Change & pat to only work with &T, and &mut with &mut T.#20554
Merged
bors merged 1 commit intorust-lang:masterfrom Jan 6, 2015
Merged
Change & pat to only work with &T, and &mut with &mut T.#20554bors merged 1 commit intorust-lang:masterfrom
& pat to only work with &T, and &mut with &mut T.#20554bors merged 1 commit intorust-lang:masterfrom
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Could you add a test to check that after let &mut x = ..., x is not actually mutable (unless it is let mut &mut x, I guess).
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r=me with the extra test |
This implements RFC 179 by making the pattern `&<pat>` require matching
against a variable of type `&T`, and introducing the pattern `&mut
<pat>` which only works with variables of type `&mut T`.
The pattern `&mut x` currently parses as `&(mut x)` i.e. a pattern match
through a `&T` or a `&mut T` that binds the variable `x` to have type
`T` and to be mutable. This should be rewritten as follows, for example,
for &mut x in slice.iter() {
becomes
for &x in slice.iter() {
let mut x = x;
Due to this, this is a
[breaking-change]
Closes rust-lang#20496.
alexcrichton
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Jan 5, 2015
Conflicts: src/librustc_typeck/check/_match.rs
alexcrichton
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Jan 6, 2015
Conflicts: src/librustc_typeck/check/_match.rs
lnicola
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Oct 27, 2025
Improvements for resolving the value of the `env!` macro
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This implements RFC 179 by making the pattern
&<pat>require matchingagainst a variable of type
&T, and introducing the pattern&mut <pat>which only works with variables of type&mut T.The pattern
&mut xcurrently parses as&(mut x)i.e. a pattern matchthrough a
&Tor a&mut Tthat binds the variablexto have typeTand to be mutable. This should be rewritten as follows, for example,becomes
Due to this, this is a
[breaking-change]
Closes #20496.