Unconditionally error at definition if default field value has const errors
Emit E0080 always on struct definition with default fields that have unconditional const errors and remove `default_field_always_invalid_const` lint.
This commit is contained in:
Esteban Küber
parent
2d6e763cc6
commit
0757641f4d
8 changed files with 29 additions and 148 deletions
|
|
@ -1104,6 +1104,25 @@ fn check_type_defn<'tcx>(
|
|||
for variant in variants.iter() {
|
||||
// All field types must be well-formed.
|
||||
for field in &variant.fields {
|
||||
if let Some(def_id) = field.value
|
||||
&& let Some(_ty) = tcx.type_of(def_id).no_bound_vars()
|
||||
{
|
||||
// FIXME(generic_const_exprs, default_field_values): this is a hack and needs to
|
||||
// be refactored to check the instantiate-ability of the code better.
|
||||
if let Some(def_id) = def_id.as_local()
|
||||
&& let hir::Node::AnonConst(anon) = tcx.hir_node_by_def_id(def_id)
|
||||
&& let expr = &tcx.hir().body(anon.body).value
|
||||
&& let hir::ExprKind::Path(hir::QPath::Resolved(None, path)) = expr.kind
|
||||
&& let Res::Def(DefKind::ConstParam, _def_id) = path.res
|
||||
{
|
||||
// Do not evaluate bare `const` params, as those would ICE and are only
|
||||
// usable if `#![feature(generic_const_exprs)]` is enabled.
|
||||
} else {
|
||||
// Evaluate the constant proactively, to emit an error if the constant has
|
||||
// an unconditional error. We only do so if the const has no type params.
|
||||
let _ = tcx.const_eval_poly(def_id.into());
|
||||
}
|
||||
}
|
||||
let field_id = field.did.expect_local();
|
||||
let hir::FieldDef { ty: hir_ty, .. } =
|
||||
tcx.hir_node_by_def_id(field_id).expect_field();
|
||||
|
|
|
|||
|
|
@ -211,10 +211,6 @@ lint_dangling_pointers_from_temporaries = a dangling pointer will be produced be
|
|||
.note = pointers do not have a lifetime; when calling `{$callee}` the `{$ty}` will be deallocated at the end of the statement because nothing is referencing it as far as the type system is concerned
|
||||
.help = for more information, see <https://doc.rust-lang.org/reference/destructors.html>
|
||||
|
||||
lint_default_field_always_invalid_const = default field fails const-evaluation
|
||||
.label = this field's constant fails const-evaluation, as seen in the previous error
|
||||
.help = you can skip const-evaluation of default fields by enabling this lint
|
||||
|
||||
lint_default_hash_types = prefer `{$preferred}` over `{$used}`, it has better performance
|
||||
.note = a `use rustc_data_structures::fx::{$preferred}` may be necessary
|
||||
|
||||
|
|
|
|||
|
|
@ -1,91 +0,0 @@
|
|||
use rustc_hir as hir;
|
||||
use rustc_middle::lint::LintLevelSource;
|
||||
use rustc_middle::mir::interpret::ErrorHandled;
|
||||
use rustc_session::lint::Level;
|
||||
use rustc_session::{declare_lint, declare_lint_pass};
|
||||
|
||||
use crate::lints::DefaultFieldAlwaysInvalidConst;
|
||||
use crate::{LateContext, LateLintPass};
|
||||
|
||||
declare_lint! {
|
||||
/// The `default_field_always_invalid_const` lint checks for structs with
|
||||
/// default fields const values that will *always* fail to be created.
|
||||
///
|
||||
/// ### Example
|
||||
///
|
||||
/// ```rust,compile_fail
|
||||
/// #![feature(default_field_values)]
|
||||
/// #[deny(default_field_always_invalid_const)]
|
||||
/// struct Foo {
|
||||
/// bar: u8 = 130 + 130, // `260` doesn't fit in `u8`
|
||||
/// }
|
||||
/// ```
|
||||
///
|
||||
/// {{produces}}
|
||||
///
|
||||
/// ### Explanation
|
||||
///
|
||||
/// Without this lint, the error would only happen only during construction
|
||||
/// of the affected type. For example, given the type above, `Foo { .. }`
|
||||
/// would always fail to build, but `Foo { bar: 0 }` would be accepted. This
|
||||
/// lint will catch accidental cases of const values that would fail to
|
||||
/// compile, but won't detect cases that are only partially evaluated.
|
||||
pub DEFAULT_FIELD_ALWAYS_INVALID_CONST,
|
||||
Deny,
|
||||
"using this default field will always fail to compile"
|
||||
}
|
||||
|
||||
declare_lint_pass!(DefaultFieldAlwaysInvalid => [DEFAULT_FIELD_ALWAYS_INVALID_CONST]);
|
||||
|
||||
impl<'tcx> LateLintPass<'tcx> for DefaultFieldAlwaysInvalid {
|
||||
fn check_item(&mut self, cx: &LateContext<'tcx>, item: &'tcx hir::Item<'tcx>) {
|
||||
let data = match item.kind {
|
||||
hir::ItemKind::Struct(data, _generics) => data,
|
||||
_ => return,
|
||||
};
|
||||
let hir::VariantData::Struct { fields, recovered: _ } = data else {
|
||||
return;
|
||||
};
|
||||
|
||||
let (level, source) =
|
||||
cx.tcx.lint_level_at_node(DEFAULT_FIELD_ALWAYS_INVALID_CONST, item.hir_id());
|
||||
match level {
|
||||
Level::Deny | Level::Forbid => {}
|
||||
Level::Warn | Level::ForceWarn(_) | Level::Expect(_) => {
|
||||
// We *can't* turn the const eval error into a warning, so we make it a
|
||||
// warning to not use `#[warn(default_field_always_invalid_const)]`.
|
||||
let invalid_msg = "lint `default_field_always_invalid_const` can't be warned on";
|
||||
#[allow(rustc::diagnostic_outside_of_impl, rustc::untranslatable_diagnostic)]
|
||||
if let LintLevelSource::Node { span, .. } = source {
|
||||
let mut err = cx.tcx.sess.dcx().struct_span_warn(span, invalid_msg);
|
||||
err.span_label(
|
||||
span,
|
||||
"either `deny` or `allow`, no other lint level is supported for this lint",
|
||||
);
|
||||
err.emit();
|
||||
} else {
|
||||
cx.tcx.sess.dcx().warn(invalid_msg);
|
||||
}
|
||||
}
|
||||
Level::Allow => {
|
||||
// We don't even look at the fields.
|
||||
return;
|
||||
}
|
||||
}
|
||||
for field in fields {
|
||||
if let Some(c) = field.default
|
||||
&& let Some(_ty) = cx.tcx.type_of(c.def_id).no_bound_vars()
|
||||
&& let Err(ErrorHandled::Reported(_, _)) = cx.tcx.const_eval_poly(c.def_id.into())
|
||||
{
|
||||
// We use the item's hir id because the const's hir id might resolve inside of a
|
||||
// foreign macro, meaning the lint won't trigger.
|
||||
cx.tcx.emit_node_span_lint(
|
||||
DEFAULT_FIELD_ALWAYS_INVALID_CONST,
|
||||
item.hir_id(),
|
||||
field.span,
|
||||
DefaultFieldAlwaysInvalidConst { span: field.span, help: () },
|
||||
);
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
|
|
@ -41,7 +41,6 @@ mod async_fn_in_trait;
|
|||
pub mod builtin;
|
||||
mod context;
|
||||
mod dangling;
|
||||
mod default_field_always_invalid;
|
||||
mod deref_into_dyn_supertrait;
|
||||
mod drop_forget_useless;
|
||||
mod early;
|
||||
|
|
@ -86,7 +85,6 @@ use async_closures::AsyncClosureUsage;
|
|||
use async_fn_in_trait::AsyncFnInTrait;
|
||||
use builtin::*;
|
||||
use dangling::*;
|
||||
use default_field_always_invalid::*;
|
||||
use deref_into_dyn_supertrait::*;
|
||||
use drop_forget_useless::*;
|
||||
use enum_intrinsics_non_enums::EnumIntrinsicsNonEnums;
|
||||
|
|
@ -195,7 +193,6 @@ late_lint_methods!(
|
|||
DropForgetUseless: DropForgetUseless,
|
||||
ImproperCTypesDeclarations: ImproperCTypesDeclarations,
|
||||
ImproperCTypesDefinitions: ImproperCTypesDefinitions,
|
||||
DefaultFieldAlwaysInvalid: DefaultFieldAlwaysInvalid,
|
||||
InvalidFromUtf8: InvalidFromUtf8,
|
||||
VariantSizeDifferences: VariantSizeDifferences,
|
||||
PathStatements: PathStatements,
|
||||
|
|
|
|||
|
|
@ -730,15 +730,6 @@ pub(crate) struct UndroppedManuallyDropsSuggestion {
|
|||
pub end_span: Span,
|
||||
}
|
||||
|
||||
#[derive(LintDiagnostic)]
|
||||
#[diag(lint_default_field_always_invalid_const)]
|
||||
pub(crate) struct DefaultFieldAlwaysInvalidConst {
|
||||
#[label]
|
||||
pub span: Span,
|
||||
#[help]
|
||||
pub help: (),
|
||||
}
|
||||
|
||||
// invalid_from_utf8.rs
|
||||
#[derive(LintDiagnostic)]
|
||||
pub(crate) enum InvalidFromUtf8Diag {
|
||||
|
|
|
|||
|
|
@ -21,6 +21,12 @@ error: default fields are not supported in tuple structs
|
|||
LL | pub struct Rak(i32 = 42);
|
||||
| ^^ default fields are only supported on structs
|
||||
|
||||
error: generic `Self` types are currently not permitted in anonymous constants
|
||||
--> $DIR/default-field-values-failures.rs:20:14
|
||||
|
|
||||
LL | bar: S = Self::S,
|
||||
| ^^^^
|
||||
|
||||
error[E0277]: the trait bound `S: Default` is not satisfied
|
||||
--> $DIR/default-field-values-failures.rs:14:5
|
||||
|
|
||||
|
|
@ -106,12 +112,6 @@ LL - let _ = Rak(.., 0);
|
|||
LL + let _ = Rak(0);
|
||||
|
|
||||
|
||||
error: generic `Self` types are currently not permitted in anonymous constants
|
||||
--> $DIR/default-field-values-failures.rs:20:14
|
||||
|
|
||||
LL | bar: S = Self::S,
|
||||
| ^^^^
|
||||
|
||||
error: aborting due to 9 previous errors
|
||||
|
||||
Some errors have detailed explanations: E0061, E0277, E0308.
|
||||
|
|
|
|||
|
|
@ -1,18 +1,15 @@
|
|||
#![feature(default_field_values, generic_const_exprs)]
|
||||
#![allow(incomplete_features)]
|
||||
|
||||
#[warn(default_field_always_invalid_const)] //~ WARN lint `default_field_always_invalid_const` can't be warned on
|
||||
pub struct Bat {
|
||||
pub bax: u8 = panic!("asdf"),
|
||||
//~^ ERROR evaluation of constant value failed
|
||||
//~| WARN default field fails const-evaluation
|
||||
}
|
||||
|
||||
pub struct Baz<const C: u8> {
|
||||
pub bax: u8 = 130 + C, // ok
|
||||
pub bat: u8 = 130 + 130,
|
||||
//~^ ERROR evaluation of `Baz::<C>::bat::{constant#0}` failed
|
||||
//~| ERROR default field fails const-evaluation
|
||||
pub bay: u8 = 1, // ok
|
||||
}
|
||||
|
||||
|
|
|
|||
|
|
@ -1,45 +1,17 @@
|
|||
warning: lint `default_field_always_invalid_const` can't be warned on
|
||||
--> $DIR/default-field-values-invalid-const.rs:4:8
|
||||
|
|
||||
LL | #[warn(default_field_always_invalid_const)]
|
||||
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ either `deny` or `allow`, no other lint level is supported for this lint
|
||||
|
||||
error[E0080]: evaluation of constant value failed
|
||||
--> $DIR/default-field-values-invalid-const.rs:6:19
|
||||
--> $DIR/default-field-values-invalid-const.rs:5:19
|
||||
|
|
||||
LL | pub bax: u8 = panic!("asdf"),
|
||||
| ^^^^^^^^^^^^^^ the evaluated program panicked at 'asdf', $DIR/default-field-values-invalid-const.rs:6:19
|
||||
| ^^^^^^^^^^^^^^ the evaluated program panicked at 'asdf', $DIR/default-field-values-invalid-const.rs:5:19
|
||||
|
|
||||
= note: this error originates in the macro `$crate::panic::panic_2015` which comes from the expansion of the macro `panic` (in Nightly builds, run with -Z macro-backtrace for more info)
|
||||
|
||||
warning: default field fails const-evaluation
|
||||
--> $DIR/default-field-values-invalid-const.rs:6:5
|
||||
|
|
||||
LL | pub bax: u8 = panic!("asdf"),
|
||||
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ this field's constant fails const-evaluation, as seen in the previous error
|
||||
|
|
||||
= help: you can skip const-evaluation of default fields by enabling this lint
|
||||
note: the lint level is defined here
|
||||
--> $DIR/default-field-values-invalid-const.rs:4:8
|
||||
|
|
||||
LL | #[warn(default_field_always_invalid_const)]
|
||||
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
||||
|
||||
error[E0080]: evaluation of `Baz::<C>::bat::{constant#0}` failed
|
||||
--> $DIR/default-field-values-invalid-const.rs:13:19
|
||||
--> $DIR/default-field-values-invalid-const.rs:11:19
|
||||
|
|
||||
LL | pub bat: u8 = 130 + 130,
|
||||
| ^^^^^^^^^ attempt to compute `130_u8 + 130_u8`, which would overflow
|
||||
|
||||
error: default field fails const-evaluation
|
||||
--> $DIR/default-field-values-invalid-const.rs:13:5
|
||||
|
|
||||
LL | pub bat: u8 = 130 + 130,
|
||||
| ^^^^^^^^^^^^^^^^^^^^^^^ this field's constant fails const-evaluation, as seen in the previous error
|
||||
|
|
||||
= help: you can skip const-evaluation of default fields by enabling this lint
|
||||
= note: `#[deny(default_field_always_invalid_const)]` on by default
|
||||
|
||||
error: aborting due to 3 previous errors; 2 warnings emitted
|
||||
error: aborting due to 2 previous errors
|
||||
|
||||
For more information about this error, try `rustc --explain E0080`.
|
||||
|
|
|
|||
Loading…
Add table
Reference in a new issue