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mem_replace_with_default: recognize some std library ctors

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This commit is contained in:
Mateusz Gacek 2021-03-01 16:49:52 +01:00
parent 6ed6f1e6a1
commit c86ba7f92d
5 changed files with 154 additions and 7 deletions
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17
clippy_lints/src/mem_replace.rs
View file

@ -200,7 +200,22 @@ fn check_replace_with_default(cx: &LateContext<'_>, src: &Expr<'_>, dest: &Expr<
if !in_external_macro(cx.tcx.sess, expr_span);
if let ExprKind::Path(ref repl_func_qpath) = repl_func.kind;
if let Some(repl_def_id) = cx.qpath_res(repl_func_qpath, repl_func.hir_id).opt_def_id();
if match_def_path(cx, repl_def_id, &paths::DEFAULT_TRAIT_METHOD);
let defaults = &[
paths::DEFAULT_TRAIT_METHOD.as_ref(),
paths::STRING_NEW.as_ref(),
paths::VEC_NEW.as_ref(),
paths::VEC_DEQUE_NEW.as_ref(),
paths::LINKED_LIST_NEW.as_ref(),
paths::HASHMAP_NEW.as_ref(),
paths::BTREEMAP_NEW.as_ref(),
paths::HASHSET_NEW.as_ref(),
paths::BTREESET_NEW.as_ref(),
paths::BINARY_HEAP_NEW.as_ref(),
];
if defaults.iter().any(|x| match_def_path(cx, repl_def_id, &x));
then {
span_lint_and_then(
cx,

8
clippy_utils/src/paths.rs
View file

@ -11,10 +11,13 @@ pub const ASREF_TRAIT: [&str; 3] = ["core", "convert", "AsRef"];
pub(super) const BEGIN_PANIC: [&str; 3] = ["std", "panicking", "begin_panic"];
pub(super) const BEGIN_PANIC_FMT: [&str; 3] = ["std", "panicking", "begin_panic_fmt"];
pub const BINARY_HEAP: [&str; 4] = ["alloc", "collections", "binary_heap", "BinaryHeap"];
pub const BINARY_HEAP_NEW: [&str; 5] = ["alloc", "collections", "binary_heap", "BinaryHeap", "new"];
pub const BORROW_TRAIT: [&str; 3] = ["core", "borrow", "Borrow"];
pub const BTREEMAP: [&str; 5] = ["alloc", "collections", "btree", "map", "BTreeMap"];
pub const BTREEMAP_NEW: [&str; 6] = ["alloc", "collections", "btree", "map", "BTreeMap", "new"];
pub const BTREEMAP_ENTRY: [&str; 6] = ["alloc", "collections", "btree", "map", "entry", "Entry"];
pub const BTREESET: [&str; 5] = ["alloc", "collections", "btree", "set", "BTreeSet"];
pub const BTREESET_NEW: [&str; 6] = ["alloc", "collections", "btree", "set", "BTreeSet", "new"];
pub const CLONE_TRAIT_METHOD: [&str; 4] = ["core", "clone", "Clone", "clone"];
pub const CMP_MAX: [&str; 3] = ["core", "cmp", "max"];
pub const CMP_MIN: [&str; 3] = ["core", "cmp", "min"];
@ -46,8 +49,10 @@ pub const FROM_ITERATOR: [&str; 5] = ["core", "iter", "traits", "collect", "From
pub const FUTURE_FROM_GENERATOR: [&str; 3] = ["core", "future", "from_generator"];
pub const HASH: [&str; 3] = ["core", "hash", "Hash"];
pub const HASHMAP: [&str; 5] = ["std", "collections", "hash", "map", "HashMap"];
pub const HASHMAP_NEW: [&str; 6] = ["std", "collections", "hash", "map", "HashMap", "new"];
pub const HASHMAP_ENTRY: [&str; 5] = ["std", "collections", "hash", "map", "Entry"];
pub const HASHSET: [&str; 5] = ["std", "collections", "hash", "set", "HashSet"];
pub const HASHSET_NEW: [&str; 6] = ["std", "collections", "hash", "set", "HashSet", "new"];
#[cfg(feature = "internal-lints")]
pub const IDENT: [&str; 3] = ["rustc_span", "symbol", "Ident"];
#[cfg(feature = "internal-lints")]
@ -67,6 +72,7 @@ pub const KW_MODULE: [&str; 3] = ["rustc_span", "symbol", "kw"];
#[cfg(feature = "internal-lints")]
pub const LATE_CONTEXT: [&str; 2] = ["rustc_lint", "LateContext"];
pub const LINKED_LIST: [&str; 4] = ["alloc", "collections", "linked_list", "LinkedList"];
pub const LINKED_LIST_NEW: [&str; 5] = ["alloc", "collections", "linked_list", "LinkedList", "new"];
#[cfg(feature = "internal-lints")]
pub const LINT: [&str; 2] = ["rustc_lint_defs", "Lint"];
pub const MEM_DISCRIMINANT: [&str; 3] = ["core", "mem", "discriminant"];
@ -134,6 +140,7 @@ pub const STD_CONVERT_IDENTITY: [&str; 3] = ["std", "convert", "identity"];
pub const STD_FS_CREATE_DIR: [&str; 3] = ["std", "fs", "create_dir"];
pub const STD_MEM_TRANSMUTE: [&str; 3] = ["std", "mem", "transmute"];
pub const STD_PTR_NULL: [&str; 3] = ["std", "ptr", "null"];
pub const STRING_NEW: [&str; 4] = ["alloc", "string", "String", "new"];
pub const STRING_AS_MUT_STR: [&str; 4] = ["alloc", "string", "String", "as_mut_str"];
pub const STRING_AS_STR: [&str; 4] = ["alloc", "string", "String", "as_str"];
pub const STR_ENDS_WITH: [&str; 4] = ["core", "str", "<impl str>", "ends_with"];
@ -161,6 +168,7 @@ pub const VEC: [&str; 3] = ["alloc", "vec", "Vec"];
pub const VEC_AS_MUT_SLICE: [&str; 4] = ["alloc", "vec", "Vec", "as_mut_slice"];
pub const VEC_AS_SLICE: [&str; 4] = ["alloc", "vec", "Vec", "as_slice"];
pub const VEC_DEQUE: [&str; 4] = ["alloc", "collections", "vec_deque", "VecDeque"];
pub const VEC_DEQUE_NEW: [&str; 5] = ["alloc", "collections", "vec_deque", "VecDeque", "new"];
pub const VEC_FROM_ELEM: [&str; 3] = ["alloc", "vec", "from_elem"];
pub const VEC_NEW: [&str; 4] = ["alloc", "vec", "Vec", "new"];
pub const VEC_RESIZE: [&str; 4] = ["alloc", "vec", "Vec", "resize"];

29
tests/ui/mem_replace.fixed
View file

@ -7,6 +7,7 @@
clippy::mem_replace_with_default
)]
use std::collections::{BTreeMap, BTreeSet, BinaryHeap, HashMap, HashSet, LinkedList, VecDeque};
use std::mem;
fn replace_option_with_none() {
@ -19,9 +20,37 @@ fn replace_option_with_none() {
fn replace_with_default() {
let mut s = String::from("foo");
let _ = std::mem::take(&mut s);
let s = &mut String::from("foo");
let _ = std::mem::take(s);
let _ = std::mem::take(s);
let mut v = vec![123];
let _ = std::mem::take(&mut v);
let _ = std::mem::take(&mut v);
let _ = std::mem::take(&mut v);
let _ = std::mem::take(&mut v);
let mut hash_map: HashMap<i32, i32> = HashMap::new();
let _ = std::mem::take(&mut hash_map);
let mut btree_map: BTreeMap<i32, i32> = BTreeMap::new();
let _ = std::mem::take(&mut btree_map);
let mut vd: VecDeque<i32> = VecDeque::new();
let _ = std::mem::take(&mut vd);
let mut hash_set: HashSet<&str> = HashSet::new();
let _ = std::mem::take(&mut hash_set);
let mut btree_set: BTreeSet<&str> = BTreeSet::new();
let _ = std::mem::take(&mut btree_set);
let mut list: LinkedList<i32> = LinkedList::new();
let _ = std::mem::take(&mut list);
let mut binary_heap: BinaryHeap<i32> = BinaryHeap::new();
let _ = std::mem::take(&mut binary_heap);
}
fn main() {

29
tests/ui/mem_replace.rs
View file

@ -7,6 +7,7 @@
clippy::mem_replace_with_default
)]
use std::collections::{BTreeMap, BTreeSet, BinaryHeap, HashMap, HashSet, LinkedList, VecDeque};
use std::mem;
fn replace_option_with_none() {
@ -19,9 +20,37 @@ fn replace_option_with_none() {
fn replace_with_default() {
let mut s = String::from("foo");
let _ = std::mem::replace(&mut s, String::default());
let s = &mut String::from("foo");
let _ = std::mem::replace(s, String::default());
let _ = std::mem::replace(s, Default::default());
let mut v = vec![123];
let _ = std::mem::replace(&mut v, Vec::default());
let _ = std::mem::replace(&mut v, Default::default());
let _ = std::mem::replace(&mut v, Vec::new());
let _ = std::mem::replace(&mut v, vec![]);
let mut hash_map: HashMap<i32, i32> = HashMap::new();
let _ = std::mem::replace(&mut hash_map, HashMap::new());
let mut btree_map: BTreeMap<i32, i32> = BTreeMap::new();
let _ = std::mem::replace(&mut btree_map, BTreeMap::new());
let mut vd: VecDeque<i32> = VecDeque::new();
let _ = std::mem::replace(&mut vd, VecDeque::new());
let mut hash_set: HashSet<&str> = HashSet::new();
let _ = std::mem::replace(&mut hash_set, HashSet::new());
let mut btree_set: BTreeSet<&str> = BTreeSet::new();
let _ = std::mem::replace(&mut btree_set, BTreeSet::new());
let mut list: LinkedList<i32> = LinkedList::new();
let _ = std::mem::replace(&mut list, LinkedList::new());
let mut binary_heap: BinaryHeap<i32> = BinaryHeap::new();
let _ = std::mem::replace(&mut binary_heap, BinaryHeap::new());
}
fn main() {

78
tests/ui/mem_replace.stderr
View file

@ -1,5 +1,5 @@
error: replacing an `Option` with `None`
--> $DIR/mem_replace.rs:14:13
--> $DIR/mem_replace.rs:15:13
|
LL | let _ = mem::replace(&mut an_option, None);
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider `Option::take()` instead: `an_option.take()`
@ -7,13 +7,13 @@ LL | let _ = mem::replace(&mut an_option, None);
= note: `-D clippy::mem-replace-option-with-none` implied by `-D warnings`
error: replacing an `Option` with `None`
--> $DIR/mem_replace.rs:16:13
--> $DIR/mem_replace.rs:17:13
|
LL | let _ = mem::replace(an_option, None);
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider `Option::take()` instead: `an_option.take()`
error: replacing a value of type `T` with `T::default()` is better expressed using `std::mem::take`
--> $DIR/mem_replace.rs:21:13
--> $DIR/mem_replace.rs:22:13
|
LL | let _ = std::mem::replace(&mut s, String::default());
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `std::mem::take(&mut s)`
@ -21,16 +21,82 @@ LL | let _ = std::mem::replace(&mut s, String::default());
= note: `-D clippy::mem-replace-with-default` implied by `-D warnings`
error: replacing a value of type `T` with `T::default()` is better expressed using `std::mem::take`
--> $DIR/mem_replace.rs:23:13
--> $DIR/mem_replace.rs:25:13
|
LL | let _ = std::mem::replace(s, String::default());
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `std::mem::take(s)`
error: replacing a value of type `T` with `T::default()` is better expressed using `std::mem::take`
--> $DIR/mem_replace.rs:24:13
--> $DIR/mem_replace.rs:26:13
|
LL | let _ = std::mem::replace(s, Default::default());
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `std::mem::take(s)`
error: aborting due to 5 previous errors
error: replacing a value of type `T` with `T::default()` is better expressed using `std::mem::take`
--> $DIR/mem_replace.rs:29:13
|
LL | let _ = std::mem::replace(&mut v, Vec::default());
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `std::mem::take(&mut v)`
error: replacing a value of type `T` with `T::default()` is better expressed using `std::mem::take`
--> $DIR/mem_replace.rs:30:13
|
LL | let _ = std::mem::replace(&mut v, Default::default());
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `std::mem::take(&mut v)`
error: replacing a value of type `T` with `T::default()` is better expressed using `std::mem::take`
--> $DIR/mem_replace.rs:31:13
|
LL | let _ = std::mem::replace(&mut v, Vec::new());
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `std::mem::take(&mut v)`
error: replacing a value of type `T` with `T::default()` is better expressed using `std::mem::take`
--> $DIR/mem_replace.rs:32:13
|
LL | let _ = std::mem::replace(&mut v, vec![]);
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `std::mem::take(&mut v)`
error: replacing a value of type `T` with `T::default()` is better expressed using `std::mem::take`
--> $DIR/mem_replace.rs:35:13
|
LL | let _ = std::mem::replace(&mut hash_map, HashMap::new());
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `std::mem::take(&mut hash_map)`
error: replacing a value of type `T` with `T::default()` is better expressed using `std::mem::take`
--> $DIR/mem_replace.rs:38:13
|
LL | let _ = std::mem::replace(&mut btree_map, BTreeMap::new());
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `std::mem::take(&mut btree_map)`
error: replacing a value of type `T` with `T::default()` is better expressed using `std::mem::take`
--> $DIR/mem_replace.rs:41:13
|
LL | let _ = std::mem::replace(&mut vd, VecDeque::new());
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `std::mem::take(&mut vd)`
error: replacing a value of type `T` with `T::default()` is better expressed using `std::mem::take`
--> $DIR/mem_replace.rs:44:13
|
LL | let _ = std::mem::replace(&mut hash_set, HashSet::new());
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `std::mem::take(&mut hash_set)`
error: replacing a value of type `T` with `T::default()` is better expressed using `std::mem::take`
--> $DIR/mem_replace.rs:47:13
|
LL | let _ = std::mem::replace(&mut btree_set, BTreeSet::new());
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `std::mem::take(&mut btree_set)`
error: replacing a value of type `T` with `T::default()` is better expressed using `std::mem::take`
--> $DIR/mem_replace.rs:50:13
|
LL | let _ = std::mem::replace(&mut list, LinkedList::new());
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `std::mem::take(&mut list)`
error: replacing a value of type `T` with `T::default()` is better expressed using `std::mem::take`
--> $DIR/mem_replace.rs:53:13
|
LL | let _ = std::mem::replace(&mut binary_heap, BinaryHeap::new());
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `std::mem::take(&mut binary_heap)`
error: aborting due to 16 previous errors