Improve SubSupConflict case with one named, one anonymous lifetime parameter #42701

Author: cengiz-io

src/librustc/infer/error_reporting/different_lifetimes.rs

@@ -60,6 +60,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
     pub fn try_report_anon_anon_conflict(&self, error: &RegionResolutionError<'tcx>) -> bool {
         let (span, sub, sup) = match *error {
             ConcreteFailure(ref origin, sub, sup) => (origin.span(), sub, sup),
+            SubSupConflict(_, ref origin, sub, _, sup) => (origin.span(), sub, sup),
             _ => return false, // inapplicable
         };
 

src/librustc/infer/error_reporting/named_anon_conflict.rs

@@ -21,6 +21,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
     pub fn try_report_named_anon_conflict(&self, error: &RegionResolutionError<'tcx>) -> bool {
         let (span, sub, sup) = match *error {
             ConcreteFailure(ref origin, sub, sup) => (origin.span(), sub, sup),
+            SubSupConflict(_, ref origin, sub, _, sup) => (origin.span(), sub, sup),
             _ => return false, // inapplicable
         };
 

src/test/compile-fail/associated-types-project-from-hrtb-in-fn-body.rs

@@ -30,7 +30,7 @@ fn bar<'a, 'b, I : for<'x> Foo<&'x isize>>(
 {
     // x and y here have two distinct lifetimes:
     let z: I::A = if cond { x } else { y };
-    //~^ ERROR cannot infer
+    //~^ ERROR lifetime mismatch
 }
 
 pub fn main() {}

src/test/compile-fail/associated-types/cache/project-fn-ret-contravariant.rs

@@ -50,9 +50,10 @@ fn baz<'a,'b>(x: &'a u32) -> &'static u32 {
 
 #[cfg(krisskross)] // two instantiations, mixing and matching: BAD
 fn transmute<'a,'b>(x: &'a u32, y: &'b u32) -> (&'a u32, &'b u32) {
-   let a = bar(foo, y); //[krisskross]~ ERROR E0495
-   let b = bar(foo, x); //[krisskross]~ ERROR E0495
-   (a, b)
+   let a = bar(foo, y);
+   let b = bar(foo, x);
+   (a, b) //[krisskross]~ ERROR 55:5: 55:6: lifetime mismatch [E0623]
+   //[krisskross]~^ ERROR 55:8: 55:9: lifetime mismatch [E0623]
 }
 
 #[rustc_error]

src/test/compile-fail/associated-types/cache/project-fn-ret-invariant.rs

@@ -45,9 +45,9 @@ fn baz<'a,'b>(x: Type<'a>, y: Type<'b>) -> (Type<'a>, Type<'b>) {
 #[cfg(oneuse)] // one instantiation: BAD
 fn baz<'a,'b>(x: Type<'a>, y: Type<'b>) -> (Type<'a>, Type<'b>) {
    let f = foo; // <-- No consistent type can be inferred for `f` here.
-   let a = bar(f, x); //[oneuse]~^ ERROR E0495
+   let a = bar(f, x);
    let b = bar(f, y);
-   (a, b)
+   (a, b) //[oneuse]~ ERROR E0623
 }
 
 #[cfg(transmute)] // one instantiations: BAD
@@ -60,9 +60,10 @@ fn baz<'a,'b>(x: Type<'a>) -> Type<'static> {
 
 #[cfg(krisskross)] // two instantiations, mixing and matching: BAD
 fn transmute<'a,'b>(x: Type<'a>, y: Type<'b>) -> (Type<'a>, Type<'b>) {
-   let a = bar(foo, y); //[krisskross]~ ERROR E0495
-   let b = bar(foo, x); //[krisskross]~ ERROR E0495
-   (a, b)
+   let a = bar(foo, y);
+   let b = bar(foo, x);
+   (a, b) //[krisskross]~ ERROR E0623
+   //[krisskross]~^ ERROR E0623
 }
 
 #[rustc_error]

src/test/compile-fail/borrowck/borrowck-reborrow-from-shorter-lived-andmut.rs

@@ -17,7 +17,7 @@ struct S<'a> {
 
 fn copy_borrowed_ptr<'a,'b>(p: &'a mut S<'b>) -> S<'b> {
     S { pointer: &mut *p.pointer }
-    //~^ ERROR cannot infer
+    //~^ ERROR lifetime mismatch
 }
 
 fn main() {

src/test/compile-fail/issue-17728.rs

@@ -21,9 +21,9 @@ trait TraversesWorld {
     fn attemptTraverse(&self, room: &Room, directionStr: &str) -> Result<&Room, &str> {
         let direction = str_to_direction(directionStr);
         let maybe_room = room.direction_to_room.get(&direction);
-        //~^ ERROR cannot infer an appropriate lifetime for autoref due to conflicting requirements
         match maybe_room {
             Some(entry) => Ok(entry),
+            //~^ ERROR 25:28: 25:37: lifetime mismatch [E0623]
             _ => Err("Direction does not exist in room.")
         }
     }

src/test/compile-fail/issue-40288-2.rs

@@ -12,12 +12,12 @@ fn prove_static<T: 'static + ?Sized>(_: &'static T) {}
 
 fn lifetime_transmute_slice<'a, T: ?Sized>(x: &'a T, y: &T) -> &'a T {
     let mut out = [x];
-    //~^ ERROR cannot infer an appropriate lifetime due to conflicting requirements
     {
         let slice: &mut [_] = &mut out;
         slice[0] = y;
     }
     out[0]
+    //~^ ERROR 19:5: 19:11: explicit lifetime required in the type of `y` [E0621]
 }
 
 struct Struct<T, U: ?Sized> {
@@ -27,12 +27,12 @@ struct Struct<T, U: ?Sized> {
 
 fn lifetime_transmute_struct<'a, T: ?Sized>(x: &'a T, y: &T) -> &'a T {
     let mut out = Struct { head: x, _tail: [()] };
-    //~^ ERROR cannot infer an appropriate lifetime due to conflicting requirements
     {
         let dst: &mut Struct<_, [()]> = &mut out;
         dst.head = y;
     }
     out.head
+    //~^ ERROR 34:5: 34:13: explicit lifetime required in the type of `y` [E0621]
 }
 
 fn main() {

src/test/compile-fail/object-lifetime-default-from-box-error.rs

@@ -38,7 +38,7 @@ fn store(ss: &mut SomeStruct, b: Box<SomeTrait>) {
 fn store1<'b>(ss: &mut SomeStruct, b: Box<SomeTrait+'b>) {
     // Here we override the lifetimes explicitly, and so naturally we get an error.
 
-    ss.r = b; //~ ERROR cannot infer an appropriate lifetime
+    ss.r = b; //~ ERROR 41:12: 41:13: explicit lifetime required in the type of `ss` [E0621]
 }
 
 fn main() {

src/test/compile-fail/region-lifetime-bounds-on-fns-where-clause.rs

@@ -21,7 +21,7 @@ fn b<'a, 'b>(x: &mut &'a isize, y: &mut &'b isize) {
 fn c<'a,'b>(x: &mut &'a isize, y: &mut &'b isize) {
     // Here we try to call `foo` but do not know that `'a` and `'b` are
     // related as required.
-    a(x, y); //~ ERROR cannot infer
+    a(x, y); //~ ERROR 24:7: 24:8: lifetime mismatch [E0623]
 }
 
 fn d() {