Stop inverting expectation in normalization errors

compiler/rustc_trait_selection/src/error_reporting/traits/fulfillment_errors.rs

@@ -1278,19 +1278,6 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
                     let normalized_term =
                         ocx.normalize(&obligation.cause, obligation.param_env, unnormalized_term);
 
-                    let is_normalized_term_expected = !matches!(
-                        obligation.cause.code().peel_derives(),
-                        ObligationCauseCode::WhereClause(..)
-                            | ObligationCauseCode::WhereClauseInExpr(..)
-                            | ObligationCauseCode::Coercion { .. }
-                    );
-
-                    let (expected, actual) = if is_normalized_term_expected {
-                        (normalized_term, data.term)
-                    } else {
-                        (data.term, normalized_term)
-                    };
-
                     // constrain inference variables a bit more to nested obligations from normalize so
                     // we can have more helpful errors.
                     //
@@ -1299,12 +1286,12 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
                     let _ = ocx.select_where_possible();
 
                     if let Err(new_err) =
-                        ocx.eq(&obligation.cause, obligation.param_env, expected, actual)
+                        ocx.eq(&obligation.cause, obligation.param_env, data.term, normalized_term)
                     {
                         (
                             Some((
                                 data.projection_term,
-                                is_normalized_term_expected,
+                                false,
                                 self.resolve_vars_if_possible(normalized_term),
                                 data.term,
                             )),
@@ -1444,12 +1431,8 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
                 &mut diag,
                 &obligation.cause,
                 secondary_span,
-                values.map(|(_, is_normalized_ty_expected, normalized_ty, expected_ty)| {
-                    infer::ValuePairs::Terms(ExpectedFound::new(
-                        is_normalized_ty_expected,
-                        normalized_ty,
-                        expected_ty,
-                    ))
+                values.map(|(_, _, normalized_ty, expected_ty)| {
+                    infer::ValuePairs::Terms(ExpectedFound::new(true, expected_ty, normalized_ty))
                 }),
                 err,
                 true,

tests/ui/associated-types/impl-trait-return-missing-constraint.stderr

@@ -2,18 +2,16 @@ error[E0271]: type mismatch resolving `<impl Bar as Foo>::Item == i32`
   --> $DIR/impl-trait-return-missing-constraint.rs:25:13
    |
 LL | fn bar() -> impl Bar {
-   |             -------- the expected opaque type
+   |             -------- the found opaque type
 ...
 LL | fn baz() -> impl Bar<Item = i32> {
-   |             ^^^^^^^^^^^^^^^^^^^^ expected associated type, found `i32`
+   |             ^^^^^^^^^^^^^^^^^^^^ expected `i32`, found associated type
 LL |
 LL |     bar()
    |     ----- return type was inferred to be `impl Bar` here
    |
-   = note: expected associated type `<impl Bar as Foo>::Item`
-                         found type `i32`
-   = help: consider constraining the associated type `<impl Bar as Foo>::Item` to `i32` or calling a method that returns `<impl Bar as Foo>::Item`
-   = note: for more information, visit https://doc.rust-lang.org/book/ch19-03-advanced-traits.html
+   = note:         expected type `i32`
+           found associated type `<impl Bar as Foo>::Item`
 help: consider constraining the associated type `<impl Bar as Foo>::Item` to `i32`
    |
 LL | fn bar() -> impl Bar<Item = i32> {

tests/ui/coroutine/type-mismatch-signature-deduction.stderr

@@ -22,10 +22,10 @@ error[E0271]: type mismatch resolving `<{coroutine@$DIR/type-mismatch-signature-
   --> $DIR/type-mismatch-signature-deduction.rs:5:13
    |
 LL | fn foo() -> impl Coroutine<Return = i32> {
-   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected `Result<{integer}, _>`, found `i32`
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected `i32`, found `Result<{integer}, _>`
    |
-   = note: expected enum `Result<{integer}, _>`
-              found type `i32`
+   = note: expected type `i32`
+              found enum `Result<{integer}, _>`
 
 error: aborting due to 2 previous errors
 

tests/ui/diagnostic_namespace/do_not_recommend/as_expression.next.stderr

@@ -29,10 +29,7 @@ error[E0271]: type mismatch resolving `<SelectInt as Expression>::SqlType == Tex
   --> $DIR/as_expression.rs:57:5
    |
 LL |     SelectInt.check("bar");
-   |     ^^^^^^^^^^^^^^^^^^^^^^ expected `Integer`, found `Text`
-   |
-   = note: expected struct `Integer`
-              found struct `Text`
+   |     ^^^^^^^^^^^^^^^^^^^^^^ expected `Text`, found `Integer`
 
 error: aborting due to 3 previous errors
 

tests/ui/impl-trait/bound-normalization-fail.stderr

@@ -7,13 +7,13 @@ LL |
 LL |         Foo(())
    |         ------- return type was inferred to be `Foo<()>` here
    |
-note: expected this to be `()`
+note: expected this to be `<T as impl_trait::Trait>::Assoc`
   --> $DIR/bound-normalization-fail.rs:14:19
    |
 LL |     type Output = T;
    |                   ^
-   = note:    expected unit type `()`
-           found associated type `<T as impl_trait::Trait>::Assoc`
+   = note: expected associated type `<T as impl_trait::Trait>::Assoc`
+                    found unit type `()`
 help: consider constraining the associated type `<T as impl_trait::Trait>::Assoc` to `()`
    |
 LL |     fn foo_fail<T: Trait<Assoc = ()>>() -> impl FooLike<Output = T::Assoc> {
@@ -28,13 +28,13 @@ LL |
 LL |         Foo(())
    |         ------- return type was inferred to be `Foo<()>` here
    |
-note: expected this to be `()`
+note: expected this to be `<T as lifetimes::Trait<'a>>::Assoc`
   --> $DIR/bound-normalization-fail.rs:14:19
    |
 LL |     type Output = T;
    |                   ^
-   = note:    expected unit type `()`
-           found associated type `<T as lifetimes::Trait<'a>>::Assoc`
+   = note: expected associated type `<T as lifetimes::Trait<'a>>::Assoc`
+                    found unit type `()`
 help: consider constraining the associated type `<T as lifetimes::Trait<'a>>::Assoc` to `()`
    |
 LL |     fn foo2_fail<'a, T: Trait<'a, Assoc = ()>>() -> impl FooLike<Output = T::Assoc> {

tests/ui/impl-trait/in-trait/default-body-type-err.stderr

@@ -2,7 +2,7 @@ error[E0271]: type mismatch resolving `<&i32 as Deref>::Target == String`
   --> $DIR/default-body-type-err.rs:4:22
    |
 LL |     fn lol(&self) -> impl Deref<Target = String> {
-   |                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected `i32`, found `String`
+   |                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected `String`, found `i32`
 LL |
 LL |         &1i32
    |         ----- return type was inferred to be `&i32` here

tests/ui/impl-trait/issues/issue-78722-2.stderr

@@ -16,7 +16,7 @@ error[E0271]: expected `{async block@$DIR/issue-78722-2.rs:13:13: 13:18}` to be
   --> $DIR/issue-78722-2.rs:11:30
    |
 LL |         fn concrete_use() -> F {
-   |                              ^ expected `()`, found `u8`
+   |                              ^ expected `u8`, found `()`
 
 error: aborting due to 2 previous errors
 

tests/ui/impl-trait/issues/issue-78722.stderr

@@ -12,7 +12,7 @@ error[E0271]: expected `{async block@$DIR/issue-78722.rs:10:13: 10:18}` to be a
   --> $DIR/issue-78722.rs:8:30
    |
 LL |         fn concrete_use() -> F {
-   |                              ^ expected `()`, found `u8`
+   |                              ^ expected `u8`, found `()`
 
 error: aborting due to 2 previous errors
 

tests/ui/impl-trait/projection-mismatch-in-impl-where-clause.stderr

@@ -4,7 +4,7 @@ error[E0271]: type mismatch resolving `<() as Super>::Assoc == ()`
 LL | fn test() -> impl Test {
    |              ^^^^^^^^^ type mismatch resolving `<() as Super>::Assoc == ()`
    |
-note: expected this to be `u8`
+note: expected this to be `()`
   --> $DIR/projection-mismatch-in-impl-where-clause.rs:6:18
    |
 LL |     type Assoc = u8;

tests/ui/issues/issue-33941.stderr

@@ -20,10 +20,10 @@ error[E0271]: expected `Iter<'_, _, _>` to be an iterator that yields `&_`, but
   --> $DIR/issue-33941.rs:6:14
    |
 LL |     for _ in HashMap::new().iter().cloned() {}
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected `(&_, &_)`, found `&_`
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected `&_`, found `(&_, &_)`
    |
-   = note:  expected tuple `(&_, &_)`
-           found reference `&_`
+   = note: expected reference `&_`
+                  found tuple `(&_, &_)`
    = note: required for `Cloned<std::collections::hash_map::Iter<'_, _, _>>` to implement `Iterator`
    = note: required for `Cloned<std::collections::hash_map::Iter<'_, _, _>>` to implement `IntoIterator`
 

tests/ui/issues/issue-67039-unsound-pin-partialeq.stderr

@@ -2,10 +2,10 @@ error[E0271]: type mismatch resolving `<Rc<Apple> as Deref>::Target == Rc<Apple>
   --> $DIR/issue-67039-unsound-pin-partialeq.rs:25:29
    |
 LL |     let _ = Pin::new(Apple) == Rc::pin(Apple);
-   |                             ^^ expected `Apple`, found `Rc<Apple>`
+   |                             ^^ expected `Rc<Apple>`, found `Apple`
    |
-   = note: expected struct `Apple`
-              found struct `Rc<Apple>`
+   = note: expected struct `Rc<Apple>`
+              found struct `Apple`
    = note: required for `Pin<Apple>` to implement `PartialEq<Pin<Rc<Apple>>>`
 
 error: aborting due to 1 previous error

tests/ui/lint/issue-106991.stderr

@@ -2,7 +2,7 @@ error[E0271]: expected `foo` to be a fn item that returns `i32`, but it returns
   --> $DIR/issue-106991.rs:5:13
    |
 LL | fn bar() -> impl Iterator<Item = i32> {
-   |             ^^^^^^^^^^^^^^^^^^^^^^^^^ expected `()`, found `i32`
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^ expected `i32`, found `()`
    |
    = note: required for `Map<std::slice::IterMut<'_, Vec<u8>>, for<'a> fn(&'a mut Vec<u8>) {foo}>` to implement `Iterator`
 

tests/ui/suggestions/trait-hidden-method.stderr

@@ -8,14 +8,14 @@ error[E0271]: expected `Box<dyn Iterator>` to be an iterator that yields `u32`,
   --> $DIR/trait-hidden-method.rs:3:32
    |
 LL | pub fn i_can_has_iterator() -> impl Iterator<Item = u32> {
-   |                                ^^^^^^^^^^^^^^^^^^^^^^^^^ expected associated type, found `u32`
+   |                                ^^^^^^^^^^^^^^^^^^^^^^^^^ expected `u32`, found associated type
 ...
 LL |     Box::new(1..=10) as Box<dyn Iterator>
    |     ------------------------------------- return type was inferred to be `Box<dyn Iterator>` here
    |
-   = note: expected associated type `<dyn Iterator as Iterator>::Item`
-                         found type `u32`
-   = help: consider constraining the associated type `<dyn Iterator as Iterator>::Item` to `u32` or calling a method that returns `<dyn Iterator as Iterator>::Item`
+   = note:         expected type `u32`
+           found associated type `<dyn Iterator as Iterator>::Item`
+   = help: consider constraining the associated type `<dyn Iterator as Iterator>::Item` to `u32`
    = note: for more information, visit https://doc.rust-lang.org/book/ch19-03-advanced-traits.html
 
 error: aborting due to 2 previous errors

tests/ui/traits/next-solver/async.fail.stderr

@@ -2,12 +2,10 @@ error[E0271]: expected `{async block@$DIR/async.rs:12:17: 12:22}` to be a future
   --> $DIR/async.rs:12:17
    |
 LL |     needs_async(async {});
-   |     ----------- ^^^^^^^^ expected `()`, found `i32`
+   |     ----------- ^^^^^^^^ expected `i32`, found `()`
    |     |
    |     required by a bound introduced by this call
    |
-   = note: expected unit type `()`
-                   found type `i32`
 note: required by a bound in `needs_async`
   --> $DIR/async.rs:8:31
    |

tests/ui/traits/next-solver/more-object-bound.stderr

@@ -2,19 +2,14 @@ error[E0271]: type mismatch resolving `<dyn Trait<A = A, B = B> as SuperTrait>::
   --> $DIR/more-object-bound.rs:12:5
    |
 LL | fn transmute<A, B>(x: A) -> B {
-   |              -  -
-   |              |  |
-   |              |  expected type parameter
-   |              |  found type parameter
+   |              -  - expected type parameter
+   |              |
    |              found type parameter
-   |              expected type parameter
 LL |     foo::<A, B, dyn Trait<A = A, B = B>>(x)
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected type parameter `A`, found type parameter `B`
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected type parameter `B`, found type parameter `A`
    |
-   = note: expected type parameter `A`
-              found type parameter `B`
-   = note: a type parameter was expected, but a different one was found; you might be missing a type parameter or trait bound
-   = note: for more information, visit https://doc.rust-lang.org/book/ch10-02-traits.html#traits-as-parameters
+   = note: expected type parameter `B`
+              found type parameter `A`
    = note: a type parameter was expected, but a different one was found; you might be missing a type parameter or trait bound
    = note: for more information, visit https://doc.rust-lang.org/book/ch10-02-traits.html#traits-as-parameters
    = note: required because it appears within the type `dyn Trait<A = A, B = B>`

tests/ui/try-block/try-block-bad-type.stderr

@@ -15,13 +15,13 @@ error[E0271]: type mismatch resolving `<Result<i32, i32> as Try>::Output == &str
   --> $DIR/try-block-bad-type.rs:12:9
    |
 LL |         ""
-   |         ^^ expected `i32`, found `&str`
+   |         ^^ expected `&str`, found `i32`
 
 error[E0271]: type mismatch resolving `<Result<i32, i32> as Try>::Output == ()`
   --> $DIR/try-block-bad-type.rs:15:39
    |
 LL |     let res: Result<i32, i32> = try { };
-   |                                       ^ expected `i32`, found `()`
+   |                                       ^ expected `()`, found `i32`
 
 error[E0277]: a `try` block must return `Result` or `Option` (or another type that implements `Try`)
   --> $DIR/try-block-bad-type.rs:17:25

tests/ui/try-block/try-block-type-error.stderr

@@ -2,18 +2,13 @@ error[E0271]: type mismatch resolving `<Option<f32> as Try>::Output == {integer}
   --> $DIR/try-block-type-error.rs:10:9
    |
 LL |         42
-   |         ^^ expected `f32`, found integer
-   |
-help: use a float literal
-   |
-LL |         42.0
-   |           ++
+   |         ^^ expected integer, found `f32`
 
 error[E0271]: type mismatch resolving `<Option<i32> as Try>::Output == ()`
   --> $DIR/try-block-type-error.rs:16:5
    |
 LL |     };
-   |     ^ expected `i32`, found `()`
+   |     ^ expected `()`, found `i32`
 
 error: aborting due to 2 previous errors
 

tests/ui/type-alias-impl-trait/hidden_type_mismatch.stderr

@@ -2,18 +2,18 @@ error[E0271]: type mismatch resolving `<() as Proj>::Assoc == i32`
   --> $DIR/hidden_type_mismatch.rs:43:9
    |
 LL |     pub type Sep = impl Sized + std::fmt::Display;
-   |                    ------------------------------ the expected opaque type
+   |                    ------------------------------ the found opaque type
 ...
 LL |         Bar { inner: 1i32, _marker: () }
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ type mismatch resolving `<() as Proj>::Assoc == i32`
    |
-note: expected this to be `Sep`
+note: expected this to be `i32`
   --> $DIR/hidden_type_mismatch.rs:20:22
    |
 LL |         type Assoc = sus::Sep;
    |                      ^^^^^^^^
-   = note: expected opaque type `Sep`
-                     found type `i32`
+   = note:     expected type `i32`
+           found opaque type `Sep`
 note: required for `Bar<()>` to implement `Copy`
   --> $DIR/hidden_type_mismatch.rs:32:39
    |

tests/ui/type-alias-impl-trait/issue-94429.stderr

@@ -2,7 +2,7 @@ error[E0271]: type mismatch resolving `<{coroutine@$DIR/issue-94429.rs:18:9: 18:
   --> $DIR/issue-94429.rs:15:26
    |
 LL |     fn run(&mut self) -> Self::Coro {
-   |                          ^^^^^^^^^^ expected integer, found `()`
+   |                          ^^^^^^^^^^ expected `()`, found integer
 
 error: aborting due to 1 previous error