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Add allocator parameter to HashMap #148545

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fe8a541
Add allocator parameter to HashMap
cramertj Nov 5, 2025
0298d44
Update UI tests for addition of HashMap allocator
cramertj Nov 5, 2025
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289 changes: 216 additions & 73 deletions library/std/src/collections/hash/map.rs
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4 changes: 0 additions & 4 deletions tests/ui/generics/wrong-number-of-args.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -321,10 +321,6 @@ mod stdlib {
//~| ERROR struct takes at least 2
//~| HELP add missing

type D = HashMap<usize, String, char, f64>;
//~^ ERROR struct takes at most 3
//~| HELP remove the

type E = HashMap<>;
//~^ ERROR struct takes at least 2 generic arguments but 0 generic arguments
//~| HELP add missing
Expand Down
24 changes: 8 additions & 16 deletions tests/ui/generics/wrong-number-of-args.stderr
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Expand Up @@ -926,16 +926,8 @@ help: add missing generic arguments
LL | type C = HashMap<'static, K, V>;
| ++++++

error[E0107]: struct takes at most 3 generic arguments but 4 generic arguments were supplied
--> $DIR/wrong-number-of-args.rs:324:18
|
LL | type D = HashMap<usize, String, char, f64>;
| ^^^^^^^ ----- help: remove the unnecessary generic argument
| |
| expected at most 3 generic arguments

error[E0107]: struct takes at least 2 generic arguments but 0 generic arguments were supplied
--> $DIR/wrong-number-of-args.rs:328:18
--> $DIR/wrong-number-of-args.rs:324:18
|
LL | type E = HashMap<>;
| ^^^^^^^ expected at least 2 generic arguments
Expand All @@ -946,7 +938,7 @@ LL | type E = HashMap<K, V>;
| ++++

error[E0107]: missing generics for enum `Result`
--> $DIR/wrong-number-of-args.rs:334:18
--> $DIR/wrong-number-of-args.rs:330:18
|
LL | type A = Result;
| ^^^^^^ expected 2 generic arguments
Expand All @@ -957,7 +949,7 @@ LL | type A = Result<T, E>;
| ++++++

error[E0107]: enum takes 2 generic arguments but 1 generic argument was supplied
--> $DIR/wrong-number-of-args.rs:338:18
--> $DIR/wrong-number-of-args.rs:334:18
|
LL | type B = Result<String>;
| ^^^^^^ ------ supplied 1 generic argument
Expand All @@ -970,15 +962,15 @@ LL | type B = Result<String, E>;
| +++

error[E0107]: enum takes 0 lifetime arguments but 1 lifetime argument was supplied
--> $DIR/wrong-number-of-args.rs:342:18
--> $DIR/wrong-number-of-args.rs:338:18
|
LL | type C = Result<'static>;
| ^^^^^^--------- help: remove the unnecessary generics
| |
| expected 0 lifetime arguments

error[E0107]: enum takes 2 generic arguments but 0 generic arguments were supplied
--> $DIR/wrong-number-of-args.rs:342:18
--> $DIR/wrong-number-of-args.rs:338:18
|
LL | type C = Result<'static>;
| ^^^^^^ expected 2 generic arguments
Expand All @@ -989,15 +981,15 @@ LL | type C = Result<'static, T, E>;
| ++++++

error[E0107]: enum takes 2 generic arguments but 3 generic arguments were supplied
--> $DIR/wrong-number-of-args.rs:348:18
--> $DIR/wrong-number-of-args.rs:344:18
|
LL | type D = Result<usize, String, char>;
| ^^^^^^ ------ help: remove the unnecessary generic argument
| |
| expected 2 generic arguments

error[E0107]: enum takes 2 generic arguments but 0 generic arguments were supplied
--> $DIR/wrong-number-of-args.rs:352:18
--> $DIR/wrong-number-of-args.rs:348:18
|
LL | type E = Result<>;
| ^^^^^^ expected 2 generic arguments
Expand All @@ -1007,7 +999,7 @@ help: add missing generic arguments
LL | type E = Result<T, E>;
| ++++

error: aborting due to 71 previous errors
error: aborting due to 70 previous errors

Some errors have detailed explanations: E0106, E0107.
For more information about an error, try `rustc --explain E0106`.
2 changes: 1 addition & 1 deletion tests/ui/inference/issue-71732.stderr
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Expand Up @@ -10,7 +10,7 @@ LL | .get(&"key".into())
- impl Borrow<str> for String;
- impl<T> Borrow<T> for T
where T: ?Sized;
note: required by a bound in `HashMap::<K, V, S>::get`
note: required by a bound in `HashMap::<K, V, S, A>::get`
--> $SRC_DIR/std/src/collections/hash/map.rs:LL:COL
help: consider specifying the generic argument
|
Expand Down
2 changes: 1 addition & 1 deletion tests/ui/moves/suggest-clone-when-some-obligation-is-unmet.stderr
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Expand Up @@ -6,7 +6,7 @@ LL | let mut copy: Vec<U> = map.clone().into_values().collect();
| |
| move occurs because value has type `HashMap<T, U, Hash128_1>`, which does not implement the `Copy` trait
|
note: `HashMap::<K, V, S>::into_values` takes ownership of the receiver `self`, which moves value
note: `HashMap::<K, V, S, A>::into_values` takes ownership of the receiver `self`, which moves value
--> $SRC_DIR/std/src/collections/hash/map.rs:LL:COL
note: if `Hash128_1` implemented `Clone`, you could clone the value
--> $DIR/suggest-clone-when-some-obligation-is-unmet.rs:8:1
Expand Down
2 changes: 1 addition & 1 deletion tests/ui/privacy/suggest-box-new.rs
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Expand Up @@ -14,7 +14,7 @@ fn main() {
let _ = std::collections::HashMap();
//~^ ERROR expected function, tuple struct or tuple variant, found struct `std::collections::HashMap`
let _ = std::collections::HashMap {};
//~^ ERROR cannot construct `HashMap<_, _, _>` with struct literal syntax due to private fields
//~^ ERROR cannot construct `HashMap<_, _, _, _>` with struct literal syntax due to private fields
let _ = Box {}; //~ ERROR cannot construct `Box<_, _>` with struct literal syntax due to private fields

// test that we properly instantiate the parameter of `Box::<T>::new` with an inference variable
Expand Down
21 changes: 12 additions & 9 deletions tests/ui/privacy/suggest-box-new.stderr
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@@ -1,25 +1,27 @@
error[E0423]: expected function, tuple struct or tuple variant, found struct `std::collections::HashMap`
--> $DIR/suggest-box-new.rs:14:13
|
LL | let _ = std::collections::HashMap();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^
LL | let _ = std::collections::HashMap();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
--> $SRC_DIR/std/src/collections/hash/map.rs:LL:COL
::: $SRC_DIR/std/src/collections/hash/map.rs:LL:COL
|
= note: `std::collections::HashMap` defined here
help: you might have meant to use an associated function to build this type
|
LL | let _ = std::collections::HashMap::new();
| +++++
LL - let _ = std::collections::HashMap();
LL + let _ = std::collections::HashMap::with_capacity(_);
LL + let _ = std::collections::HashMap::new_in(_);
|
LL - let _ = std::collections::HashMap();
LL + let _ = std::collections::HashMap::with_hasher(_);
LL + let _ = std::collections::HashMap::with_capacity(_);
|
LL - let _ = std::collections::HashMap();
LL + let _ = std::collections::HashMap::with_capacity_and_hasher(_, _);
LL + let _ = std::collections::HashMap::with_capacity_in(_, _);
|
= and 4 other candidates
help: consider using the `Default` trait
|
LL | let _ = <std::collections::HashMap as std::default::Default>::default();
Expand Down Expand Up @@ -70,7 +72,7 @@ LL - wtf: Some(Box(U {
LL + wtf: Some(<Box as std::default::Default>::default()),
|

error: cannot construct `HashMap<_, _, _>` with struct literal syntax due to private fields
error: cannot construct `HashMap<_, _, _, _>` with struct literal syntax due to private fields
--> $DIR/suggest-box-new.rs:16:13
|
LL | let _ = std::collections::HashMap {};
Expand All @@ -83,14 +85,15 @@ LL - let _ = std::collections::HashMap {};
LL + let _ = std::collections::HashMap::new();
|
LL - let _ = std::collections::HashMap {};
LL + let _ = std::collections::HashMap::with_capacity(_);
LL + let _ = std::collections::HashMap::new_in(_);
|
LL - let _ = std::collections::HashMap {};
LL + let _ = std::collections::HashMap::with_hasher(_);
LL + let _ = std::collections::HashMap::with_capacity(_);
|
LL - let _ = std::collections::HashMap {};
LL + let _ = std::collections::HashMap::with_capacity_and_hasher(_, _);
LL + let _ = std::collections::HashMap::with_capacity_in(_, _);
|
= and 4 other candidates
help: consider using the `Default` trait
|
LL - let _ = std::collections::HashMap {};
Expand Down
21 changes: 12 additions & 9 deletions tests/ui/suggestions/multi-suggestion.ascii.stderr
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Original file line number Diff line number Diff line change
@@ -1,25 +1,27 @@
error[E0423]: expected function, tuple struct or tuple variant, found struct `std::collections::HashMap`
--> $DIR/multi-suggestion.rs:17:13
|
LL | let _ = std::collections::HashMap();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^
LL | let _ = std::collections::HashMap();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
--> $SRC_DIR/std/src/collections/hash/map.rs:LL:COL
::: $SRC_DIR/std/src/collections/hash/map.rs:LL:COL
|
= note: `std::collections::HashMap` defined here
help: you might have meant to use an associated function to build this type
|
LL | let _ = std::collections::HashMap::new();
| +++++
LL - let _ = std::collections::HashMap();
LL + let _ = std::collections::HashMap::with_capacity(_);
LL + let _ = std::collections::HashMap::new_in(_);
|
LL - let _ = std::collections::HashMap();
LL + let _ = std::collections::HashMap::with_hasher(_);
LL + let _ = std::collections::HashMap::with_capacity(_);
|
LL - let _ = std::collections::HashMap();
LL + let _ = std::collections::HashMap::with_capacity_and_hasher(_, _);
LL + let _ = std::collections::HashMap::with_capacity_in(_, _);
|
= and 4 other candidates
help: consider using the `Default` trait
|
LL | let _ = <std::collections::HashMap as std::default::Default>::default();
Expand Down Expand Up @@ -70,7 +72,7 @@ LL - wtf: Some(Box(U {
LL + wtf: Some(<Box as std::default::Default>::default()),
|

error: cannot construct `HashMap<_, _, _>` with struct literal syntax due to private fields
error: cannot construct `HashMap<_, _, _, _>` with struct literal syntax due to private fields
--> $DIR/multi-suggestion.rs:19:13
|
LL | let _ = std::collections::HashMap {};
Expand All @@ -83,14 +85,15 @@ LL - let _ = std::collections::HashMap {};
LL + let _ = std::collections::HashMap::new();
|
LL - let _ = std::collections::HashMap {};
LL + let _ = std::collections::HashMap::with_capacity(_);
LL + let _ = std::collections::HashMap::new_in(_);
|
LL - let _ = std::collections::HashMap {};
LL + let _ = std::collections::HashMap::with_hasher(_);
LL + let _ = std::collections::HashMap::with_capacity(_);
|
LL - let _ = std::collections::HashMap {};
LL + let _ = std::collections::HashMap::with_capacity_and_hasher(_, _);
LL + let _ = std::collections::HashMap::with_capacity_in(_, _);
|
= and 4 other candidates
help: consider using the `Default` trait
|
LL - let _ = std::collections::HashMap {};
Expand Down
2 changes: 1 addition & 1 deletion tests/ui/suggestions/multi-suggestion.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -17,6 +17,6 @@ fn main() {
let _ = std::collections::HashMap();
//[ascii]~^ ERROR expected function, tuple struct or tuple variant, found struct `std::collections::HashMap`
let _ = std::collections::HashMap {};
//[ascii]~^ ERROR cannot construct `HashMap<_, _, _>` with struct literal syntax due to private fields
//[ascii]~^ ERROR cannot construct `HashMap<_, _, _, _>` with struct literal syntax due to private fields
let _ = Box {}; //[ascii]~ ERROR cannot construct `Box<_, _>` with struct literal syntax due to private fields
}
25 changes: 14 additions & 11 deletions tests/ui/suggestions/multi-suggestion.unicode.stderr
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Original file line number Diff line number Diff line change
@@ -1,25 +1,27 @@
error[E0423]: expected function, tuple struct or tuple variant, found struct `std::collections::HashMap`
╭▸ $DIR/multi-suggestion.rs:17:13
│
LL │ let _ = std::collections::HashMap();
│ ━━━━━━━━━━━━━━━━━━━━━━━━━━━
LL │ let _ = std::collections::HashMap();
│ ━━━━━━━━━━━━━━━━━━━━━━━━━━━
╰╴
╭▸ $SRC_DIR/std/src/collections/hash/map.rs:LL:COL
⸬ $SRC_DIR/std/src/collections/hash/map.rs:LL:COL
│
╰ note: `std::collections::HashMap` defined here
help: you might have meant to use an associated function to build this type
╭╴
LL │ let _ = std::collections::HashMap::new();
├╴ +++++
LL - let _ = std::collections::HashMap();
LL + let _ = std::collections::HashMap::with_capacity(_);
LL + let _ = std::collections::HashMap::new_in(_);
├╴
LL - let _ = std::collections::HashMap();
LL + let _ = std::collections::HashMap::with_hasher(_);
LL + let _ = std::collections::HashMap::with_capacity(_);
├╴
LL - let _ = std::collections::HashMap();
LL + let _ = std::collections::HashMap::with_capacity_and_hasher(_, _);
╰╴
LL + let _ = std::collections::HashMap::with_capacity_in(_, _);
│
╰ and 4 other candidates
help: consider using the `Default` trait
╭╴
LL │ let _ = <std::collections::HashMap as std::default::Default>::default();
Expand Down Expand Up @@ -70,7 +72,7 @@ LL - wtf: Some(Box(U {
LL + wtf: Some(<Box as std::default::Default>::default()),
╰╴

error: cannot construct `HashMap<_, _, _>` with struct literal syntax due to private fields
error: cannot construct `HashMap<_, _, _, _>` with struct literal syntax due to private fields
╭▸ $DIR/multi-suggestion.rs:19:13
│
LL │ let _ = std::collections::HashMap {};
Expand All @@ -83,14 +85,15 @@ LL - let _ = std::collections::HashMap {};
LL + let _ = std::collections::HashMap::new();
├╴
LL - let _ = std::collections::HashMap {};
LL + let _ = std::collections::HashMap::with_capacity(_);
LL + let _ = std::collections::HashMap::new_in(_);
├╴
LL - let _ = std::collections::HashMap {};
LL + let _ = std::collections::HashMap::with_hasher(_);
LL + let _ = std::collections::HashMap::with_capacity(_);
├╴
LL - let _ = std::collections::HashMap {};
LL + let _ = std::collections::HashMap::with_capacity_and_hasher(_, _);
╰╴
LL + let _ = std::collections::HashMap::with_capacity_in(_, _);
│
╰ and 4 other candidates
help: consider using the `Default` trait
╭╴
LL - let _ = std::collections::HashMap {};
Expand Down
2 changes: 1 addition & 1 deletion tests/ui/traits/issue-77982.stderr
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Expand Up @@ -10,7 +10,7 @@ LL | opts.get(opt.as_ref());
- impl Borrow<str> for String;
- impl<T> Borrow<T> for T
where T: ?Sized;
note: required by a bound in `HashMap::<K, V, S>::get`
note: required by a bound in `HashMap::<K, V, S, A>::get`
--> $SRC_DIR/std/src/collections/hash/map.rs:LL:COL
help: consider specifying the generic argument
|
Expand Down
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