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

24 files changed, 58 insertions, 30 deletions

diff --git a/src/test/ui/error-codes/E0277.stderr b/src/test/ui/error-codes/E0277.stderr
index 1f54af4d154..dea0bb259f5 100644
--- a/src/test/ui/error-codes/E0277.stderr
+++ b/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
diff --git a/src/test/ui/feature-gates/feature-gate-unsized_fn_params.stderr b/src/test/ui/feature-gates/feature-gate-unsized_fn_params.stderr
index 71acbb174ac..3631a03938a 100644
--- a/src/test/ui/feature-gates/feature-gate-unsized_fn_params.stderr
+++ b/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
diff --git a/src/test/ui/feature-gates/feature-gate-unsized_locals.stderr b/src/test/ui/feature-gates/feature-gate-unsized_locals.stderr
index 52254220872..0919c2f3a1e 100644
--- a/src/test/ui/feature-gates/feature-gate-unsized_locals.stderr
+++ b/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
 
diff --git a/src/test/ui/issues/issue-5883.rs b/src/test/ui/issues/issue-5883.rs
index 0de53502397..82866b35557 100644
--- a/src/test/ui/issues/issue-5883.rs
+++ b/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 }
 }
 
diff --git a/src/test/ui/issues/issue-5883.stderr b/src/test/ui/issues/issue-5883.stderr
index 48879eb798f..de598a70ee0 100644
--- a/src/test/ui/issues/issue-5883.stderr
+++ b/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`
    |
diff --git a/src/test/ui/resolve/issue-5035-2.stderr b/src/test/ui/resolve/issue-5035-2.stderr
index b2084a7a426..e94877fded7 100644
--- a/src/test/ui/resolve/issue-5035-2.stderr
+++ b/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
 
diff --git a/src/test/ui/suggestions/path-by-value.stderr b/src/test/ui/suggestions/path-by-value.stderr
index 19fc3406ccf..5919a6f7492 100644
--- a/src/test/ui/suggestions/path-by-value.stderr
+++ b/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
 
diff --git a/src/test/ui/traits/bound/not-on-bare-trait.stderr b/src/test/ui/traits/bound/not-on-bare-trait.stderr
index e7fc0fa5ec0..b8ae88ace02 100644
--- a/src/test/ui/traits/bound/not-on-bare-trait.stderr
+++ b/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
 
diff --git a/src/test/ui/unsized/unsized-fn-arg.fixed b/src/test/ui/unsized/unsized-fn-arg.fixed
new file mode 100644
index 00000000000..2c686c6c2b2
--- /dev/null
+++ b/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
diff --git a/src/test/ui/unsized/unsized-fn-arg.rs b/src/test/ui/unsized/unsized-fn-arg.rs
new file mode 100644
index 00000000000..9fc08bd6d3e
--- /dev/null
+++ b/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
diff --git a/src/test/ui/unsized/unsized-fn-arg.stderr b/src/test/ui/unsized/unsized-fn-arg.stderr
new file mode 100644
index 00000000000..6b802ddf542
--- /dev/null
+++ b/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`.
diff --git a/src/test/ui/unsized-tuple-impls.rs b/src/test/ui/unsized/unsized-tuple-impls.rs
index 5e385f33bee..5e385f33bee 100644
--- a/src/test/ui/unsized-tuple-impls.rs
+++ b/src/test/ui/unsized/unsized-tuple-impls.rs
diff --git a/src/test/ui/unsized.rs b/src/test/ui/unsized/unsized.rs
index 54304834d4b..54304834d4b 100644
--- a/src/test/ui/unsized.rs
+++ b/src/test/ui/unsized/unsized.rs
diff --git a/src/test/ui/unsized2.rs b/src/test/ui/unsized/unsized2.rs
index be4406399fd..be4406399fd 100644
--- a/src/test/ui/unsized2.rs
+++ b/src/test/ui/unsized/unsized2.rs
diff --git a/src/test/ui/unsized3-rpass.rs b/src/test/ui/unsized/unsized3-rpass.rs
index 65efbd6b520..65efbd6b520 100644
--- a/src/test/ui/unsized3-rpass.rs
+++ b/src/test/ui/unsized/unsized3-rpass.rs
diff --git a/src/test/ui/unsized3.rs b/src/test/ui/unsized/unsized3.rs
index f5b5d025931..f5b5d025931 100644
--- a/src/test/ui/unsized3.rs
+++ b/src/test/ui/unsized/unsized3.rs
diff --git a/src/test/ui/unsized3.stderr b/src/test/ui/unsized/unsized3.stderr
index bd36008aca0..bd36008aca0 100644
--- a/src/test/ui/unsized3.stderr
+++ b/src/test/ui/unsized/unsized3.stderr
diff --git a/src/test/ui/unsized5.rs b/src/test/ui/unsized/unsized5.rs
index befd2244d97..befd2244d97 100644
--- a/src/test/ui/unsized5.rs
+++ b/src/test/ui/unsized/unsized5.rs
diff --git a/src/test/ui/unsized5.stderr b/src/test/ui/unsized/unsized5.stderr
index 0bfd4565529..0bfd4565529 100644
--- a/src/test/ui/unsized5.stderr
+++ b/src/test/ui/unsized/unsized5.stderr
diff --git a/src/test/ui/unsized6.rs b/src/test/ui/unsized/unsized6.rs
index 79133554d54..79133554d54 100644
--- a/src/test/ui/unsized6.rs
+++ b/src/test/ui/unsized/unsized6.rs
diff --git a/src/test/ui/unsized6.stderr b/src/test/ui/unsized/unsized6.stderr
index f9f7877d542..8e5734dffb1 100644
--- a/src/test/ui/unsized6.stderr
+++ b/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
 
diff --git a/src/test/ui/unsized7.rs b/src/test/ui/unsized/unsized7.rs
index 422a784814e..422a784814e 100644
--- a/src/test/ui/unsized7.rs
+++ b/src/test/ui/unsized/unsized7.rs
diff --git a/src/test/ui/unsized7.stderr b/src/test/ui/unsized/unsized7.stderr
index 7dbddd4ed24..7dbddd4ed24 100644
--- a/src/test/ui/unsized7.stderr
+++ b/src/test/ui/unsized/unsized7.stderr
diff --git a/src/tools/clippy/tests/ui/crashes/ice-6251.stderr b/src/tools/clippy/tests/ui/crashes/ice-6251.stderr
index 9a7cf4b0919..8498c040780 100644
--- a/src/tools/clippy/tests/ui/crashes/ice-6251.stderr
+++ b/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