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FedericoBruzzoneFedericoBruzzone
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Add TooGeneric variant to LayoutError and emit Unknown one
- `check-pass` test for a MRE of #135020 - fail test for #135138 - switch to `TooGeneric` for checking CMSE fn signatures - switch to `TooGeneric` for compute `SizeSkeleton` (for transmute) - fix broken tests
1 parent 341f603 commit 66fce46

32 files changed

+242
-80
lines changed

‎compiler/rustc_const_eval/src/const_eval/error.rs‎

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -140,7 +140,7 @@ where
140140
// Don't emit a new diagnostic for these errors, they are already reported elsewhere or
141141
// should remain silent.
142142
err_inval!(AlreadyReported(info)) => ErrorHandled::Reported(info, span),
143-
err_inval!(Layout(LayoutError::Unknown(_))) | err_inval!(TooGeneric) => {
143+
err_inval!(Layout(LayoutError::TooGeneric(_))) | err_inval!(TooGeneric) => {
144144
ErrorHandled::TooGeneric(span)
145145
}
146146
err_inval!(Layout(LayoutError::ReferencesError(guar))) => {

‎compiler/rustc_hir_analysis/src/hir_ty_lowering/cmse.rs‎

Lines changed: 6 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -201,7 +201,7 @@ fn should_emit_generic_error<'tcx>(abi: ExternAbi, layout_err: &'tcx LayoutError
201201
use LayoutError::*;
202202

203203
match layout_err {
204-
Unknown(ty) => {
204+
TooGeneric(ty) => {
205205
match abi {
206206
ExternAbi::CCmseNonSecureCall => {
207207
// prevent double reporting of this error
@@ -211,7 +211,11 @@ fn should_emit_generic_error<'tcx>(abi: ExternAbi, layout_err: &'tcx LayoutError
211211
_ => bug!("invalid ABI: {abi}"),
212212
}
213213
}
214-
SizeOverflow(..) | NormalizationFailure(..) | ReferencesError(..) | Cycle(..) => {
214+
Unknown(..)
215+
| SizeOverflow(..)
216+
| NormalizationFailure(..)
217+
| ReferencesError(..)
218+
| Cycle(..) => {
215219
false // not our job to report these
216220
}
217221
}

‎compiler/rustc_middle/messages.ftl‎

Lines changed: 3 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -100,11 +100,14 @@ middle_strict_coherence_needs_negative_coherence =
100100
to use `strict_coherence` on this trait, the `with_negative_coherence` feature must be enabled
101101
.label = due to this attribute
102102
103+
middle_too_generic = `{$ty}` does not have a fixed size
104+
103105
middle_type_length_limit = reached the type-length limit while instantiating `{$shrunk}`
104106
105107
middle_unknown_layout =
106108
the type `{$ty}` has an unknown layout
107109
108110
middle_values_too_big =
109111
values of the type `{$ty}` are too big for the target architecture
112+
110113
middle_written_to_path = the full type name has been written to '{$path}'

‎compiler/rustc_middle/src/error.rs‎

Lines changed: 3 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -129,6 +129,9 @@ pub enum LayoutError<'tcx> {
129129
#[diag(middle_unknown_layout)]
130130
Unknown { ty: Ty<'tcx> },
131131

132+
#[diag(middle_too_generic)]
133+
TooGeneric { ty: Ty<'tcx> },
134+
132135
#[diag(middle_values_too_big)]
133136
Overflow { ty: Ty<'tcx> },
134137

‎compiler/rustc_middle/src/ty/layout.rs‎

Lines changed: 8 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -231,6 +231,7 @@ impl fmt::Display for ValidityRequirement {
231231
pub enum LayoutError<'tcx> {
232232
Unknown(Ty<'tcx>),
233233
SizeOverflow(Ty<'tcx>),
234+
TooGeneric(Ty<'tcx>),
234235
NormalizationFailure(Ty<'tcx>, NormalizationError<'tcx>),
235236
ReferencesError(ErrorGuaranteed),
236237
Cycle(ErrorGuaranteed),
@@ -244,6 +245,7 @@ impl<'tcx> LayoutError<'tcx> {
244245
match self {
245246
Unknown(_) => middle_unknown_layout,
246247
SizeOverflow(_) => middle_values_too_big,
248+
TooGeneric(_) => middle_too_generic,
247249
NormalizationFailure(_, _) => middle_cannot_be_normalized,
248250
Cycle(_) => middle_cycle,
249251
ReferencesError(_) => middle_layout_references_error,
@@ -257,6 +259,7 @@ impl<'tcx> LayoutError<'tcx> {
257259
match self {
258260
Unknown(ty) => E::Unknown { ty },
259261
SizeOverflow(ty) => E::Overflow { ty },
262+
TooGeneric(ty) => E::TooGeneric { ty },
260263
NormalizationFailure(ty, e) => {
261264
E::NormalizationFailure { ty, failure_ty: e.get_type_for_failure() }
262265
}
@@ -272,6 +275,9 @@ impl<'tcx> fmt::Display for LayoutError<'tcx> {
272275
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
273276
match *self {
274277
LayoutError::Unknown(ty) => write!(f, "the type `{ty}` has an unknown layout"),
278+
LayoutError::TooGeneric(ty) => {
279+
write!(f, "`{ty}` does not have a fixed size")
280+
}
275281
LayoutError::SizeOverflow(ty) => {
276282
write!(f, "values of the type `{ty}` are too big for the target architecture")
277283
}
@@ -350,10 +356,11 @@ impl<'tcx> SizeSkeleton<'tcx> {
350356
return Err(tcx.arena.alloc(LayoutError::Unknown(ty)));
351357
}
352358
}
353-
Err(err @ LayoutError::Unknown(_)) => err,
359+
Err(err @ LayoutError::TooGeneric(_)) => err,
354360
// We can't extract SizeSkeleton info from other layout errors
355361
Err(
356362
e @ LayoutError::Cycle(_)
363+
| e @ LayoutError::Unknown(_)
357364
| e @ LayoutError::SizeOverflow(_)
358365
| e @ LayoutError::NormalizationFailure(..)
359366
| e @ LayoutError::ReferencesError(_),

‎compiler/rustc_transmute/src/layout/tree.rs‎

Lines changed: 1 addition & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -197,6 +197,7 @@ pub(crate) mod rustc {
197197
match err {
198198
LayoutError::Unknown(..)
199199
| LayoutError::ReferencesError(..)
200+
| LayoutError::TooGeneric(..)
200201
| LayoutError::NormalizationFailure(..) => Self::UnknownLayout,
201202
LayoutError::SizeOverflow(..) => Self::SizeOverflow,
202203
LayoutError::Cycle(err) => Self::TypeError(*err),

‎compiler/rustc_ty_utils/src/layout.rs‎

Lines changed: 33 additions & 15 deletions
Original file line numberDiff line numberDiff line change
@@ -104,14 +104,12 @@ fn map_error<'tcx>(
104104
// This is sometimes not a compile error if there are trivially false where clauses.
105105
// See `tests/ui/layout/trivial-bounds-sized.rs` for an example.
106106
assert!(field.layout.is_unsized(), "invalid layout error {err:#?}");
107-
if !field.ty.is_sized(cx.tcx(), cx.typing_env) {
108-
let guar = cx.tcx().dcx().delayed_bug(format!(
107+
if cx.typing_env.param_env.caller_bounds().is_empty() {
108+
cx.tcx().dcx().delayed_bug(format!(
109109
"encountered unexpected unsized field in layout of {ty:?}: {field:#?}"
110110
));
111-
LayoutError::ReferencesError(guar)
112-
} else {
113-
LayoutError::Unknown(ty)
114111
}
112+
LayoutError::Unknown(ty)
115113
}
116114
LayoutCalculatorError::EmptyUnion => {
117115
// This is always a compile error.
@@ -319,17 +317,30 @@ fn layout_of_uncached<'tcx>(
319317
}
320318

321319
// Arrays and slices.
322-
ty::Array(element, mut count) => {
323-
if count.has_aliases() {
324-
count = tcx.normalize_erasing_regions(cx.typing_env, count);
325-
if count.has_aliases() {
326-
return Err(error(cx, LayoutError::Unknown(ty)));
320+
ty::Array(element, count) => {
321+
let count = match count.kind() {
322+
ty::ConstKind::Infer(_) | ty::ConstKind::Bound(..) | ty::ConstKind::Placeholder(_) => bug!("unexpected count in array type: {ty:?}"),
323+
ty::ConstKind::Value(_, valtree) => valtree
324+
.try_to_target_usize(tcx)
325+
.ok_or_else(|| error(cx, LayoutError::Unknown(ty)))?,
326+
ty::ConstKind::Error(guar) => {
327+
return Err(error(cx, LayoutError::ReferencesError(guar)));
327328
}
328-
}
329+
ty::ConstKind::Param(_) | ty::ConstKind::Expr(_) => {
330+
if !count.has_param() {
331+
bug!("no generic type found in count of array type: {ty:?}");
332+
}
333+
return Err(error(cx, LayoutError::TooGeneric(ty)));
334+
}
335+
ty::ConstKind::Unevaluated(_) => {
336+
if !count.has_param() {
337+
return Err(error(cx, LayoutError::Unknown(ty)));
338+
} else {
339+
return Err(error(cx, LayoutError::TooGeneric(ty)));
340+
}
341+
}
342+
};
329343

330-
let count = count
331-
.try_to_target_usize(tcx)
332-
.ok_or_else(|| error(cx, LayoutError::Unknown(ty)))?;
333344
let element = cx.layout_of(element)?;
334345
let size = element
335346
.size
@@ -687,6 +698,9 @@ fn layout_of_uncached<'tcx>(
687698

688699
// Types with no meaningful known layout.
689700
ty::Alias(..) => {
701+
if ty.has_param() {
702+
return Err(error(cx, LayoutError::TooGeneric(ty)));
703+
}
690704
// NOTE(eddyb) `layout_of` query should've normalized these away,
691705
// if that was possible, so there's no reason to try again here.
692706
return Err(error(cx, LayoutError::Unknown(ty)));
@@ -696,7 +710,11 @@ fn layout_of_uncached<'tcx>(
696710
bug!("Layout::compute: unexpected type `{}`", ty)
697711
}
698712

699-
ty::Placeholder(..) | ty::Param(_) => {
713+
ty::Param(_) => {
714+
return Err(error(cx, LayoutError::TooGeneric(ty)));
715+
}
716+
717+
ty::Placeholder(..) => {
700718
return Err(error(cx, LayoutError::Unknown(ty)));
701719
}
702720
})

‎src/librustdoc/html/templates/type_layout.html‎

Lines changed: 12 additions & 6 deletions
Original file line numberDiff line numberDiff line change
@@ -28,21 +28,27 @@ <h2 id="layout" class="section-header"> {# #}
2828
{% endfor %}
2929
</ul>
3030
{% endif %}
31-
{# This kind of layout error can occur with valid code, e.g. if you try to
32-
get the layout of a generic type such as `Vec<T>`. #}
31+
{# This kind of layout error can occur with valid code, for example
32+
if there are trivial bounds: `struct Foo(str, str) where str: Sized;`. #}
3333
{% when Err(LayoutError::Unknown(_)) %}
3434
<p> {# #}
35-
<strong>Note:</strong> Unable to compute type layout, {#+ #}
36-
possibly due to this type having generic parameters. {#+ #}
37-
Layout can only be computed for concrete, fully-instantiated types. {# #}
35+
<strong>Note:</strong> Unable to compute type layout. {# #}
3836
</p>
3937
{# This kind of error probably can't happen with valid code, but we don't
4038
want to panic and prevent the docs from building, so we just let the
4139
user know that we couldn't compute the layout. #}
4240
{% when Err(LayoutError::SizeOverflow(_)) %}
41+
<p> {# #}
42+
<strong>Note:</strong> Unable to compute type layout, {#+ #}
43+
possibly due to this type having generic parameters. {#+ #}
44+
Layout can only be computed for concrete, fully-instantiated types. {# #}
45+
</p>
46+
{# This kind of layout error can occur with valid code, e.g. if you try to
47+
get the layout of a generic type such as `Vec<T>`. #}
48+
{% when Err(LayoutError::TooGeneric(_)) %}
4349
<p> {# #}
4450
<strong>Note:</strong> Encountered an error during type layout; {#+ #}
45-
the type was too big. {# #}
51+
the type was too generic. {# #}
4652
</p>
4753
{% when Err(LayoutError::ReferencesError(_)) %}
4854
<p> {# #}

‎tests/crashes/135020.rs‎

Lines changed: 0 additions & 11 deletions
This file was deleted.

‎tests/rustdoc/type-layout.rs‎

Lines changed: 7 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -37,7 +37,7 @@ pub struct Y(u8);
3737
pub struct Z;
3838

3939
// We can't compute layout for generic types.
40-
//@ hasraw type_layout/struct.Generic.html 'Unable to compute type layout, possibly due to this type having generic parameters'
40+
//@ hasraw type_layout/struct.Generic.html 'Encountered an error during type layout; the type was too generic.'
4141
//@ !hasraw - 'Size: '
4242
pub struct Generic<T>(T);
4343

@@ -91,3 +91,9 @@ pub enum Uninhabited {}
9191
//@ hasraw type_layout/struct.Uninhabited2.html 'Size: '
9292
//@ hasraw - '8 bytes (<a href="https://doc.rust-lang.org/stable/reference/glossary.html#uninhabited">uninhabited</a>)'
9393
pub struct Uninhabited2(std::convert::Infallible, u64);
94+
95+
pub trait Project { type Assoc; }
96+
// We can't compute layout. A `LayoutError::Unknown` is returned.
97+
//@ hasraw type_layout/struct.Unknown.html 'Unable to compute type layout.'
98+
//@ !hasraw - 'Size: '
99+
pub struct Unknown(<() as Project>::Assoc) where for<'a> (): Project;

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