commit
b1becf41e4
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@ -2,7 +2,7 @@ use rustc::hir;
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use rustc::lint::*;
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use rustc::middle::const_val::ConstVal;
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use rustc::middle::const_qualif::ConstQualif;
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use rustc::ty::subst::{Subst, TypeSpace};
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use rustc::ty::subst::TypeSpace;
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use rustc::ty;
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use rustc_const_eval::EvalHint::ExprTypeChecked;
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use rustc_const_eval::eval_const_expr_partial;
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@ -10,9 +10,9 @@ use std::borrow::Cow;
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use std::fmt;
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use syntax::codemap::Span;
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use syntax::ptr::P;
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use utils::{get_trait_def_id, implements_trait, in_external_macro, in_macro, match_path, match_trait_method,
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match_type, method_chain_args, return_ty, same_tys, snippet, span_lint,
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span_lint_and_then, span_note_and_lint, walk_ptrs_ty, walk_ptrs_ty_depth};
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use utils::{get_trait_def_id, implements_trait, in_external_macro, in_macro, is_copy, match_path,
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match_trait_method, match_type, method_chain_args, return_ty, same_tys, snippet,
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span_lint, span_lint_and_then, span_note_and_lint, walk_ptrs_ty, walk_ptrs_ty_depth};
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use utils::MethodArgs;
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use utils::paths;
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use utils::sugg;
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@ -471,7 +471,7 @@ impl LateLintPass for Pass {
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// check conventions w.r.t. conversion method names and predicates
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let ty = cx.tcx.lookup_item_type(cx.tcx.map.local_def_id(item.id)).ty;
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let is_copy = is_copy(cx, ty, item);
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let is_copy = is_copy(cx, ty, item.id);
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for &(ref conv, self_kinds) in &CONVENTIONS {
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if_let_chain! {[
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conv.check(&name.as_str()),
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@ -1163,8 +1163,3 @@ fn is_bool(ty: &hir::Ty) -> bool {
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false
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}
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}
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fn is_copy<'a, 'ctx>(cx: &LateContext<'a, 'ctx>, ty: ty::Ty<'ctx>, item: &hir::Item) -> bool {
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let env = ty::ParameterEnvironment::for_item(cx.tcx, item.id);
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!ty.subst(cx.tcx, env.free_substs).moves_by_default(cx.tcx.global_tcx(), &env, item.span)
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}
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@ -25,7 +25,11 @@ declare_lint! {
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///
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/// **Known problems:** None?
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///
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/// **Example:** let (a, b, c, d, e, f, g) = (...);
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/// **Example:**
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///
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/// ```rust
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/// let (a, b, c, d, e, f, g) = (...);
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/// ```
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declare_lint! {
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pub MANY_SINGLE_CHAR_NAMES,
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Warn,
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@ -39,7 +39,7 @@ impl ReturnPass {
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if let Some(stmt) = block.stmts.last() {
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match stmt.node {
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StmtKind::Expr(ref expr) | StmtKind::Semi(ref expr) => {
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self.check_final_expr(cx, expr);
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self.check_final_expr(cx, expr, Some(stmt.span));
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}
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_ => (),
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}
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@ -47,11 +47,11 @@ impl ReturnPass {
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}
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// Check a the final expression in a block if it's a return.
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fn check_final_expr(&mut self, cx: &EarlyContext, expr: &Expr) {
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fn check_final_expr(&mut self, cx: &EarlyContext, expr: &Expr, span: Option<Span>) {
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match expr.node {
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// simple return is always "bad"
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ExprKind::Ret(Some(ref inner)) => {
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self.emit_return_lint(cx, (expr.span, inner.span));
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self.emit_return_lint(cx, span.expect("`else return` is not possible"), inner.span);
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}
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// a whole block? check it!
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ExprKind::Block(ref block) => {
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@ -62,25 +62,25 @@ impl ReturnPass {
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// (except for unit type functions) so we don't match it
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ExprKind::If(_, ref ifblock, Some(ref elsexpr)) => {
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self.check_block_return(cx, ifblock);
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self.check_final_expr(cx, elsexpr);
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self.check_final_expr(cx, elsexpr, None);
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}
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// a match expr, check all arms
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ExprKind::Match(_, ref arms) => {
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for arm in arms {
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self.check_final_expr(cx, &arm.body);
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self.check_final_expr(cx, &arm.body, Some(arm.body.span));
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}
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}
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_ => (),
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}
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}
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fn emit_return_lint(&mut self, cx: &EarlyContext, spans: (Span, Span)) {
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if in_external_macro(cx, spans.1) {
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fn emit_return_lint(&mut self, cx: &EarlyContext, ret_span: Span, inner_span: Span) {
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if in_external_macro(cx, inner_span) {
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return;
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}
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span_lint_and_then(cx, NEEDLESS_RETURN, spans.0, "unneeded return statement", |db| {
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if let Some(snippet) = snippet_opt(cx, spans.1) {
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db.span_suggestion(spans.0, "remove `return` as shown:", snippet);
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span_lint_and_then(cx, NEEDLESS_RETURN, ret_span, "unneeded return statement", |db| {
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if let Some(snippet) = snippet_opt(cx, inner_span) {
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db.span_suggestion(ret_span, "remove `return` as shown:", snippet);
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}
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});
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}
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@ -15,7 +15,7 @@ use std::env;
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use std::mem;
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use std::str::FromStr;
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use syntax::ast::{self, LitKind};
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use syntax::codemap::{ExpnFormat, ExpnInfo, MultiSpan, Span};
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use syntax::codemap::{ExpnFormat, ExpnInfo, MultiSpan, Span, DUMMY_SP};
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use syntax::errors::DiagnosticBuilder;
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use syntax::ptr::P;
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@ -723,3 +723,8 @@ pub fn type_is_unsafe_function(ty: ty::Ty) -> bool {
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_ => false,
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}
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}
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pub fn is_copy<'a, 'ctx>(cx: &LateContext<'a, 'ctx>, ty: ty::Ty<'ctx>, env: NodeId) -> bool {
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let env = ty::ParameterEnvironment::for_item(cx.tcx, env);
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!ty.subst(cx.tcx, env.free_substs).moves_by_default(cx.tcx.global_tcx(), &env, DUMMY_SP)
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}
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@ -1,10 +1,10 @@
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use rustc::lint::*;
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use rustc::ty::TypeVariants;
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use rustc::hir::*;
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use rustc::lint::*;
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use rustc::ty;
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use rustc_const_eval::EvalHint::ExprTypeChecked;
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use rustc_const_eval::eval_const_expr_partial;
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use syntax::codemap::Span;
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use utils::{higher, snippet, span_lint_and_then};
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use utils::{higher, is_copy, snippet, span_lint_and_then};
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/// **What it does:** This lint warns about using `&vec![..]` when using `&[..]` would be possible.
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///
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@ -35,50 +35,61 @@ impl LateLintPass for Pass {
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fn check_expr(&mut self, cx: &LateContext, expr: &Expr) {
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// search for `&vec![_]` expressions where the adjusted type is `&[_]`
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if_let_chain!{[
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let TypeVariants::TyRef(_, ref ty) = cx.tcx.expr_ty_adjusted(expr).sty,
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let TypeVariants::TySlice(..) = ty.ty.sty,
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let ty::TypeVariants::TyRef(_, ref ty) = cx.tcx.expr_ty_adjusted(expr).sty,
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let ty::TypeVariants::TySlice(..) = ty.ty.sty,
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let ExprAddrOf(_, ref addressee) = expr.node,
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let Some(vec_args) = higher::vec_macro(cx, addressee),
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], {
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check_vec_macro(cx, addressee, expr.span);
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check_vec_macro(cx, &vec_args, expr.span);
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}}
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// search for `for _ in vec![…]`
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if let Some((_, arg, _)) = higher::for_loop(expr) {
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if_let_chain!{[
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let Some((_, arg, _)) = higher::for_loop(expr),
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let Some(vec_args) = higher::vec_macro(cx, arg),
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is_copy(cx, vec_type(cx.tcx.expr_ty_adjusted(arg)), cx.tcx.map.get_parent(expr.id)),
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], {
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// report the error around the `vec!` not inside `<std macros>:`
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let span = cx.sess().codemap().source_callsite(arg.span);
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check_vec_macro(cx, arg, span);
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check_vec_macro(cx, &vec_args, span);
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}}
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}
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}
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fn check_vec_macro(cx: &LateContext, vec_args: &higher::VecArgs, span: Span) {
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let snippet = match *vec_args {
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higher::VecArgs::Repeat(elem, len) => {
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if eval_const_expr_partial(cx.tcx, len, ExprTypeChecked, None).is_ok() {
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format!("&[{}; {}]", snippet(cx, elem.span, "elem"), snippet(cx, len.span, "len")).into()
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} else {
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return;
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}
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}
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}
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higher::VecArgs::Vec(args) => {
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if let Some(last) = args.iter().last() {
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let span = Span {
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lo: args[0].span.lo,
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hi: last.span.hi,
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expn_id: args[0].span.expn_id,
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};
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format!("&[{}]", snippet(cx, span, "..")).into()
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} else {
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"&[]".into()
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}
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}
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};
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span_lint_and_then(cx, USELESS_VEC, span, "useless use of `vec!`", |db| {
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db.span_suggestion(span, "you can use a slice directly", snippet);
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});
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}
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fn check_vec_macro(cx: &LateContext, vec: &Expr, span: Span) {
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if let Some(vec_args) = higher::vec_macro(cx, vec) {
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let snippet = match vec_args {
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higher::VecArgs::Repeat(elem, len) => {
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if eval_const_expr_partial(cx.tcx, len, ExprTypeChecked, None).is_ok() {
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format!("&[{}; {}]", snippet(cx, elem.span, "elem"), snippet(cx, len.span, "len")).into()
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} else {
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return;
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}
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}
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higher::VecArgs::Vec(args) => {
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if let Some(last) = args.iter().last() {
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let span = Span {
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lo: args[0].span.lo,
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hi: last.span.hi,
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expn_id: args[0].span.expn_id,
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};
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format!("&[{}]", snippet(cx, span, "..")).into()
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} else {
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"&[]".into()
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}
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}
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};
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span_lint_and_then(cx, USELESS_VEC, span, "useless use of `vec!`", |db| {
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db.span_suggestion(span, "you can use a slice directly", snippet);
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});
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/// Return the item type of the vector (ie. the `T` in `Vec<T>`).
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fn vec_type(ty: ty::Ty) -> ty::Ty {
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if let ty::TyStruct(_, substs) = ty.sty {
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substs.types.get(ty::subst::ParamSpace::TypeSpace, 0)
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} else {
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panic!("The type of `vec!` is a not a struct?");
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}
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}
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@ -37,12 +37,11 @@ fn test_if_block() -> bool {
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fn test_match(x: bool) -> bool {
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match x {
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true => {
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return false;
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//~^ ERROR unneeded return statement
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//~| HELP remove `return` as shown
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//~| SUGGESTION false
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}
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true => return false,
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//~^ ERROR unneeded return statement
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//~| HELP remove `return` as shown
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//~| SUGGESTION false
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false => {
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return true;
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//~^ ERROR unneeded return statement
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@ -3,6 +3,9 @@
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#![deny(useless_vec)]
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#[derive(Debug)]
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struct NonCopy;
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fn on_slice(_: &[u8]) {}
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#[allow(ptr_arg)]
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fn on_vec(_: &Vec<u8>) {}
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@ -62,6 +65,10 @@ fn main() {
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//~^ ERROR useless use of `vec!`
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//~| HELP you can use
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//~| SUGGESTION for a in &[1, 2, 3] {
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println!("{}", a);
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println!("{:?}", a);
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}
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for a in vec![NonCopy, NonCopy] {
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println!("{:?}", a);
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}
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}
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Loading…
Reference in New Issue