bendns' repos / rust-analyzer
Unnamed repository; edit this file 'description' to name the repository.
Diffstat
-rw-r--r--crates/hir-def/src/hir/type_ref.rs8
-rw-r--r--crates/hir-def/src/lower.rs30
-rw-r--r--crates/hir-def/src/path/lower.rs2
-rw-r--r--crates/hir-ty/src/tests/traits.rs73
4 files changed, 112 insertions, 1 deletions
diff --git a/crates/hir-def/src/hir/type_ref.rs b/crates/hir-def/src/hir/type_ref.rs
index ec207a7f96..741ae41c74 100644
--- a/crates/hir-def/src/hir/type_ref.rs
+++ b/crates/hir-def/src/hir/type_ref.rs
@@ -245,7 +245,13 @@ impl TypeRef {
// for types are close enough for our purposes to the inner type for now...
ast::Type::ForType(inner) => TypeRef::from_ast_opt(ctx, inner.ty()),
ast::Type::ImplTraitType(inner) => {
- TypeRef::ImplTrait(type_bounds_from_ast(ctx, inner.type_bound_list()))
+ if ctx.outer_impl_trait() {
+ // Disallow nested impl traits
+ TypeRef::Error
+ } else {
+ let _guard = ctx.outer_impl_trait_scope(true);
+ TypeRef::ImplTrait(type_bounds_from_ast(ctx, inner.type_bound_list()))
+ }
}
ast::Type::DynTraitType(inner) => {
TypeRef::DynTrait(type_bounds_from_ast(ctx, inner.type_bound_list()))
diff --git a/crates/hir-def/src/lower.rs b/crates/hir-def/src/lower.rs
index ecd8d79f20..e4786a1dd4 100644
--- a/crates/hir-def/src/lower.rs
+++ b/crates/hir-def/src/lower.rs
@@ -18,6 +18,26 @@ pub struct LowerCtx<'a> {
span_map: OnceCell<SpanMap>,
ast_id_map: OnceCell<Arc<AstIdMap>>,
impl_trait_bounds: RefCell<Vec<Vec<Interned<TypeBound>>>>,
+ // Prevent nested impl traits like `impl Foo<impl Bar>`.
+ outer_impl_trait: RefCell<bool>,
+}
+
+pub(crate) struct OuterImplTraitGuard<'a> {
+ ctx: &'a LowerCtx<'a>,
+ old: bool,
+}
+
+impl<'a> OuterImplTraitGuard<'a> {
+ fn new(ctx: &'a LowerCtx<'a>, impl_trait: bool) -> Self {
+ let old = ctx.outer_impl_trait.replace(impl_trait);
+ Self { ctx, old }
+ }
+}
+
+impl<'a> Drop for OuterImplTraitGuard<'a> {
+ fn drop(&mut self) {
+ self.ctx.outer_impl_trait.replace(self.old);
+ }
}
impl<'a> LowerCtx<'a> {
@@ -28,6 +48,7 @@ impl<'a> LowerCtx<'a> {
span_map: OnceCell::new(),
ast_id_map: OnceCell::new(),
impl_trait_bounds: RefCell::new(Vec::new()),
+ outer_impl_trait: RefCell::default(),
}
}
@@ -42,6 +63,7 @@ impl<'a> LowerCtx<'a> {
span_map,
ast_id_map: OnceCell::new(),
impl_trait_bounds: RefCell::new(Vec::new()),
+ outer_impl_trait: RefCell::default(),
}
}
@@ -67,4 +89,12 @@ impl<'a> LowerCtx<'a> {
pub fn take_impl_traits_bounds(&self) -> Vec<Vec<Interned<TypeBound>>> {
self.impl_trait_bounds.take()
}
+
+ pub(crate) fn outer_impl_trait(&self) -> bool {
+ *self.outer_impl_trait.borrow()
+ }
+
+ pub(crate) fn outer_impl_trait_scope(&'a self, impl_trait: bool) -> OuterImplTraitGuard<'a> {
+ OuterImplTraitGuard::new(self, impl_trait)
+ }
}
diff --git a/crates/hir-def/src/path/lower.rs b/crates/hir-def/src/path/lower.rs
index 2b555b3998..a710c2daca 100644
--- a/crates/hir-def/src/path/lower.rs
+++ b/crates/hir-def/src/path/lower.rs
@@ -202,6 +202,8 @@ pub(super) fn lower_generic_args(
continue;
}
if let Some(name_ref) = assoc_type_arg.name_ref() {
+ // Nested impl traits like `impl Foo<Assoc = impl Bar>` are allowed
+ let _guard = lower_ctx.outer_impl_trait_scope(false);
let name = name_ref.as_name();
let args = assoc_type_arg
.generic_arg_list()
diff --git a/crates/hir-ty/src/tests/traits.rs b/crates/hir-ty/src/tests/traits.rs
index 18fc8afd18..fb07e718d1 100644
--- a/crates/hir-ty/src/tests/traits.rs
+++ b/crates/hir-ty/src/tests/traits.rs
@@ -4824,3 +4824,76 @@ fn foo() {
"#,
)
}
+
+#[test]
+fn nested_impl_traits() {
+ check_infer(
+ r#"
+//- minicore: fn
+trait Foo {}
+
+trait Bar<T> {}
+
+trait Baz {
+ type Assoc;
+}
+
+struct Qux<T> {
+ qux: T,
+}
+
+struct S;
+
+impl Foo for S {}
+
+fn not_allowed1(f: impl Fn(impl Foo)) {
+ let foo = S;
+ f(foo);
+}
+
+// This caused stack overflow in #17498
+fn not_allowed2(f: impl Fn(&impl Foo)) {
+ let foo = S;
+ f(&foo);
+}
+
+fn not_allowed3(bar: impl Bar<impl Foo>) {}
+
+// This also caused stack overflow
+fn not_allowed4(bar: impl Bar<&impl Foo>) {}
+
+fn allowed1(baz: impl Baz<Assoc = impl Foo>) {}
+
+fn allowed2<'a>(baz: impl Baz<Assoc = &'a (impl Foo + 'a)>) {}
+
+fn allowed3(baz: impl Baz<Assoc = Qux<impl Foo>>) {}
+"#,
+ expect![[r#"
+ 139..140 'f': impl Fn({unknown}) + ?Sized
+ 161..193 '{ ...oo); }': ()
+ 171..174 'foo': S
+ 177..178 'S': S
+ 184..185 'f': impl Fn({unknown}) + ?Sized
+ 184..190 'f(foo)': ()
+ 186..189 'foo': S
+ 251..252 'f': impl Fn(&'? {unknown}) + ?Sized
+ 274..307 '{ ...oo); }': ()
+ 284..287 'foo': S
+ 290..291 'S': S
+ 297..298 'f': impl Fn(&'? {unknown}) + ?Sized
+ 297..304 'f(&foo)': ()
+ 299..303 '&foo': &'? S
+ 300..303 'foo': S
+ 325..328 'bar': impl Bar<{unknown}> + ?Sized
+ 350..352 '{}': ()
+ 405..408 'bar': impl Bar<&'? {unknown}> + ?Sized
+ 431..433 '{}': ()
+ 447..450 'baz': impl Baz<Assoc = impl Foo + ?Sized> + ?Sized
+ 480..482 '{}': ()
+ 500..503 'baz': impl Baz<Assoc = &'a impl Foo + 'a + ?Sized> + ?Sized
+ 544..546 '{}': ()
+ 560..563 'baz': impl Baz<Assoc = Qux<impl Foo + ?Sized>> + ?Sized
+ 598..600 '{}': ()
+ "#]],
+ )
+}