use rustc::hir::*;
use rustc::lint::*;
+use rustc::{declare_lint, lint_array};
+use if_chain::if_chain;
use rustc::ty::{self, Ty};
-use rustc::ty::subst::Substs;
-use rustc_const_eval::ConstContext;
use syntax::codemap::Span;
-use utils::{higher, is_copy, snippet, span_lint_and_sugg};
+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.
/// ```rust,ignore
/// foo(&vec![1, 2])
/// ```
-declare_lint! {
+declare_clippy_lint! {
pub USELESS_VEC,
- Warn,
+ perf,
"useless `vec!`"
}
impl<'a, 'tcx> LateLintPass<'a, 'tcx> for Pass {
fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr) {
// search for `&vec![_]` expressions where the adjusted type is `&[_]`
- if_let_chain!{[
- let ty::TyRef(_, ref ty) = cx.tables.expr_ty_adjusted(expr).sty,
- let ty::TySlice(..) = ty.ty.sty,
- let ExprAddrOf(_, ref addressee) = expr.node,
- let Some(vec_args) = higher::vec_macro(cx, addressee),
- ], {
- check_vec_macro(cx, &vec_args, expr.span);
- }}
+ if_chain! {
+ if let ty::TyRef(_, ty, _) = cx.tables.expr_ty_adjusted(expr).sty;
+ if let ty::TySlice(..) = ty.sty;
+ if let ExprKind::AddrOf(_, ref addressee) = expr.node;
+ if let Some(vec_args) = higher::vec_macro(cx, addressee);
+ then {
+ check_vec_macro(cx, &vec_args, expr.span);
+ }
+ }
// search for `for _ in vec![…]`
- if_let_chain!{[
- let Some((_, arg, _)) = higher::for_loop(expr),
- let Some(vec_args) = higher::vec_macro(cx, arg),
- is_copy(cx, vec_type(cx.tables.expr_ty_adjusted(arg))),
- ], {
- // 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");
- check_vec_macro(cx, &vec_args, span);
- }}
+ if_chain! {
+ if let Some((_, arg, _)) = higher::for_loop(expr);
+ if let Some(vec_args) = higher::vec_macro(cx, arg);
+ if is_copy(cx, vec_type(cx.tables.expr_ty_adjusted(arg)));
+ then {
+ // 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");
+ check_vec_macro(cx, &vec_args, span);
+ }
+ }
}
}
-fn check_vec_macro(cx: &LateContext, vec_args: &higher::VecArgs, span: Span) {
+fn check_vec_macro<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, vec_args: &higher::VecArgs<'tcx>, span: Span) {
let snippet = match *vec_args {
higher::VecArgs::Repeat(elem, len) => {
- let parent_item = cx.tcx.hir.get_parent(len.id);
- let parent_def_id = cx.tcx.hir.local_def_id(parent_item);
- let substs = Substs::identity_for_item(cx.tcx, parent_def_id);
- if ConstContext::new(cx.tcx, cx.param_env.and(substs), cx.tables)
- .eval(len)
- .is_ok()
- {
- format!("&[{}; {}]", snippet(cx, elem.span, "elem"), snippet(cx, len.span, "len")).into()
+ if constant(cx, cx.tables, len).is_some() {
+ format!("&[{}; {}]", snippet(cx, elem.span, "elem"), snippet(cx, len.span, "len"))
} 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, "..")).into()
- } else {
- "&[]".into()
- }
+ format!("&[{}]", snippet(cx, span, ".."))
+ } else {
+ "&[]".into()
},
};