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Merge pull request #3478 from dtolnay/setlen

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Remove unsafe_vector_initialization lint
This commit is contained in:
Oliver S̶c̶h̶n̶e̶i̶d̶e̶r Scherer
2018-12-03 12:42:31 +01:00
committed by GitHub
parent 13438b6866 e632a1946e
commit c00210d7ba
6 changed files with 39 additions and 97 deletions
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2
README.md
View File

@@ -7,7 +7,7 @@
A collection of lints to catch common mistakes and improve your [Rust](https://github.com/rust-lang/rust) code.
[There are 290 lints included in this crate!](https://rust-lang.github.io/rust-clippy/master/index.html)
[There are 289 lints included in this crate!](https://rust-lang.github.io/rust-clippy/master/index.html)
We have a bunch of lint categories to allow you to choose how much Clippy is supposed to ~~annoy~~ help you:

11
clippy_lints/src/deprecated_lints.rs
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@@ -112,3 +112,14 @@ declare_deprecated_lint! {
pub IF_LET_REDUNDANT_PATTERN_MATCHING,
"this lint has been changed to redundant_pattern_matching"
}
/// **What it does:** Nothing. This lint has been deprecated.
///
/// **Deprecation reason:** This lint used to suggest replacing `let mut vec =
/// Vec::with_capacity(n); vec.set_len(n);` with `let vec = vec![0; n];`. The
/// replacement has very different performance characteristics so the lint is
/// deprecated.
declare_deprecated_lint! {
pub UNSAFE_VECTOR_INITIALIZATION,
"the replacement suggested by this lint had substantially different behavior"
}

6
clippy_lints/src/lib.rs
View File

@@ -330,6 +330,10 @@ pub fn register_plugins(reg: &mut rustc_plugin::Registry<'_>, conf: &Conf) {
"if_let_redundant_pattern_matching",
"this lint has been changed to redundant_pattern_matching",
);
store.register_removed(
"unsafe_vector_initialization",
"the replacement suggested by this lint had substantially different behavior",
);
// end deprecated lints, do not remove this comment, it’s used in `update_lints`
reg.register_late_lint_pass(box serde_api::Serde);
@@ -727,7 +731,6 @@ pub fn register_plugins(reg: &mut rustc_plugin::Registry<'_>, conf: &Conf) {
returns::UNUSED_UNIT,
serde_api::SERDE_API_MISUSE,
slow_vector_initialization::SLOW_VECTOR_INITIALIZATION,
slow_vector_initialization::UNSAFE_VECTOR_INITIALIZATION,
strings::STRING_LIT_AS_BYTES,
suspicious_trait_impl::SUSPICIOUS_ARITHMETIC_IMPL,
suspicious_trait_impl::SUSPICIOUS_OP_ASSIGN_IMPL,
@@ -973,7 +976,6 @@ pub fn register_plugins(reg: &mut rustc_plugin::Registry<'_>, conf: &Conf) {
ranges::ITERATOR_STEP_BY_ZERO,
regex::INVALID_REGEX,
serde_api::SERDE_API_MISUSE,
slow_vector_initialization::UNSAFE_VECTOR_INITIALIZATION,
suspicious_trait_impl::SUSPICIOUS_ARITHMETIC_IMPL,
suspicious_trait_impl::SUSPICIOUS_OP_ASSIGN_IMPL,
swap::ALMOST_SWAPPED,

53
clippy_lints/src/slow_vector_initialization.rs
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@@ -39,32 +39,12 @@ declare_clippy_lint! {
"slow vector initialization"
}
/// **What it does:** Checks unsafe vector initialization
///
/// **Why is this bad?** Changing the length of a vector may expose uninitialized memory, which
/// can lead to memory safety issues
///
/// **Known problems:** None.
///
/// **Example:**
/// ```rust
/// let mut vec1 = Vec::with_capacity(len);
/// unsafe {
/// vec1.set_len(len);
/// }
/// ```
declare_clippy_lint! {
pub UNSAFE_VECTOR_INITIALIZATION,
correctness,
"unsafe vector initialization"
}
#[derive(Copy, Clone, Default)]
pub struct Pass;
impl LintPass for Pass {
fn get_lints(&self) -> LintArray {
lint_array!(SLOW_VECTOR_INITIALIZATION, UNSAFE_VECTOR_INITIALIZATION,)
lint_array!(SLOW_VECTOR_INITIALIZATION,)
}
}
@@ -90,9 +70,6 @@ enum InitializationType<'tcx> {
/// Resize is a slow initialization with the form `vec.resize(.., 0)`
Resize(&'tcx Expr),
/// UnsafeSetLen is a slow initialization with the form `vec.set_len(..)`
UnsafeSetLen(&'tcx Expr),
}
impl<'a, 'tcx> LateLintPass<'a, 'tcx> for Pass {
@@ -188,14 +165,6 @@ impl Pass {
vec_alloc: &VecAllocation<'_>,
) {
match initialization {
InitializationType::UnsafeSetLen(e) => Self::emit_lint(
cx,
e,
vec_alloc,
"unsafe vector initialization",
UNSAFE_VECTOR_INITIALIZATION,
),
InitializationType::Extend(e) | InitializationType::Resize(e) => Self::emit_lint(
cx,
e,
@@ -282,25 +251,6 @@ impl<'a, 'tcx> VectorInitializationVisitor<'a, 'tcx> {
}
}
/// Checks if the given expression is using `set_len` to initialize the vector
fn search_unsafe_set_len(&mut self, expr: &'tcx Expr) {
if_chain! {
if self.initialization_found;
if let ExprKind::MethodCall(ref path, _, ref args) = expr.node;
if let ExprKind::Path(ref qpath_subj) = args[0].node;
if match_qpath(&qpath_subj, &[&self.vec_alloc.variable_name.to_string()]);
if path.ident.name == "set_len";
if let Some(ref len_arg) = args.get(1);
// Check that len expression is equals to `with_capacity` expression
if SpanlessEq::new(self.cx).eq_expr(len_arg, self.vec_alloc.len_expr);
then {
self.slow_expression = Some(InitializationType::UnsafeSetLen(expr));
}
}
}
/// Returns `true` if give expression is `repeat(0).take(...)`
fn is_repeat_take(&self, expr: &Expr) -> bool {
if_chain! {
@@ -349,7 +299,6 @@ impl<'a, 'tcx> Visitor<'tcx> for VectorInitializationVisitor<'a, 'tcx> {
StmtKind::Expr(ref expr, _) | StmtKind::Semi(ref expr, _) => {
self.search_slow_extend_filling(expr);
self.search_slow_resize_filling(expr);
self.search_unsafe_set_len(expr);
},
_ => (),
}

9
tests/ui/slow_vector_initialization.rs
View File

@@ -13,7 +13,6 @@ fn main() {
resize_vector();
extend_vector();
mixed_extend_resize_vector();
unsafe_vector();
}
fn extend_vector() {
@@ -63,14 +62,6 @@ fn resize_vector() {
vec1.resize(10, 0);
}
fn unsafe_vector() {
let mut unsafe_vec: Vec<u8> = Vec::with_capacity(200);
unsafe {
unsafe_vec.set_len(200);
}
}
fn do_stuff(vec: &mut Vec<u8>) {
}

55
tests/ui/slow_vector_initialization.stderr
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@@ -1,71 +1,60 @@
error: slow zero-filling initialization
--> $DIR/slow_vector_initialization.rs:23:5
--> $DIR/slow_vector_initialization.rs:22:5
|
22 | let mut vec1 = Vec::with_capacity(len);
21 | let mut vec1 = Vec::with_capacity(len);
| ----------------------- help: consider replace allocation with: `vec![0; len]`
23 | vec1.extend(repeat(0).take(len));
22 | vec1.extend(repeat(0).take(len));
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
= note: `-D clippy::slow-vector-initialization` implied by `-D warnings`
error: slow zero-filling initialization
--> $DIR/slow_vector_initialization.rs:27:5
--> $DIR/slow_vector_initialization.rs:26:5
|
26 | let mut vec2 = Vec::with_capacity(len - 10);
25 | let mut vec2 = Vec::with_capacity(len - 10);
| ---------------------------- help: consider replace allocation with: `vec![0; len - 10]`
27 | vec2.extend(repeat(0).take(len - 10));
26 | vec2.extend(repeat(0).take(len - 10));
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
error: slow zero-filling initialization
--> $DIR/slow_vector_initialization.rs:41:5
--> $DIR/slow_vector_initialization.rs:40:5
|
40 | let mut resized_vec = Vec::with_capacity(30);
39 | let mut resized_vec = Vec::with_capacity(30);
| ---------------------- help: consider replace allocation with: `vec![0; 30]`
41 | resized_vec.resize(30, 0);
40 | resized_vec.resize(30, 0);
| ^^^^^^^^^^^^^^^^^^^^^^^^^
error: slow zero-filling initialization
--> $DIR/slow_vector_initialization.rs:44:5
--> $DIR/slow_vector_initialization.rs:43:5
|
43 | let mut extend_vec = Vec::with_capacity(30);
42 | let mut extend_vec = Vec::with_capacity(30);
| ---------------------- help: consider replace allocation with: `vec![0; 30]`
44 | extend_vec.extend(repeat(0).take(30));
43 | extend_vec.extend(repeat(0).take(30));
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
error: slow zero-filling initialization
--> $DIR/slow_vector_initialization.rs:51:5
--> $DIR/slow_vector_initialization.rs:50:5
|
50 | let mut vec1 = Vec::with_capacity(len);
49 | let mut vec1 = Vec::with_capacity(len);
| ----------------------- help: consider replace allocation with: `vec![0; len]`
51 | vec1.resize(len, 0);
50 | vec1.resize(len, 0);
| ^^^^^^^^^^^^^^^^^^^
error: slow zero-filling initialization
--> $DIR/slow_vector_initialization.rs:59:5
--> $DIR/slow_vector_initialization.rs:58:5
|
58 | let mut vec3 = Vec::with_capacity(len - 10);
57 | let mut vec3 = Vec::with_capacity(len - 10);
| ---------------------------- help: consider replace allocation with: `vec![0; len - 10]`
59 | vec3.resize(len - 10, 0);
58 | vec3.resize(len - 10, 0);
| ^^^^^^^^^^^^^^^^^^^^^^^^
error: slow zero-filling initialization
--> $DIR/slow_vector_initialization.rs:63:5
--> $DIR/slow_vector_initialization.rs:62:5
|
62 | vec1 = Vec::with_capacity(10);
61 | vec1 = Vec::with_capacity(10);
| ---------------------- help: consider replace allocation with: `vec![0; 10]`
63 | vec1.resize(10, 0);
62 | vec1.resize(10, 0);
| ^^^^^^^^^^^^^^^^^^
error: unsafe vector initialization
--> $DIR/slow_vector_initialization.rs:70:9
|
67 | let mut unsafe_vec: Vec<u8> = Vec::with_capacity(200);
| ----------------------- help: consider replace allocation with: `vec![0; 200]`
...
70 | unsafe_vec.set_len(200);
| ^^^^^^^^^^^^^^^^^^^^^^^
|
= note: #[deny(clippy::unsafe_vector_initialization)] on by default
error: aborting due to 8 previous errors
error: aborting due to 7 previous errors