Update tests

Author: GuillaumeGomez

src/test/compile-fail/coercion-slice.rs

@@ -14,6 +14,5 @@ fn main() {
     let _: &[i32] = [0];
     //~^ ERROR mismatched types
     //~| expected type `&[i32]`
-    //~| found type `[{integer}; 1]`
     //~| expected &[i32], found array of 1 elements
 }

src/test/compile-fail/cross-borrow-trait.rs

@@ -20,4 +20,6 @@ pub fn main() {
     let _y: &Trait = x; //~  ERROR mismatched types
                         //~| expected type `&Trait`
                         //~| found type `std::boxed::Box<Trait>`
+                        //~| expected &Trait, found box
+                        //~| ERROR the trait bound `Box<Trait>: Trait` is not satisfied
 }

src/test/compile-fail/dst-bad-coercions.rs

@@ -23,11 +23,13 @@ pub fn main() {
     let x: *const S = &S;
     let y: &S = x; //~ ERROR mismatched types
     let y: &T = x; //~ ERROR mismatched types
+                   //~^ ERROR the trait bound `*const S: T` is not satisfied
 
     // Test that we cannot convert from *-ptr to &S and &T (mut version)
     let x: *mut S = &mut S;
     let y: &S = x; //~ ERROR mismatched types
     let y: &T = x; //~ ERROR mismatched types
+                   //~^ ERROR the trait bound `*mut S: T` is not satisfied
 
     // Test that we cannot convert an immutable ptr to a mutable one using *-ptrs
     let x: &mut T = &S; //~ ERROR mismatched types

src/test/compile-fail/issue-13058.rs

@@ -35,4 +35,5 @@ fn check<'r, I: Iterator<Item=usize>, T: Itble<'r, usize, I>>(cont: &T) -> bool
 fn main() {
     check((3, 5));
 //~^ ERROR mismatched types
+//~| HELP try with `&(3, 5)`
 }