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Merged
merged 1 commit into from
Jan 1, 2025
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Improve slow_vector_initialization suggestion #13912

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22 changes: 13 additions & 9 deletions clippy_lints/src/slow_vector_initialization.rs
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Original file line number Diff line number Diff line change
@@ -1,4 +1,4 @@
use clippy_utils::diagnostics::span_lint_and_then;
use clippy_utils::diagnostics::span_lint_and_sugg;
use clippy_utils::macros::matching_root_macro_call;
use clippy_utils::sugg::Sugg;
use clippy_utils::{
Expand Down Expand Up @@ -203,14 +203,18 @@ impl SlowVectorInit {
"len",
);

span_lint_and_then(cx, SLOW_VECTOR_INITIALIZATION, slow_fill.span, msg, |diag| {
diag.span_suggestion(
vec_alloc.allocation_expr.span.source_callsite(),
"consider replacing this with",
format!("vec![0; {len_expr}]"),
Applicability::Unspecified,
);
});
let span_to_replace = slow_fill
.span
.with_lo(vec_alloc.allocation_expr.span.source_callsite().lo());
span_lint_and_sugg(
cx,
SLOW_VECTOR_INITIALIZATION,
span_to_replace,
msg,
"consider replacing this with",
format!("vec![0; {len_expr}]"),
Applicability::Unspecified,
);
}
}

Expand Down
26 changes: 13 additions & 13 deletions tests/ui/slow_vector_initialization.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -11,22 +11,22 @@ fn extend_vector() {
// Extend with constant expression
let len = 300;
let mut vec1 = Vec::with_capacity(len);
vec1.extend(repeat(0).take(len));
//~^ ERROR: slow zero-filling initialization
//~| NOTE: `-D clippy::slow-vector-initialization` implied by `-D warnings`
vec1.extend(repeat(0).take(len));

// Extend with len expression
let mut vec2 = Vec::with_capacity(len - 10);
vec2.extend(repeat(0).take(len - 10));
//~^ ERROR: slow zero-filling initialization
vec2.extend(repeat(0).take(len - 10));

// Extend with mismatching expression should not be warned
let mut vec3 = Vec::with_capacity(24322);
vec3.extend(repeat(0).take(2));

let mut vec4 = Vec::with_capacity(len);
vec4.extend(repeat(0).take(vec4.capacity()));
//~^ ERROR: slow zero-filling initialization
vec4.extend(repeat(0).take(vec4.capacity()));
}

fn mixed_extend_resize_vector() {
Expand All @@ -36,60 +36,60 @@ fn mixed_extend_resize_vector() {

// Slow initialization
let mut resized_vec = Vec::with_capacity(30);
resized_vec.resize(30, 0);
//~^ ERROR: slow zero-filling initialization
resized_vec.resize(30, 0);

let mut extend_vec = Vec::with_capacity(30);
extend_vec.extend(repeat(0).take(30));
//~^ ERROR: slow zero-filling initialization
extend_vec.extend(repeat(0).take(30));
}

fn resize_vector() {
// Resize with constant expression
let len = 300;
let mut vec1 = Vec::with_capacity(len);
vec1.resize(len, 0);
//~^ ERROR: slow zero-filling initialization
vec1.resize(len, 0);

// Resize mismatch len
let mut vec2 = Vec::with_capacity(200);
vec2.resize(10, 0);

// Resize with len expression
let mut vec3 = Vec::with_capacity(len - 10);
vec3.resize(len - 10, 0);
//~^ ERROR: slow zero-filling initialization
vec3.resize(len - 10, 0);

let mut vec4 = Vec::with_capacity(len);
vec4.resize(vec4.capacity(), 0);
//~^ ERROR: slow zero-filling initialization
vec4.resize(vec4.capacity(), 0);

// Reinitialization should be warned
vec1 = Vec::with_capacity(10);
vec1.resize(10, 0);
//~^ ERROR: slow zero-filling initialization
vec1.resize(10, 0);
}

fn from_empty_vec() {
// Resize with constant expression
let len = 300;
let mut vec1 = Vec::new();
vec1.resize(len, 0);
//~^ ERROR: slow zero-filling initialization
vec1.resize(len, 0);

// Resize with len expression
let mut vec3 = Vec::new();
vec3.resize(len - 10, 0);
//~^ ERROR: slow zero-filling initialization
vec3.resize(len - 10, 0);

// Reinitialization should be warned
vec1 = Vec::new();
vec1.resize(10, 0);
//~^ ERROR: slow zero-filling initialization
vec1.resize(10, 0);

vec1 = vec![];
vec1.resize(10, 0);
//~^ ERROR: slow zero-filling initialization
vec1.resize(10, 0);

macro_rules! x {
() => {
Expand Down
143 changes: 78 additions & 65 deletions tests/ui/slow_vector_initialization.stderr
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Original file line number Diff line number Diff line change
@@ -1,109 +1,122 @@
error: slow zero-filling initialization
--> tests/ui/slow_vector_initialization.rs:14:5
--> tests/ui/slow_vector_initialization.rs:13:20
|
LL | let mut vec1 = Vec::with_capacity(len);
| ----------------------- help: consider replacing this with: `vec![0; len]`
LL | vec1.extend(repeat(0).take(len));
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
LL | let mut vec1 = Vec::with_capacity(len);
| ____________________^
... |
LL | | vec1.extend(repeat(0).take(len));
| |____________________________________^ help: consider replacing this with: `vec![0; len]`
|
= note: `-D clippy::slow-vector-initialization` implied by `-D warnings`
= help: to override `-D warnings` add `#[allow(clippy::slow_vector_initialization)]`

error: slow zero-filling initialization
--> tests/ui/slow_vector_initialization.rs:20:5
--> tests/ui/slow_vector_initialization.rs:19:20
|
LL | let mut vec2 = Vec::with_capacity(len - 10);
| ---------------------------- help: consider replacing this with: `vec![0; len - 10]`
LL | vec2.extend(repeat(0).take(len - 10));
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
LL | let mut vec2 = Vec::with_capacity(len - 10);
| ____________________^
LL | |
LL | | vec2.extend(repeat(0).take(len - 10));
| |_________________________________________^ help: consider replacing this with: `vec![0; len - 10]`

error: slow zero-filling initialization
--> tests/ui/slow_vector_initialization.rs:28:5
--> tests/ui/slow_vector_initialization.rs:27:20
|
LL | let mut vec4 = Vec::with_capacity(len);
| ----------------------- help: consider replacing this with: `vec![0; len]`
LL | vec4.extend(repeat(0).take(vec4.capacity()));
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
LL | let mut vec4 = Vec::with_capacity(len);
| ____________________^
LL | |
LL | | vec4.extend(repeat(0).take(vec4.capacity()));
| |________________________________________________^ help: consider replacing this with: `vec![0; len]`

error: slow zero-filling initialization
--> tests/ui/slow_vector_initialization.rs:39:5
--> tests/ui/slow_vector_initialization.rs:38:27
|
LL | let mut resized_vec = Vec::with_capacity(30);
| ---------------------- help: consider replacing this with: `vec![0; 30]`
LL | resized_vec.resize(30, 0);
| ^^^^^^^^^^^^^^^^^^^^^^^^^
LL | let mut resized_vec = Vec::with_capacity(30);
| ___________________________^
LL | |
LL | | resized_vec.resize(30, 0);
| |_____________________________^ help: consider replacing this with: `vec![0; 30]`

error: slow zero-filling initialization
--> tests/ui/slow_vector_initialization.rs:43:5
--> tests/ui/slow_vector_initialization.rs:42:26
|
LL | let mut extend_vec = Vec::with_capacity(30);
| ---------------------- help: consider replacing this with: `vec![0; 30]`
LL | extend_vec.extend(repeat(0).take(30));
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
LL | let mut extend_vec = Vec::with_capacity(30);
| __________________________^
LL | |
LL | | extend_vec.extend(repeat(0).take(30));
| |_________________________________________^ help: consider replacing this with: `vec![0; 30]`

error: slow zero-filling initialization
--> tests/ui/slow_vector_initialization.rs:51:5
--> tests/ui/slow_vector_initialization.rs:50:20
|
LL | let mut vec1 = Vec::with_capacity(len);
| ----------------------- help: consider replacing this with: `vec![0; len]`
LL | vec1.resize(len, 0);
| ^^^^^^^^^^^^^^^^^^^
LL | let mut vec1 = Vec::with_capacity(len);
| ____________________^
LL | |
LL | | vec1.resize(len, 0);
| |_______________________^ help: consider replacing this with: `vec![0; len]`

error: slow zero-filling initialization
--> tests/ui/slow_vector_initialization.rs:60:5
--> tests/ui/slow_vector_initialization.rs:59:20
|
LL | let mut vec3 = Vec::with_capacity(len - 10);
| ---------------------------- help: consider replacing this with: `vec![0; len - 10]`
LL | vec3.resize(len - 10, 0);
| ^^^^^^^^^^^^^^^^^^^^^^^^
LL | let mut vec3 = Vec::with_capacity(len - 10);
| ____________________^
LL | |
LL | | vec3.resize(len - 10, 0);
| |____________________________^ help: consider replacing this with: `vec![0; len - 10]`

error: slow zero-filling initialization
--> tests/ui/slow_vector_initialization.rs:64:5
--> tests/ui/slow_vector_initialization.rs:63:20
|
LL | let mut vec4 = Vec::with_capacity(len);
| ----------------------- help: consider replacing this with: `vec![0; len]`
LL | vec4.resize(vec4.capacity(), 0);
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
LL | let mut vec4 = Vec::with_capacity(len);
| ____________________^
LL | |
LL | | vec4.resize(vec4.capacity(), 0);
| |___________________________________^ help: consider replacing this with: `vec![0; len]`

error: slow zero-filling initialization
--> tests/ui/slow_vector_initialization.rs:69:5
--> tests/ui/slow_vector_initialization.rs:68:12
|
LL | vec1 = Vec::with_capacity(10);
| ---------------------- help: consider replacing this with: `vec![0; 10]`
LL | vec1.resize(10, 0);
| ^^^^^^^^^^^^^^^^^^
LL | vec1 = Vec::with_capacity(10);
| ____________^
LL | |
LL | | vec1.resize(10, 0);
| |______________________^ help: consider replacing this with: `vec![0; 10]`

error: slow zero-filling initialization
--> tests/ui/slow_vector_initialization.rs:77:5
--> tests/ui/slow_vector_initialization.rs:76:20
|
LL | let mut vec1 = Vec::new();
| ---------- help: consider replacing this with: `vec![0; len]`
LL | vec1.resize(len, 0);
| ^^^^^^^^^^^^^^^^^^^
LL | let mut vec1 = Vec::new();
| ____________________^
LL | |
LL | | vec1.resize(len, 0);
| |_______________________^ help: consider replacing this with: `vec![0; len]`

error: slow zero-filling initialization
--> tests/ui/slow_vector_initialization.rs:82:5
--> tests/ui/slow_vector_initialization.rs:81:20
|
LL | let mut vec3 = Vec::new();
| ---------- help: consider replacing this with: `vec![0; len - 10]`
LL | vec3.resize(len - 10, 0);
| ^^^^^^^^^^^^^^^^^^^^^^^^
LL | let mut vec3 = Vec::new();
| ____________________^
LL | |
LL | | vec3.resize(len - 10, 0);
| |____________________________^ help: consider replacing this with: `vec![0; len - 10]`

error: slow zero-filling initialization
--> tests/ui/slow_vector_initialization.rs:87:5
--> tests/ui/slow_vector_initialization.rs:86:12
|
LL | vec1 = Vec::new();
| ---------- help: consider replacing this with: `vec![0; 10]`
LL | vec1.resize(10, 0);
| ^^^^^^^^^^^^^^^^^^
LL | vec1 = Vec::new();
| ____________^
LL | |
LL | | vec1.resize(10, 0);
| |______________________^ help: consider replacing this with: `vec![0; 10]`

error: slow zero-filling initialization
--> tests/ui/slow_vector_initialization.rs:91:5
--> tests/ui/slow_vector_initialization.rs:90:12
|
LL | vec1 = vec![];
| ------ help: consider replacing this with: `vec![0; 10]`
LL | vec1.resize(10, 0);
| ^^^^^^^^^^^^^^^^^^
LL | vec1 = vec![];
| ____________^
LL | |
LL | | vec1.resize(10, 0);
| |______________________^ help: consider replacing this with: `vec![0; 10]`

error: aborting due to 13 previous errors

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