From 82ad5c95b6cdfc404ca07cd5cf791b809c390671 Mon Sep 17 00:00:00 2001
From: Michael Goulet <michael@errs.io>
Date: Tue, 26 Jul 2022 07:36:23 +0000
Subject: [PATCH 1/3] Revert "use opaque_ty_origin_unchecked instead of
destructuring HIR"
This reverts commit 5a4601fea56502e4f50df046c4205e678397599b.
---
compiler/rustc_borrowck/src/type_check/mod.rs | 16 ++++++++++++----
compiler/rustc_infer/src/infer/opaque_types.rs | 2 +-
2 files changed, 13 insertions(+), 5 deletions(-)
diff --git a/compiler/rustc_borrowck/src/type_check/mod.rs b/compiler/rustc_borrowck/src/type_check/mod.rs
index eb9df281e7d24..1db1ec4a7bf2f 100644
--- a/compiler/rustc_borrowck/src/type_check/mod.rs
+++ b/compiler/rustc_borrowck/src/type_check/mod.rs
@@ -227,9 +227,17 @@ pub(crate) fn type_check<'mir, 'tcx>(
let mut hidden_type = infcx.resolve_vars_if_possible(decl.hidden_type);
// Check that RPITs are only constrained in their outermost
// function, otherwise report a mismatched types error.
- if let OpaqueTyOrigin::FnReturn(parent) | OpaqueTyOrigin::AsyncFn(parent)
- = infcx.opaque_ty_origin_unchecked(opaque_type_key.def_id, hidden_type.span)
- && parent.to_def_id() != body.source.def_id()
+ if let hir::Node::Item(hir::Item {
+ kind:
+ hir::ItemKind::OpaqueTy(hir::OpaqueTy {
+ origin:
+ hir::OpaqueTyOrigin::AsyncFn(parent)
+ | hir::OpaqueTyOrigin::FnReturn(parent),
+ ..
+ }),
+ ..
+ }) = infcx.tcx.hir().get_by_def_id(opaque_type_key.def_id.expect_local()) &&
+ parent.to_def_id() != body.source.def_id()
{
infcx
.report_mismatched_types(
@@ -239,7 +247,7 @@ pub(crate) fn type_check<'mir, 'tcx>(
body.source.def_id().expect_local(),
),
),
- infcx.tcx.mk_opaque(opaque_type_key.def_id.to_def_id(), opaque_type_key.substs),
+ infcx.tcx.mk_opaque(opaque_type_key.def_id, opaque_type_key.substs),
hidden_type.ty,
ty::error::TypeError::Mismatch,
)
diff --git a/compiler/rustc_infer/src/infer/opaque_types.rs b/compiler/rustc_infer/src/infer/opaque_types.rs
index 7b0ff9552a3a4..3db2f822c1c2e 100644
--- a/compiler/rustc_infer/src/infer/opaque_types.rs
+++ b/compiler/rustc_infer/src/infer/opaque_types.rs
@@ -438,7 +438,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
}
#[instrument(skip(self), level = "trace")]
- pub fn opaque_ty_origin_unchecked(&self, def_id: LocalDefId, span: Span) -> OpaqueTyOrigin {
+ fn opaque_ty_origin_unchecked(&self, def_id: LocalDefId, span: Span) -> OpaqueTyOrigin {
let origin = match self.tcx.hir().expect_item(def_id).kind {
hir::ItemKind::OpaqueTy(hir::OpaqueTy { origin, .. }) => origin,
ref itemkind => {
From 90939e6bce14304c24da2f253c1b94e7feca01a9 Mon Sep 17 00:00:00 2001
From: Michael Goulet <michael@errs.io>
Date: Tue, 26 Jul 2022 07:37:54 +0000
Subject: [PATCH 2/3] Revert "Do not allow typeck children items to constrain
outer RPITs"
This reverts commit e8d9f38141a0ee8ac5484783e1fb5c218f9d2eee.
---
compiler/rustc_borrowck/src/type_check/mod.rs | 29 -------------------
1 file changed, 29 deletions(-)
diff --git a/compiler/rustc_borrowck/src/type_check/mod.rs b/compiler/rustc_borrowck/src/type_check/mod.rs
index 1db1ec4a7bf2f..cf2140097e6da 100644
--- a/compiler/rustc_borrowck/src/type_check/mod.rs
+++ b/compiler/rustc_borrowck/src/type_check/mod.rs
@@ -21,7 +21,6 @@ use rustc_infer::infer::type_variable::{TypeVariableOrigin, TypeVariableOriginKi
use rustc_infer::infer::{
InferCtxt, InferOk, LateBoundRegion, LateBoundRegionConversionTime, NllRegionVariableOrigin,
};
-use rustc_infer::traits::ObligationCause;
use rustc_middle::mir::tcx::PlaceTy;
use rustc_middle::mir::visit::{NonMutatingUseContext, PlaceContext, Visitor};
use rustc_middle::mir::AssertKind;
@@ -225,34 +224,6 @@ pub(crate) fn type_check<'mir, 'tcx>(
)
.unwrap();
let mut hidden_type = infcx.resolve_vars_if_possible(decl.hidden_type);
- // Check that RPITs are only constrained in their outermost
- // function, otherwise report a mismatched types error.
- if let hir::Node::Item(hir::Item {
- kind:
- hir::ItemKind::OpaqueTy(hir::OpaqueTy {
- origin:
- hir::OpaqueTyOrigin::AsyncFn(parent)
- | hir::OpaqueTyOrigin::FnReturn(parent),
- ..
- }),
- ..
- }) = infcx.tcx.hir().get_by_def_id(opaque_type_key.def_id.expect_local()) &&
- parent.to_def_id() != body.source.def_id()
- {
- infcx
- .report_mismatched_types(
- &ObligationCause::misc(
- hidden_type.span,
- infcx.tcx.hir().local_def_id_to_hir_id(
- body.source.def_id().expect_local(),
- ),
- ),
- infcx.tcx.mk_opaque(opaque_type_key.def_id, opaque_type_key.substs),
- hidden_type.ty,
- ty::error::TypeError::Mismatch,
- )
- .emit();
- }
trace!(
"finalized opaque type {:?} to {:#?}",
opaque_type_key,
From 5e8f1e80d8bff9995bbc34a959b8aa75e2a5cc00 Mon Sep 17 00:00:00 2001
From: Michael Goulet <michael@errs.io>
Date: Sat, 9 Jul 2022 07:11:03 +0000
Subject: [PATCH 3/3] Check that RPITs constrained by a recursive call in a
closure are compatible
---
compiler/rustc_typeck/src/collect/type_of.rs | 148 +++++++++++++++----
src/test/ui/impl-trait/issue-99073-2.rs | 2 +-
src/test/ui/impl-trait/issue-99073-2.stderr | 15 +-
src/test/ui/impl-trait/issue-99073.rs | 6 +-
src/test/ui/impl-trait/issue-99073.stderr | 18 +--
5 files changed, 139 insertions(+), 50 deletions(-)
diff --git a/compiler/rustc_typeck/src/collect/type_of.rs b/compiler/rustc_typeck/src/collect/type_of.rs
index 1d7406e00ad0a..64ac655e0c393 100644
--- a/compiler/rustc_typeck/src/collect/type_of.rs
+++ b/compiler/rustc_typeck/src/collect/type_of.rs
@@ -335,37 +335,11 @@ pub(super) fn type_of(tcx: TyCtxt<'_>, def_id: DefId) -> Ty<'_> {
tcx.mk_adt(def, substs)
}
ItemKind::OpaqueTy(OpaqueTy { origin: hir::OpaqueTyOrigin::TyAlias, .. }) => {
- find_opaque_ty_constraints(tcx, def_id)
+ find_opaque_ty_constraints_for_tait(tcx, def_id)
}
// Opaque types desugared from `impl Trait`.
ItemKind::OpaqueTy(OpaqueTy { origin: hir::OpaqueTyOrigin::FnReturn(owner) | hir::OpaqueTyOrigin::AsyncFn(owner), .. }) => {
- let concrete_ty = tcx
- .mir_borrowck(owner)
- .concrete_opaque_types
- .get(&def_id)
- .copied()
- .map(|concrete| concrete.ty)
- .unwrap_or_else(|| {
- let table = tcx.typeck(owner);
- if let Some(_) = table.tainted_by_errors {
- // Some error in the
- // owner fn prevented us from populating
- // the `concrete_opaque_types` table.
- tcx.ty_error()
- } else {
- table.concrete_opaque_types.get(&def_id).copied().unwrap_or_else(|| {
- // We failed to resolve the opaque type or it
- // resolves to itself. We interpret this as the
- // no values of the hidden type ever being constructed,
- // so we can just make the hidden type be `!`.
- // For backwards compatibility reasons, we fall back to
- // `()` until we the diverging default is changed.
- Some(tcx.mk_diverging_default())
- }).expect("RPIT always have a hidden type from typeck")
- }
- });
- debug!("concrete_ty = {:?}", concrete_ty);
- concrete_ty
+ find_opaque_ty_constraints_for_rpit(tcx, def_id, owner)
}
ItemKind::Trait(..)
| ItemKind::TraitAlias(..)
@@ -519,7 +493,7 @@ pub(super) fn type_of(tcx: TyCtxt<'_>, def_id: DefId) -> Ty<'_> {
/// fn b<T>() -> Foo<T, u32> { .. }
/// ```
///
-fn find_opaque_ty_constraints(tcx: TyCtxt<'_>, def_id: LocalDefId) -> Ty<'_> {
+fn find_opaque_ty_constraints_for_tait(tcx: TyCtxt<'_>, def_id: LocalDefId) -> Ty<'_> {
use rustc_hir::{Expr, ImplItem, Item, TraitItem};
struct ConstraintLocator<'tcx> {
@@ -660,6 +634,122 @@ fn find_opaque_ty_constraints(tcx: TyCtxt<'_>, def_id: LocalDefId) -> Ty<'_> {
}
}
+fn find_opaque_ty_constraints_for_rpit(
+ tcx: TyCtxt<'_>,
+ def_id: LocalDefId,
+ owner_def_id: LocalDefId,
+) -> Ty<'_> {
+ use rustc_hir::{Expr, ImplItem, Item, TraitItem};
+
+ struct ConstraintChecker<'tcx> {
+ tcx: TyCtxt<'tcx>,
+
+ /// def_id of the opaque type whose defining uses are being checked
+ def_id: LocalDefId,
+
+ found: ty::OpaqueHiddenType<'tcx>,
+ }
+
+ impl ConstraintChecker<'_> {
+ #[instrument(skip(self), level = "debug")]
+ fn check(&self, def_id: LocalDefId) {
+ // Use borrowck to get the type with unerased regions.
+ let concrete_opaque_types = &self.tcx.mir_borrowck(def_id).concrete_opaque_types;
+ debug!(?concrete_opaque_types);
+ for &(def_id, concrete_type) in concrete_opaque_types {
+ if def_id != self.def_id {
+ // Ignore constraints for other opaque types.
+ continue;
+ }
+
+ debug!(?concrete_type, "found constraint");
+
+ if concrete_type.ty != self.found.ty
+ && !(concrete_type, self.found).references_error()
+ {
+ self.found.report_mismatch(&concrete_type, self.tcx);
+ }
+ }
+ }
+ }
+
+ impl<'tcx> intravisit::Visitor<'tcx> for ConstraintChecker<'tcx> {
+ type NestedFilter = nested_filter::OnlyBodies;
+
+ fn nested_visit_map(&mut self) -> Self::Map {
+ self.tcx.hir()
+ }
+ fn visit_expr(&mut self, ex: &'tcx Expr<'tcx>) {
+ if let hir::ExprKind::Closure { .. } = ex.kind {
+ let def_id = self.tcx.hir().local_def_id(ex.hir_id);
+ self.check(def_id);
+ }
+ intravisit::walk_expr(self, ex);
+ }
+ fn visit_item(&mut self, it: &'tcx Item<'tcx>) {
+ trace!(?it.def_id);
+ // The opaque type itself or its children are not within its reveal scope.
+ if it.def_id != self.def_id {
+ self.check(it.def_id);
+ intravisit::walk_item(self, it);
+ }
+ }
+ fn visit_impl_item(&mut self, it: &'tcx ImplItem<'tcx>) {
+ trace!(?it.def_id);
+ // The opaque type itself or its children are not within its reveal scope.
+ if it.def_id != self.def_id {
+ self.check(it.def_id);
+ intravisit::walk_impl_item(self, it);
+ }
+ }
+ fn visit_trait_item(&mut self, it: &'tcx TraitItem<'tcx>) {
+ trace!(?it.def_id);
+ self.check(it.def_id);
+ intravisit::walk_trait_item(self, it);
+ }
+ }
+
+ let concrete = tcx.mir_borrowck(owner_def_id).concrete_opaque_types.get(&def_id).copied();
+
+ if let Some(concrete) = concrete {
+ let scope = tcx.hir().local_def_id_to_hir_id(owner_def_id);
+ debug!(?scope);
+ let mut locator = ConstraintChecker { def_id: def_id, tcx, found: concrete };
+
+ match tcx.hir().get(scope) {
+ Node::Item(it) => intravisit::walk_item(&mut locator, it),
+ Node::ImplItem(it) => intravisit::walk_impl_item(&mut locator, it),
+ Node::TraitItem(it) => intravisit::walk_trait_item(&mut locator, it),
+ other => bug!("{:?} is not a valid scope for an opaque type item", other),
+ }
+ }
+
+ concrete.map(|concrete| concrete.ty).unwrap_or_else(|| {
+ let table = tcx.typeck(owner_def_id);
+ if let Some(_) = table.tainted_by_errors {
+ // Some error in the
+ // owner fn prevented us from populating
+ // the `concrete_opaque_types` table.
+ tcx.ty_error()
+ } else {
+ table
+ .concrete_opaque_types
+ .get(&def_id)
+ .copied()
+ .unwrap_or_else(|| {
+ // We failed to resolve the opaque type or it
+ // resolves to itself. We interpret this as the
+ // no values of the hidden type ever being constructed,
+ // so we can just make the hidden type be `!`.
+ // For backwards compatibility reasons, we fall back to
+ // `()` until we the diverging default is changed.
+ Some(tcx.mk_diverging_default())
+ })
+ .expect("RPIT always have a hidden type from typeck")
+ }
+ })
+}
+
fn infer_placeholder_type<'a>(
tcx: TyCtxt<'a>,
def_id: LocalDefId,
diff --git a/src/test/ui/impl-trait/issue-99073-2.rs b/src/test/ui/impl-trait/issue-99073-2.rs
index bebd8286de9fe..14ac688806bda 100644
--- a/src/test/ui/impl-trait/issue-99073-2.rs
+++ b/src/test/ui/impl-trait/issue-99073-2.rs
@@ -7,7 +7,7 @@ fn main() {
fn test<T: Display>(t: T, recurse: bool) -> impl Display {
let f = || {
let i: u32 = test::<i32>(-1, false);
- //~^ ERROR mismatched types
+ //~^ ERROR concrete type differs from previous defining opaque type use
println!("{i}");
};
if recurse {
diff --git a/src/test/ui/impl-trait/issue-99073-2.stderr b/src/test/ui/impl-trait/issue-99073-2.stderr
index c1e4b823c08e7..913bc8f5674ac 100644
--- a/src/test/ui/impl-trait/issue-99073-2.stderr
+++ b/src/test/ui/impl-trait/issue-99073-2.stderr
@@ -1,15 +1,14 @@
-error[E0308]: mismatched types
+error: concrete type differs from previous defining opaque type use
--> $DIR/issue-99073-2.rs:9:22
|
-LL | fn test<T: Display>(t: T, recurse: bool) -> impl Display {
- | ------------ the expected opaque type
-LL | let f = || {
LL | let i: u32 = test::<i32>(-1, false);
- | ^^^^^^^^^^^^^^^^^^^^^^ types differ
+ | ^^^^^^^^^^^^^^^^^^^^^^ expected `T`, got `u32`
|
- = note: expected opaque type `impl std::fmt::Display`
- found type `u32`
+note: previous use here
+ --> $DIR/issue-99073-2.rs:16:5
+ |
+LL | t
+ | ^
error: aborting due to previous error
-For more information about this error, try `rustc --explain E0308`.
diff --git a/src/test/ui/impl-trait/issue-99073.rs b/src/test/ui/impl-trait/issue-99073.rs
index 1d75f6086664f..7798e247df0a2 100644
--- a/src/test/ui/impl-trait/issue-99073.rs
+++ b/src/test/ui/impl-trait/issue-99073.rs
@@ -1,8 +1,8 @@
fn main() {
- let _ = fix(|_: &dyn Fn()| {});
+ let _ = fix(|_: &dyn Fn()| {});
}
fn fix<F: Fn(G), G: Fn()>(f: F) -> impl Fn() {
- move || f(fix(&f))
- //~^ ERROR mismatched types
+ move || f(fix(&f))
+ //~^ ERROR concrete type differs from previous defining opaque type use
}
diff --git a/src/test/ui/impl-trait/issue-99073.stderr b/src/test/ui/impl-trait/issue-99073.stderr
index b35d58093d5fc..5463679534968 100644
--- a/src/test/ui/impl-trait/issue-99073.stderr
+++ b/src/test/ui/impl-trait/issue-99073.stderr
@@ -1,14 +1,14 @@
-error[E0308]: mismatched types
- --> $DIR/issue-99073.rs:6:13
+error: concrete type differs from previous defining opaque type use
+ --> $DIR/issue-99073.rs:6:11
|
-LL | fn fix<F: Fn(G), G: Fn()>(f: F) -> impl Fn() {
- | --------- the expected opaque type
-LL | move || f(fix(&f))
- | ^^^^^^^^^^ types differ
+LL | move || f(fix(&f))
+ | ^^^^^^^^^^ expected `[closure@$DIR/issue-99073.rs:6:3: 6:10]`, got `G`
|
- = note: expected opaque type `impl Fn()`
- found type parameter `G`
+note: previous use here
+ --> $DIR/issue-99073.rs:6:3
+ |
+LL | move || f(fix(&f))
+ | ^^^^^^^^^^^^^^^^^^
error: aborting due to previous error
-For more information about this error, try `rustc --explain E0308`.