tests: cases where we now do the right thing but did not before

Fixes #33684

src/test/ui/hr-subtype/hr-subtype.bound_a_b_ret_a_vs_bound_a_ret_a.stderr

@@ -1,16 +1,19 @@
-error[E0308]: mismatched types
+error[E0495]: cannot infer an appropriate lifetime for lifetime parameter 'a in generic type due to conflicting requirements
   --> $DIR/hr-subtype.rs:39:26
    |
 LL |               gimme::<$t1>(None::<$t2>);
-   |                            ^^^^^^^^^^^ expected concrete lifetime, found bound lifetime parameter 'a
+   |                            ^^^^^^^^^^^
 ...
 LL | / check! { bound_a_b_ret_a_vs_bound_a_ret_a: (for<'a,'b> fn(&'a u32, &'b u32) -> &'a u32,
 LL | |                                             for<'a>    fn(&'a u32, &'a u32) -> &'a u32) }
    | |_________________________________________________________________________________________- in this macro invocation
    |
-   = note: expected type `std::option::Option<for<'a, 'b> fn(&'a u32, &'b u32) -> &'a u32>`
+   = note: first, the lifetime cannot outlive lifetime RePlaceholder(Placeholder { universe: U1, name: BrNamed(crate0:DefIndex(1:26), 'b) })...
-              found type `std::option::Option<for<'a> fn(&'a u32, &'a u32) -> &'a u32>`
+   = note: ...but the lifetime must also be valid for lifetime RePlaceholder(Placeholder { universe: U1, name: BrNamed(crate0:DefIndex(1:25), 'a) })...
+   = note: ...so that the expression is assignable:
+           expected std::option::Option<for<'a, 'b> fn(&'a u32, &'b u32) -> &'a u32>
+              found std::option::Option<for<'a> fn(&'a u32, &'a u32) -> &'a u32>
 
 error: aborting due to previous error
 
-For more information about this error, try `rustc --explain E0308`.
+For more information about this error, try `rustc --explain E0495`.

src/test/ui/hr-subtype/hr-subtype.bound_a_b_vs_bound_a.stderr

@@ -1,16 +1,14 @@
-error[E0308]: mismatched types
+error: compilation successful
-  --> $DIR/hr-subtype.rs:39:26
+  --> $DIR/hr-subtype.rs:96:1
    |
-LL |               gimme::<$t1>(None::<$t2>);
+LL | / fn main() {
-   |                            ^^^^^^^^^^^ expected concrete lifetime, found bound lifetime parameter 'a
+LL | | //[bound_a_vs_bound_a]~^ ERROR compilation successful
-...
+LL | | //[bound_a_vs_bound_b]~^^ ERROR compilation successful
-LL | / check! { bound_a_b_vs_bound_a: (for<'a,'b> fn(&'a u32, &'b u32),
+LL | | //[bound_inv_a_vs_bound_inv_b]~^^^ ERROR compilation successful
-LL | |                                 for<'a>    fn(&'a u32, &'a u32)) }
+...  |
-   | |__________________________________________________________________- in this macro invocation
+LL | | //[bound_contra_a_contra_b_ret_co_a]~^^^^^^^^^ ERROR compilation successful
-   |
+LL | | }
-   = note: expected type `std::option::Option<for<'a, 'b> fn(&'a u32, &'b u32)>`
+   | |_^
-              found type `std::option::Option<for<'a> fn(&'a u32, &'a u32)>`
 
 error: aborting due to previous error
 
-For more information about this error, try `rustc --explain E0308`.

src/test/ui/hr-subtype/hr-subtype.bound_a_vs_bound_a.stderr

@@ -1,12 +1,12 @@
 error: compilation successful
-  --> $DIR/hr-subtype.rs:100:1
+  --> $DIR/hr-subtype.rs:96:1
    |
 LL | / fn main() {
 LL | | //[bound_a_vs_bound_a]~^ ERROR compilation successful
 LL | | //[bound_a_vs_bound_b]~^^ ERROR compilation successful
 LL | | //[bound_inv_a_vs_bound_inv_b]~^^^ ERROR compilation successful
-LL | | //[bound_co_a_vs_bound_co_b]~^^^^ ERROR compilation successful
+...  |
-LL | | //[free_x_vs_free_x]~^^^^^ ERROR compilation successful
+LL | | //[bound_contra_a_contra_b_ret_co_a]~^^^^^^^^^ ERROR compilation successful
 LL | | }
    | |_^
 

src/test/ui/hr-subtype/hr-subtype.bound_a_vs_bound_b.stderr

@@ -1,12 +1,12 @@
 error: compilation successful
-  --> $DIR/hr-subtype.rs:100:1
+  --> $DIR/hr-subtype.rs:96:1
    |
 LL | / fn main() {
 LL | | //[bound_a_vs_bound_a]~^ ERROR compilation successful
 LL | | //[bound_a_vs_bound_b]~^^ ERROR compilation successful
 LL | | //[bound_inv_a_vs_bound_inv_b]~^^^ ERROR compilation successful
-LL | | //[bound_co_a_vs_bound_co_b]~^^^^ ERROR compilation successful
+...  |
-LL | | //[free_x_vs_free_x]~^^^^^ ERROR compilation successful
+LL | | //[bound_contra_a_contra_b_ret_co_a]~^^^^^^^^^ ERROR compilation successful
 LL | | }
    | |_^
 

src/test/ui/hr-subtype/hr-subtype.bound_a_vs_free_x.stderr

@@ -2,7 +2,7 @@ error[E0308]: mismatched types
   --> $DIR/hr-subtype.rs:39:26
    |
 LL |               gimme::<$t1>(None::<$t2>);
-   |                            ^^^^^^^^^^^ expected concrete lifetime, found bound lifetime parameter 'a
+   |                            ^^^^^^^^^^^ lifetime mismatch
 ...
 LL | / check! { bound_a_vs_free_x: (for<'a> fn(&'a u32),
 LL | |                              fn(&'x u32)) }
@@ -10,6 +10,16 @@ LL | |                              fn(&'x u32)) }
    |
    = note: expected type `std::option::Option<for<'a> fn(&'a u32)>`
               found type `std::option::Option<fn(&'x u32)>`
+   = note: lifetime RePlaceholder(Placeholder { universe: U1, name: BrNamed(crate0:DefIndex(1:23), 'a) })...
+note: ...does not necessarily outlive the lifetime 'x as defined on the function body at 48:22
+  --> $DIR/hr-subtype.rs:48:22
+   |
+LL |           fn supertype<'x,'y:'x,'z:'y>() {
+   |                        ^^
+...
+LL | / check! { bound_a_vs_free_x: (for<'a> fn(&'a u32),
+LL | |                              fn(&'x u32)) }
+   | |___________________________________________- in this macro invocation
 
 error: aborting due to previous error
 

src/test/ui/hr-subtype/hr-subtype.bound_co_a_b_vs_bound_co_a.stderr

@@ -1,16 +1,14 @@
-error[E0308]: mismatched types
+error: compilation successful
-  --> $DIR/hr-subtype.rs:39:26
+  --> $DIR/hr-subtype.rs:96:1
    |
-LL |               gimme::<$t1>(None::<$t2>);
+LL | / fn main() {
-   |                            ^^^^^^^^^^^ expected concrete lifetime, found bound lifetime parameter 'a
+LL | | //[bound_a_vs_bound_a]~^ ERROR compilation successful
-...
+LL | | //[bound_a_vs_bound_b]~^^ ERROR compilation successful
-LL | / check! { bound_co_a_b_vs_bound_co_a: (for<'a,'b> fn(Co<'a>, Co<'b>),
+LL | | //[bound_inv_a_vs_bound_inv_b]~^^^ ERROR compilation successful
-LL | |                                       for<'a>    fn(Co<'a>, Co<'a>)) }
+...  |
-   | |______________________________________________________________________- in this macro invocation
+LL | | //[bound_contra_a_contra_b_ret_co_a]~^^^^^^^^^ ERROR compilation successful
-   |
+LL | | }
-   = note: expected type `std::option::Option<for<'a, 'b> fn(Co<'a>, Co<'b>)>`
+   | |_^
-              found type `std::option::Option<for<'a> fn(Co<'a>, Co<'a>)>`
 
 error: aborting due to previous error
 
-For more information about this error, try `rustc --explain E0308`.

src/test/ui/hr-subtype/hr-subtype.bound_co_a_co_b_ret_contra_a.stderr

@@ -1,16 +1,14 @@
-error[E0308]: mismatched types
+error: compilation successful
-  --> $DIR/hr-subtype.rs:39:26
+  --> $DIR/hr-subtype.rs:96:1
    |
-LL |               gimme::<$t1>(None::<$t2>);
+LL | / fn main() {
-   |                            ^^^^^^^^^^^ expected concrete lifetime, found bound lifetime parameter 'a
+LL | | //[bound_a_vs_bound_a]~^ ERROR compilation successful
-...
+LL | | //[bound_a_vs_bound_b]~^^ ERROR compilation successful
-LL | / check! { bound_co_a_co_b_ret_contra_a: (for<'a,'b> fn(Co<'a>, Co<'b>) -> Contra<'a>,
+LL | | //[bound_inv_a_vs_bound_inv_b]~^^^ ERROR compilation successful
-LL | |                                         for<'a>    fn(Co<'a>, Co<'a>) -> Contra<'a>) }
+...  |
-   | |______________________________________________________________________________________- in this macro invocation
+LL | | //[bound_contra_a_contra_b_ret_co_a]~^^^^^^^^^ ERROR compilation successful
-   |
+LL | | }
-   = note: expected type `std::option::Option<for<'a, 'b> fn(Co<'a>, Co<'b>) -> Contra<'a>>`
+   | |_^
-              found type `std::option::Option<for<'a> fn(Co<'a>, Co<'a>) -> Contra<'a>>`
 
 error: aborting due to previous error
 
-For more information about this error, try `rustc --explain E0308`.

src/test/ui/hr-subtype/hr-subtype.bound_co_a_vs_bound_co_b.stderr

@@ -1,12 +1,12 @@
 error: compilation successful
-  --> $DIR/hr-subtype.rs:100:1
+  --> $DIR/hr-subtype.rs:96:1
    |
 LL | / fn main() {
 LL | | //[bound_a_vs_bound_a]~^ ERROR compilation successful
 LL | | //[bound_a_vs_bound_b]~^^ ERROR compilation successful
 LL | | //[bound_inv_a_vs_bound_inv_b]~^^^ ERROR compilation successful
-LL | | //[bound_co_a_vs_bound_co_b]~^^^^ ERROR compilation successful
+...  |
-LL | | //[free_x_vs_free_x]~^^^^^ ERROR compilation successful
+LL | | //[bound_contra_a_contra_b_ret_co_a]~^^^^^^^^^ ERROR compilation successful
 LL | | }
    | |_^
 

src/test/ui/hr-subtype/hr-subtype.bound_contra_a_contra_b_ret_co_a.stderr

@@ -1,16 +1,14 @@
-error[E0308]: mismatched types
+error: compilation successful
-  --> $DIR/hr-subtype.rs:39:26
+  --> $DIR/hr-subtype.rs:96:1
    |
-LL |               gimme::<$t1>(None::<$t2>);
+LL | / fn main() {
-   |                            ^^^^^^^^^^^ expected concrete lifetime, found bound lifetime parameter 'a
+LL | | //[bound_a_vs_bound_a]~^ ERROR compilation successful
-...
+LL | | //[bound_a_vs_bound_b]~^^ ERROR compilation successful
-LL | / check! { bound_contra_a_contra_b_ret_co_a: (for<'a,'b> fn(Contra<'a>, Contra<'b>) -> Co<'a>,
+LL | | //[bound_inv_a_vs_bound_inv_b]~^^^ ERROR compilation successful
-LL | |                                             for<'a>    fn(Contra<'a>, Contra<'a>) -> Co<'a>) }
+...  |
-   | |______________________________________________________________________________________________- in this macro invocation
+LL | | //[bound_contra_a_contra_b_ret_co_a]~^^^^^^^^^ ERROR compilation successful
-   |
+LL | | }
-   = note: expected type `std::option::Option<for<'a, 'b> fn(Contra<'a>, Contra<'b>) -> Co<'a>>`
+   | |_^
-              found type `std::option::Option<for<'a> fn(Contra<'a>, Contra<'a>) -> Co<'a>>`
 
 error: aborting due to previous error
 
-For more information about this error, try `rustc --explain E0308`.

src/test/ui/hr-subtype/hr-subtype.bound_inv_a_b_vs_bound_inv_a.stderr

@@ -1,16 +1,19 @@
-error[E0308]: mismatched types
+error[E0495]: cannot infer an appropriate lifetime for lifetime parameter 'a in generic type due to conflicting requirements
   --> $DIR/hr-subtype.rs:39:26
    |
 LL |               gimme::<$t1>(None::<$t2>);
-   |                            ^^^^^^^^^^^ expected concrete lifetime, found bound lifetime parameter 'a
+   |                            ^^^^^^^^^^^
 ...
 LL | / check! { bound_inv_a_b_vs_bound_inv_a: (for<'a,'b> fn(Inv<'a>, Inv<'b>),
 LL | |                                         for<'a>    fn(Inv<'a>, Inv<'a>)) }
    | |__________________________________________________________________________- in this macro invocation
    |
-   = note: expected type `std::option::Option<for<'a, 'b> fn(Inv<'a>, Inv<'b>)>`
+   = note: first, the lifetime cannot outlive lifetime RePlaceholder(Placeholder { universe: U1, name: BrNamed(crate0:DefIndex(1:25), 'a) })...
-              found type `std::option::Option<for<'a> fn(Inv<'a>, Inv<'a>)>`
+   = note: ...but the lifetime must also be valid for lifetime RePlaceholder(Placeholder { universe: U1, name: BrNamed(crate0:DefIndex(1:26), 'b) })...
+   = note: ...so that the expression is assignable:
+           expected std::option::Option<for<'a, 'b> fn(Inv<'a>, Inv<'b>)>
+              found std::option::Option<for<'a> fn(Inv<'a>, Inv<'a>)>
 
 error: aborting due to previous error
 
-For more information about this error, try `rustc --explain E0308`.
+For more information about this error, try `rustc --explain E0495`.

src/test/ui/hr-subtype/hr-subtype.bound_inv_a_vs_bound_inv_b.stderr

@@ -1,12 +1,12 @@
 error: compilation successful
-  --> $DIR/hr-subtype.rs:100:1
+  --> $DIR/hr-subtype.rs:96:1
    |
 LL | / fn main() {
 LL | | //[bound_a_vs_bound_a]~^ ERROR compilation successful
 LL | | //[bound_a_vs_bound_b]~^^ ERROR compilation successful
 LL | | //[bound_inv_a_vs_bound_inv_b]~^^^ ERROR compilation successful
-LL | | //[bound_co_a_vs_bound_co_b]~^^^^ ERROR compilation successful
+...  |
-LL | | //[free_x_vs_free_x]~^^^^^ ERROR compilation successful
+LL | | //[bound_contra_a_contra_b_ret_co_a]~^^^^^^^^^ ERROR compilation successful
 LL | | }
    | |_^
 

src/test/ui/hr-subtype/hr-subtype.free_x_vs_free_x.stderr

@@ -1,12 +1,12 @@
 error: compilation successful
-  --> $DIR/hr-subtype.rs:100:1
+  --> $DIR/hr-subtype.rs:96:1
    |
 LL | / fn main() {
 LL | | //[bound_a_vs_bound_a]~^ ERROR compilation successful
 LL | | //[bound_a_vs_bound_b]~^^ ERROR compilation successful
 LL | | //[bound_inv_a_vs_bound_inv_b]~^^^ ERROR compilation successful
-LL | | //[bound_co_a_vs_bound_co_b]~^^^^ ERROR compilation successful
+...  |
-LL | | //[free_x_vs_free_x]~^^^^^ ERROR compilation successful
+LL | | //[bound_contra_a_contra_b_ret_co_a]~^^^^^^^^^ ERROR compilation successful
 LL | | }
    | |_^
 

src/test/ui/hr-subtype/hr-subtype.rs

@@ -31,21 +31,17 @@ macro_rules! check {
         #[cfg($rev)]
         fn subtype<'x,'y:'x,'z:'y>() {
             gimme::<$t2>(None::<$t1>);
-            //[free_inv_x_vs_free_inv_y]~^ ERROR mismatched types
+            //[free_inv_x_vs_free_inv_y]~^ ERROR
         }
 
         #[cfg($rev)]
         fn supertype<'x,'y:'x,'z:'y>() {
             gimme::<$t1>(None::<$t2>);
-            //[bound_a_vs_free_x]~^ ERROR mismatched types
+            //[bound_a_vs_free_x]~^ ERROR
-            //[free_x_vs_free_y]~^^ ERROR mismatched types
+            //[free_x_vs_free_y]~^^ ERROR
-            //[bound_inv_a_b_vs_bound_inv_a]~^^^ ERROR mismatched types
+            //[bound_inv_a_b_vs_bound_inv_a]~^^^ ERROR
-            //[bound_a_b_ret_a_vs_bound_a_ret_a]~^^^^ ERROR mismatched types
+            //[bound_a_b_ret_a_vs_bound_a_ret_a]~^^^^ ERROR
-            //[free_inv_x_vs_free_inv_y]~^^^^^ ERROR mismatched types
+            //[free_inv_x_vs_free_inv_y]~^^^^^ ERROR
-            //[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
         }
     }
 }
@@ -103,4 +99,8 @@ 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_co_b_ret_contra_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
 }

src/test/ui/lub-glb/old-lub-glb-hr.rs

@@ -1,11 +1,16 @@
 // Test that we give a note when the old LUB/GLB algorithm would have
-// succeeded but the new code (which is stricter) gives an error.
+// succeeded but the new code (which requires equality) gives an
+// error. However, now that we handle subtyping correctly, we no
+// longer get an error, because we recognize these two types as
+// equivalent!
+//
+// compile-pass
 
 fn foo(
     x: fn(&u8, &u8),
     y: for<'a> fn(&'a u8, &'a u8),
 ) {
-    let z = match 22 { //~ ERROR incompatible types
+    let z = match 22 {
         0 => x,
         _ => y,
     };

src/test/ui/lub-glb/old-lub-glb-hr.stderr

@@ -1,17 +0,0 @@
-error[E0308]: match arms have incompatible types
-  --> $DIR/old-lub-glb-hr.rs:8:13
-   |
-LL |       let z = match 22 { //~ ERROR incompatible types
-   |  _____________^
-LL | |         0 => x,
-LL | |         _ => y,
-   | |              - match arm with an incompatible type
-LL | |     };
-   | |_____^ expected bound lifetime parameter, found concrete lifetime
-   |
-   = note: expected type `for<'r, 's> fn(&'r u8, &'s u8)`
-              found type `for<'a> fn(&'a u8, &'a u8)`
-
-error: aborting due to previous error
-
-For more information about this error, try `rustc --explain E0308`.

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

@@ -37,8 +37,7 @@ 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);
-    want_F(bar); //~ ERROR E0308
 
     want_F(baz);
 }
@@ -46,11 +45,7 @@ fn supply_F() {
 fn supply_G() {
     want_G(foo);
     want_G(bar);
-    want_G(baz);
+    want_G(baz); //~ ERROR
-    //~^ 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() {

src/test/ui/regions-fn-subtyping-return-static-fail.stderr

@@ -1,21 +1,15 @@
-error[E0308]: mismatched types
+error[E0495]: cannot infer an appropriate lifetime for lifetime parameter in generic type due to conflicting requirements
-  --> $DIR/regions-fn-subtyping-return-static-fail.rs:41:12
+  --> $DIR/regions-fn-subtyping-return-static-fail.rs:48:12
    |
-LL |     want_F(bar); //~ ERROR E0308
+LL |     want_G(baz); //~ ERROR
-   |            ^^^ expected concrete lifetime, found bound lifetime parameter 'cx
+   |            ^^^
    |
-   = note: expected type `for<'cx> fn(&'cx S) -> &'cx S`
+   = note: first, the lifetime cannot outlive lifetime RePlaceholder(Placeholder { universe: U3, name: BrNamed(crate0:DefIndex(1:11), 'cx) })...
-              found type `for<'a> fn(&'a S) -> &S {bar::<'_>}`
+   = note: ...but the lifetime must also be valid for the static lifetime...
+   = note: ...so that the expression is assignable:
+           expected for<'cx> fn(&'cx S) -> &'static S
+              found for<'r> fn(&'r S) -> &'r S
 
-error[E0308]: mismatched types
+error: aborting due to previous error
-  --> $DIR/regions-fn-subtyping-return-static-fail.rs:49:12
-   |
-LL |     want_G(baz);
-   |            ^^^ expected concrete lifetime, found bound lifetime parameter 'cx
-   |
-   = note: expected type `for<'cx> fn(&'cx S) -> &'static S`
-              found type `for<'r> fn(&'r S) -> &'r S {baz}`
 
-error: aborting due to 2 previous errors
+For more information about this error, try `rustc --explain E0495`.
-
-For more information about this error, try `rustc --explain E0308`.

src/test/ui/regions/regions-fn-subtyping-return-static.rs

@@ -5,6 +5,8 @@
 // *ANY* lifetime and returns a reference with the 'static lifetime.
 // This can safely be considered to be an instance of `F` because all
 // lifetimes are sublifetimes of 'static.
+//
+// compile-pass
 
 #![allow(dead_code)]
 #![allow(unused_variables)]
@@ -37,8 +39,7 @@ 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);
-    want_F(bar); //~ ERROR E0308
 
     want_F(baz);
 }

src/test/ui/regions/regions-fn-subtyping-return-static.stderr

@@ -1,12 +1,26 @@
-error[E0308]: mismatched types
+warning: function `want_F` should have a snake case name such as `want_f`
-  --> $DIR/regions-fn-subtyping-return-static.rs:41:12
+  --> $DIR/regions-fn-subtyping-return-static.rs:18:1
    |
-LL |     want_F(bar); //~ ERROR E0308
+LL | fn want_F(f: F) { }
-   |            ^^^ expected concrete lifetime, found bound lifetime parameter 'cx
+   | ^^^^^^^^^^^^^^^^^^^
    |
-   = note: expected type `for<'cx> fn(&'cx S) -> &'cx S`
+   = note: #[warn(non_snake_case)] on by default
-              found type `for<'a> fn(&'a S) -> &S {bar::<'_>}`
 
-error: aborting due to previous error
+warning: function `want_G` should have a snake case name such as `want_g`
+  --> $DIR/regions-fn-subtyping-return-static.rs:22:1
+   |
+LL | fn want_G(f: G) { }
+   | ^^^^^^^^^^^^^^^^^^^
+
+warning: function `supply_F` should have a snake case name such as `supply_f`
+  --> $DIR/regions-fn-subtyping-return-static.rs:39:1
+   |
+LL | / fn supply_F() {
+LL | |     want_F(foo);
+LL | |
+LL | |     want_F(bar);
+LL | |
+LL | |     want_F(baz);
+LL | | }
+   | |_^
 
-For more information about this error, try `rustc --explain E0308`.