use crate::utils::{get_parent_expr, implements_trait, snippet, span_lint_and_sugg};
use if_chain::if_chain;
-use rustc_ast::util::parser::ExprPrecedence;
+use rustc_ast::util::parser::{ExprPrecedence, PREC_POSTFIX, PREC_PREFIX};
use rustc_errors::Applicability;
use rustc_hir::{Expr, ExprKind};
use rustc_lint::{LateContext, LateLintPass};
declare_clippy_lint! {
/// **What it does:** Checks for explicit `deref()` or `deref_mut()` method calls.
///
- /// **Why is this bad?** Derefencing by `&*x` or `&mut *x` is clearer and more concise,
+ /// **Why is this bad?** Dereferencing by `&*x` or `&mut *x` is clearer and more concise,
/// when not part of a method chain.
///
/// **Example:**
EXPLICIT_DEREF_METHODS
]);
-impl<'a, 'tcx> LateLintPass<'a, 'tcx> for Dereferencing {
- fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr<'_>) {
+impl<'tcx> LateLintPass<'tcx> for Dereferencing {
+ fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
if_chain! {
if !expr.span.from_expansion();
- if let ExprKind::MethodCall(ref method_name, _, ref args) = &expr.kind;
+ if let ExprKind::MethodCall(ref method_name, _, ref args, _) = &expr.kind;
if args.len() == 1;
then {
if let ExprKind::MethodCall(..) = parent_expr.kind {
return;
}
- // Check for unary precedence
- if let ExprPrecedence::Unary = parent_expr.precedence() {
- return;
+ // Check for Expr that we don't want to be linted
+ let precedence = parent_expr.precedence();
+ match precedence {
+ // Lint a Call is ok though
+ ExprPrecedence::Call | ExprPrecedence::AddrOf => (),
+ _ => {
+ if precedence.order() >= PREC_PREFIX && precedence.order() <= PREC_POSTFIX {
+ return;
+ }
+ }
}
}
let name = method_name.ident.as_str();
}
}
-fn lint_deref(cx: &LateContext<'_, '_>, method_name: &str, call_expr: &Expr<'_>, var_span: Span, expr_span: Span) {
+fn lint_deref(cx: &LateContext<'_>, method_name: &str, call_expr: &Expr<'_>, var_span: Span, expr_span: Span) {
match method_name {
"deref" => {
- if cx
- .tcx
- .lang_items()
- .deref_trait()
- .map_or(false, |id| implements_trait(cx, cx.tables.expr_ty(&call_expr), id, &[]))
- {
+ let impls_deref_trait = cx.tcx.lang_items().deref_trait().map_or(false, |id| {
+ implements_trait(cx, cx.typeck_results().expr_ty(&call_expr), id, &[])
+ });
+ if impls_deref_trait {
span_lint_and_sugg(
cx,
EXPLICIT_DEREF_METHODS,
}
},
"deref_mut" => {
- if cx
- .tcx
- .lang_items()
- .deref_mut_trait()
- .map_or(false, |id| implements_trait(cx, cx.tables.expr_ty(&call_expr), id, &[]))
- {
+ let impls_deref_mut_trait = cx.tcx.lang_items().deref_mut_trait().map_or(false, |id| {
+ implements_trait(cx, cx.typeck_results().expr_ty(&call_expr), id, &[])
+ });
+ if impls_deref_mut_trait {
span_lint_and_sugg(
cx,
EXPLICIT_DEREF_METHODS,