Change recomendation to: &[type] from Cow<type>

This commit is contained in:
bootandy 2018-03-02 19:13:54 -05:00
parent fc5b377cec
commit e3c13da830
2 changed files with 28 additions and 17 deletions

View File

@ -3,6 +3,7 @@
use std::borrow::Cow;
use rustc::hir::*;
use rustc::hir::map::NodeItem;
use rustc::hir::QPath;
use rustc::lint::*;
use rustc::ty;
use syntax::ast::NodeId;
@ -214,20 +215,32 @@ fn check_fn(cx: &LateContext, decl: &FnDecl, fn_id: NodeId, opt_body_id: Option<
);
}
} else if match_type(cx, ty, &paths::COW) {
let as_str = format!("{}", snippet_opt(cx, arg.span).unwrap());
let mut cc = as_str.chars();
cc.next();
let replacement: String = cc.collect();
span_lint_and_then(
cx,
PTR_ARG,
arg.span,
"using a reference to `Cow` is not recommended.",
|db| {
db.span_suggestion(arg.span, "change this to", replacement);
},
);
if_chain! {
if let TyRptr(_, MutTy { ref ty, ..} ) = arg.node;
if let TyPath(ref path) = ty.node;
if let QPath::Resolved(None, ref pp) = *path;
if let [ref bx] = *pp.segments;
if let Some(ref params) = bx.parameters;
if !params.parenthesized;
if let [ref inner] = *params.types;
then {
let replacement = snippet_opt(cx, inner.span);
match replacement {
Some(r) => {
span_lint_and_then(
cx,
PTR_ARG,
arg.span,
"using a reference to `Cow` is not recommended.",
|db| {
db.span_suggestion(arg.span, "change this to", "&".to_owned() + &r);
},
);
},
None => (),
}
}
}
}
}
}

View File

@ -38,13 +38,11 @@ error: this pattern creates a reference to a reference
50 | let _ = v.iter().filter(|&ref a| a.is_empty());
| ^^^^^ help: change this to: `a`
a> $DIR/needless_borrow.rs:56:25: 56:36
b> $DIR/needless_borrow.rs:56:25: 56:36
error: using a reference to `Cow` is not recommended.
--> $DIR/needless_borrow.rs:56:25
|
56 | fn test_cow_with_ref(c: &Cow<[i32]>) {
| ^^^^^^^^^^^ help: change this to: `Cow<[i32]>`
| ^^^^^^^^^^^ help: change this to: `&[i32]`
|
= note: `-D ptr-arg` implied by `-D warnings`