diff --git a/tests/ui/traits/const-traits/call-const-in-tilde-const.rs b/tests/ui/traits/const-traits/call-const-in-tilde-const.rs
new file mode 100644
index 000000000000..970ee93fd49a
--- /dev/null
+++ b/tests/ui/traits/const-traits/call-const-in-tilde-const.rs
@@ -0,0 +1,14 @@
+//@ compile-flags: -Znext-solver
+#![feature(const_trait_impl, effects)]
+//~^ WARN the feature `effects` is incomplete
+
+#[const_trait] trait Foo {
+    fn foo();
+}
+
+const fn foo<T: ~const Foo>() {
+    const { T::foo() }
+    //~^ ERROR the trait bound `T: const Foo` is not satisfied
+}
+
+fn main() {}
diff --git a/tests/ui/traits/const-traits/call-const-in-tilde-const.stderr b/tests/ui/traits/const-traits/call-const-in-tilde-const.stderr
new file mode 100644
index 000000000000..49c310f1f751
--- /dev/null
+++ b/tests/ui/traits/const-traits/call-const-in-tilde-const.stderr
@@ -0,0 +1,18 @@
+warning: the feature `effects` is incomplete and may not be safe to use and/or cause compiler crashes
+  --> $DIR/call-const-in-tilde-const.rs:2:30
+   |
+LL | #![feature(const_trait_impl, effects)]
+   |                              ^^^^^^^
+   |
+   = note: see issue #102090 <https://github.com/rust-lang/rust/issues/102090> for more information
+   = note: `#[warn(incomplete_features)]` on by default
+
+error[E0277]: the trait bound `T: const Foo` is not satisfied
+  --> $DIR/call-const-in-tilde-const.rs:10:13
+   |
+LL |     const { T::foo() }
+   |             ^^^^^^^^
+
+error: aborting due to 1 previous error; 1 warning emitted
+
+For more information about this error, try `rustc --explain E0277`.
diff --git a/tests/ui/traits/const-traits/const-bound-in-host.rs b/tests/ui/traits/const-traits/const-bound-in-host.rs
new file mode 100644
index 000000000000..6fbc21074b68
--- /dev/null
+++ b/tests/ui/traits/const-traits/const-bound-in-host.rs
@@ -0,0 +1,15 @@
+//@ compile-flags: -Znext-solver
+//@ check-pass
+
+#![feature(const_trait_impl, effects)]
+//~^ WARN the feature `effects` is incomplete
+
+#[const_trait] trait Foo {
+    fn foo();
+}
+
+fn foo<T: const Foo>() {
+    const { T::foo() }
+}
+
+fn main() {}
diff --git a/tests/ui/traits/const-traits/const-bound-in-host.stderr b/tests/ui/traits/const-traits/const-bound-in-host.stderr
new file mode 100644
index 000000000000..b815f745ee8f
--- /dev/null
+++ b/tests/ui/traits/const-traits/const-bound-in-host.stderr
@@ -0,0 +1,11 @@
+warning: the feature `effects` is incomplete and may not be safe to use and/or cause compiler crashes
+  --> $DIR/const-bound-in-host.rs:4:30
+   |
+LL | #![feature(const_trait_impl, effects)]
+   |                              ^^^^^^^
+   |
+   = note: see issue #102090 <https://github.com/rust-lang/rust/issues/102090> for more information
+   = note: `#[warn(incomplete_features)]` on by default
+
+warning: 1 warning emitted
+
diff --git a/tests/ui/traits/const-traits/const-in-closure.rs b/tests/ui/traits/const-traits/const-in-closure.rs
new file mode 100644
index 000000000000..51b22c530361
--- /dev/null
+++ b/tests/ui/traits/const-traits/const-in-closure.rs
@@ -0,0 +1,25 @@
+//@ compile-flags: -Znext-solver
+//@ check-pass
+
+#![feature(const_trait_impl, effects)]
+//~^ WARN the feature `effects` is incomplete
+
+#[const_trait] trait Trait {
+    fn method();
+}
+
+const fn foo<T: Trait>() {
+    let _ = || {
+        // Make sure this doesn't enforce `T: ~const Trait`
+        T::method();
+    };
+}
+
+fn bar<T: const Trait>() {
+    let _ = || {
+        // Make sure unconditionally const bounds propagate from parent.
+        const { T::method(); };
+    };
+}
+
+fn main() {}
diff --git a/tests/ui/traits/const-traits/const-in-closure.stderr b/tests/ui/traits/const-traits/const-in-closure.stderr
new file mode 100644
index 000000000000..f4b03b9ed201
--- /dev/null
+++ b/tests/ui/traits/const-traits/const-in-closure.stderr
@@ -0,0 +1,11 @@
+warning: the feature `effects` is incomplete and may not be safe to use and/or cause compiler crashes
+  --> $DIR/const-in-closure.rs:4:30
+   |
+LL | #![feature(const_trait_impl, effects)]
+   |                              ^^^^^^^
+   |
+   = note: see issue #102090 <https://github.com/rust-lang/rust/issues/102090> for more information
+   = note: `#[warn(incomplete_features)]` on by default
+
+warning: 1 warning emitted
+
diff --git a/tests/ui/traits/const-traits/dont-observe-host-opaque.rs b/tests/ui/traits/const-traits/dont-observe-host-opaque.rs
new file mode 100644
index 000000000000..4a5ae346e396
--- /dev/null
+++ b/tests/ui/traits/const-traits/dont-observe-host-opaque.rs
@@ -0,0 +1,12 @@
+//@ compile-flags: -Znext-solver
+//@ check-pass
+
+#![feature(const_trait_impl, effects)]
+//~^ WARN the feature `effects` is incomplete
+
+const fn opaque() -> impl Sized {}
+
+fn main() {
+    let mut x = const { opaque() };
+    x = opaque();
+}
diff --git a/tests/ui/traits/const-traits/dont-observe-host-opaque.stderr b/tests/ui/traits/const-traits/dont-observe-host-opaque.stderr
new file mode 100644
index 000000000000..1b457ab76432
--- /dev/null
+++ b/tests/ui/traits/const-traits/dont-observe-host-opaque.stderr
@@ -0,0 +1,11 @@
+warning: the feature `effects` is incomplete and may not be safe to use and/or cause compiler crashes
+  --> $DIR/dont-observe-host-opaque.rs:4:30
+   |
+LL | #![feature(const_trait_impl, effects)]
+   |                              ^^^^^^^
+   |
+   = note: see issue #102090 <https://github.com/rust-lang/rust/issues/102090> for more information
+   = note: `#[warn(incomplete_features)]` on by default
+
+warning: 1 warning emitted
+
diff --git a/tests/ui/traits/const-traits/dont-observe-host.rs b/tests/ui/traits/const-traits/dont-observe-host.rs
new file mode 100644
index 000000000000..d027d578c42f
--- /dev/null
+++ b/tests/ui/traits/const-traits/dont-observe-host.rs
@@ -0,0 +1,23 @@
+//@ compile-flags: -Znext-solver
+//@ check-pass
+
+#![feature(const_trait_impl, effects)]
+//~^ WARN the feature `effects` is incomplete
+
+#[const_trait]
+trait Trait {
+    fn method() {}
+}
+
+impl const Trait for () {}
+
+fn main() {
+    let mut x = const {
+        let x = <()>::method;
+        x();
+        x
+    };
+    let y = <()>::method;
+    y();
+    x = y;
+}
diff --git a/tests/ui/traits/const-traits/dont-observe-host.stderr b/tests/ui/traits/const-traits/dont-observe-host.stderr
new file mode 100644
index 000000000000..64ef611f011c
--- /dev/null
+++ b/tests/ui/traits/const-traits/dont-observe-host.stderr
@@ -0,0 +1,11 @@
+warning: the feature `effects` is incomplete and may not be safe to use and/or cause compiler crashes
+  --> $DIR/dont-observe-host.rs:4:30
+   |
+LL | #![feature(const_trait_impl, effects)]
+   |                              ^^^^^^^
+   |
+   = note: see issue #102090 <https://github.com/rust-lang/rust/issues/102090> for more information
+   = note: `#[warn(incomplete_features)]` on by default
+
+warning: 1 warning emitted
+
diff --git a/tests/ui/traits/const-traits/fn-ptr-lub.rs b/tests/ui/traits/const-traits/fn-ptr-lub.rs
new file mode 100644
index 000000000000..0fc326788270
--- /dev/null
+++ b/tests/ui/traits/const-traits/fn-ptr-lub.rs
@@ -0,0 +1,20 @@
+//@ compile-flags: -Znext-solver
+//@ check-pass
+
+#![feature(const_trait_impl, effects)]
+//~^ WARN the feature `effects` is incomplete
+
+const fn foo() {}
+const fn bar() {}
+fn baz() {}
+
+const fn caller(branch: bool) {
+    let mut x = if branch {
+      foo
+    } else {
+      bar
+    };
+    x = baz;
+}
+
+fn main() {}
diff --git a/tests/ui/traits/const-traits/fn-ptr-lub.stderr b/tests/ui/traits/const-traits/fn-ptr-lub.stderr
new file mode 100644
index 000000000000..b333311b660e
--- /dev/null
+++ b/tests/ui/traits/const-traits/fn-ptr-lub.stderr
@@ -0,0 +1,11 @@
+warning: the feature `effects` is incomplete and may not be safe to use and/or cause compiler crashes
+  --> $DIR/fn-ptr-lub.rs:4:30
+   |
+LL | #![feature(const_trait_impl, effects)]
+   |                              ^^^^^^^
+   |
+   = note: see issue #102090 <https://github.com/rust-lang/rust/issues/102090> for more information
+   = note: `#[warn(incomplete_features)]` on by default
+
+warning: 1 warning emitted
+
diff --git a/tests/ui/traits/const-traits/item-bound-entailment-fails.rs b/tests/ui/traits/const-traits/item-bound-entailment-fails.rs
new file mode 100644
index 000000000000..42799e3700ca
--- /dev/null
+++ b/tests/ui/traits/const-traits/item-bound-entailment-fails.rs
@@ -0,0 +1,31 @@
+//@ compile-flags: -Znext-solver
+#![feature(const_trait_impl, effects)]
+//~^ WARN the feature `effects` is incomplete
+
+#[const_trait] trait Foo {
+    type Assoc<T>: ~const Bar
+    where
+        T: ~const Bar;
+}
+
+#[const_trait] trait Bar {}
+struct N<T>(T);
+impl<T> Bar for N<T> where T: Bar {}
+struct C<T>(T);
+impl<T> const Bar for C<T> where T: ~const Bar {}
+
+impl const Foo for u32 {
+    type Assoc<T> = N<T>
+    //~^ ERROR the trait bound `N<T>: ~const Bar` is not satisfied
+    where
+        T: ~const Bar;
+}
+
+impl const Foo for i32 {
+    type Assoc<T> = C<T>
+    //~^ ERROR the trait bound `T: ~const Bar` is not satisfied
+    where
+        T: Bar;
+}
+
+fn main() {}
diff --git a/tests/ui/traits/const-traits/item-bound-entailment-fails.stderr b/tests/ui/traits/const-traits/item-bound-entailment-fails.stderr
new file mode 100644
index 000000000000..3b3868c4bc84
--- /dev/null
+++ b/tests/ui/traits/const-traits/item-bound-entailment-fails.stderr
@@ -0,0 +1,36 @@
+warning: the feature `effects` is incomplete and may not be safe to use and/or cause compiler crashes
+  --> $DIR/item-bound-entailment-fails.rs:2:30
+   |
+LL | #![feature(const_trait_impl, effects)]
+   |                              ^^^^^^^
+   |
+   = note: see issue #102090 <https://github.com/rust-lang/rust/issues/102090> for more information
+   = note: `#[warn(incomplete_features)]` on by default
+
+error[E0277]: the trait bound `N<T>: ~const Bar` is not satisfied
+  --> $DIR/item-bound-entailment-fails.rs:18:21
+   |
+LL |     type Assoc<T> = N<T>
+   |                     ^^^^
+   |
+note: required by a bound in `Foo::Assoc`
+  --> $DIR/item-bound-entailment-fails.rs:6:20
+   |
+LL |     type Assoc<T>: ~const Bar
+   |                    ^^^^^^^^^^ required by this bound in `Foo::Assoc`
+
+error[E0277]: the trait bound `T: ~const Bar` is not satisfied
+  --> $DIR/item-bound-entailment-fails.rs:25:21
+   |
+LL |     type Assoc<T> = C<T>
+   |                     ^^^^
+   |
+note: required by a bound in `Foo::Assoc`
+  --> $DIR/item-bound-entailment-fails.rs:6:20
+   |
+LL |     type Assoc<T>: ~const Bar
+   |                    ^^^^^^^^^^ required by this bound in `Foo::Assoc`
+
+error: aborting due to 2 previous errors; 1 warning emitted
+
+For more information about this error, try `rustc --explain E0277`.
diff --git a/tests/ui/traits/const-traits/item-bound-entailment.rs b/tests/ui/traits/const-traits/item-bound-entailment.rs
new file mode 100644
index 000000000000..3670eabd66c0
--- /dev/null
+++ b/tests/ui/traits/const-traits/item-bound-entailment.rs
@@ -0,0 +1,31 @@
+//@ compile-flags: -Znext-solver
+//@ check-pass
+
+#![feature(const_trait_impl, effects)]
+//~^ WARN the feature `effects` is incomplete
+
+#[const_trait] trait Foo {
+    type Assoc<T>: ~const Bar
+    where
+        T: ~const Bar;
+}
+
+#[const_trait] trait Bar {}
+struct N<T>(T);
+impl<T> Bar for N<T> where T: Bar {}
+struct C<T>(T);
+impl<T> const Bar for C<T> where T: ~const Bar {}
+
+impl Foo for u32 {
+    type Assoc<T> = N<T>
+    where
+        T: Bar;
+}
+
+impl const Foo for i32 {
+    type Assoc<T> = C<T>
+    where
+        T: ~const Bar;
+}
+
+fn main() {}
diff --git a/tests/ui/traits/const-traits/item-bound-entailment.stderr b/tests/ui/traits/const-traits/item-bound-entailment.stderr
new file mode 100644
index 000000000000..b4a4ebdbee27
--- /dev/null
+++ b/tests/ui/traits/const-traits/item-bound-entailment.stderr
@@ -0,0 +1,11 @@
+warning: the feature `effects` is incomplete and may not be safe to use and/or cause compiler crashes
+  --> $DIR/item-bound-entailment.rs:4:30
+   |
+LL | #![feature(const_trait_impl, effects)]
+   |                              ^^^^^^^
+   |
+   = note: see issue #102090 <https://github.com/rust-lang/rust/issues/102090> for more information
+   = note: `#[warn(incomplete_features)]` on by default
+
+warning: 1 warning emitted
+
diff --git a/tests/ui/traits/const-traits/predicate-entailment-fails.rs b/tests/ui/traits/const-traits/predicate-entailment-fails.rs
new file mode 100644
index 000000000000..5d6109bfad3a
--- /dev/null
+++ b/tests/ui/traits/const-traits/predicate-entailment-fails.rs
@@ -0,0 +1,43 @@
+//@ compile-flags: -Znext-solver
+#![feature(const_trait_impl, effects)]
+//~^ WARN the feature `effects` is incomplete
+
+#[const_trait] trait Bar {}
+impl const Bar for () {}
+
+
+#[const_trait] trait TildeConst {
+    type Bar<T> where T: ~const Bar;
+
+    fn foo<T>() where T: ~const Bar;
+}
+impl TildeConst for () {
+    type Bar<T> = () where T: const Bar;
+    //~^ ERROR impl has stricter requirements than trait
+
+    fn foo<T>() where T: const Bar {}
+    //~^ ERROR impl has stricter requirements than trait
+}
+
+
+#[const_trait] trait NeverConst {
+    type Bar<T> where T: Bar;
+
+    fn foo<T>() where T: Bar;
+}
+impl NeverConst for i32 {
+    type Bar<T> = () where T: const Bar;
+    //~^ ERROR impl has stricter requirements than trait
+
+    fn foo<T>() where T: const Bar {}
+    //~^ ERROR impl has stricter requirements than trait
+}
+impl const NeverConst for u32 {
+    type Bar<T> = () where T: ~const Bar;
+    //~^ ERROR impl has stricter requirements than trait
+
+    fn foo<T>() where T: ~const Bar {}
+    //~^ ERROR impl has stricter requirements than trait
+}
+
+fn main() {}
diff --git a/tests/ui/traits/const-traits/predicate-entailment-fails.stderr b/tests/ui/traits/const-traits/predicate-entailment-fails.stderr
new file mode 100644
index 000000000000..9538630cbd3f
--- /dev/null
+++ b/tests/ui/traits/const-traits/predicate-entailment-fails.stderr
@@ -0,0 +1,66 @@
+warning: the feature `effects` is incomplete and may not be safe to use and/or cause compiler crashes
+  --> $DIR/predicate-entailment-fails.rs:2:30
+   |
+LL | #![feature(const_trait_impl, effects)]
+   |                              ^^^^^^^
+   |
+   = note: see issue #102090 <https://github.com/rust-lang/rust/issues/102090> for more information
+   = note: `#[warn(incomplete_features)]` on by default
+
+error[E0276]: impl has stricter requirements than trait
+  --> $DIR/predicate-entailment-fails.rs:15:31
+   |
+LL |     type Bar<T> where T: ~const Bar;
+   |     ----------- definition of `Bar` from trait
+...
+LL |     type Bar<T> = () where T: const Bar;
+   |                               ^^^^^^^^^ impl has extra requirement `T: constBar`
+
+error[E0276]: impl has stricter requirements than trait
+  --> $DIR/predicate-entailment-fails.rs:18:26
+   |
+LL |     fn foo<T>() where T: ~const Bar;
+   |     -------------------------------- definition of `foo` from trait
+...
+LL |     fn foo<T>() where T: const Bar {}
+   |                          ^^^^^^^^^ impl has extra requirement `T: constBar`
+
+error[E0276]: impl has stricter requirements than trait
+  --> $DIR/predicate-entailment-fails.rs:29:31
+   |
+LL |     type Bar<T> where T: Bar;
+   |     ----------- definition of `Bar` from trait
+...
+LL |     type Bar<T> = () where T: const Bar;
+   |                               ^^^^^^^^^ impl has extra requirement `T: constBar`
+
+error[E0276]: impl has stricter requirements than trait
+  --> $DIR/predicate-entailment-fails.rs:32:26
+   |
+LL |     fn foo<T>() where T: Bar;
+   |     ------------------------- definition of `foo` from trait
+...
+LL |     fn foo<T>() where T: const Bar {}
+   |                          ^^^^^^^^^ impl has extra requirement `T: constBar`
+
+error[E0276]: impl has stricter requirements than trait
+  --> $DIR/predicate-entailment-fails.rs:36:31
+   |
+LL |     type Bar<T> where T: Bar;
+   |     ----------- definition of `Bar` from trait
+...
+LL |     type Bar<T> = () where T: ~const Bar;
+   |                               ^^^^^^^^^^ impl has extra requirement `T: ~constBar`
+
+error[E0276]: impl has stricter requirements than trait
+  --> $DIR/predicate-entailment-fails.rs:39:26
+   |
+LL |     fn foo<T>() where T: Bar;
+   |     ------------------------- definition of `foo` from trait
+...
+LL |     fn foo<T>() where T: ~const Bar {}
+   |                          ^^^^^^^^^^ impl has extra requirement `T: ~constBar`
+
+error: aborting due to 6 previous errors; 1 warning emitted
+
+For more information about this error, try `rustc --explain E0276`.
diff --git a/tests/ui/traits/const-traits/predicate-entailment-passes.rs b/tests/ui/traits/const-traits/predicate-entailment-passes.rs
new file mode 100644
index 000000000000..b660329151be
--- /dev/null
+++ b/tests/ui/traits/const-traits/predicate-entailment-passes.rs
@@ -0,0 +1,39 @@
+//@ compile-flags: -Znext-solver
+//@ check-pass
+
+#![feature(const_trait_impl, effects)]
+//~^ WARN the feature `effects` is incomplete
+
+#[const_trait] trait Bar {}
+impl const Bar for () {}
+
+
+#[const_trait] trait TildeConst {
+    type Bar<T> where T: ~const Bar;
+
+    fn foo<T>() where T: ~const Bar;
+}
+impl TildeConst for () {
+    type Bar<T> = () where T: Bar;
+
+    fn foo<T>() where T: Bar {}
+}
+
+
+#[const_trait] trait AlwaysConst {
+    type Bar<T> where T: const Bar;
+
+    fn foo<T>() where T: const Bar;
+}
+impl AlwaysConst for i32 {
+    type Bar<T> = () where T: Bar;
+
+    fn foo<T>() where T: Bar {}
+}
+impl const AlwaysConst for u32 {
+    type Bar<T> = () where T: ~const Bar;
+
+    fn foo<T>() where T: ~const Bar {}
+}
+
+fn main() {}
diff --git a/tests/ui/traits/const-traits/predicate-entailment-passes.stderr b/tests/ui/traits/const-traits/predicate-entailment-passes.stderr
new file mode 100644
index 000000000000..dcaeea73b580
--- /dev/null
+++ b/tests/ui/traits/const-traits/predicate-entailment-passes.stderr
@@ -0,0 +1,11 @@
+warning: the feature `effects` is incomplete and may not be safe to use and/or cause compiler crashes
+  --> $DIR/predicate-entailment-passes.rs:4:30
+   |
+LL | #![feature(const_trait_impl, effects)]
+   |                              ^^^^^^^
+   |
+   = note: see issue #102090 <https://github.com/rust-lang/rust/issues/102090> for more information
+   = note: `#[warn(incomplete_features)]` on by default
+
+warning: 1 warning emitted
+