Rollup merge of #84313 - lcnr:sized-err-msg, r=petrochenkov

fix suggestion for unsized function parameters

taken from `@fasterthanlime's` article https://fasterthanli.me/articles/whats-in-the-box

src/test/ui/error-codes/E0277.stderr

@@ -9,8 +9,8 @@ LL | fn f(p: Path) { }
    = help: unsized fn params are gated as an unstable feature
 help: function arguments must have a statically known size, borrowed types always have a known size
    |
-LL | fn f(&p: Path) { }
-   |      ^
+LL | fn f(p: &Path) { }
+   |         ^
 
 error[E0277]: the trait bound `i32: Foo` is not satisfied
   --> $DIR/E0277.rs:15:15

src/test/ui/feature-gates/feature-gate-unsized_fn_params.stderr

@@ -8,8 +8,8 @@ LL | fn foo(x: dyn Foo) {
    = help: unsized fn params are gated as an unstable feature
 help: function arguments must have a statically known size, borrowed types always have a known size
    |
-LL | fn foo(&x: dyn Foo) {
-   |        ^
+LL | fn foo(x: &dyn Foo) {
+   |           ^
 
 error[E0277]: the size for values of type `(dyn Foo + 'static)` cannot be known at compilation time
   --> $DIR/feature-gate-unsized_fn_params.rs:24:5

src/test/ui/feature-gates/feature-gate-unsized_locals.stderr

@@ -8,8 +8,8 @@ LL | fn f(f: dyn FnOnce()) {}
    = help: unsized fn params are gated as an unstable feature
 help: function arguments must have a statically known size, borrowed types always have a known size
    |
-LL | fn f(&f: dyn FnOnce()) {}
-   |      ^
+LL | fn f(f: &dyn FnOnce()) {}
+   |         ^
 
 error: aborting due to previous error
 

src/test/ui/issues/issue-5883.rs

@@ -4,9 +4,9 @@ struct Struct {
     r: dyn A + 'static
 }
 
-fn new_struct(r: dyn A + 'static)
-    -> Struct { //~^ ERROR the size for values of type
-    //~^ ERROR the size for values of type
+fn new_struct(
+    r: dyn A + 'static //~ ERROR the size for values of type
+) -> Struct {          //~ ERROR the size for values of type
     Struct { r: r }
 }
 

src/test/ui/issues/issue-5883.stderr

@@ -1,22 +1,21 @@
 error[E0277]: the size for values of type `(dyn A + 'static)` cannot be known at compilation time
-  --> $DIR/issue-5883.rs:7:15
+  --> $DIR/issue-5883.rs:8:5
    |
-LL | fn new_struct(r: dyn A + 'static)
-   |               ^ doesn't have a size known at compile-time
+LL |     r: dyn A + 'static
+   |     ^ doesn't have a size known at compile-time
    |
    = help: the trait `Sized` is not implemented for `(dyn A + 'static)`
    = help: unsized fn params are gated as an unstable feature
 help: function arguments must have a statically known size, borrowed types always have a known size
    |
-LL | fn new_struct(&r: dyn A + 'static)
-   |               ^
+LL |     r: &dyn A + 'static
+   |        ^
 
 error[E0277]: the size for values of type `(dyn A + 'static)` cannot be known at compilation time
-  --> $DIR/issue-5883.rs:8:8
+  --> $DIR/issue-5883.rs:9:6
    |
-LL |     -> Struct {
-   |        ^^^^^^ doesn't have a size known at compile-time
-LL |
+LL | ) -> Struct {
+   |      ^^^^^^ doesn't have a size known at compile-time
 LL |     Struct { r: r }
    |     --------------- this returned value is of type `Struct`
    |

src/test/ui/resolve/issue-5035-2.stderr

@@ -8,8 +8,8 @@ LL | fn foo(_x: K) {}
    = help: unsized fn params are gated as an unstable feature
 help: function arguments must have a statically known size, borrowed types always have a known size
    |
-LL | fn foo(&_x: K) {}
-   |        ^
+LL | fn foo(_x: &K) {}
+   |            ^
 
 error: aborting due to previous error
 

src/test/ui/suggestions/path-by-value.stderr

@@ -9,8 +9,8 @@ LL | fn f(p: Path) { }
    = help: unsized fn params are gated as an unstable feature
 help: function arguments must have a statically known size, borrowed types always have a known size
    |
-LL | fn f(&p: Path) { }
-   |      ^
+LL | fn f(p: &Path) { }
+   |         ^
 
 error: aborting due to previous error
 

src/test/ui/traits/bound/not-on-bare-trait.stderr

@@ -16,8 +16,8 @@ LL | fn foo(_x: Foo + Send) {
    = help: unsized fn params are gated as an unstable feature
 help: function arguments must have a statically known size, borrowed types always have a known size
    |
-LL | fn foo(&_x: Foo + Send) {
-   |        ^
+LL | fn foo(_x: &Foo + Send) {
+   |            ^
 
 error: aborting due to previous error; 1 warning emitted
 

src/test/ui/unsized/unsized-fn-arg.fixed

@@ -0,0 +1,6 @@
+// run-rustfix
+#![crate_type="lib"]
+#![allow(unused)]
+
+fn f<T: ?Sized>(t: &T) {}
+//~^ ERROR the size for values of type `T` cannot be known at compilation time

src/test/ui/unsized/unsized-fn-arg.rs

@@ -0,0 +1,6 @@
+// run-rustfix
+#![crate_type="lib"]
+#![allow(unused)]
+
+fn f<T: ?Sized>(t: T) {}
+//~^ ERROR the size for values of type `T` cannot be known at compilation time

src/test/ui/unsized/unsized-fn-arg.stderr

@@ -0,0 +1,17 @@
+error[E0277]: the size for values of type `T` cannot be known at compilation time
+  --> $DIR/unsized-fn-arg.rs:5:17
+   |
+LL | fn f<T: ?Sized>(t: T) {}
+   |      -          ^ doesn't have a size known at compile-time
+   |      |
+   |      this type parameter needs to be `std::marker::Sized`
+   |
+   = help: unsized fn params are gated as an unstable feature
+help: function arguments must have a statically known size, borrowed types always have a known size
+   |
+LL | fn f<T: ?Sized>(t: &T) {}
+   |                    ^
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0277`.

src/test/ui/unsized/unsized6.stderr

@@ -135,8 +135,8 @@ LL | fn g1<X: ?Sized>(x: X) {}
    = help: unsized fn params are gated as an unstable feature
 help: function arguments must have a statically known size, borrowed types always have a known size
    |
-LL | fn g1<X: ?Sized>(&x: X) {}
-   |                  ^
+LL | fn g1<X: ?Sized>(x: &X) {}
+   |                     ^
 
 error[E0277]: the size for values of type `X` cannot be known at compilation time
   --> $DIR/unsized6.rs:40:22
@@ -149,8 +149,8 @@ LL | fn g2<X: ?Sized + T>(x: X) {}
    = help: unsized fn params are gated as an unstable feature
 help: function arguments must have a statically known size, borrowed types always have a known size
    |
-LL | fn g2<X: ?Sized + T>(&x: X) {}
-   |                      ^
+LL | fn g2<X: ?Sized + T>(x: &X) {}
+   |                         ^
 
 error: aborting due to 13 previous errors
 

src/tools/clippy/tests/ui/crashes/ice-6251.stderr

@@ -16,8 +16,8 @@ LL | fn bug<T>() -> impl Iterator<Item = [(); { |x: [u8]| x }]> {
    = help: unsized fn params are gated as an unstable feature
 help: function arguments must have a statically known size, borrowed types always have a known size
    |
-LL | fn bug<T>() -> impl Iterator<Item = [(); { |&x: [u8]| x }]> {
-   |                                             ^
+LL | fn bug<T>() -> impl Iterator<Item = [(); { |x: &[u8]| x }]> {
+   |                                                ^
 
 error[E0277]: the size for values of type `[u8]` cannot be known at compilation time
   --> $DIR/ice-6251.rs:4:54