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Refactor drop_ref.rs to use the if_let_chain macro.

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This commit is contained in:
Theemathas Chirananthavat 2016-12-29 19:22:24 -08:00
parent 3050d90930
commit f55d20ff46
1 changed files with 17 additions and 24 deletions
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41
clippy_lints/src/drop_ref.rs
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@ -1,7 +1,6 @@
use rustc::lint::*;
use rustc::ty;
use rustc::hir::*;
use syntax::codemap::Span;
use utils::{match_def_path, paths, span_note_and_lint};
/// **What it does:** Checks for calls to `std::mem::drop` with a reference
@ -37,29 +36,23 @@ impl LintPass for Pass {
impl<'a, 'tcx> LateLintPass<'a, 'tcx> for Pass {
fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr) {
if let ExprCall(ref path, ref args) = expr.node {
if let ExprPath(ref qpath) = path.node {
let def_id = cx.tcx.tables().qpath_def(qpath, path.id).def_id();
if match_def_path(cx, def_id, &paths::DROP) {
if args.len() != 1 {
return;
}
check_drop_arg(cx, expr.span, &args[0]);
}
if_let_chain!{[
let ExprCall(ref path, ref args) = expr.node,
let ExprPath(ref qpath) = path.node,
match_def_path(cx, cx.tcx.tables().qpath_def(qpath, path.id).def_id(), &paths::DROP),
args.len() == 1,
], {
let arg = &args[0];
let arg_ty = cx.tcx.tables().expr_ty(arg);
if let ty::TyRef(..) = arg_ty.sty {
span_note_and_lint(cx,
DROP_REF,
expr.span,
"call to `std::mem::drop` with a reference argument. \
Dropping a reference does nothing",
arg.span,
&format!("argument has type {}", arg_ty.sty));
}
}
}
}
fn check_drop_arg(cx: &LateContext, call_span: Span, arg: &Expr) {
let arg_ty = cx.tcx.tables().expr_ty(arg);
if let ty::TyRef(..) = arg_ty.sty {
span_note_and_lint(cx,
DROP_REF,
call_span,
"call to `std::mem::drop` with a reference argument. \
Dropping a reference does nothing",
arg.span,
&format!("argument has type {}", arg_ty.sty));
}}
}
}