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Auto merge of #98900 - lcnr:region-stuff, r=jackh726

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const_generics: correctly deal with bound variables

removes the hack in `resolve` which was needed because we evaluated constants without caring about their bound variables.

Each commit should be fairly self-contained, even if they build on each other

r? `@jackh726`
This commit is contained in:
bors 2022-09-08 10:30:00 +00:00
commit ccb5595df2
12 changed files with 76 additions and 83 deletions
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2
compiler/rustc_const_eval/src/interpret/intrinsics.rs
View File

@ -79,9 +79,9 @@ pub(crate) fn eval_nullary_intrinsic<'tcx>(
ty::Projection(_)
| ty::Opaque(_, _)
| ty::Param(_)
| ty::Bound(_, _)
| ty::Placeholder(_)
| ty::Infer(_) => throw_inval!(TooGeneric),
ty::Bound(_, _) => bug!("bound ty during ctfe"),
ty::Bool
| ty::Char
| ty::Int(_)

4
compiler/rustc_const_eval/src/interpret/operand.rs
View File

@ -559,7 +559,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
layout: Option<TyAndLayout<'tcx>>,
) -> InterpResult<'tcx, OpTy<'tcx, M::Provenance>> {
match c.kind() {
ty::ConstKind::Param(_) | ty::ConstKind::Bound(..) => throw_inval!(TooGeneric),
ty::ConstKind::Param(_) | ty::ConstKind::Placeholder(..) => throw_inval!(TooGeneric),
ty::ConstKind::Error(DelaySpanBugEmitted { reported, .. }) => {
throw_inval!(AlreadyReported(reported))
}
@ -567,7 +567,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
let instance = self.resolve(uv.def, uv.substs)?;
Ok(self.eval_to_allocation(GlobalId { instance, promoted: uv.promoted })?.into())
}
ty::ConstKind::Infer(..) | ty::ConstKind::Placeholder(..) => {
ty::ConstKind::Bound(..) | ty::ConstKind::Infer(..) => {
span_bug!(self.cur_span(), "const_to_op: Unexpected ConstKind {:?}", c)
}
ty::ConstKind::Value(valtree) => {

20
compiler/rustc_infer/src/infer/combine.rs
View File

@ -486,7 +486,7 @@ struct Generalizer<'cx, 'tcx> {
param_env: ty::ParamEnv<'tcx>,
cache: SsoHashMap<Ty<'tcx>, RelateResult<'tcx, Ty<'tcx>>>,
cache: SsoHashMap<Ty<'tcx>, Ty<'tcx>>,
}
/// Result from a generalization operation. This includes
@ -593,8 +593,8 @@ impl<'tcx> TypeRelation<'tcx> for Generalizer<'_, 'tcx> {
fn tys(&mut self, t: Ty<'tcx>, t2: Ty<'tcx>) -> RelateResult<'tcx, Ty<'tcx>> {
assert_eq!(t, t2); // we are abusing TypeRelation here; both LHS and RHS ought to be ==
if let Some(result) = self.cache.get(&t) {
return result.clone();
if let Some(&result) = self.cache.get(&t) {
return Ok(result);
}
debug!("generalize: t={:?}", t);
@ -664,10 +664,10 @@ impl<'tcx> TypeRelation<'tcx> for Generalizer<'_, 'tcx> {
Ok(t)
}
_ => relate::super_relate_tys(self, t, t),
};
}?;
self.cache.insert(t, result.clone());
return result;
self.cache.insert(t, result);
Ok(result)
}
fn regions(
@ -743,9 +743,7 @@ impl<'tcx> TypeRelation<'tcx> for Generalizer<'_, 'tcx> {
}
}
}
ty::ConstKind::Unevaluated(ty::Unevaluated { def, substs, promoted })
if self.tcx().lazy_normalization() =>
{
ty::ConstKind::Unevaluated(ty::Unevaluated { def, substs, promoted }) => {
assert_eq!(promoted, None);
let substs = self.relate_with_variance(
ty::Variance::Invariant,
@ -967,9 +965,7 @@ impl<'tcx> TypeRelation<'tcx> for ConstInferUnifier<'_, 'tcx> {
}
}
}
ty::ConstKind::Unevaluated(ty::Unevaluated { def, substs, promoted })
if self.tcx().lazy_normalization() =>
{
ty::ConstKind::Unevaluated(ty::Unevaluated { def, substs, promoted }) => {
assert_eq!(promoted, None);
let substs = self.relate_with_variance(
ty::Variance::Invariant,

1
compiler/rustc_middle/src/ty/consts/kind.rs
View File

@ -180,6 +180,7 @@ impl<'tcx> ConstKind<'tcx> {
param_env: ParamEnv<'tcx>,
eval_mode: EvalMode,
) -> Option<Result<EvalResult<'tcx>, ErrorGuaranteed>> {
assert!(!self.has_escaping_bound_vars(), "escaping vars in {self:?}");
if let ConstKind::Unevaluated(unevaluated) = self {
use crate::mir::interpret::ErrorHandled;

4
compiler/rustc_middle/src/ty/relate.rs
View File

@ -594,10 +594,6 @@ pub fn super_relate_consts<'tcx, R: TypeRelation<'tcx>>(
);
}
let eagerly_eval = |x: ty::Const<'tcx>| x.eval(tcx, relation.param_env());
let a = eagerly_eval(a);
let b = eagerly_eval(b);
// Currently, the values that can be unified are primitive types,
// and those that derive both `PartialEq` and `Eq`, corresponding
// to structural-match types.

48
compiler/rustc_trait_selection/src/traits/project.rs
View File

@ -635,13 +635,18 @@ impl<'a, 'b, 'tcx> TypeFolder<'tcx> for AssocTypeNormalizer<'a, 'b, 'tcx> {
#[instrument(skip(self), level = "debug")]
fn fold_const(&mut self, constant: ty::Const<'tcx>) -> ty::Const<'tcx> {
if self.selcx.tcx().lazy_normalization() || !self.eager_inference_replacement {
let tcx = self.selcx.tcx();
if tcx.lazy_normalization() {
constant
} else {
let constant = constant.super_fold_with(self);
debug!(?constant);
debug!("self.param_env: {:?}", self.param_env);
constant.eval(self.selcx.tcx(), self.param_env)
debug!(?constant, ?self.param_env);
with_replaced_escaping_bound_vars(
self.selcx.infcx(),
&mut self.universes,
constant,
|constant| constant.eval(tcx, self.param_env),
)
}
}
@ -671,6 +676,41 @@ pub struct BoundVarReplacer<'me, 'tcx> {
universe_indices: &'me mut Vec<Option<ty::UniverseIndex>>,
}
/// Executes `f` on `value` after replacing all escaping bound variables with placeholders
/// and then replaces these placeholders with the original bound variables in the result.
///
/// In most places, bound variables should be replaced right when entering a binder, making
/// this function unnecessary. However, normalization currently does not do that, so we have
/// to do this lazily.
///
/// You should not add any additional uses of this function, at least not without first
/// discussing it with t-types.
///
/// FIXME(@lcnr): We may even consider experimenting with eagerly replacing bound vars during
/// normalization as well, at which point this function will be unnecessary and can be removed.
pub fn with_replaced_escaping_bound_vars<'a, 'tcx, T: TypeFoldable<'tcx>, R: TypeFoldable<'tcx>>(
infcx: &'a InferCtxt<'a, 'tcx>,
universe_indices: &'a mut Vec<Option<ty::UniverseIndex>>,
value: T,
f: impl FnOnce(T) -> R,
) -> R {
if value.has_escaping_bound_vars() {
let (value, mapped_regions, mapped_types, mapped_consts) =
BoundVarReplacer::replace_bound_vars(infcx, universe_indices, value);
let result = f(value);
PlaceholderReplacer::replace_placeholders(
infcx,
mapped_regions,
mapped_types,
mapped_consts,
universe_indices,
result,
)
} else {
f(value)
}
}
impl<'me, 'tcx> BoundVarReplacer<'me, 'tcx> {
/// Returns `Some` if we *were* able to replace bound vars. If there are any bound vars that
/// use a binding level above `universe_indices.len()`, we fail.

19
compiler/rustc_trait_selection/src/traits/query/normalize.rs
View File

@ -6,7 +6,7 @@ use crate::infer::at::At;
use crate::infer::canonical::OriginalQueryValues;
use crate::infer::{InferCtxt, InferOk};
use crate::traits::error_reporting::InferCtxtExt;
use crate::traits::project::needs_normalization;
use crate::traits::project::{needs_normalization, BoundVarReplacer, PlaceholderReplacer};
use crate::traits::{Obligation, ObligationCause, PredicateObligation, Reveal};
use rustc_data_structures::sso::SsoHashMap;
use rustc_data_structures::stack::ensure_sufficient_stack;
@ -283,11 +283,7 @@ impl<'cx, 'tcx> FallibleTypeFolder<'tcx> for QueryNormalizer<'cx, 'tcx> {
let tcx = self.infcx.tcx;
let infcx = self.infcx;
let (data, mapped_regions, mapped_types, mapped_consts) =
crate::traits::project::BoundVarReplacer::replace_bound_vars(
infcx,
&mut self.universes,
data,
);
BoundVarReplacer::replace_bound_vars(infcx, &mut self.universes, data);
let data = data.try_fold_with(self)?;
let mut orig_values = OriginalQueryValues::default();
@ -313,8 +309,7 @@ impl<'cx, 'tcx> FallibleTypeFolder<'tcx> for QueryNormalizer<'cx, 'tcx> {
debug!("QueryNormalizer: result = {:#?}", result);
debug!("QueryNormalizer: obligations = {:#?}", obligations);
self.obligations.extend(obligations);
let res = crate::traits::project::PlaceholderReplacer::replace_placeholders(
let res = PlaceholderReplacer::replace_placeholders(
infcx,
mapped_regions,
mapped_types,
@ -343,7 +338,13 @@ impl<'cx, 'tcx> FallibleTypeFolder<'tcx> for QueryNormalizer<'cx, 'tcx> {
constant: ty::Const<'tcx>,
) -> Result<ty::Const<'tcx>, Self::Error> {
let constant = constant.try_super_fold_with(self)?;
Ok(constant.eval(self.infcx.tcx, self.param_env))
debug!(?constant, ?self.param_env);
Ok(crate::traits::project::with_replaced_escaping_bound_vars(
self.infcx,
&mut self.universes,
constant,
|constant| constant.eval(self.infcx.tcx, self.param_env),
))
}
fn try_fold_mir_const(

9
compiler/rustc_typeck/src/check/fn_ctxt/_impl.rs
View File

@ -495,13 +495,10 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
pub fn to_const(&self, ast_c: &hir::AnonConst) -> ty::Const<'tcx> {
let const_def_id = self.tcx.hir().local_def_id(ast_c.hir_id);
let span = self.tcx.hir().span(ast_c.hir_id);
let c = ty::Const::from_anon_const(self.tcx, const_def_id);
self.register_wf_obligation(
c.into(),
self.tcx.hir().span(ast_c.hir_id),
ObligationCauseCode::WellFormed(None),
);
c
self.register_wf_obligation(c.into(), span, ObligationCauseCode::WellFormed(None));
self.normalize_associated_types_in(span, c)
}
pub fn const_arg_to_const(

1
src/test/ui/closures/issue-52437.rs
View File

@ -2,5 +2,4 @@ fn main() {
[(); &(&'static: loop { |x| {}; }) as *const _ as usize]
//~^ ERROR: invalid label name `'static`
//~| ERROR: type annotations needed
//~| ERROR mismatched types
}

13
src/test/ui/closures/issue-52437.stderr
View File

@ -15,15 +15,6 @@ help: consider giving this closure parameter an explicit type
LL | [(); &(&'static: loop { |x: _| {}; }) as *const _ as usize]
| +++
error[E0308]: mismatched types
--> $DIR/issue-52437.rs:2:5
|
LL | fn main() {
| - expected `()` because of default return type
LL | [(); &(&'static: loop { |x| {}; }) as *const _ as usize]
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected `()`, found array `[(); _]`
error: aborting due to 2 previous errors
error: aborting due to 3 previous errors
Some errors have detailed explanations: E0282, E0308.
For more information about an error, try `rustc --explain E0282`.
For more information about this error, try `rustc --explain E0282`.

3
src/test/ui/issues/issue-66706.rs
View File

@ -2,7 +2,6 @@ fn a() {
[0; [|_: _ &_| ()].len()]
//~^ ERROR expected `,`, found `&`
//~| ERROR type annotations needed
//~| ERROR mismatched types
}
fn b() {
@ -13,13 +12,11 @@ fn b() {
fn c() {
[0; [|&_: _ &_| {}; 0 ].len()]
//~^ ERROR expected `,`, found `&`
//~| ERROR mismatched types
}
fn d() {
[0; match [|f @ &ref _| () ] {} ]
//~^ ERROR expected identifier, found reserved identifier `_`
//~| ERROR mismatched types
}
fn main() {}

35
src/test/ui/issues/issue-66706.stderr
View File

@ -7,13 +7,13 @@ LL | [0; [|_: _ &_| ()].len()]
| help: missing `,`
error: expected identifier, found reserved identifier `_`
--> $DIR/issue-66706.rs:9:20
--> $DIR/issue-66706.rs:8:20
|
LL | [0; [|f @ &ref _| {} ; 0 ].len() ];
| ^ expected identifier, found reserved identifier
error: expected `,`, found `&`
--> $DIR/issue-66706.rs:14:17
--> $DIR/issue-66706.rs:13:17
|
LL | [0; [|&_: _ &_| {}; 0 ].len()]
| -^ expected `,`
@ -21,7 +21,7 @@ LL | [0; [|&_: _ &_| {}; 0 ].len()]
| help: missing `,`
error: expected identifier, found reserved identifier `_`
--> $DIR/issue-66706.rs:20:26
--> $DIR/issue-66706.rs:18:26
|
LL | [0; match [|f @ &ref _| () ] {} ]
| ^ expected identifier, found reserved identifier
@ -32,31 +32,6 @@ error[E0282]: type annotations needed
LL | [0; [|_: _ &_| ()].len()]
| ^ cannot infer type
error[E0308]: mismatched types
--> $DIR/issue-66706.rs:2:5
|
LL | fn a() {
| - help: try adding a return type: `-> [i32; _]`
LL | [0; [|_: _ &_| ()].len()]
| ^^^^^^^^^^^^^^^^^^^^^^^^^ expected `()`, found array `[{integer}; _]`
error: aborting due to 5 previous errors
error[E0308]: mismatched types
--> $DIR/issue-66706.rs:14:5
|
LL | fn c() {
| - help: try adding a return type: `-> [i32; _]`
LL | [0; [|&_: _ &_| {}; 0 ].len()]
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected `()`, found array `[{integer}; _]`
error[E0308]: mismatched types
--> $DIR/issue-66706.rs:20:5
|
LL | fn d() {
| - help: try adding a return type: `-> [i32; _]`
LL | [0; match [|f @ &ref _| () ] {} ]
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected `()`, found array `[{integer}; _]`
error: aborting due to 8 previous errors
Some errors have detailed explanations: E0282, E0308.
For more information about an error, try `rustc --explain E0282`.
For more information about this error, try `rustc --explain E0282`.