Modify mutable deref rule for &mut T
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src/expressions.md
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| @@ -241,7 +241,7 @@ The following expressions can be mutable place expression contexts: | |||
| * [Temporary values]. | |||
| * [Fields][field]: this evaluates the subexpression in a mutable place expression context. | |||
| * [Dereferences][deref] of a `*mut T` pointer. | |||
| * Dereference of a variable, or field of a variable, with type `&mut T`. | |||
| * Dereference of a movable place, with type `&mut T`. This includes variables and their fields, as well as temporaries. | |||
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| * Dereference of a movable place, with type `&mut T`. This includes variables and their fields, as well as temporaries. | |
| * Dereference of a movable place with type `&mut T`. This includes variables and their fields, as well as temporaries. |
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We could add an internal link on "movable place" also.
traviscross
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Mar 20, 2025
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https://play.rust-lang.org/?version=stable&mode=debug&edition=2024 I checked something and this might be a bit trickerier. According to [expr.move.movable-place], |
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This indicates that any movable place expression of type
&mut Tcan be dereferenced to yield a mutable place.Presently the rule only lists variables and fields of variables. However, if a
&mut Tis contained within a movableBox, it is also valid to deref the&mut Tand use the resulting place mutably, even if theBoxwas immutable. See the following playgrounds:BoxvariableBoxvariable (correctly) does not yield a mutable place.