Rollup merge of rust-lang#155900 - theemathas:fndef-is-function-item, r=Kivooeo

Refer to `FnDef` as "function item", not "function pointer"

Author: jhpratt

compiler/rustc_borrowck/src/diagnostics/region_errors.rs

@@ -533,7 +533,7 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
                     ty::FnDef(def_id, _) => {
                         let name = self.infcx.tcx.item_name(*def_id);
                         let identity_args = GenericArgs::identity_for_item(self.infcx.tcx, *def_id);
-                        let desc = format!("a function pointer to `{name}`");
+                        let desc = format!("the function item type defined by `{name}`");
                         let note = format!(
                             "the function `{name}` is invariant over the parameter `{}`",
                             identity_args[param_index as usize]

tests/ui/fn/fn_def_coercion.stderr

@@ -9,7 +9,7 @@ LL |     let mut x = foo::<&'a ()>;
    |                 ^^^^^^^^^^^^^ assignment requires that `'b` must outlive `'a`
    |
    = help: consider adding the following bound: `'b: 'a`
-   = note: requirement occurs because of a function pointer to `foo`
+   = note: requirement occurs because of the function item type defined by `foo`
    = note: the function `foo` is invariant over the parameter `T`
    = help: see <https://doc.rust-lang.org/nomicon/subtyping.html> for more information about variance
 
@@ -25,7 +25,7 @@ LL |     x = foo::<&'b ()>;
    |     ^^^^^^^^^^^^^^^^^ assignment requires that `'a` must outlive `'b`
    |
    = help: consider adding the following bound: `'a: 'b`
-   = note: requirement occurs because of a function pointer to `foo`
+   = note: requirement occurs because of the function item type defined by `foo`
    = note: the function `foo` is invariant over the parameter `T`
    = help: see <https://doc.rust-lang.org/nomicon/subtyping.html> for more information about variance
 
@@ -56,7 +56,7 @@ LL |     x = foo::<&'b ()>;
    |     ^^^^^^^^^^^^^^^^^ assignment requires that `'a` must outlive `'b`
    |
    = help: consider adding the following bound: `'a: 'b`
-   = note: requirement occurs because of a function pointer to `foo`
+   = note: requirement occurs because of the function item type defined by `foo`
    = note: the function `foo` is invariant over the parameter `T`
    = help: see <https://doc.rust-lang.org/nomicon/subtyping.html> for more information about variance
 
@@ -72,7 +72,7 @@ LL |     x = foo::<&'a ()>;
    |     ^^^^^^^^^^^^^^^^^ assignment requires that `'b` must outlive `'a`
    |
    = help: consider adding the following bound: `'b: 'a`
-   = note: requirement occurs because of a function pointer to `foo`
+   = note: requirement occurs because of the function item type defined by `foo`
    = note: the function `foo` is invariant over the parameter `T`
    = help: see <https://doc.rust-lang.org/nomicon/subtyping.html> for more information about variance
 
@@ -92,7 +92,7 @@ LL |         true => foo::<&'b ()>,
    |                 ^^^^^^^^^^^^^ assignment requires that `'a` must outlive `'b`
    |
    = help: consider adding the following bound: `'a: 'b`
-   = note: requirement occurs because of a function pointer to `foo`
+   = note: requirement occurs because of the function item type defined by `foo`
    = note: the function `foo` is invariant over the parameter `T`
    = help: see <https://doc.rust-lang.org/nomicon/subtyping.html> for more information about variance
 
@@ -108,7 +108,7 @@ LL |         false => foo::<&'a ()>,
    |                  ^^^^^^^^^^^^^ assignment requires that `'b` must outlive `'a`
    |
    = help: consider adding the following bound: `'b: 'a`
-   = note: requirement occurs because of a function pointer to `foo`
+   = note: requirement occurs because of the function item type defined by `foo`
    = note: the function `foo` is invariant over the parameter `T`
    = help: see <https://doc.rust-lang.org/nomicon/subtyping.html> for more information about variance
 
@@ -128,7 +128,7 @@ LL |         true => foo::<&'c ()>,
    |                 ^^^^^^^^^^^^^ assignment requires that `'a` must outlive `'c`
    |
    = help: consider adding the following bound: `'a: 'c`
-   = note: requirement occurs because of a function pointer to `foo`
+   = note: requirement occurs because of the function item type defined by `foo`
    = note: the function `foo` is invariant over the parameter `T`
    = help: see <https://doc.rust-lang.org/nomicon/subtyping.html> for more information about variance
 
@@ -144,7 +144,7 @@ LL |         false => foo::<&'a ()>,
    |                  ^^^^^^^^^^^^^ assignment requires that `'b` must outlive `'a`
    |
    = help: consider adding the following bound: `'b: 'a`
-   = note: requirement occurs because of a function pointer to `foo`
+   = note: requirement occurs because of the function item type defined by `foo`
    = note: the function `foo` is invariant over the parameter `T`
    = help: see <https://doc.rust-lang.org/nomicon/subtyping.html> for more information about variance