Use sup instead of eq when unifying self type

compiler/rustc_hir_typeck/src/method/probe.rs

@@ -1376,8 +1376,8 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> {
                     (xform_self_ty, xform_ret_ty) =
                         self.xform_self_ty(probe.item, impl_ty, impl_args);
                     xform_self_ty = ocx.normalize(cause, self.param_env, xform_self_ty);
-                    // FIXME: Make this `ocx.eq` once we define opaques more eagerly.
-                    match self.at(cause, self.param_env).eq(
+                    // FIXME: Make this `ocx.sup` once we define opaques more eagerly.
+                    match self.at(cause, self.param_env).sup(
                         DefineOpaqueTypes::No,
                         xform_self_ty,
                         self_ty,
@@ -1437,8 +1437,8 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> {
                     (xform_self_ty, xform_ret_ty) =
                         self.xform_self_ty(probe.item, trait_ref.self_ty(), trait_ref.args);
                     xform_self_ty = ocx.normalize(cause, self.param_env, xform_self_ty);
-                    // FIXME: Make this `ocx.eq` once we define opaques more eagerly.
-                    match self.at(cause, self.param_env).eq(
+                    // FIXME: Make this `ocx.sup` once we define opaques more eagerly.
+                    match self.at(cause, self.param_env).sup(
                         DefineOpaqueTypes::No,
                         xform_self_ty,
                         self_ty,
@@ -1489,8 +1489,8 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> {
                     (xform_self_ty, xform_ret_ty) =
                         self.xform_self_ty(probe.item, trait_ref.self_ty(), trait_ref.args);
                     xform_self_ty = ocx.normalize(cause, self.param_env, xform_self_ty);
-                    // FIXME: Make this `ocx.eq` once we define opaques more eagerly.
-                    match self.at(cause, self.param_env).eq(
+                    // FIXME: Make this `ocx.sup` once we define opaques more eagerly.
+                    match self.at(cause, self.param_env).sup(
                         DefineOpaqueTypes::No,
                         xform_self_ty,
                         self_ty,

tests/ui/impl-trait/issues/issue-62742.rs

@@ -1,12 +1,17 @@
 use std::marker::PhantomData;
 
-fn _alias_check() {
+fn a() {
     WrongImpl::foo(0i32);
-    //~^ ERROR the trait bound `RawImpl<_>: Raw<_>` is not satisfied
-    //~| ERROR the function or associated item `foo` exists for struct `SafeImpl<_, RawImpl<_>>`, but its trait bounds were not satisfied
+    //~^ ERROR overflow assigning `_` to `[_]`
+}
+
+fn b() {
     WrongImpl::<()>::foo(0i32);
     //~^ ERROR the trait bound `RawImpl<()>: Raw<()>` is not satisfied
     //~| ERROR trait bounds were not satisfied
+}
+
+fn c() {
     CorrectImpl::foo(0i32);
 }
 

tests/ui/impl-trait/issues/issue-62742.stderr

@@ -1,30 +1,11 @@
-error[E0599]: the function or associated item `foo` exists for struct `SafeImpl<_, RawImpl<_>>`, but its trait bounds were not satisfied
+error[E0275]: overflow assigning `_` to `[_]`
   --> $DIR/issue-62742.rs:4:16
    |
 LL |     WrongImpl::foo(0i32);
-   |                ^^^ function or associated item cannot be called on `SafeImpl<_, RawImpl<_>>` due to unsatisfied trait bounds
-...
-LL | pub struct RawImpl<T>(PhantomData<T>);
-   | --------------------- doesn't satisfy `RawImpl<_>: Raw<_>`
-...
-LL | pub struct SafeImpl<T: ?Sized, A: Raw<T>>(PhantomData<(A, T)>);
-   | ----------------------------------------- function or associated item `foo` not found for this struct
-   |
-note: trait bound `RawImpl<_>: Raw<_>` was not satisfied
-  --> $DIR/issue-62742.rs:29:20
-   |
-LL | impl<T: ?Sized, A: Raw<T>> SafeImpl<T, A> {
-   |                    ^^^^^^  --------------
-   |                    |
-   |                    unsatisfied trait bound introduced here
-note: the trait `Raw` must be implemented
-  --> $DIR/issue-62742.rs:13:1
-   |
-LL | pub trait Raw<T: ?Sized> {
-   | ^^^^^^^^^^^^^^^^^^^^^^^^
+   |                ^^^
 
 error[E0599]: the function or associated item `foo` exists for struct `SafeImpl<(), RawImpl<()>>`, but its trait bounds were not satisfied
-  --> $DIR/issue-62742.rs:7:22
+  --> $DIR/issue-62742.rs:9:22
    |
 LL |     WrongImpl::<()>::foo(0i32);
    |                      ^^^ function or associated item cannot be called on `SafeImpl<(), RawImpl<()>>` due to unsatisfied trait bounds
@@ -36,46 +17,33 @@ LL | pub struct SafeImpl<T: ?Sized, A: Raw<T>>(PhantomData<(A, T)>);
    | ----------------------------------------- function or associated item `foo` not found for this struct
    |
 note: trait bound `RawImpl<()>: Raw<()>` was not satisfied
-  --> $DIR/issue-62742.rs:29:20
+  --> $DIR/issue-62742.rs:34:20
    |
 LL | impl<T: ?Sized, A: Raw<T>> SafeImpl<T, A> {
    |                    ^^^^^^  --------------
    |                    |
    |                    unsatisfied trait bound introduced here
 note: the trait `Raw` must be implemented
-  --> $DIR/issue-62742.rs:13:1
+  --> $DIR/issue-62742.rs:18:1
    |
 LL | pub trait Raw<T: ?Sized> {
    | ^^^^^^^^^^^^^^^^^^^^^^^^
 
-error[E0277]: the trait bound `RawImpl<_>: Raw<_>` is not satisfied
-  --> $DIR/issue-62742.rs:4:5
-   |
-LL |     WrongImpl::foo(0i32);
-   |     ^^^^^^^^^ the trait `Raw<_>` is not implemented for `RawImpl<_>`
-   |
-   = help: the trait `Raw<[_]>` is implemented for `RawImpl<_>`
-note: required by a bound in `SafeImpl`
-  --> $DIR/issue-62742.rs:27:35
-   |
-LL | pub struct SafeImpl<T: ?Sized, A: Raw<T>>(PhantomData<(A, T)>);
-   |                                   ^^^^^^ required by this bound in `SafeImpl`
-
 error[E0277]: the trait bound `RawImpl<()>: Raw<()>` is not satisfied
-  --> $DIR/issue-62742.rs:7:5
+  --> $DIR/issue-62742.rs:9:5
    |
 LL |     WrongImpl::<()>::foo(0i32);
    |     ^^^^^^^^^^^^^^^ the trait `Raw<()>` is not implemented for `RawImpl<()>`
    |
    = help: the trait `Raw<[()]>` is implemented for `RawImpl<()>`
    = help: for that trait implementation, expected `[()]`, found `()`
 note: required by a bound in `SafeImpl`
-  --> $DIR/issue-62742.rs:27:35
+  --> $DIR/issue-62742.rs:32:35
    |
 LL | pub struct SafeImpl<T: ?Sized, A: Raw<T>>(PhantomData<(A, T)>);
    |                                   ^^^^^^ required by this bound in `SafeImpl`
 
-error: aborting due to 4 previous errors
+error: aborting due to 3 previous errors
 
-Some errors have detailed explanations: E0277, E0599.
-For more information about an error, try `rustc --explain E0277`.
+Some errors have detailed explanations: E0275, E0277, E0599.
+For more information about an error, try `rustc --explain E0275`.

tests/ui/impl-trait/issues/issue-84073.rs

@@ -30,5 +30,5 @@ where
 
 fn main() {
     Race::new(|race| race.when());
-    //~^ ERROR the method `when` exists for struct `RaceBuilder<_, Never<_>>`, but its trait bounds were not satisfied
+    //~^ ERROR overflow assigning `_` to `Option<_>`
 }

tests/ui/impl-trait/issues/issue-84073.stderr

@@ -1,29 +1,9 @@
-error[E0599]: the method `when` exists for struct `RaceBuilder<_, Never<_>>`, but its trait bounds were not satisfied
+error[E0275]: overflow assigning `_` to `Option<_>`
   --> $DIR/issue-84073.rs:32:27
    |
-LL | pub struct Never<T>(PhantomData<T>);
-   | ------------------- doesn't satisfy `Never<_>: StatefulFuture<Option<_>>`
-...
-LL | pub struct RaceBuilder<F, S> {
-   | ---------------------------- method `when` not found for this struct
-...
 LL |     Race::new(|race| race.when());
-   |                           ^^^^ method cannot be called on `RaceBuilder<_, Never<_>>` due to unsatisfied trait bounds
-   |
-note: trait bound `Never<_>: StatefulFuture<Option<_>>` was not satisfied
-  --> $DIR/issue-84073.rs:14:8
-   |
-LL | impl<T, F> RaceBuilder<T, F>
-   |            -----------------
-LL | where
-LL |     F: StatefulFuture<Option<T>>,
-   |        ^^^^^^^^^^^^^^^^^^^^^^^^^ unsatisfied trait bound introduced here
-note: the trait `StatefulFuture` must be implemented
-  --> $DIR/issue-84073.rs:3:1
-   |
-LL | pub trait StatefulFuture<S> {}
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |                           ^^^^
 
 error: aborting due to 1 previous error
 
-For more information about this error, try `rustc --explain E0599`.
+For more information about this error, try `rustc --explain E0275`.

tests/ui/methods/self-type-is-sup-no-eq.rs

@@ -0,0 +1,24 @@
+//@ check-pass
+
+// Test that we use `sup` not `eq` during method probe, since this has an effect
+// on the leak check. This is (conceptually) minimized from a crater run for
+// `wrend 0.3.6`.
+
+use std::ops::Deref;
+
+struct A;
+
+impl Deref for A {
+    type Target = B<dyn Fn(&())>;
+
+    fn deref(&self) -> &<Self as Deref>::Target { todo!() }
+}
+
+struct B<T: ?Sized>(T);
+impl<T> B<dyn Fn(T)> {
+    fn method(&self) {}
+}
+
+fn main() {
+    A.method();
+}