#![deny(forgetting_references)]
use std::mem::forget;
struct SomeStruct;
fn main() {
forget(&SomeStruct); //~ ERROR calls to `std::mem::forget`
let mut owned = SomeStruct;
forget(&owned); //~ ERROR calls to `std::mem::forget`
forget(&&owned); //~ ERROR calls to `std::mem::forget`
forget(&mut owned); //~ ERROR calls to `std::mem::forget`
forget(owned);
let reference1 = &SomeStruct;
forget(&*reference1); //~ ERROR calls to `std::mem::forget`
let reference2 = &mut SomeStruct;
forget(reference2); //~ ERROR calls to `std::mem::forget`
let ref reference3 = SomeStruct;
forget(reference3); //~ ERROR calls to `std::mem::forget`
}
#[allow(dead_code)]
fn test_generic_fn_forget<T>(val: T) {
forget(&val); //~ ERROR calls to `std::mem::forget`
forget(val);
}
#[allow(dead_code)]
fn test_similarly_named_function() {
fn forget<T>(_val: T) {}
forget(&SomeStruct); //OK; call to unrelated function which happens to have the same name
std::mem::forget(&SomeStruct); //~ ERROR calls to `std::mem::forget`
}

133
tests/ui/lint/forgetting_references-can-fixed.stderr Normal file
View File

@ -0,0 +1,133 @@
error: calls to `std::mem::forget` with a reference instead of an owned value does nothing
--> $DIR/forgetting_references-can-fixed.rs:11:5
|
LL | forget(&SomeStruct);
| ^^^^^^^-----------^
| |
| argument has type `&SomeStruct`
|
note: the lint level is defined here
--> $DIR/forgetting_references-can-fixed.rs:4:9
|
LL | #![deny(forgetting_references)]
| ^^^^^^^^^^^^^^^^^^^^^
help: use `let _ = ...` to ignore the expression or result
|
LL - forget(&SomeStruct);
LL + let _ = &SomeStruct;
|
error: calls to `std::mem::forget` with a reference instead of an owned value does nothing
--> $DIR/forgetting_references-can-fixed.rs:14:5
|
LL | forget(&owned);
| ^^^^^^^------^
| |
| argument has type `&SomeStruct`
|
help: use `let _ = ...` to ignore the expression or result
|
LL - forget(&owned);
LL + let _ = &owned;
|
error: calls to `std::mem::forget` with a reference instead of an owned value does nothing
--> $DIR/forgetting_references-can-fixed.rs:15:5
|
LL | forget(&&owned);
| ^^^^^^^-------^
| |
| argument has type `&&SomeStruct`
|
help: use `let _ = ...` to ignore the expression or result
|
LL - forget(&&owned);
LL + let _ = &&owned;
|
error: calls to `std::mem::forget` with a reference instead of an owned value does nothing
--> $DIR/forgetting_references-can-fixed.rs:16:5
|
LL | forget(&mut owned);
| ^^^^^^^----------^
| |
| argument has type `&mut SomeStruct`
|
help: use `let _ = ...` to ignore the expression or result
|
LL - forget(&mut owned);
LL + let _ = &mut owned;
|
error: calls to `std::mem::forget` with a reference instead of an owned value does nothing
--> $DIR/forgetting_references-can-fixed.rs:20:5
|
LL | forget(&*reference1);
| ^^^^^^^------------^
| |
| argument has type `&SomeStruct`
|
help: use `let _ = ...` to ignore the expression or result
|
LL - forget(&*reference1);
LL + let _ = &*reference1;
|
error: calls to `std::mem::forget` with a reference instead of an owned value does nothing
--> $DIR/forgetting_references-can-fixed.rs:23:5
|
LL | forget(reference2);
| ^^^^^^^----------^
| |
| argument has type `&mut SomeStruct`
|
help: use `let _ = ...` to ignore the expression or result
|
LL - forget(reference2);
LL + let _ = reference2;
|
error: calls to `std::mem::forget` with a reference instead of an owned value does nothing
--> $DIR/forgetting_references-can-fixed.rs:26:5
|
LL | forget(reference3);
| ^^^^^^^----------^
| |
| argument has type `&SomeStruct`
|
help: use `let _ = ...` to ignore the expression or result
|
LL - forget(reference3);
LL + let _ = reference3;
|
error: calls to `std::mem::forget` with a reference instead of an owned value does nothing
--> $DIR/forgetting_references-can-fixed.rs:31:5
|
LL | forget(&val);
| ^^^^^^^----^
| |
| argument has type `&T`
|
help: use `let _ = ...` to ignore the expression or result
|
LL - forget(&val);
LL + let _ = &val;
|
error: calls to `std::mem::forget` with a reference instead of an owned value does nothing
--> $DIR/forgetting_references-can-fixed.rs:39:5
|
LL | std::mem::forget(&SomeStruct);
| ^^^^^^^^^^^^^^^^^-----------^
| |
| argument has type `&SomeStruct`
|
help: use `let _ = ...` to ignore the expression or result
|
LL - std::mem::forget(&SomeStruct);
LL + let _ = &SomeStruct;
|
error: aborting due to 9 previous errors

10
tests/ui/lint/forgetting_references.rs
View File

@ -23,6 +23,16 @@ fn main() {
let ref reference3 = SomeStruct;
forget(reference3); //~ WARN calls to `std::mem::forget`
let ref reference4 = SomeStruct;
let a = 1;
match a {
1 => forget(&*reference1), //~ WARN calls to `std::mem::forget`
2 => forget(reference3), //~ WARN calls to `std::mem::forget`
3 => forget(reference4), //~ WARN calls to `std::mem::forget`
_ => {}
}
}
#[allow(dead_code)]

88
tests/ui/lint/forgetting_references.stderr
View File

@ -6,12 +6,16 @@ LL | forget(&SomeStruct);
| |
| argument has type `&SomeStruct`
|
= note: use `let _ = ...` to ignore the expression or result
note: the lint level is defined here
--> $DIR/forgetting_references.rs:3:9
|
LL | #![warn(forgetting_references)]
| ^^^^^^^^^^^^^^^^^^^^^
help: use `let _ = ...` to ignore the expression or result
|
LL - forget(&SomeStruct);
LL + let _ = &SomeStruct;
|
warning: calls to `std::mem::forget` with a reference instead of an owned value does nothing
--> $DIR/forgetting_references.rs:13:5
@ -21,7 +25,11 @@ LL | forget(&owned);
| |
| argument has type `&SomeStruct`
|
= note: use `let _ = ...` to ignore the expression or result
help: use `let _ = ...` to ignore the expression or result
|
LL - forget(&owned);
LL + let _ = &owned;
|
warning: calls to `std::mem::forget` with a reference instead of an owned value does nothing
--> $DIR/forgetting_references.rs:14:5
@ -31,7 +39,11 @@ LL | forget(&&owned);
| |
| argument has type `&&SomeStruct`
|
= note: use `let _ = ...` to ignore the expression or result
help: use `let _ = ...` to ignore the expression or result
|
LL - forget(&&owned);
LL + let _ = &&owned;
|
warning: calls to `std::mem::forget` with a reference instead of an owned value does nothing
--> $DIR/forgetting_references.rs:15:5
@ -41,7 +53,11 @@ LL | forget(&mut owned);
| |
| argument has type `&mut SomeStruct`
|
= note: use `let _ = ...` to ignore the expression or result
help: use `let _ = ...` to ignore the expression or result
|
LL - forget(&mut owned);
LL + let _ = &mut owned;
|
warning: calls to `std::mem::forget` with a reference instead of an owned value does nothing
--> $DIR/forgetting_references.rs:19:5
@ -51,7 +67,11 @@ LL | forget(&*reference1);
| |
| argument has type `&SomeStruct`
|
= note: use `let _ = ...` to ignore the expression or result
help: use `let _ = ...` to ignore the expression or result
|
LL - forget(&*reference1);
LL + let _ = &*reference1;
|
warning: calls to `std::mem::forget` with a reference instead of an owned value does nothing
--> $DIR/forgetting_references.rs:22:5
@ -61,7 +81,11 @@ LL | forget(reference2);
| |
| argument has type `&mut SomeStruct`
|
= note: use `let _ = ...` to ignore the expression or result
help: use `let _ = ...` to ignore the expression or result
|
LL - forget(reference2);
LL + let _ = reference2;
|
warning: calls to `std::mem::forget` with a reference instead of an owned value does nothing
--> $DIR/forgetting_references.rs:25:5
@ -71,27 +95,69 @@ LL | forget(reference3);
| |
| argument has type `&SomeStruct`
|
help: use `let _ = ...` to ignore the expression or result
|
LL - forget(reference3);
LL + let _ = reference3;
|
warning: calls to `std::mem::forget` with a reference instead of an owned value does nothing
--> $DIR/forgetting_references.rs:31:14
|
LL | 1 => forget(&*reference1),
| ^^^^^^^------------^
| |
| argument has type `&SomeStruct`
|
= note: use `let _ = ...` to ignore the expression or result
warning: calls to `std::mem::forget` with a reference instead of an owned value does nothing
--> $DIR/forgetting_references.rs:30:5
--> $DIR/forgetting_references.rs:32:14
|
LL | 2 => forget(reference3),
| ^^^^^^^----------^
| |
| argument has type `&SomeStruct`
|
= note: use `let _ = ...` to ignore the expression or result
warning: calls to `std::mem::forget` with a reference instead of an owned value does nothing
--> $DIR/forgetting_references.rs:33:14
|
LL | 3 => forget(reference4),
| ^^^^^^^----------^
| |
| argument has type `&SomeStruct`
|
= note: use `let _ = ...` to ignore the expression or result
warning: calls to `std::mem::forget` with a reference instead of an owned value does nothing
--> $DIR/forgetting_references.rs:40:5
|
LL | forget(&val);
| ^^^^^^^----^
| |
| argument has type `&T`
|
= note: use `let _ = ...` to ignore the expression or result
help: use `let _ = ...` to ignore the expression or result
|
LL - forget(&val);
LL + let _ = &val;
|
warning: calls to `std::mem::forget` with a reference instead of an owned value does nothing
--> $DIR/forgetting_references.rs:38:5
--> $DIR/forgetting_references.rs:48:5
|
LL | std::mem::forget(&SomeStruct);
| ^^^^^^^^^^^^^^^^^-----------^
| |
| argument has type `&SomeStruct`
|
= note: use `let _ = ...` to ignore the expression or result
help: use `let _ = ...` to ignore the expression or result
|
LL - std::mem::forget(&SomeStruct);
LL + let _ = &SomeStruct;
|
warning: 9 warnings emitted
warning: 12 warnings emitted