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lint &PathBuf instead of &Path in PTR_ARG
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- extract get_only_generic_arg_snippet to improve readability
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@alex-700
alex-700 committed Dec 25, 2020
1 parent 02399f4 commit 4fddb15
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Showing 3 changed files with 104 additions and 23 deletions.
60 changes: 45 additions & 15 deletions clippy_lints/src/ptr.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -182,20 +182,6 @@ fn check_fn(cx: &LateContext<'_>, decl: &FnDecl<'_>, fn_id: HirId, opt_body_id:

if let ty::Ref(_, ty, Mutability::Not) = ty.kind() {
if is_type_diagnostic_item(cx, ty, sym::vec_type) {
let mut ty_snippet = None;
if_chain! {
if let TyKind::Path(QPath::Resolved(_, ref path)) = walk_ptrs_hir_ty(arg).kind;
if let Some(&PathSegment{args: Some(ref parameters), ..}) = path.segments.last();
then {
let types: Vec<_> = parameters.args.iter().filter_map(|arg| match arg {
GenericArg::Type(ty) => Some(ty),
_ => None,
}).collect();
if types.len() == 1 {
ty_snippet = snippet_opt(cx, types[0].span);
}
}
};
if let Some(spans) = get_spans(cx, opt_body_id, idx, &[("clone", ".to_owned()")]) {
span_lint_and_then(
cx,
Expand All @@ -204,7 +190,7 @@ fn check_fn(cx: &LateContext<'_>, decl: &FnDecl<'_>, fn_id: HirId, opt_body_id:
"writing `&Vec<_>` instead of `&[_]` involves one more reference and cannot be used \
with non-Vec-based slices.",
|diag| {
if let Some(ref snippet) = ty_snippet {
if let Some(ref snippet) = get_only_generic_arg_snippet(cx, arg) {
diag.span_suggestion(
arg.span,
"change this to",
Expand Down Expand Up @@ -247,6 +233,33 @@ fn check_fn(cx: &LateContext<'_>, decl: &FnDecl<'_>, fn_id: HirId, opt_body_id:
},
);
}
} else if match_type(cx, ty, &paths::PATH_BUF) {
if let Some(spans) = get_spans(cx, opt_body_id, idx, &[("clone", ".to_path_buf()"), ("as_path", "")]) {
span_lint_and_then(
cx,
PTR_ARG,
arg.span,
"writing `&PathBuf` instead of `&Path` involves a new object where a slice will do.",
|diag| {
diag.span_suggestion(
arg.span,
"change this to",
"&Path".into(),
Applicability::Unspecified,
);
for (clonespan, suggestion) in spans {
diag.span_suggestion_short(
clonespan,
&snippet_opt(cx, clonespan).map_or("change the call to".into(), |x| {
Cow::Owned(format!("change `{}` to", x))
}),
suggestion.into(),
Applicability::Unspecified,
);
}
},
);
}
} else if match_type(cx, ty, &paths::COW) {
if_chain! {
if let TyKind::Rptr(_, MutTy { ref ty, ..} ) = arg.kind;
Expand Down Expand Up @@ -309,6 +322,23 @@ fn check_fn(cx: &LateContext<'_>, decl: &FnDecl<'_>, fn_id: HirId, opt_body_id:
}
}

fn get_only_generic_arg_snippet(cx: &LateContext<'_>, arg: &Ty<'_>) -> Option<String> {
if_chain! {
if let TyKind::Path(QPath::Resolved(_, ref path)) = walk_ptrs_hir_ty(arg).kind;
if let Some(&PathSegment{args: Some(ref parameters), ..}) = path.segments.last();
let types: Vec<_> = parameters.args.iter().filter_map(|arg| match arg {
GenericArg::Type(ty) => Some(ty),
_ => None,
}).collect();
if types.len() == 1;
then {
snippet_opt(cx, types[0].span)
} else {
None
}
}
}

fn get_rptr_lm<'tcx>(ty: &'tcx Ty<'tcx>) -> Option<(&'tcx Lifetime, Mutability, Span)> {
if let TyKind::Rptr(ref lt, ref m) = ty.kind {
Some((lt, m.mutbl, ty.span))
Expand Down
22 changes: 22 additions & 0 deletions tests/ui/ptr_arg.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -2,6 +2,7 @@
#![warn(clippy::ptr_arg)]

use std::borrow::Cow;
use std::path::PathBuf;

fn do_vec(x: &Vec<i64>) {
//Nothing here
Expand All @@ -21,6 +22,15 @@ fn do_str_mut(x: &mut String) {
//Nothing here either
}

fn do_path(x: &PathBuf) {
//Nothing here either
}

fn do_path_mut(x: &mut PathBuf) {
// no error here
//Nothing here either
}

fn main() {}

trait Foo {
Expand Down Expand Up @@ -55,6 +65,14 @@ fn str_cloned(x: &String) -> String {
x.clone()
}

fn path_cloned(x: &PathBuf) -> PathBuf {
let a = x.clone();
let b = x.clone();
let c = b.clone();
let d = a.clone().clone().clone();
x.clone()
}

fn false_positive_capacity(x: &Vec<u8>, y: &String) {
let a = x.capacity();
let b = y.clone();
Expand Down Expand Up @@ -87,10 +105,12 @@ impl Foo2 for String {
// Check that the allow attribute on parameters is honored
mod issue_5644 {
use std::borrow::Cow;
use std::path::PathBuf;

fn allowed(
#[allow(clippy::ptr_arg)] _v: &Vec<u32>,
#[allow(clippy::ptr_arg)] _s: &String,
#[allow(clippy::ptr_arg)] _p: &PathBuf,
#[allow(clippy::ptr_arg)] _c: &Cow<[i32]>,
) {
}
Expand All @@ -100,6 +120,7 @@ mod issue_5644 {
fn allowed(
#[allow(clippy::ptr_arg)] _v: &Vec<u32>,
#[allow(clippy::ptr_arg)] _s: &String,
#[allow(clippy::ptr_arg)] _p: &PathBuf,
#[allow(clippy::ptr_arg)] _c: &Cow<[i32]>,
) {
}
Expand All @@ -109,6 +130,7 @@ mod issue_5644 {
fn allowed(
#[allow(clippy::ptr_arg)] _v: &Vec<u32>,
#[allow(clippy::ptr_arg)] _s: &String,
#[allow(clippy::ptr_arg)] _p: &PathBuf,
#[allow(clippy::ptr_arg)] _c: &Cow<[i32]>,
) {
}
Expand Down
45 changes: 37 additions & 8 deletions tests/ui/ptr_arg.stderr
View file
Original file line number Diff line number Diff line change
@@ -1,25 +1,31 @@
error: writing `&Vec<_>` instead of `&[_]` involves one more reference and cannot be used with non-Vec-based slices.
--> $DIR/ptr_arg.rs:6:14
--> $DIR/ptr_arg.rs:7:14
|
LL | fn do_vec(x: &Vec<i64>) {
| ^^^^^^^^^ help: change this to: `&[i64]`
|
= note: `-D clippy::ptr-arg` implied by `-D warnings`

error: writing `&String` instead of `&str` involves a new object where a slice will do.
--> $DIR/ptr_arg.rs:15:14
--> $DIR/ptr_arg.rs:16:14
|
LL | fn do_str(x: &String) {
| ^^^^^^^ help: change this to: `&str`

error: writing `&PathBuf` instead of `&Path` involves a new object where a slice will do.
--> $DIR/ptr_arg.rs:25:15
|
LL | fn do_path(x: &PathBuf) {
| ^^^^^^^^ help: change this to: `&Path`

error: writing `&Vec<_>` instead of `&[_]` involves one more reference and cannot be used with non-Vec-based slices.
--> $DIR/ptr_arg.rs:28:18
--> $DIR/ptr_arg.rs:38:18
|
LL | fn do_vec(x: &Vec<i64>);
| ^^^^^^^^^ help: change this to: `&[i64]`

error: writing `&Vec<_>` instead of `&[_]` involves one more reference and cannot be used with non-Vec-based slices.
--> $DIR/ptr_arg.rs:41:14
--> $DIR/ptr_arg.rs:51:14
|
LL | fn cloned(x: &Vec<u8>) -> Vec<u8> {
| ^^^^^^^^
Expand All @@ -38,7 +44,7 @@ LL | x.to_owned()
|

error: writing `&String` instead of `&str` involves a new object where a slice will do.
--> $DIR/ptr_arg.rs:50:18
--> $DIR/ptr_arg.rs:60:18
|
LL | fn str_cloned(x: &String) -> String {
| ^^^^^^^
Expand All @@ -60,8 +66,31 @@ help: change `x.clone()` to
LL | x.to_string()
|

error: writing `&PathBuf` instead of `&Path` involves a new object where a slice will do.
--> $DIR/ptr_arg.rs:68:19
|
LL | fn path_cloned(x: &PathBuf) -> PathBuf {
| ^^^^^^^^
|
help: change this to
|
LL | fn path_cloned(x: &Path) -> PathBuf {
| ^^^^^
help: change `x.clone()` to
|
LL | let a = x.to_path_buf();
| ^^^^^^^^^^^^^^^
help: change `x.clone()` to
|
LL | let b = x.to_path_buf();
| ^^^^^^^^^^^^^^^
help: change `x.clone()` to
|
LL | x.to_path_buf()
|

error: writing `&String` instead of `&str` involves a new object where a slice will do.
--> $DIR/ptr_arg.rs:58:44
--> $DIR/ptr_arg.rs:76:44
|
LL | fn false_positive_capacity(x: &Vec<u8>, y: &String) {
| ^^^^^^^
Expand All @@ -80,10 +109,10 @@ LL | let c = y;
| ^

error: using a reference to `Cow` is not recommended.
--> $DIR/ptr_arg.rs:72:25
--> $DIR/ptr_arg.rs:90:25
|
LL | fn test_cow_with_ref(c: &Cow<[i32]>) {}
| ^^^^^^^^^^^ help: change this to: `&[i32]`

error: aborting due to 7 previous errors
error: aborting due to 9 previous errors

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