Remove caveats related to `format_args!` expansion
The behavior of `format_args!`, with respect to `super let`, had some
caveats that we can remove now that Rust [#145880] has landed, so
let's remove our remarks on that and simplify the tests accordingly.
[#145880]: https://github.com/rust-lang/rust/issues/145880
diff --git a/src/destructors.md b/src/destructors.md
index bc5c58b..1598064 100644
--- a/src/destructors.md
+++ b/src/destructors.md
@@ -540,9 +540,7 @@
# x;
let x = pin!({ &mut temp() }); // As above.
# x;
-# // FIXME: Simplify after this PR lands:
-# // <https://github.com/rust-lang/rust/pull/145882>.
-let x = format_args!("{:?}{:?}", (), temp()); // As above.
+let x = format_args!("{:?}", temp()); // As above.
# x;
//
// All of the temporaries above are still live here.
@@ -613,11 +611,10 @@
pin!({ &temp() }); // ERROR
```
-<!-- FIXME: Simplify after https://github.com/rust-lang/rust/pull/145882 lands. -->
```rust,edition2024,compile_fail,E0716
# fn temp() {}
// As above.
-format_args!("{:?}{:?}", (), { &temp() }); // ERROR
+format_args!("{:?}", { &temp() }); // ERROR
```
r[destructors.forget]
diff --git a/src/expressions.md b/src/expressions.md
index 4287454..6d8d6cf 100644
--- a/src/expressions.md
+++ b/src/expressions.md
@@ -270,30 +270,22 @@
r[expr.super-macros.format_args.super-operands]
Except for the format string argument, all arguments passed to [`format_args!`] are *super operands*.
-<!-- FIXME: Remove after https://github.com/rust-lang/rust/pull/145882 lands. -->
-> [!NOTE]
-> When there is only one placeholder, `rustc` does not yet treat the corresponding argument as a super operand. This is a bug.
->
-> For details, see Rust issue [#145880](https://github.com/rust-lang/rust/issues/145880).
-
-<!-- FIXME: Simplify after https://github.com/rust-lang/rust/pull/145882 lands. -->
```rust,edition2024
# fn temp() -> String { String::from("") }
// Due to the call being an extending expression and the argument
// being a super operand, the inner block is an extending expression,
// so the scope of the temporary created in its trailing expression
// is extended.
-let _ = format_args!("{:?}{}", (), { &temp() }); // OK
+let _ = format_args!("{}", { &temp() }); // OK
```
r[expr.super-macros.format_args.super-temporaries]
The super operands of [`format_args!`] are [implicitly borrowed] and are therefore [place expression contexts]. When a [value expression] is passed as an argument, it creates a *super temporary*.
-<!-- FIXME: Simplify after https://github.com/rust-lang/rust/pull/145882 lands. -->
```rust
# fn temp() -> String { String::from("") }
-let x = format_args!("{}{}", temp(), temp());
-x; // <-- The temporaries are extended, allowing use here.
+let x = format_args!("{}", temp());
+x; // <-- The temporary is extended, allowing use here.
```
The expansion of a call to [`format_args!`] sometimes creates other internal *super temporaries*.
