rust-lang · sjwang05 · Jul 11, 2026
diff --git a/compiler/rustc_hir_analysis/src/check/wfcheck.rs b/compiler/rustc_hir_analysis/src/check/wfcheck.rs
@@ -22,7 +22,7 @@ use rustc_middle::mir::interpret::ErrorHandled;
 use rustc_middle::traits::solve::NoSolution;
 use rustc_middle::ty::trait_def::TraitSpecializationKind;
 use rustc_middle::ty::{
-    self, GenericArgKind, GenericArgs, GenericParamDefKind, Ty, TyCtxt, TypeFlags, TypeFoldable,
+    self, GenericArgKind, GenericArgs, GenericParamDefKind, Ty, TyCtxt, TypeFoldable,
     TypeSuperVisitable, TypeVisitable, TypeVisitableExt, TypeVisitor, TypingMode, Unnormalized,
     Upcast,
 };
@@ -2293,7 +2293,8 @@ impl<'tcx> WfCheckingCtxt<'_, 'tcx> {
     /// aren't true.
     #[instrument(level = "debug", skip(self))]
     fn check_false_global_bounds(&mut self) {
-        let tcx = self.ocx.infcx.tcx;
+        let infcx = self.ocx.infcx;
+        let tcx = infcx.tcx;
         let mut span = tcx.def_span(self.body_def_id);
         let empty_env = ty::ParamEnv::empty();
 
@@ -2312,10 +2313,8 @@ impl<'tcx> WfCheckingCtxt<'_, 'tcx> {
                 _ => {}
             }
 
-            // Match the existing behavior.
-            if pred.is_global() && !pred.has_type_flags(TypeFlags::HAS_BINDER_VARS) {
-                let pred = self.normalize(span, None, Unnormalized::new_wip(pred));
-
+            let pred = self.deeply_normalize(span, None, Unnormalized::new_wip(pred));
+            if pred.is_global() && pred.kind().bound_vars().is_empty() {
                 // only use the span of the predicate clause (#90869)
                 let hir_node = tcx.hir_node_by_def_id(self.body_def_id);
                 if let Some(hir::Generics { predicates, .. }) = hir_node.generics() {
@@ -2327,16 +2326,12 @@ impl<'tcx> WfCheckingCtxt<'_, 'tcx> {
                         .unwrap_or(obligation_span);
                 }
 
-                let obligation = Obligation::new(
-                    tcx,
-                    traits::ObligationCause::new(
-                        span,
-                        self.body_def_id,
-                        ObligationCauseCode::TrivialBound,
-                    ),
-                    empty_env,
-                    pred,
+                let cause = traits::ObligationCause::new(
+                    span,
+                    self.body_def_id,
+                    ObligationCauseCode::TrivialBound,
                 );
+                let obligation = Obligation::new(tcx, cause, empty_env, pred);
                 self.ocx.register_obligation(obligation);
             }
         }

diff --git a/tests/crashes/148630.rs b/tests/crashes/148630.rs
diff --git a/tests/rustdoc-ui/synthetic-auto-trait-impls/projections-in-super-trait-bound-unsatisfied.rs b/tests/rustdoc-ui/synthetic-auto-trait-impls/projections-in-super-trait-bound-unsatisfied.rs
@@ -14,5 +14,6 @@ pub(crate) const B: usize = 5;
 pub trait Tec: Bar<B> {}
 
 pub struct Structure<C: Tec> { //~ ERROR the trait bound `C: Bar<5>` is not satisfied
-    _field: C::BarType, //~ ERROR the trait bound `C: Bar<5>` is not satisfied
+    //~| ERROR the trait bound `C: Bar<5>` is not satisfied
+    _field: C::BarType,
 }
diff --git a/...rustdoc-ui/synthetic-auto-trait-impls/projections-in-super-trait-bound-unsatisfied.stderr b/...rustdoc-ui/synthetic-auto-trait-impls/projections-in-super-trait-bound-unsatisfied.stderr
@@ -10,11 +10,12 @@ LL | pub struct Structure<C: Tec + Bar<5>> {
    |                             ++++++++
 
 error[E0277]: the trait bound `C: Bar<5>` is not satisfied
-  --> $DIR/projections-in-super-trait-bound-unsatisfied.rs:17:13
+  --> $DIR/projections-in-super-trait-bound-unsatisfied.rs:16:1
    |
-LL |     _field: C::BarType,
-   |             ^^^^^^^^^^ the trait `Bar<5>` is not implemented for `C`
+LL | pub struct Structure<C: Tec> {
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `Bar<5>` is not implemented for `C`
    |
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 help: consider further restricting type parameter `C` with trait `Bar`
    |
 LL | pub struct Structure<C: Tec + Bar<5>> {

diff --git a/tests/ui/associated-types/issue-38821.rs b/tests/ui/associated-types/issue-38821.rs
@@ -34,14 +34,14 @@ pub trait Column: Expression {}
 //~| ERROR the trait bound `<Col as Expression>::SqlType: NotNull` is not satisfied
 //~| ERROR the trait bound `<Col as Expression>::SqlType: NotNull` is not satisfied
 //~| ERROR the trait bound `<Col as Expression>::SqlType: NotNull` is not satisfied
-pub enum ColumnInsertValue<Col, Expr> where
-//~^ ERROR the trait bound `<Col as Expression>::SqlType: NotNull` is not satisfied
 //~| ERROR the trait bound `<Col as Expression>::SqlType: NotNull` is not satisfied
 //~| ERROR the trait bound `<Col as Expression>::SqlType: NotNull` is not satisfied
+//~| ERROR the trait bound `<Col as Expression>::SqlType: NotNull` is not satisfied
+pub enum ColumnInsertValue<Col, Expr> where
+//~^ ERROR the trait bound `<Col as Expression>::SqlType: NotNull` is not satisfied
 //~| ERROR the trait bound `<Col as Expression>::SqlType: NotNull` is not satisfied
     Col: Column,
     Expr: Expression<SqlType=<Col::SqlType as IntoNullable>::Nullable>,
-//~^ ERROR the trait bound `<Col as Expression>::SqlType: IntoNullable` is not satisfied
 {
     Expression(Col, Expr),
     Default(Col),

diff --git a/tests/ui/associated-types/issue-38821.stderr b/tests/ui/associated-types/issue-38821.stderr
@@ -1,5 +1,5 @@
 error[E0277]: the trait bound `<Col as Expression>::SqlType: NotNull` is not satisfied
-  --> $DIR/issue-38821.rs:37:1
+  --> $DIR/issue-38821.rs:40:1
    |
 LL | pub enum ColumnInsertValue<Col, Expr> where
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `NotNull` is not implemented for `<Col as Expression>::SqlType`
@@ -16,11 +16,11 @@ help: consider extending the `where` clause, but there might be an alternative b
 LL |     Expr: Expression<SqlType=<Col::SqlType as IntoNullable>::Nullable>, <Col as Expression>::SqlType: NotNull
    |                                                                         +++++++++++++++++++++++++++++++++++++
 
-error[E0277]: the trait bound `<Col as Expression>::SqlType: IntoNullable` is not satisfied
-  --> $DIR/issue-38821.rs:43:22
+error[E0277]: the trait bound `<Col as Expression>::SqlType: NotNull` is not satisfied
+  --> $DIR/issue-38821.rs:40:1
    |
-LL |     Expr: Expression<SqlType=<Col::SqlType as IntoNullable>::Nullable>,
-   |                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `NotNull` is not implemented for `<Col as Expression>::SqlType`
+LL | pub enum ColumnInsertValue<Col, Expr> where
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `NotNull` is not implemented for `<Col as Expression>::SqlType`
    |
 note: required for `<Col as Expression>::SqlType` to implement `IntoNullable`
   --> $DIR/issue-38821.rs:9:18
@@ -29,6 +29,7 @@ LL | impl<T: NotNull> IntoNullable for T {
    |         -------  ^^^^^^^^^^^^     ^
    |         |
    |         unsatisfied trait bound introduced here
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 help: consider extending the `where` clause, but there might be an alternative better way to express this requirement
    |
 LL |     Expr: Expression<SqlType=<Col::SqlType as IntoNullable>::Nullable>, <Col as Expression>::SqlType: NotNull
@@ -82,13 +83,10 @@ LL | impl<T: NotNull> IntoNullable for T {
    = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 
 error[E0277]: the trait bound `<Col as Expression>::SqlType: NotNull` is not satisfied
-  --> $DIR/issue-38821.rs:37:10
+  --> $DIR/issue-38821.rs:23:10
    |
 LL | #[derive(Debug, Copy, Clone)]
-   |          ----- in this derive macro expansion
-...
-LL | pub enum ColumnInsertValue<Col, Expr> where
-   |          ^^^^^^^^^^^^^^^^^ the trait `NotNull` is not implemented for `<Col as Expression>::SqlType`
+   |          ^^^^^ the trait `NotNull` is not implemented for `<Col as Expression>::SqlType`
    |
 note: required for `<Col as Expression>::SqlType` to implement `IntoNullable`
   --> $DIR/issue-38821.rs:9:18
@@ -97,19 +95,7 @@ LL | impl<T: NotNull> IntoNullable for T {
    |         -------  ^^^^^^^^^^^^     ^
    |         |
    |         unsatisfied trait bound introduced here
-note: required for `ColumnInsertValue<Col, Expr>` to implement `Debug`
-  --> $DIR/issue-38821.rs:37:10
-   |
-LL | #[derive(Debug, Copy, Clone)]
-   |          ----- in this derive macro expansion
-...
-LL | pub enum ColumnInsertValue<Col, Expr> where
-   |          ^^^^^^^^^^^^^^^^^
-...
-LL |     Expr: Expression<SqlType=<Col::SqlType as IntoNullable>::Nullable>,
-   |                      ------------------------------------------------ unsatisfied trait bound
-   = help: consider manually implementing `Debug` to avoid undesired bounds caused by "imperfect derives"
-   = note: to learn more, visit <https://github.com/rust-lang/rust/issues/26925>
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 help: consider further restricting the associated type
    |
 LL |     Expr: Expression<SqlType=<Col::SqlType as IntoNullable>::Nullable>, <Col as Expression>::SqlType: NotNull,
@@ -134,13 +120,10 @@ LL |     Expr: Expression<SqlType=<Col::SqlType as IntoNullable>::Nullable>, <Co
    |                                                                       +++++++++++++++++++++++++++++++++++++++
 
 error[E0277]: the trait bound `<Col as Expression>::SqlType: NotNull` is not satisfied
-  --> $DIR/issue-38821.rs:37:10
+  --> $DIR/issue-38821.rs:23:17
    |
 LL | #[derive(Debug, Copy, Clone)]
-   |                 ---- in this derive macro expansion
-...
-LL | pub enum ColumnInsertValue<Col, Expr> where
-   |          ^^^^^^^^^^^^^^^^^ the trait `NotNull` is not implemented for `<Col as Expression>::SqlType`
+   |                 ^^^^ the trait `NotNull` is not implemented for `<Col as Expression>::SqlType`
    |
 note: required for `<Col as Expression>::SqlType` to implement `IntoNullable`
   --> $DIR/issue-38821.rs:9:18
@@ -149,17 +132,7 @@ LL | impl<T: NotNull> IntoNullable for T {
    |         -------  ^^^^^^^^^^^^     ^
    |         |
    |         unsatisfied trait bound introduced here
-note: required for `ColumnInsertValue<Col, Expr>` to implement `Copy`
-  --> $DIR/issue-38821.rs:37:10
-   |
-LL | #[derive(Debug, Copy, Clone)]
-   |                 ---- in this derive macro expansion
-...
-LL | pub enum ColumnInsertValue<Col, Expr> where
-   |          ^^^^^^^^^^^^^^^^^
-...
-LL |     Expr: Expression<SqlType=<Col::SqlType as IntoNullable>::Nullable>,
-   |                      ------------------------------------------------ unsatisfied trait bound
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 help: consider further restricting the associated type
    |
 LL |     Expr: Expression<SqlType=<Col::SqlType as IntoNullable>::Nullable>, <Col as Expression>::SqlType: NotNull,
@@ -213,13 +186,10 @@ LL | impl<T: NotNull> IntoNullable for T {
    = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 
 error[E0277]: the trait bound `<Col as Expression>::SqlType: NotNull` is not satisfied
-  --> $DIR/issue-38821.rs:37:10
+  --> $DIR/issue-38821.rs:23:23
    |
 LL | #[derive(Debug, Copy, Clone)]
-   |                       ----- in this derive macro expansion
-...
-LL | pub enum ColumnInsertValue<Col, Expr> where
-   |          ^^^^^^^^^^^^^^^^^ the trait `NotNull` is not implemented for `<Col as Expression>::SqlType`
+   |                       ^^^^^ the trait `NotNull` is not implemented for `<Col as Expression>::SqlType`
    |
 note: required for `<Col as Expression>::SqlType` to implement `IntoNullable`
   --> $DIR/issue-38821.rs:9:18
@@ -228,19 +198,7 @@ LL | impl<T: NotNull> IntoNullable for T {
    |         -------  ^^^^^^^^^^^^     ^
    |         |
    |         unsatisfied trait bound introduced here
-note: required for `ColumnInsertValue<Col, Expr>` to implement `Clone`
-  --> $DIR/issue-38821.rs:37:10
-   |
-LL | #[derive(Debug, Copy, Clone)]
-   |                       ----- in this derive macro expansion
-...
-LL | pub enum ColumnInsertValue<Col, Expr> where
-   |          ^^^^^^^^^^^^^^^^^
-...
-LL |     Expr: Expression<SqlType=<Col::SqlType as IntoNullable>::Nullable>,
-   |                      ------------------------------------------------ unsatisfied trait bound
-   = help: consider manually implementing `Clone` to avoid undesired bounds caused by "imperfect derives"
-   = note: to learn more, visit <https://github.com/rust-lang/rust/issues/26925>
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 help: consider further restricting the associated type
    |
 LL |     Expr: Expression<SqlType=<Col::SqlType as IntoNullable>::Nullable>, <Col as Expression>::SqlType: NotNull,

diff --git a/tests/ui/associated-types/issue-59324.rs b/tests/ui/associated-types/issue-59324.rs
@@ -10,8 +10,8 @@ pub trait Service {
 
 pub trait ThriftService<Bug: NotFoo>:
 //~^ ERROR the trait bound `Bug: Foo` is not satisfied
+//~| ERROR the trait bound `Bug: Foo` is not satisfied
     Service<AssocType = <Bug as Foo>::OnlyFoo>
-//~^ ERROR the trait bound `Bug: Foo` is not satisfied
 {
     fn get_service(
     //~^ ERROR the trait bound `Bug: Foo` is not satisfied

diff --git a/tests/ui/associated-types/issue-59324.stderr b/tests/ui/associated-types/issue-59324.stderr
@@ -2,7 +2,7 @@ error[E0277]: the trait bound `Bug: Foo` is not satisfied
   --> $DIR/issue-59324.rs:11:1
    |
 LL | / pub trait ThriftService<Bug: NotFoo>:
-LL | |
+...  |
 LL | |     Service<AssocType = <Bug as Foo>::OnlyFoo>
    | |______________________________________________^ the trait `Foo` is not implemented for `Bug`
    |
@@ -12,11 +12,14 @@ LL | pub trait ThriftService<Bug: NotFoo + Foo>:
    |                                     +++++
 
 error[E0277]: the trait bound `Bug: Foo` is not satisfied
-  --> $DIR/issue-59324.rs:13:13
+  --> $DIR/issue-59324.rs:11:1
    |
-LL |     Service<AssocType = <Bug as Foo>::OnlyFoo>
-   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `Foo` is not implemented for `Bug`
+LL | / pub trait ThriftService<Bug: NotFoo>:
+...  |
+LL | |     Service<AssocType = <Bug as Foo>::OnlyFoo>
+   | |______________________________________________^ the trait `Foo` is not implemented for `Bug`
    |
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 help: consider further restricting type parameter `Bug` with trait `Foo`
    |
 LL | pub trait ThriftService<Bug: NotFoo + Foo>:

diff --git a/tests/ui/associated-types/issue-69398.rs b/tests/ui/associated-types/issue-69398.rs
@@ -1,5 +1,3 @@
-//@ check-pass
-
 pub trait Foo {
     type Bar;
 }
@@ -12,6 +10,7 @@ pub trait Broken {
 impl<T> Broken for T {
     type Assoc = ();
     fn broken(&self) where Self::Assoc: Foo {
+    //~^ ERROR the trait bound `(): Foo` is not satisfied
         let _x: <Self::Assoc as Foo>::Bar;
     }
 }

diff --git a/tests/ui/associated-types/issue-69398.stderr b/tests/ui/associated-types/issue-69398.stderr
@@ -0,0 +1,19 @@
+error[E0277]: the trait bound `(): Foo` is not satisfied
+  --> $DIR/issue-69398.rs:12:28
+   |
+LL |     fn broken(&self) where Self::Assoc: Foo {
+   |                            ^^^^^^^^^^^^^^^^ the trait `Foo` is not implemented for `()`
+   |
+help: this trait has no implementations, consider adding one
+  --> $DIR/issue-69398.rs:1:1
+   |
+LL | pub trait Foo {
+   | ^^^^^^^^^^^^^
+help: add `#![feature(trivial_bounds)]` to the crate attributes to enable
+   |
+LL + #![feature(trivial_bounds)]
+   |
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0277`.
diff --git a/tests/ui/assumptions_on_binders/type_relation_binders_inside_solver-3.rs b/tests/ui/assumptions_on_binders/type_relation_binders_inside_solver-3.rs
@@ -1,4 +1,3 @@
-//@ check-pass
 //@ compile-flags: -Znext-solver -Zassumptions-on-binders
 
 #![crate_type = "lib"]
@@ -16,6 +15,7 @@ fn mk() -> for<'b> fn(&'b ()) { loop {} }
 fn ice()
 where
     (for<'b> fn(&'b ())): Trait
+    //~^ ERROR the trait bound `for<'b> fn(&'b ()): Trait` is not satisfied
 {
     req_trait(mk());
 }
diff --git a/tests/ui/assumptions_on_binders/type_relation_binders_inside_solver-3.stderr b/tests/ui/assumptions_on_binders/type_relation_binders_inside_solver-3.stderr
@@ -0,0 +1,19 @@
+error[E0277]: the trait bound `for<'b> fn(&'b ()): Trait` is not satisfied
+  --> $DIR/type_relation_binders_inside_solver-3.rs:17:5
+   |
+LL |     (for<'b> fn(&'b ())): Trait
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `Trait` is not implemented for `for<'b> fn(&'b ())`
+   |
+help: this trait has no implementations, consider adding one
+  --> $DIR/type_relation_binders_inside_solver-3.rs:9:1
+   |
+LL | trait Trait { }
+   | ^^^^^^^^^^^
+help: add `#![feature(trivial_bounds)]` to the crate attributes to enable
+   |
+LL + #![feature(trivial_bounds)]
+   |
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0277`.
diff --git a/tests/ui/const-generics/mgca/assoc-const-projection-in-bound.rs b/tests/ui/const-generics/mgca/assoc-const-projection-in-bound.rs
@@ -1,5 +1,4 @@
 //! regression test for <https://github.com/rust-lang/rust/issues/141014>
-//@ run-pass
 #![expect(incomplete_features)]
 #![feature(min_generic_const_args)]
 #![allow(dead_code)]
@@ -19,6 +18,7 @@ trait S<const K: usize> {}
 trait Handler<T: Abc>
 where
     (): S<{ <T as A>::VALUE }>,
+    //~^ ERROR the trait bound `(): S<0>` is not satisfied
 {
 }
 

diff --git a/tests/ui/const-generics/mgca/assoc-const-projection-in-bound.stderr b/tests/ui/const-generics/mgca/assoc-const-projection-in-bound.stderr
@@ -0,0 +1,19 @@
+error[E0277]: the trait bound `(): S<0>` is not satisfied
+  --> $DIR/assoc-const-projection-in-bound.rs:20:5
+   |
+LL |     (): S<{ <T as A>::VALUE }>,
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `S<0>` is not implemented for `()`
+   |
+help: this trait has no implementations, consider adding one
+  --> $DIR/assoc-const-projection-in-bound.rs:16:1
+   |
+LL | trait S<const K: usize> {}
+   | ^^^^^^^^^^^^^^^^^^^^^^^
+help: add `#![feature(trivial_bounds)]` to the crate attributes to enable
+   |
+LL + #![feature(trivial_bounds)]
+   |
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0277`.