we now handle higher-ranked subtyping correctly

Fixes rust-lang#33684

Author: nikomatsakis

src/test/compile-fail/hr-subtype.rs

@@ -52,10 +52,6 @@ macro_rules! check {
             //[bound_inv_a_b_vs_bound_inv_a]~^^^ ERROR mismatched types
             //[bound_a_b_ret_a_vs_bound_a_ret_a]~^^^^ ERROR mismatched types
             //[free_inv_x_vs_free_inv_y]~^^^^^ ERROR mismatched types
-            //[bound_a_b_vs_bound_a]~^^^^^^ ERROR mismatched types
-            //[bound_co_a_b_vs_bound_co_a]~^^^^^^^ ERROR mismatched types
-            //[bound_contra_a_contra_b_ret_co_a]~^^^^^^^^ ERROR mismatched types
-            //[bound_co_a_co_b_ret_contra_a]~^^^^^^^^^ ERROR mismatched types
         }
     }
 }
@@ -113,4 +109,8 @@ fn main() {
 //[bound_inv_a_vs_bound_inv_b]~^^^ ERROR compilation successful
 //[bound_co_a_vs_bound_co_b]~^^^^ ERROR compilation successful
 //[free_x_vs_free_x]~^^^^^ ERROR compilation successful
+//[bound_a_b_vs_bound_a]~^^^^^^ ERROR compilation successful
+//[bound_co_a_b_vs_bound_co_a]~^^^^^^^ ERROR compilation successful
+//[bound_contra_a_contra_b_ret_co_a]~^^^^^^^^ ERROR compilation successful
+//[bound_co_a_co_b_ret_contra_a]~^^^^^^^^^ ERROR compilation successful
 }

src/test/compile-fail/regions-fn-subtyping-return-static.rs

@@ -47,8 +47,7 @@ fn baz(x: &S) -> &S {
 fn supply_F() {
     want_F(foo);
 
-    // FIXME(#33684) -- this should be a subtype, but current alg. rejects it incorrectly
-    want_F(bar); //~ ERROR E0308
+    want_F(bar);
 
     want_F(baz);
 }
@@ -58,9 +57,6 @@ fn supply_G() {
     want_G(bar);
     want_G(baz);
     //~^ ERROR mismatched types
-    //~| expected type `for<'cx> fn(&'cx S) -> &'static S`
-    //~| found type `for<'r> fn(&'r S) -> &'r S {baz}`
-    //~| expected concrete lifetime, found bound lifetime parameter 'cx
 }
 
 pub fn main() {