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add suggestions to clone_on_copy

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also:

* don't report clone_on_copy when reporting clone_on_double_ref
* don't suggest `((x))`
This commit is contained in:
Oliver Schneider 2016-08-08 16:43:45 +02:00
parent ac5abcf593
commit 7e67f447ce
No known key found for this signature in database
GPG Key ID: 56D6EEA0FC67AC46
3 changed files with 34 additions and 14 deletions
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30
clippy_lints/src/methods.rs
View File

@ -514,8 +514,7 @@ impl LateLintPass for Pass {
let self_ty = cx.tcx.expr_ty_adjusted(&args[0]);
if args.len() == 1 && name.node.as_str() == "clone" {
lint_clone_on_copy(cx, expr);
lint_clone_double_ref(cx, expr, &args[0], self_ty);
lint_clone_on_copy(cx, expr, &args[0], self_ty);
}
match self_ty.sty {
@ -703,19 +702,11 @@ fn lint_or_fun_call(cx: &LateContext, expr: &hir::Expr, name: &str, args: &[P<hi
}
/// Checks for the `CLONE_ON_COPY` lint.
fn lint_clone_on_copy(cx: &LateContext, expr: &hir::Expr) {
fn lint_clone_on_copy(cx: &LateContext, expr: &hir::Expr, arg: &hir::Expr, arg_ty: ty::Ty) {
let ty = cx.tcx.expr_ty(expr);
let parent = cx.tcx.map.get_parent(expr.id);
let parameter_environment = ty::ParameterEnvironment::for_item(cx.tcx, parent);
if !ty.moves_by_default(cx.tcx.global_tcx(), &parameter_environment, expr.span) {
span_lint(cx, CLONE_ON_COPY, expr.span, "using `clone` on a `Copy` type");
}
}
/// Checks for the `CLONE_DOUBLE_REF` lint.
fn lint_clone_double_ref(cx: &LateContext, expr: &hir::Expr, arg: &hir::Expr, ty: ty::Ty) {
if let ty::TyRef(_, ty::TypeAndMut { ty: inner, .. }) = ty.sty {
if let ty::TyRef(_, ty::TypeAndMut { ty: inner, .. }) = arg_ty.sty {
if let ty::TyRef(..) = inner.sty {
span_lint_and_then(cx,
CLONE_DOUBLE_REF,
@ -725,8 +716,23 @@ fn lint_clone_double_ref(cx: &LateContext, expr: &hir::Expr, arg: &hir::Expr, ty
|db| if let Some(snip) = sugg::Sugg::hir_opt(cx, arg) {
db.span_suggestion(expr.span, "try dereferencing it", format!("({}).clone()", snip.deref()));
});
return; // don't report clone_on_copy
}
}
if !ty.moves_by_default(cx.tcx.global_tcx(), &parameter_environment, expr.span) {
span_lint_and_then(cx,
CLONE_ON_COPY,
expr.span,
"using `clone` on a `Copy` type",
|db| if let Some(snip) = sugg::Sugg::hir_opt(cx, arg) {
if let ty::TyRef(..) = cx.tcx.expr_ty(arg).sty {
db.span_suggestion(expr.span, "try dereferencing it", format!("{}", snip.deref()));
} else {
db.span_suggestion(expr.span, "try removing the `clone` call", format!("{}", snip));
}
});
}
}
fn lint_extend(cx: &LateContext, expr: &hir::Expr, args: &MethodArgs) {

8
clippy_lints/src/utils/sugg.rs
View File

@ -161,7 +161,13 @@ impl<'a> Sugg<'a> {
pub fn maybe_par(self) -> Self {
match self {
Sugg::NonParen(..) => self,
Sugg::MaybeParen(sugg) | Sugg::BinOp(_, sugg) => Sugg::NonParen(format!("({})", sugg).into()),
// (x) and (x).y() both don't need additional parens
Sugg::MaybeParen(sugg) => if sugg.starts_with('(') && sugg.ends_with(')') {
Sugg::MaybeParen(sugg)
} else {
Sugg::NonParen(format!("({})", sugg).into())
},
Sugg::BinOp(_, sugg) => Sugg::NonParen(format!("({})", sugg).into()),
}
}
}

10
tests/compile-fail/methods.rs
View File

@ -435,13 +435,22 @@ fn use_extend_from_slice() {
fn clone_on_copy() {
42.clone(); //~ERROR using `clone` on a `Copy` type
//~| HELP try removing the `clone` call
//~| SUGGESTION 42
vec![1].clone(); // ok, not a Copy type
Some(vec![1]).clone(); // ok, not a Copy type
(&42).clone(); //~ERROR using `clone` on a `Copy` type
//~| HELP try dereferencing it
//~| SUGGESTION *(&42)
}
fn clone_on_copy_generic<T: Copy>(t: T) {
t.clone(); //~ERROR using `clone` on a `Copy` type
//~| HELP try removing the `clone` call
//~| SUGGESTION t
Some(t).clone(); //~ERROR using `clone` on a `Copy` type
//~| HELP try removing the `clone` call
//~| SUGGESTION Some(t)
}
fn clone_on_double_ref() {
@ -450,7 +459,6 @@ fn clone_on_double_ref() {
let z: &Vec<_> = y.clone(); //~ERROR using `clone` on a double
//~| HELP try dereferencing it
//~| SUGGESTION let z: &Vec<_> = (*y).clone();
//~^^^ERROR using `clone` on a `Copy` type
println!("{:p} {:p}",*y, z);
}