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Rollup merge of #102336 - compiler-errors:issue-102333, r=jackh726
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Fix associated type bindings with anon const in GAT position

The first commit formats `type_of.rs`, which is really hard to maintain since it uses a bunch of features like `let`-chains and `if let` match arm bindings. Best if you just review the second two diffs.

Fixes #102333
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@Dylan-DPC
Dylan-DPC authored Sep 29, 2022
2 parents 8a497b7 + 92561f4 commit 1be9ec5
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Showing 2 changed files with 102 additions and 30 deletions.
117 changes: 87 additions & 30 deletions compiler/rustc_hir_analysis/src/collect/type_of.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -333,7 +333,12 @@ pub(super) fn type_of(tcx: TyCtxt<'_>, def_id: DefId) -> Ty<'_> {
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), in_trait, .. }) => {
ItemKind::OpaqueTy(OpaqueTy {
origin:
hir::OpaqueTyOrigin::FnReturn(owner) | hir::OpaqueTyOrigin::AsyncFn(owner),
in_trait,
..
}) => {
if in_trait {
span_bug!(item.span, "impl-trait in trait has no default")
} else {
Expand Down Expand Up @@ -378,7 +383,9 @@ pub(super) fn type_of(tcx: TyCtxt<'_>, def_id: DefId) -> Ty<'_> {

Node::Field(field) => icx.to_ty(field.ty),

Node::Expr(&Expr { kind: ExprKind::Closure{..}, .. }) => tcx.typeck(def_id).node_type(hir_id),
Node::Expr(&Expr { kind: ExprKind::Closure { .. }, .. }) => {
tcx.typeck(def_id).node_type(hir_id)
}

Node::AnonConst(_) if let Some(param) = tcx.opt_const_param_of(def_id) => {
// We defer to `type_of` of the corresponding parameter
Expand Down Expand Up @@ -410,40 +417,91 @@ pub(super) fn type_of(tcx: TyCtxt<'_>, def_id: DefId) -> Ty<'_> {
| Node::Item(&Item { kind: ItemKind::GlobalAsm(asm), .. })
if asm.operands.iter().any(|(op, _op_sp)| match op {
hir::InlineAsmOperand::Const { anon_const }
| hir::InlineAsmOperand::SymFn { anon_const } => anon_const.hir_id == hir_id,
| hir::InlineAsmOperand::SymFn { anon_const } => {
anon_const.hir_id == hir_id
}
_ => false,
}) =>
{
tcx.typeck(def_id).node_type(hir_id)
}

Node::Variant(Variant { disr_expr: Some(ref e), .. }) if e.hir_id == hir_id => tcx
.adt_def(tcx.hir().get_parent_item(hir_id))
.repr()
.discr_type()
.to_ty(tcx),
Node::Variant(Variant { disr_expr: Some(ref e), .. }) if e.hir_id == hir_id => {
tcx.adt_def(tcx.hir().get_parent_item(hir_id)).repr().discr_type().to_ty(tcx)
}

Node::TypeBinding(binding @ &TypeBinding { hir_id: binding_id, .. })
if let Node::TraitRef(trait_ref) = tcx.hir().get(
tcx.hir().get_parent_node(binding_id)
) =>
Node::TypeBinding(
binding @ &TypeBinding {
hir_id: binding_id,
kind: TypeBindingKind::Equality { term: Term::Const(ref e) },
..
},
) if let Node::TraitRef(trait_ref) =
tcx.hir().get(tcx.hir().get_parent_node(binding_id))
&& e.hir_id == hir_id =>
{
let Some(trait_def_id) = trait_ref.trait_def_id() else {
return tcx.ty_error_with_message(DUMMY_SP, "Could not find trait");
};
let assoc_items = tcx.associated_items(trait_def_id);
let assoc_item = assoc_items.find_by_name_and_kind(
tcx, binding.ident, ty::AssocKind::Const, def_id.to_def_id(),
);
if let Some(assoc_item) = assoc_item {
tcx.type_of(assoc_item.def_id)
} else {
// FIXME(associated_const_equality): add a useful error message here.
tcx.ty_error_with_message(
DUMMY_SP,
"Could not find associated const on trait",
)
}
let Some(trait_def_id) = trait_ref.trait_def_id() else {
return tcx.ty_error_with_message(DUMMY_SP, "Could not find trait");
};
let assoc_items = tcx.associated_items(trait_def_id);
let assoc_item = assoc_items.find_by_name_and_kind(
tcx,
binding.ident,
ty::AssocKind::Const,
def_id.to_def_id(),
);
if let Some(assoc_item) = assoc_item {
tcx.type_of(assoc_item.def_id)
} else {
// FIXME(associated_const_equality): add a useful error message here.
tcx.ty_error_with_message(
DUMMY_SP,
"Could not find associated const on trait",
)
}
}

Node::TypeBinding(
binding @ &TypeBinding { hir_id: binding_id, gen_args, ref kind, .. },
) if let Node::TraitRef(trait_ref) =
tcx.hir().get(tcx.hir().get_parent_node(binding_id))
&& let Some((idx, _)) =
gen_args.args.iter().enumerate().find(|(_, arg)| {
if let GenericArg::Const(ct) = arg {
ct.value.hir_id == hir_id
} else {
false
}
}) =>
{
let Some(trait_def_id) = trait_ref.trait_def_id() else {
return tcx.ty_error_with_message(DUMMY_SP, "Could not find trait");
};
let assoc_items = tcx.associated_items(trait_def_id);
let assoc_item = assoc_items.find_by_name_and_kind(
tcx,
binding.ident,
match kind {
// I think `<A: T>` type bindings requires that `A` is a type
TypeBindingKind::Constraint { .. }
| TypeBindingKind::Equality { term: Term::Ty(..) } => {
ty::AssocKind::Type
}
TypeBindingKind::Equality { term: Term::Const(..) } => {
ty::AssocKind::Const
}
},
def_id.to_def_id(),
);
if let Some(assoc_item) = assoc_item {
tcx.type_of(tcx.generics_of(assoc_item.def_id).params[idx].def_id)
} else {
// FIXME(associated_const_equality): add a useful error message here.
tcx.ty_error_with_message(
DUMMY_SP,
"Could not find associated const on trait",
)
}
}

Node::GenericParam(&GenericParam {
Expand All @@ -452,8 +510,7 @@ pub(super) fn type_of(tcx: TyCtxt<'_>, def_id: DefId) -> Ty<'_> {
..
}) if ct.hir_id == hir_id => tcx.type_of(tcx.hir().local_def_id(param_hir_id)),

x =>
tcx.ty_error_with_message(
x => tcx.ty_error_with_message(
DUMMY_SP,
&format!("unexpected const parent in type_of(): {x:?}"),
),
Expand Down
15 changes: 15 additions & 0 deletions src/test/ui/generic-associated-types/issue-102333.rs
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Original file line number Diff line number Diff line change
@@ -0,0 +1,15 @@
// check-pass

trait A {
type T: B<U<1i32> = ()>;
}

trait B {
type U<const C: i32>;
}

fn f<T: A>() {
let _: <<T as A>::T as B>::U<1i32> = ();
}

fn main() {}

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