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Prevent two opaque types in their defining scopes from being defined via the other
This commit is contained in:
Oli Scherer
parent
bae04fb3de
commit
7f608eb9ed
@ -80,47 +80,69 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
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}
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if self.defining_use_anchor.is_some() {
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let process = |a: Ty<'tcx>, b: Ty<'tcx>| match *a.kind() {
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ty::Opaque(def_id, substs) => Some(self.register_hidden_type(
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OpaqueTypeKey { def_id, substs },
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cause.clone(),
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param_env,
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b,
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// Check that this is `impl Trait` type is
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// declared by `parent_def_id` -- i.e., one whose
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// value we are inferring. At present, this is
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// always true during the first phase of
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// type-check, but not always true later on during
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// NLL. Once we support named opaque types more fully,
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// this same scenario will be able to arise during all phases.
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//
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// Here is an example using type alias `impl Trait`
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// that indicates the distinction we are checking for:
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//
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// ```rust
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// mod a {
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// pub type Foo = impl Iterator;
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// pub fn make_foo() -> Foo { .. }
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// }
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//
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// mod b {
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// fn foo() -> a::Foo { a::make_foo() }
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// }
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// ```
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//
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// Here, the return type of `foo` references an
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// `Opaque` indeed, but not one whose value is
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// presently being inferred. You can get into a
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// similar situation with closure return types
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// today:
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//
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// ```rust
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// fn foo() -> impl Iterator { .. }
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// fn bar() {
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// let x = || foo(); // returns the Opaque assoc with `foo`
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// }
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// ```
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self.opaque_type_origin(def_id, cause.span)?,
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)),
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ty::Opaque(def_id, substs) => {
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if let ty::Opaque(did2, _) = *b.kind() {
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if self.opaque_type_origin(did2, cause.span).is_some() {
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self.tcx
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.sess
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.struct_span_err(
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cause.span,
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"opaque type's hidden type cannot be another opaque type from the same scope",
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)
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.span_label(cause.span, "one of the two opaque types used here has to be outside its defining scope")
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.span_note(
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self.tcx.def_span(def_id),
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"opaque type whose hidden type is being assigned",
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)
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.span_note(
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self.tcx.def_span(did2),
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"opaque type being used as hidden type",
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)
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.emit();
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}
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}
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Some(self.register_hidden_type(
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OpaqueTypeKey { def_id, substs },
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cause.clone(),
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param_env,
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b,
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// Check that this is `impl Trait` type is
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// declared by `parent_def_id` -- i.e., one whose
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// value we are inferring. At present, this is
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// always true during the first phase of
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// type-check, but not always true later on during
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// NLL. Once we support named opaque types more fully,
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// this same scenario will be able to arise during all phases.
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//
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// Here is an example using type alias `impl Trait`
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// that indicates the distinction we are checking for:
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//
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// ```rust
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// mod a {
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// pub type Foo = impl Iterator;
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// pub fn make_foo() -> Foo { .. }
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// }
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//
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// mod b {
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// fn foo() -> a::Foo { a::make_foo() }
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// }
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// ```
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//
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// Here, the return type of `foo` references an
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// `Opaque` indeed, but not one whose value is
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// presently being inferred. You can get into a
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// similar situation with closure return types
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// today:
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//
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// ```rust
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// fn foo() -> impl Iterator { .. }
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// fn bar() {
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// let x = || foo(); // returns the Opaque assoc with `foo`
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// }
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// ```
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self.opaque_type_origin(def_id, cause.span)?,
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))
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}
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_ => None,
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};
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if let Some(res) = process(a, b) {
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@ -1,4 +1,3 @@
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// run-pass
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// ignore-compare-mode-chalk
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#![feature(fn_traits,
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@ -590,7 +589,7 @@ fn test_format_month() {
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fn format_months(it: impl Iterator<Item = impl DateIterator>)
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-> impl Iterator<Item=impl Iterator<Item=String>>
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{
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it.map(format_month)
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it.map(format_month) //~ ERROR opaque type's hidden type cannot be another opaque type
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}
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/// Takes an iterator of iterators of strings; the sub-iterators are consumed
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19
src/test/ui/impl-trait/example-calendar.stderr
Normal file
19
src/test/ui/impl-trait/example-calendar.stderr
Normal file
@ -0,0 +1,19 @@
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error: opaque type's hidden type cannot be another opaque type from the same scope
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--> $DIR/example-calendar.rs:592:5
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LL | it.map(format_month)
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| ^^^^^^^^^^^^^^^^^^^^ one of the two opaque types used here has to be outside its defining scope
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note: opaque type whose hidden type is being assigned
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--> $DIR/example-calendar.rs:560:43
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LL | fn format_month(it: impl DateIterator) -> impl Iterator<Item=String> {
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^
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note: opaque type being used as hidden type
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--> $DIR/example-calendar.rs:590:39
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LL | -> impl Iterator<Item=impl Iterator<Item=String>>
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^
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error: aborting due to previous error
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@ -1,7 +1,5 @@
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#![feature(type_alias_impl_trait)]
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// check-pass
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type FooArg<'a> = &'a dyn ToString;
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type FooRet = impl std::fmt::Debug;
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@ -30,7 +28,7 @@ fn ham() -> Foo {
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fn oof() -> impl std::fmt::Debug {
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let mut bar = ham();
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let func = bar.next().unwrap();
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return func(&"oof");
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return func(&"oof"); //~ ERROR opaque type's hidden type cannot be another opaque type
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}
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fn main() {
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19
src/test/ui/impl-trait/issues/issue-70877.stderr
Normal file
19
src/test/ui/impl-trait/issues/issue-70877.stderr
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@ -0,0 +1,19 @@
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error: opaque type's hidden type cannot be another opaque type from the same scope
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--> $DIR/issue-70877.rs:31:12
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LL | return func(&"oof");
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| ^^^^^^^^^^^^ one of the two opaque types used here has to be outside its defining scope
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note: opaque type whose hidden type is being assigned
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--> $DIR/issue-70877.rs:28:13
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LL | fn oof() -> impl std::fmt::Debug {
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| ^^^^^^^^^^^^^^^^^^^^
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note: opaque type being used as hidden type
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--> $DIR/issue-70877.rs:4:15
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LL | type FooRet = impl std::fmt::Debug;
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| ^^^^^^^^^^^^^^^^^^^^
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error: aborting due to previous error
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39
src/test/ui/impl-trait/issues/issue-88236-2.nll.stderr
Normal file
39
src/test/ui/impl-trait/issues/issue-88236-2.nll.stderr
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@ -0,0 +1,39 @@
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error: higher-ranked subtype error
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--> $DIR/issue-88236-2.rs:17:5
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LL | &()
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| ^^^
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error: higher-ranked subtype error
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--> $DIR/issue-88236-2.rs:17:5
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LL | &()
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| ^^^
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error: lifetime may not live long enough
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--> $DIR/issue-88236-2.rs:20:5
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LL | fn make_bad_impl<'b>(x: &'b ()) -> impl for<'a> Hrtb<'a, Assoc = impl Send + 'a> {
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| -- lifetime `'b` defined here
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LL | x
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| ^ returning this value requires that `'b` must outlive `'static`
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help: to allow this `impl Trait` to capture borrowed data with lifetime `'b`, add `'b` as a bound
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LL | fn make_bad_impl<'b>(x: &'b ()) -> impl for<'a> Hrtb<'a, Assoc = impl Send + 'a> + 'b {
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| ++++
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error: higher-ranked subtype error
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--> $DIR/issue-88236-2.rs:20:5
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LL | x
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| ^
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error: higher-ranked subtype error
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--> $DIR/issue-88236-2.rs:20:5
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LL | x
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| ^
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error: aborting due to 5 previous errors
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@ -1,7 +1,5 @@
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#![feature(type_alias_impl_trait)]
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// check-pass
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type A = impl Foo;
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type B = impl Foo;
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@ -12,6 +10,7 @@ fn muh(x: A) -> B {
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return Bar; // B's hidden type is Bar
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}
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x // A's hidden type is `Bar`, because all the hidden types of `B` are compared with each other
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//~^ ERROR opaque type's hidden type cannot be another opaque type
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}
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struct Bar;
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19
src/test/ui/impl-trait/two_tait_defining_each_other.stderr
Normal file
19
src/test/ui/impl-trait/two_tait_defining_each_other.stderr
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@ -0,0 +1,19 @@
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error: opaque type's hidden type cannot be another opaque type from the same scope
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--> $DIR/two_tait_defining_each_other.rs:12:5
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LL | x // A's hidden type is `Bar`, because all the hidden types of `B` are compared with each other
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| ^ one of the two opaque types used here has to be outside its defining scope
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note: opaque type whose hidden type is being assigned
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--> $DIR/two_tait_defining_each_other.rs:4:10
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LL | type B = impl Foo;
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| ^^^^^^^^
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note: opaque type being used as hidden type
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--> $DIR/two_tait_defining_each_other.rs:3:10
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LL | type A = impl Foo;
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| ^^^^^^^^
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error: aborting due to previous error
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@ -1,13 +1,13 @@
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#![feature(type_alias_impl_trait)]
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type A = impl Foo;
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//~^ ERROR unconstrained opaque type
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type B = impl Foo;
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trait Foo {}
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fn muh(x: A) -> B {
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x // B's hidden type is A (opaquely)
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//~^ ERROR opaque type's hidden type cannot be another opaque type
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}
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struct Bar;
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@ -1,10 +1,19 @@
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error: unconstrained opaque type
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error: opaque type's hidden type cannot be another opaque type from the same scope
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--> $DIR/two_tait_defining_each_other2.rs:9:5
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LL | x // B's hidden type is A (opaquely)
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| ^ one of the two opaque types used here has to be outside its defining scope
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note: opaque type whose hidden type is being assigned
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--> $DIR/two_tait_defining_each_other2.rs:4:10
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LL | type B = impl Foo;
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| ^^^^^^^^
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note: opaque type being used as hidden type
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--> $DIR/two_tait_defining_each_other2.rs:3:10
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LL | type A = impl Foo;
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| ^^^^^^^^
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= note: `A` must be used in combination with a concrete type within the same module
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error: aborting due to previous error
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@ -1,7 +1,5 @@
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#![feature(type_alias_impl_trait)]
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// check-pass
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type A = impl Foo;
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type B = impl Foo;
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@ -10,6 +8,7 @@ trait Foo {}
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fn muh(x: A) -> B {
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if false {
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return x; // B's hidden type is A (opaquely)
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//~^ ERROR opaque type's hidden type cannot be another opaque type
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}
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Bar // A's hidden type is `Bar`, because all the return types are compared with each other
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}
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19
src/test/ui/impl-trait/two_tait_defining_each_other3.stderr
Normal file
19
src/test/ui/impl-trait/two_tait_defining_each_other3.stderr
Normal file
@ -0,0 +1,19 @@
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error: opaque type's hidden type cannot be another opaque type from the same scope
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--> $DIR/two_tait_defining_each_other3.rs:10:16
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LL | return x; // B's hidden type is A (opaquely)
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| ^ one of the two opaque types used here has to be outside its defining scope
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note: opaque type whose hidden type is being assigned
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--> $DIR/two_tait_defining_each_other3.rs:4:10
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LL | type B = impl Foo;
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| ^^^^^^^^
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note: opaque type being used as hidden type
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--> $DIR/two_tait_defining_each_other3.rs:3:10
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LL | type A = impl Foo;
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| ^^^^^^^^
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error: aborting due to previous error
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@ -1,5 +1,5 @@
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#![feature(type_alias_impl_trait)]
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// build-pass (FIXME(62277): could be check-pass?)
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mod my_mod {
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use std::fmt::Debug;
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@ -11,7 +11,7 @@ mod my_mod {
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}
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pub fn get_foot() -> Foot {
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get_foo()
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get_foo() //~ ERROR opaque type's hidden type cannot be another opaque type
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}
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}
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@ -0,0 +1,19 @@
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error: opaque type's hidden type cannot be another opaque type from the same scope
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--> $DIR/nested_type_alias_impl_trait.rs:14:9
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LL | get_foo()
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| ^^^^^^^^^ one of the two opaque types used here has to be outside its defining scope
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note: opaque type whose hidden type is being assigned
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--> $DIR/nested_type_alias_impl_trait.rs:7:21
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LL | pub type Foot = impl Debug;
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| ^^^^^^^^^^
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note: opaque type being used as hidden type
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--> $DIR/nested_type_alias_impl_trait.rs:6:20
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LL | pub type Foo = impl Debug;
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| ^^^^^^^^^^
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error: aborting due to previous error
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