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Add some regression tests for opaque types and const generics
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6 files changed

+174
-2
lines changed

6 files changed

+174
-2
lines changed

‎compiler/rustc_trait_selection/src/traits/fulfill.rs

+2-1
Original file line numberDiff line numberDiff line change
@@ -429,7 +429,8 @@ impl<'a, 'tcx> ObligationProcessor for FulfillProcessor<'a, 'tcx> {
429429
// as the cause of an overflow.
430430
ty::PredicateKind::Clause(ty::ClauseKind::ConstArgHasType(ct, ty)) => {
431431
match self.selcx.infcx.at(&obligation.cause, obligation.param_env).eq(
432-
DefineOpaqueTypes::No,
432+
// Only really excercised by generic_const_exprs
433+
DefineOpaqueTypes::Yes,
433434
ct.ty(),
434435
ty,
435436
) {

‎compiler/rustc_trait_selection/src/traits/select/mod.rs

+2-1
Original file line numberDiff line numberDiff line change
@@ -982,7 +982,8 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
982982
ty::PredicateKind::Ambiguous => Ok(EvaluatedToAmbig),
983983
ty::PredicateKind::Clause(ty::ClauseKind::ConstArgHasType(ct, ty)) => {
984984
match self.infcx.at(&obligation.cause, obligation.param_env).eq(
985-
DefineOpaqueTypes::No,
985+
// Only really excercised by generic_const_exprs
986+
DefineOpaqueTypes::Yes,
986987
ct.ty(),
987988
ty,
988989
) {

‎tests/ui/const-generics/opaque_types.rs

+13
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,13 @@
1+
#![feature(type_alias_impl_trait)]
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type Foo = impl Sized;
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//~^ ERROR: cycle
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//~| ERROR: cycle
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fn foo<const C: Foo>() {}
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//~^ ERROR: `Foo` is forbidden as the type of a const generic parameter
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fn main() {
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foo::<42>();
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//~^ ERROR: mismatched types
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}

‎tests/ui/const-generics/opaque_types.stderr

+125
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,125 @@
1+
error[E0308]: mismatched types
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--> $DIR/opaque_types.rs:11:11
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|
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LL | type Foo = impl Sized;
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| ---------- the expected opaque type
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...
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LL | foo::<42>();
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| ^^ expected opaque type, found integer
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|
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= note: expected opaque type `Foo`
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found type `{integer}`
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error[E0391]: cycle detected when computing type of `Foo::{opaque#0}`
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--> $DIR/opaque_types.rs:3:12
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|
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LL | type Foo = impl Sized;
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| ^^^^^^^^^^
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|
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note: ...which requires computing type of opaque `Foo::{opaque#0}`...
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--> $DIR/opaque_types.rs:3:12
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|
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LL | type Foo = impl Sized;
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| ^^^^^^^^^^
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note: ...which requires type-checking `main`...
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--> $DIR/opaque_types.rs:10:1
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|
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LL | fn main() {
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| ^^^^^^^^^
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note: ...which requires evaluating type-level constant...
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--> $DIR/opaque_types.rs:11:11
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|
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LL | foo::<42>();
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| ^^
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note: ...which requires const-evaluating + checking `main::{constant#0}`...
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--> $DIR/opaque_types.rs:11:11
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|
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LL | foo::<42>();
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| ^^
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note: ...which requires caching mir of `main::{constant#0}` for CTFE...
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--> $DIR/opaque_types.rs:11:11
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|
42+
LL | foo::<42>();
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| ^^
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note: ...which requires elaborating drops for `main::{constant#0}`...
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--> $DIR/opaque_types.rs:11:11
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|
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LL | foo::<42>();
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| ^^
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= note: ...which requires normalizing `Foo`...
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= note: ...which again requires computing type of `Foo::{opaque#0}`, completing the cycle
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note: cycle used when checking that `Foo::{opaque#0}` is well-formed
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--> $DIR/opaque_types.rs:3:12
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|
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LL | type Foo = impl Sized;
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| ^^^^^^^^^^
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= note: see https://rustc-dev-guide.rust-lang.org/overview.html#queries and https://rustc-dev-guide.rust-lang.org/query.html for more information
57+
58+
error: `Foo` is forbidden as the type of a const generic parameter
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--> $DIR/opaque_types.rs:7:17
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|
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LL | fn foo<const C: Foo>() {}
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| ^^^
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|
64+
= note: the only supported types are integers, `bool` and `char`
65+
66+
error[E0391]: cycle detected when computing type of opaque `Foo::{opaque#0}`
67+
--> $DIR/opaque_types.rs:3:12
68+
|
69+
LL | type Foo = impl Sized;
70+
| ^^^^^^^^^^
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|
72+
note: ...which requires type-checking `main`...
73+
--> $DIR/opaque_types.rs:10:1
74+
|
75+
LL | fn main() {
76+
| ^^^^^^^^^
77+
note: ...which requires evaluating type-level constant...
78+
--> $DIR/opaque_types.rs:11:11
79+
|
80+
LL | foo::<42>();
81+
| ^^
82+
note: ...which requires const-evaluating + checking `main::{constant#0}`...
83+
--> $DIR/opaque_types.rs:11:11
84+
|
85+
LL | foo::<42>();
86+
| ^^
87+
note: ...which requires caching mir of `main::{constant#0}` for CTFE...
88+
--> $DIR/opaque_types.rs:11:11
89+
|
90+
LL | foo::<42>();
91+
| ^^
92+
note: ...which requires elaborating drops for `main::{constant#0}`...
93+
--> $DIR/opaque_types.rs:11:11
94+
|
95+
LL | foo::<42>();
96+
| ^^
97+
note: ...which requires borrow-checking `main::{constant#0}`...
98+
--> $DIR/opaque_types.rs:11:11
99+
|
100+
LL | foo::<42>();
101+
| ^^
102+
note: ...which requires promoting constants in MIR for `main::{constant#0}`...
103+
--> $DIR/opaque_types.rs:11:11
104+
|
105+
LL | foo::<42>();
106+
| ^^
107+
note: ...which requires const checking `main::{constant#0}`...
108+
--> $DIR/opaque_types.rs:11:11
109+
|
110+
LL | foo::<42>();
111+
| ^^
112+
= note: ...which requires computing whether `Foo` is freeze...
113+
= note: ...which requires evaluating trait selection obligation `Foo: core::marker::Freeze`...
114+
= note: ...which again requires computing type of opaque `Foo::{opaque#0}`, completing the cycle
115+
note: cycle used when computing type of `Foo::{opaque#0}`
116+
--> $DIR/opaque_types.rs:3:12
117+
|
118+
LL | type Foo = impl Sized;
119+
| ^^^^^^^^^^
120+
= note: see https://rustc-dev-guide.rust-lang.org/overview.html#queries and https://rustc-dev-guide.rust-lang.org/query.html for more information
121+
122+
error: aborting due to 4 previous errors
123+
124+
Some errors have detailed explanations: E0308, E0391.
125+
For more information about an error, try `rustc --explain E0308`.

‎tests/ui/const-generics/opaque_types2.rs

+17
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,17 @@
1+
#![feature(type_alias_impl_trait)]
2+
3+
type Foo = impl Sized;
4+
5+
fn foo<const C: u32>() {}
6+
7+
const C: Foo = 42;
8+
9+
fn bar()
10+
where
11+
Foo:,
12+
{
13+
foo::<C>();
14+
//~^ ERROR: mismatched types
15+
}
16+
17+
fn main() {}

‎tests/ui/const-generics/opaque_types2.stderr

+15
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,15 @@
1+
error[E0308]: mismatched types
2+
--> $DIR/opaque_types2.rs:13:11
3+
|
4+
LL | type Foo = impl Sized;
5+
| ---------- the found opaque type
6+
...
7+
LL | foo::<C>();
8+
| ^ expected `u32`, found opaque type
9+
|
10+
= note: expected type `u32`
11+
found opaque type `Foo`
12+
13+
error: aborting due to 1 previous error
14+
15+
For more information about this error, try `rustc --explain E0308`.

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