+use crate::consts::constant;
+use crate::utils::{higher, is_copy, snippet_with_applicability, span_lint_and_sugg};
+use if_chain::if_chain;
use rustc::hir::*;
use rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
-use rustc::{declare_lint, lint_array};
-use if_chain::if_chain;
use rustc::ty::{self, Ty};
+use rustc::{declare_lint_pass, declare_tool_lint};
+use rustc_errors::Applicability;
use syntax::source_map::Span;
-use crate::utils::{higher, is_copy, snippet, span_lint_and_sugg};
-use crate::consts::constant;
-/// **What it does:** Checks for usage of `&vec![..]` when using `&[..]` would
-/// be possible.
-///
-/// **Why is this bad?** This is less efficient.
-///
-/// **Known problems:** None.
-///
-/// **Example:**
-/// ```rust,ignore
-/// foo(&vec![1, 2])
-/// ```
declare_clippy_lint! {
+ /// **What it does:** Checks for usage of `&vec![..]` when using `&[..]` would
+ /// be possible.
+ ///
+ /// **Why is this bad?** This is less efficient.
+ ///
+ /// **Known problems:** None.
+ ///
+ /// **Example:**
+ /// ```rust,ignore
+ /// foo(&vec![1, 2])
+ /// ```
pub USELESS_VEC,
perf,
"useless `vec!`"
}
-#[derive(Copy, Clone, Debug)]
-pub struct Pass;
-
-impl LintPass for Pass {
- fn get_lints(&self) -> LintArray {
- lint_array!(USELESS_VEC)
- }
-}
+declare_lint_pass!(UselessVec => [USELESS_VEC]);
-impl<'a, 'tcx> LateLintPass<'a, 'tcx> for Pass {
+impl<'a, 'tcx> LateLintPass<'a, 'tcx> for UselessVec {
fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr) {
// search for `&vec![_]` expressions where the adjusted type is `&[_]`
if_chain! {
// report the error around the `vec!` not inside `<std macros>:`
let span = arg.span
.ctxt()
- .outer()
- .expn_info()
- .map(|info| info.call_site)
- .expect("unable to get call_site");
+ .outer_expn_data()
+ .call_site
+ .ctxt()
+ .outer_expn_data()
+ .call_site;
check_vec_macro(cx, &vec_args, span);
}
}
}
fn check_vec_macro<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, vec_args: &higher::VecArgs<'tcx>, span: Span) {
+ let mut applicability = Applicability::MachineApplicable;
let snippet = match *vec_args {
higher::VecArgs::Repeat(elem, len) => {
if constant(cx, cx.tables, len).is_some() {
- format!("&[{}; {}]", snippet(cx, elem.span, "elem"), snippet(cx, len.span, "len"))
+ format!(
+ "&[{}; {}]",
+ snippet_with_applicability(cx, elem.span, "elem", &mut applicability),
+ snippet_with_applicability(cx, len.span, "len", &mut applicability)
+ )
} else {
return;
}
},
- higher::VecArgs::Vec(args) => if let Some(last) = args.iter().last() {
- let span = args[0].span.to(last.span);
+ higher::VecArgs::Vec(args) => {
+ if let Some(last) = args.iter().last() {
+ let span = args[0].span.to(last.span);
- format!("&[{}]", snippet(cx, span, ".."))
- } else {
- "&[]".into()
+ format!("&[{}]", snippet_with_applicability(cx, span, "..", &mut applicability))
+ } else {
+ "&[]".into()
+ }
},
};
"useless use of `vec!`",
"you can use a slice directly",
snippet,
+ applicability,
);
}
-/// Return the item type of the vector (ie. the `T` in `Vec<T>`).
+/// Returns the item type of the vector (i.e., the `T` in `Vec<T>`).
fn vec_type(ty: Ty<'_>) -> Ty<'_> {
if let ty::Adt(_, substs) = ty.sty {
substs.type_at(0)