Simplify for loop desugar

src/test/ui/borrowck/return-local-binding-from-desugaring.rs

@@ -27,7 +27,7 @@ where
         let key = f(x);
         result.entry(key).or_insert(Vec::new()).push(x);
     }
-    result //~ ERROR cannot return value referencing local binding
+    result //~ ERROR cannot return value referencing temporary value
 }
 
 fn main() {}

src/test/ui/borrowck/return-local-binding-from-desugaring.stderr

@@ -1,8 +1,8 @@
-error[E0515]: cannot return value referencing local binding
+error[E0515]: cannot return value referencing temporary value
   --> $DIR/return-local-binding-from-desugaring.rs:30:5
    |
 LL |     for ref x in xs {
-   |                  -- local binding introduced here
+   |                  -- temporary value created here
 ...
 LL |     result
    |     ^^^^^^ returns a value referencing data owned by the current function

src/test/ui/for/for-loop-unconstrained-element-type.stderr

@@ -1,8 +1,10 @@
 error[E0282]: type annotations needed
-  --> $DIR/for-loop-unconstrained-element-type.rs:8:14
+  --> $DIR/for-loop-unconstrained-element-type.rs:8:9
    |
 LL |     for i in Vec::new() { }
-   |              ^^^^^^^^^^ the element type for this iterator is not specified
+   |         ^    ---------- the element type for this iterator is not specified
+   |         |
+   |         cannot infer type
 
 error: aborting due to previous error
 

src/test/ui/issues/issue-20261.stderr

@@ -1,8 +1,8 @@
-error[E0282]: type annotations needed for `&(_,)`
+error[E0282]: type annotations needed for `(_,)`
   --> $DIR/issue-20261.rs:4:11
    |
 LL |     for (ref i,) in [].iter() {
-   |                     --------- the element type for this iterator is not specified
+   |                     --------- this method call resolves to `std::slice::Iter<'_, T>`
 LL |         i.clone();
    |           ^^^^^ cannot infer type
    |

src/test/ui/issues/issue-33941.rs

@@ -3,5 +3,4 @@ use std::collections::HashMap;
 fn main() {
     for _ in HashMap::new().iter().cloned() {} //~ ERROR type mismatch
     //~^ ERROR type mismatch
-    //~| ERROR type mismatch
 }

src/test/ui/issues/issue-33941.stderr

@@ -23,16 +23,6 @@ LL |     for _ in HashMap::new().iter().cloned() {}
    = note: required because of the requirements on the impl of `Iterator` for `Cloned<std::collections::hash_map::Iter<'_, _, _>>`
    = note: required because of the requirements on the impl of `IntoIterator` for `Cloned<std::collections::hash_map::Iter<'_, _, _>>`
 
-error[E0271]: type mismatch resolving `<std::collections::hash_map::Iter<'_, _, _> as Iterator>::Item == &_`
-  --> $DIR/issue-33941.rs:4:14
-   |
-LL |     for _ in HashMap::new().iter().cloned() {}
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected reference, found tuple
-   |
-   = note: expected reference `&_`
-                  found tuple `(&_, &_)`
-   = note: required because of the requirements on the impl of `Iterator` for `Cloned<std::collections::hash_map::Iter<'_, _, _>>`
-
-error: aborting due to 3 previous errors
+error: aborting due to 2 previous errors
 
 For more information about this error, try `rustc --explain E0271`.

src/test/ui/nll/dont-print-desugared.stderr

@@ -2,7 +2,7 @@ error[E0596]: cannot borrow data in a `&` reference as mutable
   --> $DIR/dont-print-desugared.rs:4:10
    |
 LL |     for &ref mut x in s {}
-   |          ^^^^^^^^^ cannot borrow as mutable through `&` reference
+   |          ^^^^^^^^^ cannot borrow as mutable
 
 error[E0597]: `y` does not live long enough
   --> $DIR/dont-print-desugared.rs:17:16

src/test/ui/nll/issue-53773.stderr

@@ -2,12 +2,10 @@ error[E0713]: borrow may still be in use when destructor runs
   --> $DIR/issue-53773.rs:41:22
    |
 LL |         members.push(child.raw);
-   |                      ^^^^^^^^^
+   |         -------------^^^^^^^^^- borrow later used here
 LL |
 LL |     }
    |     - here, drop of `child` needs exclusive access to `*child.raw`, because the type `C<'_>` implements the `Drop` trait
-LL |     members.len();
-   |     ------------- borrow later used here
    |
    = note: consider using a `let` binding to create a longer lived value
 

src/test/ui/reachable/unreachable-loop-patterns.rs

@@ -17,5 +17,4 @@ impl Iterator for Void {
 fn main() {
     for _ in unimplemented!() as Void {}
     //~^ ERROR unreachable pattern
-    //~^^ ERROR unreachable pattern
 }

src/test/ui/reachable/unreachable-loop-patterns.stderr

@@ -10,11 +10,5 @@ note: the lint level is defined here
 LL | #![deny(unreachable_patterns)]
    |         ^^^^^^^^^^^^^^^^^^^^
 
-error: unreachable pattern
-  --> $DIR/unreachable-loop-patterns.rs:18:14
-   |
-LL |     for _ in unimplemented!() as Void {}
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^
-
-error: aborting due to 2 previous errors
+error: aborting due to previous error