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Expand "recursive opaque type" diagnostic

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Fix #70968, partially address #66523.
This commit is contained in:
Esteban Küber 2020-04-19 16:52:15 -07:00
parent ff4a2533a0
commit 96f5584b80
13 changed files with 374 additions and 115 deletions
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9
src/test/ui/impl-trait/binding-without-value.rs Normal file
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@ -0,0 +1,9 @@
#![allow(incomplete_features)]
#![feature(impl_trait_in_bindings)]
fn foo() {
let _ : impl Copy;
//~^ ERROR cannot resolve opaque type
}
fn main() {}

16
src/test/ui/impl-trait/binding-without-value.stderr Normal file
View file

@ -0,0 +1,16 @@
error[E0720]: cannot resolve opaque type to a concrete type
--> $DIR/binding-without-value.rs:5:13
|
LL | let _ : impl Copy;
| - ^^^^^^^^^ cannot resolve to a concrete type
| |
| this binding might not have a concrete type
|
help: set the binding to a value for a concrete type to be resolved
|
LL | let _ : impl Copy = /* value */;
| ^^^^^^^^^^^^^
error: aborting due to previous error
For more information about this error, try `rustc --explain E0720`.

4
src/test/ui/impl-trait/issues/infinite-impl-trait-issue-38064.rs
View file

@ -5,13 +5,13 @@
trait Quux {}
fn foo() -> impl Quux { //~ opaque type expands to a recursive type
fn foo() -> impl Quux { //~ ERROR cannot resolve opaque type
struct Foo<T>(T);
impl<T> Quux for Foo<T> {}
Foo(bar())
}
fn bar() -> impl Quux { //~ opaque type expands to a recursive type
fn bar() -> impl Quux { //~ ERROR cannot resolve opaque type
struct Bar<T>(T);
impl<T> Quux for Bar<T> {}
Bar(foo())

24
src/test/ui/impl-trait/issues/infinite-impl-trait-issue-38064.stderr
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@ -1,18 +1,26 @@
error[E0720]: opaque type expands to a recursive type
error[E0720]: cannot resolve opaque type to a concrete type
--> $DIR/infinite-impl-trait-issue-38064.rs:8:13
|
LL | fn foo() -> impl Quux {
| ^^^^^^^^^ expands to a recursive type
|
= note: expanded type is `foo::Foo<bar::Bar<impl Quux>>`
| ^^^^^^^^^ recursive opaque type
...
LL | Foo(bar())
| ---------- returning here with type `foo::Foo<impl Quux>`
...
LL | fn bar() -> impl Quux {
| --------- returning this opaque type `foo::Foo<impl Quux>`
error[E0720]: opaque type expands to a recursive type
error[E0720]: cannot resolve opaque type to a concrete type
--> $DIR/infinite-impl-trait-issue-38064.rs:14:13
|
LL | fn foo() -> impl Quux {
| --------- returning this opaque type `bar::Bar<impl Quux>`
...
LL | fn bar() -> impl Quux {
| ^^^^^^^^^ expands to a recursive type
|
= note: expanded type is `bar::Bar<foo::Foo<impl Quux>>`
| ^^^^^^^^^ recursive opaque type
...
LL | Bar(foo())
| ---------- returning here with type `bar::Bar<impl Quux>`
error: aborting due to 2 previous errors

9
src/test/ui/impl-trait/recursive-impl-trait-type-direct.stderr
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@ -1,10 +1,11 @@
error[E0720]: opaque type expands to a recursive type
error[E0720]: cannot resolve opaque type to a concrete type
--> $DIR/recursive-impl-trait-type-direct.rs:5:14
|
LL | fn test() -> impl Sized {
| ^^^^^^^^^^ expands to a recursive type
|
= note: type resolves to itself
| ^^^^^^^^^^ recursive opaque type
LL |
LL | test()
| ------ returning here with type `impl Sized`
error: aborting due to previous error

153
src/test/ui/impl-trait/recursive-impl-trait-type-indirect.stderr
View file

@ -1,114 +1,147 @@
error[E0720]: opaque type expands to a recursive type
error[E0720]: cannot resolve opaque type to a concrete type
--> $DIR/recursive-impl-trait-type-indirect.rs:7:22
|
LL | fn option(i: i32) -> impl Sized {
| ^^^^^^^^^^ expands to a recursive type
|
= note: expanded type is `std::option::Option<(impl Sized, i32)>`
| ^^^^^^^^^^ recursive opaque type
LL |
LL | if i < 0 { None } else { Some((option(i - 1), i)) }
| ---- ------------------------ returning here with type `std::option::Option<(impl Sized, i32)>`
| |
| returning here with type `std::option::Option<(impl Sized, i32)>`
error[E0720]: opaque type expands to a recursive type
error[E0720]: cannot resolve opaque type to a concrete type
--> $DIR/recursive-impl-trait-type-indirect.rs:12:15
|
LL | fn tuple() -> impl Sized {
| ^^^^^^^^^^ expands to a recursive type
|
= note: expanded type is `(impl Sized,)`
| ^^^^^^^^^^ recursive opaque type
LL |
LL | (tuple(),)
| ---------- returning here with type `(impl Sized,)`
error[E0720]: opaque type expands to a recursive type
error[E0720]: cannot resolve opaque type to a concrete type
--> $DIR/recursive-impl-trait-type-indirect.rs:17:15
|
LL | fn array() -> impl Sized {
| ^^^^^^^^^^ expands to a recursive type
|
= note: expanded type is `[impl Sized; 1]`
| ^^^^^^^^^^ recursive opaque type
LL |
LL | [array()]
| --------- returning here with type `[impl Sized; 1]`
error[E0720]: opaque type expands to a recursive type
error[E0720]: cannot resolve opaque type to a concrete type
--> $DIR/recursive-impl-trait-type-indirect.rs:22:13
|
LL | fn ptr() -> impl Sized {
| ^^^^^^^^^^ expands to a recursive type
|
= note: expanded type is `*const impl Sized`
| ^^^^^^^^^^ recursive opaque type
LL |
LL | &ptr() as *const _
| ------------------ returning here with type `*const impl Sized`
error[E0720]: opaque type expands to a recursive type
error[E0720]: cannot resolve opaque type to a concrete type
--> $DIR/recursive-impl-trait-type-indirect.rs:27:16
|
LL | fn fn_ptr() -> impl Sized {
| ^^^^^^^^^^ expands to a recursive type
|
= note: expanded type is `fn() -> impl Sized`
| ^^^^^^^^^^ recursive opaque type
LL |
LL | fn_ptr as fn() -> _
| ------------------- returning here with type `fn() -> impl Sized`
error[E0720]: opaque type expands to a recursive type
error[E0720]: cannot resolve opaque type to a concrete type
--> $DIR/recursive-impl-trait-type-indirect.rs:32:25
|
LL | fn closure_capture() -> impl Sized {
| ^^^^^^^^^^ expands to a recursive type
|
= note: expanded type is `[closure@$DIR/recursive-impl-trait-type-indirect.rs:35:5: 37:6 x:impl Sized]`
LL | fn closure_capture() -> impl Sized {
| ^^^^^^^^^^ recursive opaque type
...
LL | / move || {
LL | | x;
LL | | }
| |_____- returning here with type `[closure@$DIR/recursive-impl-trait-type-indirect.rs:35:5: 37:6 x:impl Sized]`
error[E0720]: opaque type expands to a recursive type
error[E0720]: cannot resolve opaque type to a concrete type
--> $DIR/recursive-impl-trait-type-indirect.rs:40:29
|
LL | fn closure_ref_capture() -> impl Sized {
| ^^^^^^^^^^ expands to a recursive type
|
= note: expanded type is `[closure@$DIR/recursive-impl-trait-type-indirect.rs:43:5: 45:6 x:impl Sized]`
LL | fn closure_ref_capture() -> impl Sized {
| ^^^^^^^^^^ recursive opaque type
...
LL | / move || {
LL | | &x;
LL | | }
| |_____- returning here with type `[closure@$DIR/recursive-impl-trait-type-indirect.rs:43:5: 45:6 x:impl Sized]`
error[E0720]: opaque type expands to a recursive type
error[E0720]: cannot resolve opaque type to a concrete type
--> $DIR/recursive-impl-trait-type-indirect.rs:48:21
|
LL | fn closure_sig() -> impl Sized {
| ^^^^^^^^^^ expands to a recursive type
|
= note: expanded type is `[closure@$DIR/recursive-impl-trait-type-indirect.rs:50:5: 50:21]`
| ^^^^^^^^^^ recursive opaque type
LL |
LL | || closure_sig()
| ---------------- returning here with type `[closure@$DIR/recursive-impl-trait-type-indirect.rs:50:5: 50:21]`
error[E0720]: opaque type expands to a recursive type
error[E0720]: cannot resolve opaque type to a concrete type
--> $DIR/recursive-impl-trait-type-indirect.rs:53:23
|
LL | fn generator_sig() -> impl Sized {
| ^^^^^^^^^^ expands to a recursive type
|
= note: expanded type is `[closure@$DIR/recursive-impl-trait-type-indirect.rs:55:5: 55:23]`
| ^^^^^^^^^^ recursive opaque type
LL |
LL | || generator_sig()
| ------------------ returning here with type `[closure@$DIR/recursive-impl-trait-type-indirect.rs:55:5: 55:23]`
error[E0720]: opaque type expands to a recursive type
error[E0720]: cannot resolve opaque type to a concrete type
--> $DIR/recursive-impl-trait-type-indirect.rs:58:27
|
LL | fn generator_capture() -> impl Sized {
| ^^^^^^^^^^ expands to a recursive type
|
= note: expanded type is `[generator@$DIR/recursive-impl-trait-type-indirect.rs:61:5: 64:6 x:impl Sized {()}]`
LL | fn generator_capture() -> impl Sized {
| ^^^^^^^^^^ recursive opaque type
...
LL | / move || {
LL | | yield;
LL | | x;
LL | | }
| |_____- returning here with type `[generator@$DIR/recursive-impl-trait-type-indirect.rs:61:5: 64:6 x:impl Sized {()}]`
error[E0720]: opaque type expands to a recursive type
error[E0720]: cannot resolve opaque type to a concrete type
--> $DIR/recursive-impl-trait-type-indirect.rs:67:35
|
LL | fn substs_change<T: 'static>() -> impl Sized {
| ^^^^^^^^^^ expands to a recursive type
|
= note: expanded type is `(impl Sized,)`
| ^^^^^^^^^^ recursive opaque type
LL |
LL | (substs_change::<&T>(),)
| ------------------------ returning here with type `(impl Sized,)`
error[E0720]: opaque type expands to a recursive type
error[E0720]: cannot resolve opaque type to a concrete type
--> $DIR/recursive-impl-trait-type-indirect.rs:72:24
|
LL | fn generator_hold() -> impl Sized {
| ^^^^^^^^^^ expands to a recursive type
|
= note: expanded type is `[generator@$DIR/recursive-impl-trait-type-indirect.rs:74:5: 78:6 {impl Sized, ()}]`
LL | fn generator_hold() -> impl Sized {
| ^^^^^^^^^^ recursive opaque type
LL |
LL | / move || {
LL | | let x = generator_hold();
LL | | yield;
LL | | x;
LL | | }
| |_____- returning here with type `[generator@$DIR/recursive-impl-trait-type-indirect.rs:74:5: 78:6 {impl Sized, ()}]`
error[E0720]: opaque type expands to a recursive type
error[E0720]: cannot resolve opaque type to a concrete type
--> $DIR/recursive-impl-trait-type-indirect.rs:86:26
|
LL | fn mutual_recursion() -> impl Sync {
| ^^^^^^^^^ expands to a recursive type
|
= note: type resolves to itself
| ^^^^^^^^^ recursive opaque type
LL |
LL | mutual_recursion_b()
| -------------------- returning here with type `impl Sized`
...
LL | fn mutual_recursion_b() -> impl Sized {
| ---------- returning this opaque type `impl Sized`
error[E0720]: opaque type expands to a recursive type
error[E0720]: cannot resolve opaque type to a concrete type
--> $DIR/recursive-impl-trait-type-indirect.rs:91:28
|
LL | fn mutual_recursion() -> impl Sync {
| --------- returning this opaque type `impl std::marker::Sync`
...
LL | fn mutual_recursion_b() -> impl Sized {
| ^^^^^^^^^^ expands to a recursive type
|
= note: type resolves to itself
| ^^^^^^^^^^ recursive opaque type
LL |
LL | mutual_recursion()
| ------------------ returning here with type `impl std::marker::Sync`
error: aborting due to 14 previous errors

8
src/test/ui/impl-trait/recursive-impl-trait-type-through-non-recursive.rs
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@ -4,21 +4,21 @@
fn id<T>(t: T) -> impl Sized { t }
fn recursive_id() -> impl Sized { //~ ERROR opaque type expands to a recursive type
fn recursive_id() -> impl Sized { //~ ERROR cannot resolve opaque type
id(recursive_id2())
}
fn recursive_id2() -> impl Sized { //~ ERROR opaque type expands to a recursive type
fn recursive_id2() -> impl Sized { //~ ERROR cannot resolve opaque type
id(recursive_id())
}
fn wrap<T>(t: T) -> impl Sized { (t,) }
fn recursive_wrap() -> impl Sized { //~ ERROR opaque type expands to a recursive type
fn recursive_wrap() -> impl Sized { //~ ERROR cannot resolve opaque type
wrap(recursive_wrap2())
}
fn recursive_wrap2() -> impl Sized { //~ ERROR opaque type expands to a recursive type
fn recursive_wrap2() -> impl Sized { //~ ERROR cannot resolve opaque type
wrap(recursive_wrap())
}

44
src/test/ui/impl-trait/recursive-impl-trait-type-through-non-recursive.stderr
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@ -1,34 +1,46 @@
error[E0720]: opaque type expands to a recursive type
error[E0720]: cannot resolve opaque type to a concrete type
--> $DIR/recursive-impl-trait-type-through-non-recursive.rs:7:22
|
LL | fn id<T>(t: T) -> impl Sized { t }
| ---------- returning this opaque type `impl Sized`
LL |
LL | fn recursive_id() -> impl Sized {
| ^^^^^^^^^^ expands to a recursive type
|
= note: type resolves to itself
| ^^^^^^^^^^ recursive opaque type
LL | id(recursive_id2())
| ------------------- returning here with type `impl Sized`
error[E0720]: opaque type expands to a recursive type
error[E0720]: cannot resolve opaque type to a concrete type
--> $DIR/recursive-impl-trait-type-through-non-recursive.rs:11:23
|
LL | fn id<T>(t: T) -> impl Sized { t }
| ---------- returning this opaque type `impl Sized`
...
LL | fn recursive_id2() -> impl Sized {
| ^^^^^^^^^^ expands to a recursive type
|
= note: type resolves to itself
| ^^^^^^^^^^ recursive opaque type
LL | id(recursive_id())
| ------------------ returning here with type `impl Sized`
error[E0720]: opaque type expands to a recursive type
error[E0720]: cannot resolve opaque type to a concrete type
--> $DIR/recursive-impl-trait-type-through-non-recursive.rs:17:24
|
LL | fn wrap<T>(t: T) -> impl Sized { (t,) }
| ---------- returning this opaque type `impl Sized`
LL |
LL | fn recursive_wrap() -> impl Sized {
| ^^^^^^^^^^ expands to a recursive type
|
= note: expanded type is `((impl Sized,),)`
| ^^^^^^^^^^ recursive opaque type
LL | wrap(recursive_wrap2())
| ----------------------- returning here with type `impl Sized`
error[E0720]: opaque type expands to a recursive type
error[E0720]: cannot resolve opaque type to a concrete type
--> $DIR/recursive-impl-trait-type-through-non-recursive.rs:21:25
|
LL | fn wrap<T>(t: T) -> impl Sized { (t,) }
| ---------- returning this opaque type `impl Sized`
...
LL | fn recursive_wrap2() -> impl Sized {
| ^^^^^^^^^^ expands to a recursive type
|
= note: expanded type is `((impl Sized,),)`
| ^^^^^^^^^^ recursive opaque type
LL | wrap(recursive_wrap())
| ---------------------- returning here with type `impl Sized`
error: aborting due to 4 previous errors

3
src/test/ui/impl-trait/where-allowed-2.rs
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@ -3,7 +3,6 @@
use std::fmt::Debug;
// Disallowed
fn in_adt_in_return() -> Vec<impl Debug> { panic!() }
//~^ ERROR opaque type expands to a recursive type
fn in_adt_in_return() -> Vec<impl Debug> { panic!() } //~ ERROR cannot resolve opaque type
fn main() {}

8
src/test/ui/impl-trait/where-allowed-2.stderr
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@ -1,10 +1,12 @@
error[E0720]: opaque type expands to a recursive type
error[E0720]: cannot resolve opaque type to a concrete type
--> $DIR/where-allowed-2.rs:6:30
|
LL | fn in_adt_in_return() -> Vec<impl Debug> { panic!() }
| ^^^^^^^^^^ expands to a recursive type
| ^^^^^^^^^^ -------- this returned value is of `!` type
| |
| cannot resolve to a concrete type
|
= note: type resolves to itself
= help: this error will resolve once the item's body returns a concrete type
error: aborting due to previous error