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check_consts: fix duplicate errors, make importance consistent #120933

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Feb 12, 2024
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check_consts: fix duplicate errors, make importance consistent #120933

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d5de9a6
check_consts: fix some duplicate errors by not calling check_static u…
RalfJung Feb 11, 2024
e13de31
make Primary/Secondary importance consistent between CellBorrow and M…
RalfJung Feb 11, 2024
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8 changes: 5 additions & 3 deletions compiler/rustc_const_eval/src/transform/check_consts/check.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -619,9 +619,11 @@ impl<'tcx> Visitor<'tcx> for Checker<'_, 'tcx> {
if base_ty.is_unsafe_ptr() {
if place_ref.projection.is_empty() {
let decl = &self.body.local_decls[place_ref.local];
if let LocalInfo::StaticRef { def_id, .. } = *decl.local_info() {
let span = decl.source_info.span;
self.check_static(def_id, span);
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@RalfJung RalfJung Feb 11, 2024 •
edited

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We already check_static each operand we see, so I don't understand why this was checked again here.

// If this is a static, then this is not really dereferencing a pointer,
// just directly accessing a static. That is not subject to any feature
// gates (except for the one about whether statics can even be used, but
// that is checked already by `visit_operand`).
if let LocalInfo::StaticRef { .. } = *decl.local_info() {
return;
}
}
Expand Down
14 changes: 7 additions & 7 deletions compiler/rustc_const_eval/src/transform/check_consts/ops.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -409,11 +409,6 @@ impl<'tcx> NonConstOp<'tcx> for TransientCellBorrow {
fn status_in_item(&self, _: &ConstCx<'_, 'tcx>) -> Status {
Status::Unstable(sym::const_refs_to_cell)
}
fn importance(&self) -> DiagnosticImportance {
// The cases that cannot possibly work will already emit a `CellBorrow`, so we should
// not additionally emit a feature gate error if activating the feature gate won't work.
DiagnosticImportance::Secondary
}
fn build_error(&self, ccx: &ConstCx<'_, 'tcx>, span: Span) -> DiagnosticBuilder<'tcx> {
ccx.tcx
.sess
Expand All @@ -427,6 +422,11 @@ impl<'tcx> NonConstOp<'tcx> for TransientCellBorrow {
/// it in the future for static items.
pub struct CellBorrow;
impl<'tcx> NonConstOp<'tcx> for CellBorrow {
fn importance(&self) -> DiagnosticImportance {
// Most likely the code will try to do mutation with these borrows, which
// triggers its own errors. Only show this one if that does not happen.
DiagnosticImportance::Secondary
}
fn build_error(&self, ccx: &ConstCx<'_, 'tcx>, span: Span) -> DiagnosticBuilder<'tcx> {
// FIXME: Maybe a more elegant solution to this if else case
if let hir::ConstContext::Static(_) = ccx.const_kind() {
Expand Down Expand Up @@ -459,8 +459,8 @@ impl<'tcx> NonConstOp<'tcx> for MutBorrow {
}

fn importance(&self) -> DiagnosticImportance {
// If there were primary errors (like non-const function calls), do not emit further
// errors about mutable references.
// Most likely the code will try to do mutation with these borrows, which
// triggers its own errors. Only show this one if that does not happen.
DiagnosticImportance::Secondary
}

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1 change: 0 additions & 1 deletion tests/ui/consts/issue-17718-const-bad-values.rs
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Expand Up @@ -4,7 +4,6 @@ const C1: &'static mut [usize] = &mut [];
static mut S: usize = 3;
const C2: &'static mut usize = unsafe { &mut S };
//~^ ERROR: referencing statics in constants
//~| ERROR: referencing statics in constants
//~| WARN mutable reference of mutable static is discouraged [static_mut_ref]

fn main() {}
15 changes: 1 addition & 14 deletions tests/ui/consts/issue-17718-const-bad-values.stderr
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Expand Up @@ -31,20 +31,7 @@ LL | const C2: &'static mut usize = unsafe { &mut S };
= note: `static` and `const` variables can refer to other `const` variables. A `const` variable, however, cannot refer to a `static` variable.
= help: to fix this, the value can be extracted to a `const` and then used.

error[E0658]: referencing statics in constants is unstable
--> $DIR/issue-17718-const-bad-values.rs:5:46
|
LL | const C2: &'static mut usize = unsafe { &mut S };
| ^
|
= note: see issue #119618 <https://github.com/rust-lang/rust/issues/119618> for more information
= help: add `#![feature(const_refs_to_static)]` to the crate attributes to enable
= note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
= note: `static` and `const` variables can refer to other `const` variables. A `const` variable, however, cannot refer to a `static` variable.
= help: to fix this, the value can be extracted to a `const` and then used.
= note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`

error: aborting due to 3 previous errors; 1 warning emitted
error: aborting due to 2 previous errors; 1 warning emitted

Some errors have detailed explanations: E0658, E0764.
For more information about an error, try `rustc --explain E0658`.
5 changes: 0 additions & 5 deletions tests/ui/consts/miri_unleashed/const_refers_to_static.32bit.stderr
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Expand Up @@ -49,11 +49,6 @@ help: skipping check for `const_refs_to_static` feature
|
LL | const READ_MUT: u32 = unsafe { MUTABLE };
| ^^^^^^^
help: skipping check for `const_refs_to_static` feature
--> $DIR/const_refers_to_static.rs:18:32
|
LL | const READ_MUT: u32 = unsafe { MUTABLE };
| ^^^^^^^
help: skipping check for `const_refs_to_static` feature
--> $DIR/const_refers_to_static.rs:24:18
|
Expand Down
5 changes: 0 additions & 5 deletions tests/ui/consts/miri_unleashed/const_refers_to_static.64bit.stderr
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Expand Up @@ -49,11 +49,6 @@ help: skipping check for `const_refs_to_static` feature
|
LL | const READ_MUT: u32 = unsafe { MUTABLE };
| ^^^^^^^
help: skipping check for `const_refs_to_static` feature
--> $DIR/const_refers_to_static.rs:18:32
|
LL | const READ_MUT: u32 = unsafe { MUTABLE };
| ^^^^^^^
help: skipping check for `const_refs_to_static` feature
--> $DIR/const_refers_to_static.rs:24:18
|
Expand Down
35 changes: 0 additions & 35 deletions tests/ui/consts/miri_unleashed/const_refers_to_static_cross_crate.32bit.stderr
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Expand Up @@ -83,21 +83,6 @@ help: skipping check for `const_refs_to_static` feature
|
LL | unsafe { &static_cross_crate::ZERO }
| ^^^^^^^^^^^^^^^^^^^^^^^^
help: skipping check for `const_refs_to_static` feature
--> $DIR/const_refers_to_static_cross_crate.rs:12:15
|
LL | unsafe { &static_cross_crate::ZERO }
| ^^^^^^^^^^^^^^^^^^^^^^^^
help: skipping check for `const_refs_to_static` feature
--> $DIR/const_refers_to_static_cross_crate.rs:18:15
|
LL | unsafe { &static_cross_crate::ZERO[0] }
| ^^^^^^^^^^^^^^^^^^^^^^^^
help: skipping check for `const_refs_to_static` feature
--> $DIR/const_refers_to_static_cross_crate.rs:18:15
|
LL | unsafe { &static_cross_crate::ZERO[0] }
| ^^^^^^^^^^^^^^^^^^^^^^^^
help: skipping check for `const_refs_to_static` feature
--> $DIR/const_refers_to_static_cross_crate.rs:18:15
|
Expand All @@ -113,26 +98,6 @@ help: skipping check for `const_refs_to_static` feature
|
LL | match static_cross_crate::OPT_ZERO {
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
help: skipping check for `const_refs_to_static` feature
--> $DIR/const_refers_to_static_cross_crate.rs:28:15
|
LL | match static_cross_crate::OPT_ZERO {
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
help: skipping check for `const_refs_to_static` feature
--> $DIR/const_refers_to_static_cross_crate.rs:28:15
|
LL | match static_cross_crate::OPT_ZERO {
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
help: skipping check for `const_refs_to_static` feature
--> $DIR/const_refers_to_static_cross_crate.rs:28:15
|
LL | match static_cross_crate::OPT_ZERO {
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
help: skipping check for `const_refs_to_static` feature
--> $DIR/const_refers_to_static_cross_crate.rs:28:15
|
LL | match static_cross_crate::OPT_ZERO {
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^

error: aborting due to 8 previous errors; 2 warnings emitted

Expand Down
35 changes: 0 additions & 35 deletions tests/ui/consts/miri_unleashed/const_refers_to_static_cross_crate.64bit.stderr
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Expand Up @@ -83,21 +83,6 @@ help: skipping check for `const_refs_to_static` feature
|
LL | unsafe { &static_cross_crate::ZERO }
| ^^^^^^^^^^^^^^^^^^^^^^^^
help: skipping check for `const_refs_to_static` feature
--> $DIR/const_refers_to_static_cross_crate.rs:12:15
|
LL | unsafe { &static_cross_crate::ZERO }
| ^^^^^^^^^^^^^^^^^^^^^^^^
help: skipping check for `const_refs_to_static` feature
--> $DIR/const_refers_to_static_cross_crate.rs:18:15
|
LL | unsafe { &static_cross_crate::ZERO[0] }
| ^^^^^^^^^^^^^^^^^^^^^^^^
help: skipping check for `const_refs_to_static` feature
--> $DIR/const_refers_to_static_cross_crate.rs:18:15
|
LL | unsafe { &static_cross_crate::ZERO[0] }
| ^^^^^^^^^^^^^^^^^^^^^^^^
help: skipping check for `const_refs_to_static` feature
--> $DIR/const_refers_to_static_cross_crate.rs:18:15
|
Expand All @@ -113,26 +98,6 @@ help: skipping check for `const_refs_to_static` feature
|
LL | match static_cross_crate::OPT_ZERO {
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
help: skipping check for `const_refs_to_static` feature
--> $DIR/const_refers_to_static_cross_crate.rs:28:15
|
LL | match static_cross_crate::OPT_ZERO {
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
help: skipping check for `const_refs_to_static` feature
--> $DIR/const_refers_to_static_cross_crate.rs:28:15
|
LL | match static_cross_crate::OPT_ZERO {
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
help: skipping check for `const_refs_to_static` feature
--> $DIR/const_refers_to_static_cross_crate.rs:28:15
|
LL | match static_cross_crate::OPT_ZERO {
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
help: skipping check for `const_refs_to_static` feature
--> $DIR/const_refers_to_static_cross_crate.rs:28:15
|
LL | match static_cross_crate::OPT_ZERO {
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^

error: aborting due to 8 previous errors; 2 warnings emitted

Expand Down
15 changes: 0 additions & 15 deletions tests/ui/consts/miri_unleashed/mutable_references_err.32bit.stderr
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Expand Up @@ -114,11 +114,6 @@ help: skipping check for `const_refs_to_static` feature
|
LL | const SUBTLE: &mut i32 = unsafe { &mut FOO };
| ^^^
help: skipping check for `const_refs_to_static` feature
--> $DIR/mutable_references_err.rs:32:40
|
LL | const SUBTLE: &mut i32 = unsafe { &mut FOO };
| ^^^
help: skipping check that does not even have a feature gate
--> $DIR/mutable_references_err.rs:32:35
|
Expand All @@ -144,16 +139,6 @@ help: skipping check for `const_refs_to_static` feature
|
LL | const POINTS_TO_MUTABLE1: &i32 = unsafe { &MUTABLE };
| ^^^^^^^
help: skipping check for `const_refs_to_static` feature
--> $DIR/mutable_references_err.rs:47:44
|
LL | const POINTS_TO_MUTABLE1: &i32 = unsafe { &MUTABLE };
| ^^^^^^^
help: skipping check for `const_refs_to_static` feature
--> $DIR/mutable_references_err.rs:51:45
|
LL | const POINTS_TO_MUTABLE2: &i32 = unsafe { &*MUTABLE_REF };
| ^^^^^^^^^^^
help: skipping check for `const_refs_to_static` feature
--> $DIR/mutable_references_err.rs:51:45
|
Expand Down
15 changes: 0 additions & 15 deletions tests/ui/consts/miri_unleashed/mutable_references_err.64bit.stderr
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Expand Up @@ -114,11 +114,6 @@ help: skipping check for `const_refs_to_static` feature
|
LL | const SUBTLE: &mut i32 = unsafe { &mut FOO };
| ^^^
help: skipping check for `const_refs_to_static` feature
--> $DIR/mutable_references_err.rs:32:40
|
LL | const SUBTLE: &mut i32 = unsafe { &mut FOO };
| ^^^
help: skipping check that does not even have a feature gate
--> $DIR/mutable_references_err.rs:32:35
|
Expand All @@ -144,16 +139,6 @@ help: skipping check for `const_refs_to_static` feature
|
LL | const POINTS_TO_MUTABLE1: &i32 = unsafe { &MUTABLE };
| ^^^^^^^
help: skipping check for `const_refs_to_static` feature
--> $DIR/mutable_references_err.rs:47:44
|
LL | const POINTS_TO_MUTABLE1: &i32 = unsafe { &MUTABLE };
| ^^^^^^^
help: skipping check for `const_refs_to_static` feature
--> $DIR/mutable_references_err.rs:51:45
|
LL | const POINTS_TO_MUTABLE2: &i32 = unsafe { &*MUTABLE_REF };
| ^^^^^^^^^^^
help: skipping check for `const_refs_to_static` feature
--> $DIR/mutable_references_err.rs:51:45
|
Expand Down
1 change: 0 additions & 1 deletion tests/ui/feature-gates/feature-gate-const-refs-to-static.rs
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Expand Up @@ -6,7 +6,6 @@ const C1_READ: () = {
assert!(*C1 == 0);
};
const C2: *const i32 = unsafe { std::ptr::addr_of!(S_MUT) }; //~ERROR: referencing statics in constants is unstable
//~^ERROR: referencing statics in constants is unstable

fn main() {
}
15 changes: 1 addition & 14 deletions tests/ui/feature-gates/feature-gate-const-refs-to-static.stderr
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Expand Up @@ -22,19 +22,6 @@ LL | const C2: *const i32 = unsafe { std::ptr::addr_of!(S_MUT) };
= note: `static` and `const` variables can refer to other `const` variables. A `const` variable, however, cannot refer to a `static` variable.
= help: to fix this, the value can be extracted to a `const` and then used.

error[E0658]: referencing statics in constants is unstable
--> $DIR/feature-gate-const-refs-to-static.rs:8:52
|
LL | const C2: *const i32 = unsafe { std::ptr::addr_of!(S_MUT) };
| ^^^^^
|
= note: see issue #119618 <https://github.com/rust-lang/rust/issues/119618> for more information
= help: add `#![feature(const_refs_to_static)]` to the crate attributes to enable
= note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
= note: `static` and `const` variables can refer to other `const` variables. A `const` variable, however, cannot refer to a `static` variable.
= help: to fix this, the value can be extracted to a `const` and then used.
= note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`

error: aborting due to 3 previous errors
error: aborting due to 2 previous errors

For more information about this error, try `rustc --explain E0658`.
1 change: 0 additions & 1 deletion tests/ui/thread-local/thread-local-static.rs
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Expand Up @@ -12,7 +12,6 @@ const fn g(x: &mut [u32; 8]) {
//~^^ ERROR thread-local statics cannot be accessed
//~| ERROR mutable references are not allowed
//~| ERROR use of mutable static is unsafe
//~| referencing statics
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Here this was not a literal duplicate -- the other error is "thread-local statics cannot be accessed". So the old error was even wrong, since STATIC_VAR_2 is a thread-local static, not a regular static, and saying that this is "unstable" and needs the const_refs_to_static feature gate is not correct.

}

fn main() {}
14 changes: 1 addition & 13 deletions tests/ui/thread-local/thread-local-static.stderr
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Expand Up @@ -37,18 +37,6 @@ error[E0625]: thread-local statics cannot be accessed at compile-time
LL | std::mem::swap(x, &mut STATIC_VAR_2)
| ^^^^^^^^^^^^

error[E0658]: referencing statics in constant functions is unstable
--> $DIR/thread-local-static.rs:10:28
|
LL | std::mem::swap(x, &mut STATIC_VAR_2)
| ^^^^^^^^^^^^
|
= note: see issue #119618 <https://github.com/rust-lang/rust/issues/119618> for more information
= help: add `#![feature(const_refs_to_static)]` to the crate attributes to enable
= note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
= note: `static` and `const` variables can refer to other `const` variables. A `const` variable, however, cannot refer to a `static` variable.
= help: to fix this, the value can be extracted to a `const` and then used.

error[E0658]: mutable references are not allowed in constant functions
--> $DIR/thread-local-static.rs:10:23
|
Expand All @@ -59,7 +47,7 @@ LL | std::mem::swap(x, &mut STATIC_VAR_2)
= help: add `#![feature(const_mut_refs)]` to the crate attributes to enable
= note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date

error: aborting due to 5 previous errors; 1 warning emitted
error: aborting due to 4 previous errors; 1 warning emitted

Some errors have detailed explanations: E0133, E0625, E0658.
For more information about an error, try `rustc --explain E0133`.