add red test

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

@@ -12,6 +12,26 @@ LL | impl AsExpression<Text> for &'_ str {
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    = help: for that trait implementation, expected `Text`, found `Integer`
 
-error: aborting due to 1 previous error
+error[E0277]: the trait bound `X: A` is not satisfied
+  --> $DIR/as_expression.rs:60:5
+   |
+LL |     X.start().foo().finish();
+   |     ^^^^^^^^^ unsatisfied trait bound
+   |
+help: the trait `A` is not implemented for `X`
+  --> $DIR/as_expression.rs:70:1
+   |
+LL | struct X;
+   | ^^^^^^^^
+note: required by a bound in `Ext::foo`
+  --> $DIR/as_expression.rs:79:23
+   |
+LL |     fn foo(self) -> Self
+   |        --- required by a bound in this associated function
+LL |     where
+LL |         Self: Sized + A;
+   |                       ^ required by this bound in `Ext::foo`
+
+error: aborting due to 2 previous errors
 
 For more information about this error, try `rustc --explain E0277`.

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

@@ -22,6 +22,26 @@ LL |     where
 LL |         T: AsExpression<Self::SqlType>,
    |            ^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `Foo::check`
 
-error: aborting due to 1 previous error
+error[E0277]: the trait bound `X: A` is not satisfied
+  --> $DIR/as_expression.rs:60:15
+   |
+LL |     X.start().foo().finish();
+   |               ^^^ unsatisfied trait bound
+   |
+help: the trait `A` is not implemented for `X`
+  --> $DIR/as_expression.rs:70:1
+   |
+LL | struct X;
+   | ^^^^^^^^
+note: required by a bound in `Ext::foo`
+  --> $DIR/as_expression.rs:79:23
+   |
+LL |     fn foo(self) -> Self
+   |        --- required by a bound in this associated function
+LL |     where
+LL |         Self: Sized + A;
+   |                       ^ required by this bound in `Ext::foo`
+
+error: aborting due to 2 previous errors
 
 For more information about this error, try `rustc --explain E0277`.

tests/ui/diagnostic_namespace/do_not_recommend/as_expression.rs

@@ -55,4 +55,49 @@ impl<T> Foo for T where T: Expression {}
 fn main() {
     SelectInt.check("bar");
     //~^ ERROR the trait bound `&str: AsExpression<Integer>` is not satisfied
+
+    // Regression test for https://github.com/rust-lang/rust/issues/156475.
+    X.start().foo().finish();
+    //~^ ERROR the trait bound `X: A` is not satisfied
+}
+
+trait A {}
+trait B {}
+
+#[diagnostic::do_not_recommend]
+impl<T: B> A for T {}
+
+struct X;
+
+trait Start {
+    fn start(self) -> Self;
+}
+
+trait Ext {
+    fn foo(self) -> Self
+    where
+        Self: Sized + A;
+}
+
+trait Finish {
+    fn finish(self);
+}
+
+impl<T> Start for T {
+    fn start(self) -> Self {
+        self
+    }
+}
+
+impl<T> Ext for T {
+    fn foo(self) -> Self
+    where
+        Self: Sized + A,
+    {
+        self
+    }
+}
+
+impl<T> Finish for T {
+    fn finish(self) {}
 }