add additional tests

Author: lcnr

tests/ui/closures/deduce-signature/infer-higher-ranked-signature.rs

@@ -0,0 +1,20 @@
+//@ revisions: current next
+//@ ignore-compare-mode-next-solver (explicit revisions)
+//@[next] compile-flags: -Znext-solver
+//@ check-pass
+
+trait Foo {}
+fn needs_foo<T>(_: T)
+where
+    Wrap<T>: Foo,
+{
+}
+
+struct Wrap<T>(T);
+impl<T> Foo for Wrap<T> where T: for<'a> Fn(&'a i32) {}
+
+fn main() {
+    needs_foo(|x| {
+        x.to_string();
+    });
+}

tests/ui/closures/deduce-signature/obligation-with-leaking-placeholders.current.stderr

@@ -0,0 +1,15 @@
+error: implementation of `Foo` is not general enough
+  --> $DIR/obligation-with-leaking-placeholders.rs:18:5
+   |
+LL | /     needs_foo(|x| {
+LL | |
+LL | |
+LL | |         x.to_string();
+LL | |     });
+   | |______^ implementation of `Foo` is not general enough
+   |
+   = note: `Wrap<{closure@$DIR/obligation-with-leaking-placeholders.rs:18:15: 18:18}>` must implement `Foo<'0>`, for any lifetime `'0`...
+   = note: ...but it actually implements `Foo<'1>`, for some specific lifetime `'1`
+
+error: aborting due to 1 previous error
+

tests/ui/closures/deduce-signature/obligation-with-leaking-placeholders.next.stderr

@@ -0,0 +1,17 @@
+error[E0282]: type annotations needed
+  --> $DIR/obligation-with-leaking-placeholders.rs:18:16
+   |
+LL |     needs_foo(|x| {
+   |                ^
+...
+LL |         x.to_string();
+   |         - type must be known at this point
+   |
+help: consider giving this closure parameter an explicit type
+   |
+LL |     needs_foo(|x: /* Type */| {
+   |                 ++++++++++++
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0282`.

tests/ui/closures/deduce-signature/obligation-with-leaking-placeholders.rs

@@ -0,0 +1,23 @@
+//@ revisions: current next
+//@ ignore-compare-mode-next-solver (explicit revisions)
+//@[next] compile-flags: -Znext-solver
+
+// See #124385 for more details. 
+
+trait Foo<'a> {}
+fn needs_foo<T>(_: T)
+where
+    for<'a> Wrap<T>: Foo<'a>,
+{
+}
+
+struct Wrap<T>(T);
+impl<'a, T> Foo<'a> for Wrap<T> where T: Fn(&'a i32) {}
+
+fn main() {
+    needs_foo(|x| {
+        //[current]~^ implementation of `Foo` is not general enough
+        //[next]~^^ ERROR type annotations needed
+        x.to_string();
+    });
+}