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Auto merge of #111047 - compiler-errors:rtn-no-ty-ct-params, r=spasto…
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…rino

Emit an error when return-type-notation is used with type/const params

These are not intended to be supported initially, even though the compiler supports them internally...
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bors committed Jun 7, 2023
2 parents 10b7e46 + b0eaaca commit e94bda3
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Showing 8 changed files with 100 additions and 44 deletions.
7 changes: 7 additions & 0 deletions compiler/rustc_hir_analysis/messages.ftl
Original file line number Diff line number Diff line change
Expand Up @@ -195,6 +195,13 @@ hir_analysis_return_type_notation_conflicting_bound =
hir_analysis_return_type_notation_equality_bound =
return type notation is not allowed to use type equality
hir_analysis_return_type_notation_illegal_param_const =
return type notation is not allowed for functions that have const parameters
.label = const parameter declared here
hir_analysis_return_type_notation_illegal_param_type =
return type notation is not allowed for functions that have type parameters
.label = type parameter declared here
hir_analysis_return_type_notation_missing_method =
cannot find associated function `{$assoc_name}` for `{$ty_name}`
Expand Down
63 changes: 24 additions & 39 deletions compiler/rustc_hir_analysis/src/astconv/mod.rs
Original file line number Diff line number Diff line change
Expand Up @@ -26,10 +26,8 @@ use rustc_hir::def::{CtorOf, DefKind, Namespace, Res};
use rustc_hir::def_id::{DefId, LocalDefId};
use rustc_hir::intravisit::{walk_generics, Visitor as _};
use rustc_hir::{GenericArg, GenericArgs, OpaqueTyOrigin};
use rustc_infer::infer::type_variable::{TypeVariableOrigin, TypeVariableOriginKind};
use rustc_infer::infer::{InferCtxt, TyCtxtInferExt};
use rustc_infer::traits::ObligationCause;
use rustc_middle::infer::unify_key::{ConstVariableOrigin, ConstVariableOriginKind};
use rustc_middle::middle::stability::AllowUnstable;
use rustc_middle::ty::fold::FnMutDelegate;
use rustc_middle::ty::subst::{self, GenericArgKind, InternalSubsts, SubstsRef};
Expand Down Expand Up @@ -1215,6 +1213,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
}

let projection_ty = if return_type_notation {
let mut emitted_bad_param_err = false;
// If we have an method return type bound, then we need to substitute
// the method's early bound params with suitable late-bound params.
let mut num_bound_vars = candidate.bound_vars().len();
Expand All @@ -1230,16 +1229,35 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
},
)
.into(),
GenericParamDefKind::Type { .. } => tcx
.mk_bound(
GenericParamDefKind::Type { .. } => {
if !emitted_bad_param_err {
tcx.sess.emit_err(
crate::errors::ReturnTypeNotationIllegalParam::Type {
span: path_span,
param_span: tcx.def_span(param.def_id),
},
);
emitted_bad_param_err = true;
}
tcx.mk_bound(
ty::INNERMOST,
ty::BoundTy {
var: ty::BoundVar::from_usize(num_bound_vars),
kind: ty::BoundTyKind::Param(param.def_id, param.name),
},
)
.into(),
.into()
}
GenericParamDefKind::Const { .. } => {
if !emitted_bad_param_err {
tcx.sess.emit_err(
crate::errors::ReturnTypeNotationIllegalParam::Const {
span: path_span,
param_span: tcx.def_span(param.def_id),
},
);
emitted_bad_param_err = true;
}
let ty = tcx
.type_of(param.def_id)
.no_bound_vars()
Expand Down Expand Up @@ -2472,7 +2490,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
infcx.probe(|_| {
let ocx = ObligationCtxt::new_in_snapshot(&infcx);

let impl_substs = infcx.fresh_item_substs(impl_);
let impl_substs = infcx.fresh_substs_for_item(span, impl_);
let impl_ty = tcx.type_of(impl_).subst(tcx, impl_substs);
let impl_ty = ocx.normalize(&cause, param_env, impl_ty);

Expand Down Expand Up @@ -3759,36 +3777,3 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
}
}
}

pub trait InferCtxtExt<'tcx> {
fn fresh_item_substs(&self, def_id: DefId) -> SubstsRef<'tcx>;
}

impl<'tcx> InferCtxtExt<'tcx> for InferCtxt<'tcx> {
fn fresh_item_substs(&self, def_id: DefId) -> SubstsRef<'tcx> {
InternalSubsts::for_item(self.tcx, def_id, |param, _| match param.kind {
GenericParamDefKind::Lifetime => self.tcx.lifetimes.re_erased.into(),
GenericParamDefKind::Type { .. } => self
.next_ty_var(TypeVariableOrigin {
kind: TypeVariableOriginKind::SubstitutionPlaceholder,
span: self.tcx.def_span(def_id),
})
.into(),
GenericParamDefKind::Const { .. } => {
let span = self.tcx.def_span(def_id);
let origin = ConstVariableOrigin {
kind: ConstVariableOriginKind::SubstitutionPlaceholder,
span,
};
self.next_const_var(
self.tcx
.type_of(param.def_id)
.no_bound_vars()
.expect("const parameter types cannot be generic"),
origin,
)
.into()
}
})
}
}
18 changes: 18 additions & 0 deletions compiler/rustc_hir_analysis/src/errors.rs
Original file line number Diff line number Diff line change
Expand Up @@ -857,3 +857,21 @@ pub(crate) enum DropImplPolarity {
span: Span,
},
}

#[derive(Diagnostic)]
pub(crate) enum ReturnTypeNotationIllegalParam {
#[diag(hir_analysis_return_type_notation_illegal_param_type)]
Type {
#[primary_span]
span: Span,
#[label]
param_span: Span,
},
#[diag(hir_analysis_return_type_notation_illegal_param_const)]
Const {
#[primary_span]
span: Span,
#[label]
param_span: Span,
},
}
5 changes: 2 additions & 3 deletions compiler/rustc_hir_typeck/src/method/probe.rs
Original file line number Diff line number Diff line change
Expand Up @@ -9,7 +9,6 @@ use rustc_data_structures::fx::FxHashSet;
use rustc_errors::Applicability;
use rustc_hir as hir;
use rustc_hir::def::DefKind;
use rustc_hir_analysis::astconv::InferCtxtExt as _;
use rustc_hir_analysis::autoderef::{self, Autoderef};
use rustc_infer::infer::canonical::OriginalQueryValues;
use rustc_infer::infer::canonical::{Canonical, QueryResponse};
Expand Down Expand Up @@ -954,7 +953,7 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> {
trait_def_id: DefId,
) {
debug!("assemble_extension_candidates_for_trait(trait_def_id={:?})", trait_def_id);
let trait_substs = self.fresh_item_substs(trait_def_id);
let trait_substs = self.fresh_substs_for_item(self.span, trait_def_id);
let trait_ref = ty::TraitRef::new(self.tcx, trait_def_id, trait_substs);

if self.tcx.is_trait_alias(trait_def_id) {
Expand Down Expand Up @@ -1899,7 +1898,7 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> {
&self,
impl_def_id: DefId,
) -> (ty::EarlyBinder<Ty<'tcx>>, SubstsRef<'tcx>) {
(self.tcx.type_of(impl_def_id), self.fresh_item_substs(impl_def_id))
(self.tcx.type_of(impl_def_id), self.fresh_substs_for_item(self.span, impl_def_id))
}

/// Replaces late-bound-regions bound by `value` with `'static` using
Expand Down
1 change: 0 additions & 1 deletion compiler/rustc_infer/src/infer/type_variable.rs
Original file line number Diff line number Diff line change
Expand Up @@ -129,7 +129,6 @@ pub enum TypeVariableOriginKind {
/// (before it has been determined).
// FIXME(eddyb) distinguish upvar inference variables from the rest.
ClosureSynthetic,
SubstitutionPlaceholder,
AutoDeref,
AdjustmentType,

Expand Down
1 change: 0 additions & 1 deletion compiler/rustc_middle/src/infer/unify_key.rs
Original file line number Diff line number Diff line change
Expand Up @@ -116,7 +116,6 @@ pub enum ConstVariableOriginKind {
MiscVariable,
ConstInference,
ConstParameterDefinition(Symbol, DefId),
SubstitutionPlaceholder,
}

#[derive(Copy, Clone, Debug)]
Expand Down
20 changes: 20 additions & 0 deletions tests/ui/async-await/return-type-notation/ty-or-ct-params.rs
Original file line number Diff line number Diff line change
@@ -0,0 +1,20 @@
// edition: 2021

#![feature(async_fn_in_trait, return_type_notation)]
//~^ WARN the feature `return_type_notation` is incomplete

trait Foo {
async fn bar<T>() {}

async fn baz<const N: usize>() {}
}

fn test<T>()
where
T: Foo<bar(): Send, baz(): Send>,
//~^ ERROR return type notation is not allowed for functions that have const parameters
//~| ERROR return type notation is not allowed for functions that have type parameters
{
}

fn main() {}
29 changes: 29 additions & 0 deletions tests/ui/async-await/return-type-notation/ty-or-ct-params.stderr
Original file line number Diff line number Diff line change
@@ -0,0 +1,29 @@
warning: the feature `return_type_notation` is incomplete and may not be safe to use and/or cause compiler crashes
--> $DIR/ty-or-ct-params.rs:3:31
|
LL | #![feature(async_fn_in_trait, return_type_notation)]
| ^^^^^^^^^^^^^^^^^^^^
|
= note: see issue #109417 <https://github.com/rust-lang/rust/issues/109417> for more information
= note: `#[warn(incomplete_features)]` on by default

error: return type notation is not allowed for functions that have type parameters
--> $DIR/ty-or-ct-params.rs:14:12
|
LL | async fn bar<T>() {}
| - type parameter declared here
...
LL | T: Foo<bar(): Send, baz(): Send>,
| ^^^^^^^^^^^

error: return type notation is not allowed for functions that have const parameters
--> $DIR/ty-or-ct-params.rs:14:25
|
LL | async fn baz<const N: usize>() {}
| -------------- const parameter declared here
...
LL | T: Foo<bar(): Send, baz(): Send>,
| ^^^^^^^^^^^

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

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