Warn/error on self ctor from outer item in inner item

This commit is contained in:
Michael Goulet 2024-04-19 22:54:53 -04:00
parent 685a80f7a0
commit 5ee4db4e05
10 changed files with 199 additions and 83 deletions

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@ -137,6 +137,10 @@ hir_typeck_rpit_change_return_type = you could change the return type to be a bo
hir_typeck_rustcall_incorrect_args =
functions with the "rust-call" ABI must take a single non-self tuple argument
hir_typeck_self_ctor_from_outer_item = can't reference `Self` constructor from outer item
.label = the inner item doesn't inherit generics from this impl, so `Self` is invalid to reference
.suggestion = replace `Self` with the actual type
hir_typeck_struct_expr_non_exhaustive =
cannot create non-exhaustive {$what} using struct expression

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@ -651,3 +651,31 @@ pub enum SuggestBoxingForReturnImplTrait {
ends: Vec<Span>,
},
}
#[derive(Diagnostic)]
#[diag(hir_typeck_self_ctor_from_outer_item, code = E0401)]
pub struct SelfCtorFromOuterItem {
#[primary_span]
pub span: Span,
#[label]
pub impl_span: Span,
#[subdiagnostic]
pub sugg: Option<ReplaceWithName>,
}
#[derive(LintDiagnostic)]
#[diag(hir_typeck_self_ctor_from_outer_item)]
pub struct SelfCtorFromOuterItemLint {
#[label]
pub impl_span: Span,
#[subdiagnostic]
pub sugg: Option<ReplaceWithName>,
}
#[derive(Subdiagnostic)]
#[suggestion(hir_typeck_suggestion, code = "{name}", applicability = "machine-applicable")]
pub struct ReplaceWithName {
#[primary_span]
pub span: Span,
pub name: String,
}

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@ -1,5 +1,5 @@
use crate::callee::{self, DeferredCallResolution};
use crate::errors::CtorIsPrivate;
use crate::errors::{self, CtorIsPrivate};
use crate::method::{self, MethodCallee, SelfSource};
use crate::rvalue_scopes;
use crate::{BreakableCtxt, Diverges, Expectation, FnCtxt, LoweredTy};
@ -21,6 +21,7 @@ use rustc_hir_analysis::hir_ty_lowering::{
use rustc_infer::infer::canonical::{Canonical, OriginalQueryValues, QueryResponse};
use rustc_infer::infer::error_reporting::TypeAnnotationNeeded::E0282;
use rustc_infer::infer::{DefineOpaqueTypes, InferResult};
use rustc_lint::builtin::SELF_CONSTRUCTOR_FROM_OUTER_ITEM;
use rustc_middle::ty::adjustment::{Adjust, Adjustment, AutoBorrow, AutoBorrowMutability};
use rustc_middle::ty::error::TypeError;
use rustc_middle::ty::fold::TypeFoldable;
@ -1162,6 +1163,43 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
span,
tcx.at(span).type_of(impl_def_id).instantiate_identity(),
);
// Firstly, check that this SelfCtor even comes from the item we're currently
// typechecking. This can happen because we never validated the resolution of
// SelfCtors, and when we started doing so, we noticed regressions. After
// sufficiently long time, we can remove this check and turn it into a hard
// error in `validate_res_from_ribs` -- it's just difficult to tell whether the
// self type has any generic types during rustc_resolve, which is what we use
// to determine if this is a hard error or warning.
if std::iter::successors(Some(self.body_id.to_def_id()), |def_id| {
self.tcx.generics_of(def_id).parent
})
.all(|def_id| def_id != impl_def_id)
{
let sugg = ty.normalized.ty_adt_def().map(|def| errors::ReplaceWithName {
span: path_span,
name: self.tcx.item_name(def.did()).to_ident_string(),
});
if ty.raw.has_param() {
let guar = self.tcx.dcx().emit_err(errors::SelfCtorFromOuterItem {
span: path_span,
impl_span: tcx.def_span(impl_def_id),
sugg,
});
return (Ty::new_error(self.tcx, guar), res);
} else {
self.tcx.emit_node_span_lint(
SELF_CONSTRUCTOR_FROM_OUTER_ITEM,
hir_id,
path_span,
errors::SelfCtorFromOuterItemLint {
impl_span: tcx.def_span(impl_def_id),
sugg,
},
);
}
}
match ty.normalized.ty_adt_def() {
Some(adt_def) if adt_def.has_ctor() => {
let (ctor_kind, ctor_def_id) = adt_def.non_enum_variant().ctor.unwrap();

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@ -90,6 +90,7 @@ declare_lint_pass! {
RUST_2021_PREFIXES_INCOMPATIBLE_SYNTAX,
RUST_2021_PRELUDE_COLLISIONS,
RUST_2024_INCOMPATIBLE_PAT,
SELF_CONSTRUCTOR_FROM_OUTER_ITEM,
SEMICOLON_IN_EXPRESSIONS_FROM_MACROS,
SINGLE_USE_LIFETIMES,
SOFT_UNSTABLE,
@ -3149,6 +3150,47 @@ declare_lint! {
"detects `#[unstable]` on stable trait implementations for stable types"
}
declare_lint! {
/// The `self_constructor_from_outer_item` lint detects cases where the `Self` constructor
/// was silently allowed due to a bug in the resolver, and which may produce surprising
/// and unintended behavior.
///
/// Using a `Self` type alias from an outer item was never intended, but was silently allowed.
/// This is deprecated -- and is a hard error when the `Self` type alias references generics
/// that are not in scope.
///
/// ### Example
///
/// ```rust,compile_fail
/// #![deny(self_constructor_from_outer_item)]
///
/// struct S0(usize);
///
/// impl S0 {
/// fn foo() {
/// const C: S0 = Self(0);
/// fn bar() -> S0 {
/// Self(0)
/// }
/// }
/// }
/// ```
///
/// {{produces}}
///
/// ### Explanation
///
/// The `Self` type alias should not be reachable because nested items are not associated with
/// the scope of the parameters from the parent item.
pub SELF_CONSTRUCTOR_FROM_OUTER_ITEM,
Warn,
"detect unsupported use of `Self` from outer item",
@future_incompatible = FutureIncompatibleInfo {
reason: FutureIncompatibilityReason::FutureReleaseErrorDontReportInDeps,
reference: "issue #124186 <https://github.com/rust-lang/rust/issues/124186>",
};
}
declare_lint! {
/// The `semicolon_in_expressions_from_macros` lint detects trailing semicolons
/// in macro bodies when the macro is invoked in expression position.

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@ -1,7 +1,12 @@
struct A<B>(B);
impl<B>A<B>{fn d(){fn d(){Self(1)}}}
//~^ ERROR the size for values of type `B` cannot be known at compilation time
//~| ERROR the size for values of type `B` cannot be known at compilation time
//~| ERROR mismatched types
//~| ERROR mismatched types
//~| ERROR `main` function not found in crate
impl<B> A<B> {
fn d() {
fn d() {
Self(1)
//~^ ERROR can't reference `Self` constructor from outer item
}
}
}
fn main() {}

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@ -1,79 +1,12 @@
error[E0601]: `main` function not found in crate `do_not_ice_on_note_and_explain`
--> $DIR/do-not-ice-on-note_and_explain.rs:2:37
error[E0401]: can't reference `Self` constructor from outer item
--> $DIR/do-not-ice-on-note_and_explain.rs:6:13
|
LL | impl<B>A<B>{fn d(){fn d(){Self(1)}}}
| ^ consider adding a `main` function to `$DIR/do-not-ice-on-note_and_explain.rs`
LL | impl<B> A<B> {
| ------------ the inner item doesn't inherit generics from this impl, so `Self` is invalid to reference
...
LL | Self(1)
| ^^^^ help: replace `Self` with the actual type: `A`
error[E0277]: the size for values of type `B` cannot be known at compilation time
--> $DIR/do-not-ice-on-note_and_explain.rs:2:32
|
LL | impl<B>A<B>{fn d(){fn d(){Self(1)}}}
| - ---- ^ doesn't have a size known at compile-time
| | |
| | required by a bound introduced by this call
| this type parameter needs to be `Sized`
|
note: required by a bound in `A`
--> $DIR/do-not-ice-on-note_and_explain.rs:1:10
|
LL | struct A<B>(B);
| ^ required by this bound in `A`
error: aborting due to 1 previous error
error[E0308]: mismatched types
--> $DIR/do-not-ice-on-note_and_explain.rs:2:32
|
LL | impl<B>A<B>{fn d(){fn d(){Self(1)}}}
| ---- ^ expected type parameter `B`, found integer
| |
| arguments to this function are incorrect
|
= note: expected type parameter `B`
found type `{integer}`
note: tuple struct defined here
--> $DIR/do-not-ice-on-note_and_explain.rs:1:8
|
LL | struct A<B>(B);
| ^
error[E0308]: mismatched types
--> $DIR/do-not-ice-on-note_and_explain.rs:2:27
|
LL | impl<B>A<B>{fn d(){fn d(){Self(1)}}}
| ^^^^^^^ expected `()`, found `A<B>`
|
= note: expected unit type `()`
found struct `A<B>`
help: consider using a semicolon here
|
LL | impl<B>A<B>{fn d(){fn d(){Self(1);}}}
| +
help: try adding a return type
|
LL | impl<B>A<B>{fn d(){fn d() -> A<B>{Self(1)}}}
| +++++++
error[E0277]: the size for values of type `B` cannot be known at compilation time
--> $DIR/do-not-ice-on-note_and_explain.rs:2:27
|
LL | impl<B>A<B>{fn d(){fn d(){Self(1)}}}
| - ^^^^^^^ doesn't have a size known at compile-time
| |
| this type parameter needs to be `Sized`
|
note: required by an implicit `Sized` bound in `A`
--> $DIR/do-not-ice-on-note_and_explain.rs:1:10
|
LL | struct A<B>(B);
| ^ required by the implicit `Sized` requirement on this type parameter in `A`
help: you could relax the implicit `Sized` bound on `B` if it were used through indirection like `&B` or `Box<B>`
--> $DIR/do-not-ice-on-note_and_explain.rs:1:10
|
LL | struct A<B>(B);
| ^ - ...if indirection were used here: `Box<B>`
| |
| this could be changed to `B: ?Sized`...
error: aborting due to 5 previous errors
Some errors have detailed explanations: E0277, E0308, E0601.
For more information about an error, try `rustc --explain E0277`.
For more information about this error, try `rustc --explain E0401`.

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@ -6,8 +6,12 @@ struct S0(usize);
impl S0 {
fn foo() {
const C: S0 = Self(0);
//~^ WARN can't reference `Self` constructor from outer item
//~| WARN this was previously accepted by the compiler but is being phased out
fn bar() -> S0 {
Self(0)
//~^ WARN can't reference `Self` constructor from outer item
//~| WARN this was previously accepted by the compiler but is being phased out
}
}
}

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@ -0,0 +1,27 @@
warning: can't reference `Self` constructor from outer item
--> $DIR/self-ctor-nongeneric.rs:8:23
|
LL | impl S0 {
| ------- the inner item doesn't inherit generics from this impl, so `Self` is invalid to reference
LL | fn foo() {
LL | const C: S0 = Self(0);
| ^^^^ help: replace `Self` with the actual type: `S0`
|
= warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
= note: for more information, see issue #124186 <https://github.com/rust-lang/rust/issues/124186>
= note: `#[warn(self_constructor_from_outer_item)]` on by default
warning: can't reference `Self` constructor from outer item
--> $DIR/self-ctor-nongeneric.rs:12:13
|
LL | impl S0 {
| ------- the inner item doesn't inherit generics from this impl, so `Self` is invalid to reference
...
LL | Self(0)
| ^^^^ help: replace `Self` with the actual type: `S0`
|
= warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
= note: for more information, see issue #124186 <https://github.com/rust-lang/rust/issues/124186>
warning: 2 warnings emitted

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@ -0,0 +1,14 @@
struct S0<T>(T);
impl<T> S0<T> {
fn foo() {
const C: S0<i32> = Self(0);
//~^ ERROR can't reference `Self` constructor from outer item
fn bar() -> S0<i32> {
Self(0)
//~^ ERROR can't reference `Self` constructor from outer item
}
}
}
fn main() {}

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@ -0,0 +1,21 @@
error[E0401]: can't reference `Self` constructor from outer item
--> $DIR/self-ctor.rs:5:28
|
LL | impl<T> S0<T> {
| ------------- the inner item doesn't inherit generics from this impl, so `Self` is invalid to reference
LL | fn foo() {
LL | const C: S0<i32> = Self(0);
| ^^^^ help: replace `Self` with the actual type: `S0`
error[E0401]: can't reference `Self` constructor from outer item
--> $DIR/self-ctor.rs:8:13
|
LL | impl<T> S0<T> {
| ------------- the inner item doesn't inherit generics from this impl, so `Self` is invalid to reference
...
LL | Self(0)
| ^^^^ help: replace `Self` with the actual type: `S0`
error: aborting due to 2 previous errors
For more information about this error, try `rustc --explain E0401`.