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Rollup merge of #111757 - lowr:fix/lint-attr-on-match-arm, r=eholk

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Consider lint check attributes on match arms

Currently, lint check attributes on match arms have no effect for some lints. This PR makes some lint passes to take those attributes into account.

- `LateContextAndPass` for late lint doesn't update `last_node_with_lint_attrs` when it visits match arms. This leads to lint check attributes on match arms taking no effects on late lints that operate on the arms' pattern:

  ```rust
  match value {
      #[deny(non_snake_case)]
      PAT => {} // `non_snake_case` only warned due to default lint level
  }
  ```

  To be honest, I'm not sure whether this is intentional or just an oversight. I've dug the implementation history and searched up issues/PRs but couldn't find any discussion on this.

- `MatchVisitor` doesn't update its lint level when it visits match arms. This leads to check lint attributes on match arms taking no effect on some lints handled by this visitor, namely: `bindings_with_variant_name` and `irrefutable_let_patterns`.

  This seems to be a fallout from #108504. Before 05082f57af, when the visitor operated on HIR rather than THIR, check lint attributes for the said lints were effective. [This playground][play] compiles successfully on current stable (1.69) but fails on current beta and nightly.

  I wasn't sure where best to place the test for this. Let me know if there's a better place.

[play]: https://play.rust-lang.org/?version=stable&mode=debug&edition=2021&gist=38432b79e535cb175f8f7d6d236d29c3
[play-match]: https://play.rust-lang.org/?version=beta&mode=debug&edition=2021&gist=629aa71b7c84b269beadeba664e2221d
This commit is contained in:
Michael Goulet 2023-05-25 13:58:00 -07:00 committed by GitHub
commit 9d4527bc80
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8 changed files with 170 additions and 64 deletions
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6
compiler/rustc_lint/src/late.rs
View File

@ -240,8 +240,10 @@ fn visit_block(&mut self, b: &'tcx hir::Block<'tcx>) {
}
fn visit_arm(&mut self, a: &'tcx hir::Arm<'tcx>) {
lint_callback!(self, check_arm, a);
hir_visit::walk_arm(self, a);
self.with_lint_attrs(a.hir_id, |cx| {
lint_callback!(cx, check_arm, a);
hir_visit::walk_arm(cx, a);
})
}
fn visit_generic_param(&mut self, p: &'tcx hir::GenericParam<'tcx>) {

34
compiler/rustc_mir_build/src/thir/pattern/check_match.rs
View File

@ -90,14 +90,15 @@ fn thir(&self) -> &'a Thir<'tcx> {
#[instrument(level = "trace", skip(self))]
fn visit_arm(&mut self, arm: &Arm<'tcx>) {
self.with_lint_level(arm.lint_level, |this| {
match arm.guard {
Some(Guard::If(expr)) => {
self.with_let_source(LetSource::IfLetGuard, |this| {
this.with_let_source(LetSource::IfLetGuard, |this| {
this.visit_expr(&this.thir[expr])
});
}
Some(Guard::IfLet(ref pat, expr)) => {
self.with_let_source(LetSource::IfLetGuard, |this| {
this.with_let_source(LetSource::IfLetGuard, |this| {
this.check_let(pat, expr, LetSource::IfLetGuard, pat.span);
this.visit_pat(pat);
this.visit_expr(&this.thir[expr]);
@ -105,20 +106,18 @@ fn visit_arm(&mut self, arm: &Arm<'tcx>) {
}
None => {}
}
self.visit_pat(&arm.pattern);
self.visit_expr(&self.thir[arm.body]);
this.visit_pat(&arm.pattern);
this.visit_expr(&self.thir[arm.body]);
});
}
#[instrument(level = "trace", skip(self))]
fn visit_expr(&mut self, ex: &Expr<'tcx>) {
match ex.kind {
ExprKind::Scope { value, lint_level, .. } => {
let old_lint_level = self.lint_level;
if let LintLevel::Explicit(hir_id) = lint_level {
self.lint_level = hir_id;
}
self.visit_expr(&self.thir[value]);
self.lint_level = old_lint_level;
self.with_lint_level(lint_level, |this| {
this.visit_expr(&this.thir[value]);
});
return;
}
ExprKind::If { cond, then, else_opt, if_then_scope: _ } => {
@ -190,6 +189,17 @@ fn with_let_source(&mut self, let_source: LetSource, f: impl FnOnce(&mut Self))
self.let_source = old_let_source;
}
fn with_lint_level(&mut self, new_lint_level: LintLevel, f: impl FnOnce(&mut Self)) {
if let LintLevel::Explicit(hir_id) = new_lint_level {
let old_lint_level = self.lint_level;
self.lint_level = hir_id;
f(self);
self.lint_level = old_lint_level;
} else {
f(self);
}
}
fn check_patterns(&self, pat: &Pat<'tcx>, rf: RefutableFlag) {
pat.walk_always(|pat| check_borrow_conflicts_in_at_patterns(self, pat));
check_for_bindings_named_same_as_variants(self, pat, rf);
@ -236,7 +246,9 @@ fn check_match(
for &arm in arms {
// Check the arm for some things unrelated to exhaustiveness.
let arm = &self.thir.arms[arm];
self.check_patterns(&arm.pattern, Refutable);
self.with_lint_level(arm.lint_level, |this| {
this.check_patterns(&arm.pattern, Refutable);
});
}
let tarms: Vec<_> = arms

8
tests/ui/lint/lint-attr-everywhere-early.rs
View File

@ -134,6 +134,14 @@ struct Match{f1: i32}
}
}
match f {
#[deny(ellipsis_inclusive_range_patterns)]
Match{f1: 0...100} => {}
//~^ ERROR range patterns are deprecated
//~| WARNING this is accepted in the current edition
_ => {}
}
// Statement Block
{
#![deny(unsafe_code)]

48
tests/ui/lint/lint-attr-everywhere-early.stderr
View File

@ -384,92 +384,106 @@ note: the lint level is defined here
LL | #[deny(while_true)]
| ^^^^^^^^^^
error: `...` range patterns are deprecated
--> $DIR/lint-attr-everywhere-early.rs:139:20
|
LL | Match{f1: 0...100} => {}
| ^^^ help: use `..=` for an inclusive range
|
= warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
= note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
note: the lint level is defined here
--> $DIR/lint-attr-everywhere-early.rs:138:16
|
LL | #[deny(ellipsis_inclusive_range_patterns)]
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
error: usage of an `unsafe` block
--> $DIR/lint-attr-everywhere-early.rs:140:9
--> $DIR/lint-attr-everywhere-early.rs:148:9
|
LL | unsafe {}
| ^^^^^^^^^
|
note: the lint level is defined here
--> $DIR/lint-attr-everywhere-early.rs:139:17
--> $DIR/lint-attr-everywhere-early.rs:147:17
|
LL | #![deny(unsafe_code)]
| ^^^^^^^^^^^
error: usage of an `unsafe` block
--> $DIR/lint-attr-everywhere-early.rs:144:9
--> $DIR/lint-attr-everywhere-early.rs:152:9
|
LL | unsafe {}
| ^^^^^^^^^
|
note: the lint level is defined here
--> $DIR/lint-attr-everywhere-early.rs:143:16
--> $DIR/lint-attr-everywhere-early.rs:151:16
|
LL | #[deny(unsafe_code)]
| ^^^^^^^^^^^
error: usage of an `unsafe` block
--> $DIR/lint-attr-everywhere-early.rs:149:5
--> $DIR/lint-attr-everywhere-early.rs:157:5
|
LL | unsafe {};
| ^^^^^^^^^
|
note: the lint level is defined here
--> $DIR/lint-attr-everywhere-early.rs:148:12
--> $DIR/lint-attr-everywhere-early.rs:156:12
|
LL | #[deny(unsafe_code)]
| ^^^^^^^^^^^
error: usage of an `unsafe` block
--> $DIR/lint-attr-everywhere-early.rs:151:27
--> $DIR/lint-attr-everywhere-early.rs:159:27
|
LL | [#[deny(unsafe_code)] unsafe {123}];
| ^^^^^^^^^^^^
|
note: the lint level is defined here
--> $DIR/lint-attr-everywhere-early.rs:151:13
--> $DIR/lint-attr-everywhere-early.rs:159:13
|
LL | [#[deny(unsafe_code)] unsafe {123}];
| ^^^^^^^^^^^
error: usage of an `unsafe` block
--> $DIR/lint-attr-everywhere-early.rs:152:27
--> $DIR/lint-attr-everywhere-early.rs:160:27
|
LL | (#[deny(unsafe_code)] unsafe {123},);
| ^^^^^^^^^^^^
|
note: the lint level is defined here
--> $DIR/lint-attr-everywhere-early.rs:152:13
--> $DIR/lint-attr-everywhere-early.rs:160:13
|
LL | (#[deny(unsafe_code)] unsafe {123},);
| ^^^^^^^^^^^
error: usage of an `unsafe` block
--> $DIR/lint-attr-everywhere-early.rs:154:31
--> $DIR/lint-attr-everywhere-early.rs:162:31
|
LL | call(#[deny(unsafe_code)] unsafe {123});
| ^^^^^^^^^^^^
|
note: the lint level is defined here
--> $DIR/lint-attr-everywhere-early.rs:154:17
--> $DIR/lint-attr-everywhere-early.rs:162:17
|
LL | call(#[deny(unsafe_code)] unsafe {123});
| ^^^^^^^^^^^
error: usage of an `unsafe` block
--> $DIR/lint-attr-everywhere-early.rs:156:38
--> $DIR/lint-attr-everywhere-early.rs:164:38
|
LL | TupleStruct(#[deny(unsafe_code)] unsafe {123});
| ^^^^^^^^^^^^
|
note: the lint level is defined here
--> $DIR/lint-attr-everywhere-early.rs:156:24
--> $DIR/lint-attr-everywhere-early.rs:164:24
|
LL | TupleStruct(#[deny(unsafe_code)] unsafe {123});
| ^^^^^^^^^^^
error: `...` range patterns are deprecated
--> $DIR/lint-attr-everywhere-early.rs:167:18
--> $DIR/lint-attr-everywhere-early.rs:175:18
|
LL | f1: 0...100,
| ^^^ help: use `..=` for an inclusive range
@ -477,10 +491,10 @@ LL | f1: 0...100,
= warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
= note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
note: the lint level is defined here
--> $DIR/lint-attr-everywhere-early.rs:166:20
--> $DIR/lint-attr-everywhere-early.rs:174:20
|
LL | #[deny(ellipsis_inclusive_range_patterns)]
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
error: aborting due to 36 previous errors
error: aborting due to 37 previous errors

5
tests/ui/lint/lint-attr-everywhere-late.rs
View File

@ -162,6 +162,11 @@ struct Match{f1: i32}
}
}
match 123 {
#[deny(non_snake_case)]
ARM_VAR => {} //~ ERROR variable `ARM_VAR` should have a snake case name
}
// Statement Block
{
#![deny(enum_intrinsics_non_enums)]

56
tests/ui/lint/lint-attr-everywhere-late.stderr
View File

@ -305,124 +305,136 @@ note: the lint level is defined here
LL | #[deny(enum_intrinsics_non_enums)]
| ^^^^^^^^^^^^^^^^^^^^^^^^^
error: variable `ARM_VAR` should have a snake case name
--> $DIR/lint-attr-everywhere-late.rs:167:9
|
LL | ARM_VAR => {}
| ^^^^^^^ help: convert the identifier to snake case: `arm_var`
|
note: the lint level is defined here
--> $DIR/lint-attr-everywhere-late.rs:166:16
|
LL | #[deny(non_snake_case)]
| ^^^^^^^^^^^^^^
error: the return value of `mem::discriminant` is unspecified when called with a non-enum type
--> $DIR/lint-attr-everywhere-late.rs:168:9
--> $DIR/lint-attr-everywhere-late.rs:173:9
|
LL | discriminant::<i32>(&123);
| ^^^^^^^^^^^^^^^^^^^^^^^^^
|
note: the argument to `discriminant` should be a reference to an enum, but it was passed a reference to a `i32`, which is not an enum.
--> $DIR/lint-attr-everywhere-late.rs:168:29
--> $DIR/lint-attr-everywhere-late.rs:173:29
|
LL | discriminant::<i32>(&123);
| ^^^^
note: the lint level is defined here
--> $DIR/lint-attr-everywhere-late.rs:167:17
--> $DIR/lint-attr-everywhere-late.rs:172:17
|
LL | #![deny(enum_intrinsics_non_enums)]
| ^^^^^^^^^^^^^^^^^^^^^^^^^
error: the return value of `mem::discriminant` is unspecified when called with a non-enum type
--> $DIR/lint-attr-everywhere-late.rs:172:9
--> $DIR/lint-attr-everywhere-late.rs:177:9
|
LL | discriminant::<i32>(&123);
| ^^^^^^^^^^^^^^^^^^^^^^^^^
|
note: the argument to `discriminant` should be a reference to an enum, but it was passed a reference to a `i32`, which is not an enum.
--> $DIR/lint-attr-everywhere-late.rs:172:29
--> $DIR/lint-attr-everywhere-late.rs:177:29
|
LL | discriminant::<i32>(&123);
| ^^^^
note: the lint level is defined here
--> $DIR/lint-attr-everywhere-late.rs:171:16
--> $DIR/lint-attr-everywhere-late.rs:176:16
|
LL | #[deny(enum_intrinsics_non_enums)]
| ^^^^^^^^^^^^^^^^^^^^^^^^^
error: the return value of `mem::discriminant` is unspecified when called with a non-enum type
--> $DIR/lint-attr-everywhere-late.rs:177:5
--> $DIR/lint-attr-everywhere-late.rs:182:5
|
LL | discriminant::<i32>(&123);
| ^^^^^^^^^^^^^^^^^^^^^^^^^
|
note: the argument to `discriminant` should be a reference to an enum, but it was passed a reference to a `i32`, which is not an enum.
--> $DIR/lint-attr-everywhere-late.rs:177:25
--> $DIR/lint-attr-everywhere-late.rs:182:25
|
LL | discriminant::<i32>(&123);
| ^^^^
note: the lint level is defined here
--> $DIR/lint-attr-everywhere-late.rs:176:12
--> $DIR/lint-attr-everywhere-late.rs:181:12
|
LL | #[deny(enum_intrinsics_non_enums)]
| ^^^^^^^^^^^^^^^^^^^^^^^^^
error: the return value of `mem::discriminant` is unspecified when called with a non-enum type
--> $DIR/lint-attr-everywhere-late.rs:179:41
--> $DIR/lint-attr-everywhere-late.rs:184:41
|
LL | [#[deny(enum_intrinsics_non_enums)] discriminant::<i32>(&123)];
| ^^^^^^^^^^^^^^^^^^^^^^^^^
|
note: the argument to `discriminant` should be a reference to an enum, but it was passed a reference to a `i32`, which is not an enum.
--> $DIR/lint-attr-everywhere-late.rs:179:61
--> $DIR/lint-attr-everywhere-late.rs:184:61
|
LL | [#[deny(enum_intrinsics_non_enums)] discriminant::<i32>(&123)];
| ^^^^
note: the lint level is defined here
--> $DIR/lint-attr-everywhere-late.rs:179:13
--> $DIR/lint-attr-everywhere-late.rs:184:13
|
LL | [#[deny(enum_intrinsics_non_enums)] discriminant::<i32>(&123)];
| ^^^^^^^^^^^^^^^^^^^^^^^^^
error: the return value of `mem::discriminant` is unspecified when called with a non-enum type
--> $DIR/lint-attr-everywhere-late.rs:180:41
--> $DIR/lint-attr-everywhere-late.rs:185:41
|
LL | (#[deny(enum_intrinsics_non_enums)] discriminant::<i32>(&123),);
| ^^^^^^^^^^^^^^^^^^^^^^^^^
|
note: the argument to `discriminant` should be a reference to an enum, but it was passed a reference to a `i32`, which is not an enum.
--> $DIR/lint-attr-everywhere-late.rs:180:61
--> $DIR/lint-attr-everywhere-late.rs:185:61
|
LL | (#[deny(enum_intrinsics_non_enums)] discriminant::<i32>(&123),);
| ^^^^
note: the lint level is defined here
--> $DIR/lint-attr-everywhere-late.rs:180:13
--> $DIR/lint-attr-everywhere-late.rs:185:13
|
LL | (#[deny(enum_intrinsics_non_enums)] discriminant::<i32>(&123),);
| ^^^^^^^^^^^^^^^^^^^^^^^^^
error: the return value of `mem::discriminant` is unspecified when called with a non-enum type
--> $DIR/lint-attr-everywhere-late.rs:182:45
--> $DIR/lint-attr-everywhere-late.rs:187:45
|
LL | call(#[deny(enum_intrinsics_non_enums)] discriminant::<i32>(&123));
| ^^^^^^^^^^^^^^^^^^^^^^^^^
|
note: the argument to `discriminant` should be a reference to an enum, but it was passed a reference to a `i32`, which is not an enum.
--> $DIR/lint-attr-everywhere-late.rs:182:65
--> $DIR/lint-attr-everywhere-late.rs:187:65
|
LL | call(#[deny(enum_intrinsics_non_enums)] discriminant::<i32>(&123));
| ^^^^
note: the lint level is defined here
--> $DIR/lint-attr-everywhere-late.rs:182:17
--> $DIR/lint-attr-everywhere-late.rs:187:17
|
LL | call(#[deny(enum_intrinsics_non_enums)] discriminant::<i32>(&123));
| ^^^^^^^^^^^^^^^^^^^^^^^^^
error: the return value of `mem::discriminant` is unspecified when called with a non-enum type
--> $DIR/lint-attr-everywhere-late.rs:184:52
--> $DIR/lint-attr-everywhere-late.rs:189:52
|
LL | TupleStruct(#[deny(enum_intrinsics_non_enums)] discriminant::<i32>(&123));
| ^^^^^^^^^^^^^^^^^^^^^^^^^
|
note: the argument to `discriminant` should be a reference to an enum, but it was passed a reference to a `i32`, which is not an enum.
--> $DIR/lint-attr-everywhere-late.rs:184:72
--> $DIR/lint-attr-everywhere-late.rs:189:72
|
LL | TupleStruct(#[deny(enum_intrinsics_non_enums)] discriminant::<i32>(&123));
| ^^^^
note: the lint level is defined here
--> $DIR/lint-attr-everywhere-late.rs:184:24
--> $DIR/lint-attr-everywhere-late.rs:189:24
|
LL | TupleStruct(#[deny(enum_intrinsics_non_enums)] discriminant::<i32>(&123));
| ^^^^^^^^^^^^^^^^^^^^^^^^^
error: aborting due to 31 previous errors
error: aborting due to 32 previous errors

24
tests/ui/lint/lint-match-arms-2.rs Normal file
View File

@ -0,0 +1,24 @@
#![feature(if_let_guard)]
#![allow(unused, non_snake_case)]
enum E {
A,
}
#[allow(bindings_with_variant_name, irrefutable_let_patterns)]
fn foo() {
match E::A {
#[deny(bindings_with_variant_name)]
A => {}
//~^ ERROR pattern binding `A` is named the same as one of the variants of the type `E`
}
match &E::A {
#[deny(irrefutable_let_patterns)]
a if let b = a => {}
//~^ ERROR irrefutable `if let` guard pattern
_ => {}
}
}
fn main() { }

29
tests/ui/lint/lint-match-arms-2.stderr Normal file
View File

@ -0,0 +1,29 @@
error[E0170]: pattern binding `A` is named the same as one of the variants of the type `E`
--> $DIR/lint-match-arms-2.rs:12:9
|
LL | A => {}
| ^ help: to match on the variant, qualify the path: `E::A`
|
note: the lint level is defined here
--> $DIR/lint-match-arms-2.rs:11:16
|
LL | #[deny(bindings_with_variant_name)]
| ^^^^^^^^^^^^^^^^^^^^^^^^^^
error: irrefutable `if let` guard pattern
--> $DIR/lint-match-arms-2.rs:18:18
|
LL | a if let b = a => {}
| ^
|
= note: this pattern will always match, so the guard is useless
= help: consider removing the guard and adding a `let` inside the match arm
note: the lint level is defined here
--> $DIR/lint-match-arms-2.rs:17:16
|
LL | #[deny(irrefutable_let_patterns)]
| ^^^^^^^^^^^^^^^^^^^^^^^^
error: aborting due to 2 previous errors
For more information about this error, try `rustc --explain E0170`.