-use crate::utils::{
- in_macro, match_def_path, match_qpath, paths, snippet, snippet_with_applicability, span_lint_and_help,
- span_lint_and_sugg, span_lint_and_then,
-};
+use clippy_utils::diagnostics::{span_lint_and_help, span_lint_and_sugg, span_lint_and_then};
+use clippy_utils::source::{snippet, snippet_with_applicability};
+use clippy_utils::{in_macro, is_diag_trait_item, is_lang_ctor, match_def_path, meets_msrv, msrvs, paths};
use if_chain::if_chain;
use rustc_errors::Applicability;
+use rustc_hir::def_id::DefId;
+use rustc_hir::LangItem::OptionNone;
use rustc_hir::{BorrowKind, Expr, ExprKind, Mutability, QPath};
-use rustc_lint::{LateContext, LateLintPass};
+use rustc_lint::{LateContext, LateLintPass, LintContext};
use rustc_middle::lint::in_external_macro;
-use rustc_session::{declare_lint_pass, declare_tool_lint};
+use rustc_semver::RustcVersion;
+use rustc_session::{declare_tool_lint, impl_lint_pass};
use rustc_span::source_map::Span;
use rustc_span::symbol::sym;
"replacing a value of type `T` with `T::default()` instead of using `std::mem::take`"
}
-declare_lint_pass!(MemReplace =>
+impl_lint_pass!(MemReplace =>
[MEM_REPLACE_OPTION_WITH_NONE, MEM_REPLACE_WITH_UNINIT, MEM_REPLACE_WITH_DEFAULT]);
-fn check_replace_option_with_none(cx: &LateContext<'_, '_>, src: &Expr<'_>, dest: &Expr<'_>, expr_span: Span) {
+fn check_replace_option_with_none(cx: &LateContext<'_>, src: &Expr<'_>, dest: &Expr<'_>, expr_span: Span) {
if let ExprKind::Path(ref replacement_qpath) = src.kind {
// Check that second argument is `Option::None`
- if match_qpath(replacement_qpath, &paths::OPTION_NONE) {
+ if is_lang_ctor(cx, replacement_qpath, OptionNone) {
// Since this is a late pass (already type-checked),
// and we already know that the second argument is an
// `Option`, we do not need to check the first
// argument's type. All that's left is to get
// replacee's path.
let replaced_path = match dest.kind {
- ExprKind::AddrOf(BorrowKind::Ref, Mutability::Mut, ref replaced) => {
- if let ExprKind::Path(QPath::Resolved(None, ref replaced_path)) = replaced.kind {
+ ExprKind::AddrOf(BorrowKind::Ref, Mutability::Mut, replaced) => {
+ if let ExprKind::Path(QPath::Resolved(None, replaced_path)) = replaced.kind {
replaced_path
} else {
return;
}
},
- ExprKind::Path(QPath::Resolved(None, ref replaced_path)) => replaced_path,
+ ExprKind::Path(QPath::Resolved(None, replaced_path)) => replaced_path,
_ => return,
};
}
}
-fn check_replace_with_uninit(cx: &LateContext<'_, '_>, src: &Expr<'_>, dest: &Expr<'_>, expr_span: Span) {
+fn check_replace_with_uninit(cx: &LateContext<'_>, src: &Expr<'_>, dest: &Expr<'_>, expr_span: Span) {
if_chain! {
// check if replacement is mem::MaybeUninit::uninit().assume_init()
- if let Some(method_def_id) = cx.tables.type_dependent_def_id(src.hir_id);
+ if let Some(method_def_id) = cx.typeck_results().type_dependent_def_id(src.hir_id);
if cx.tcx.is_diagnostic_item(sym::assume_init, method_def_id);
then {
let mut applicability = Applicability::MachineApplicable;
}
if_chain! {
- if let ExprKind::Call(ref repl_func, ref repl_args) = src.kind;
+ if let ExprKind::Call(repl_func, repl_args) = src.kind;
if repl_args.is_empty();
if let ExprKind::Path(ref repl_func_qpath) = repl_func.kind;
- if let Some(repl_def_id) = cx.tables.qpath_res(repl_func_qpath, repl_func.hir_id).opt_def_id();
+ if let Some(repl_def_id) = cx.qpath_res(repl_func_qpath, repl_func.hir_id).opt_def_id();
then {
if cx.tcx.is_diagnostic_item(sym::mem_uninitialized, repl_def_id) {
let mut applicability = Applicability::MachineApplicable;
applicability,
);
} else if cx.tcx.is_diagnostic_item(sym::mem_zeroed, repl_def_id) &&
- !cx.tables.expr_ty(src).is_primitive() {
+ !cx.typeck_results().expr_ty(src).is_primitive() {
span_lint_and_help(
cx,
MEM_REPLACE_WITH_UNINIT,
}
}
-fn check_replace_with_default(cx: &LateContext<'_, '_>, src: &Expr<'_>, dest: &Expr<'_>, expr_span: Span) {
- if let ExprKind::Call(ref repl_func, _) = src.kind {
- if_chain! {
- if !in_external_macro(cx.tcx.sess, expr_span);
- if let ExprKind::Path(ref repl_func_qpath) = repl_func.kind;
- if let Some(repl_def_id) = cx.tables.qpath_res(repl_func_qpath, repl_func.hir_id).opt_def_id();
- if match_def_path(cx, repl_def_id, &paths::DEFAULT_TRAIT_METHOD);
- then {
- span_lint_and_then(
- cx,
- MEM_REPLACE_WITH_DEFAULT,
- expr_span,
- "replacing a value of type `T` with `T::default()` is better expressed using `std::mem::take`",
- |diag| {
- if !in_macro(expr_span) {
- let suggestion = format!("std::mem::take({})", snippet(cx, dest.span, ""));
-
- diag.span_suggestion(
- expr_span,
- "consider using",
- suggestion,
- Applicability::MachineApplicable
- );
- }
- }
- );
+/// Returns true if the `def_id` associated with the `path` is recognized as a "default-equivalent"
+/// constructor from the std library
+fn is_default_equivalent_ctor(cx: &LateContext<'_>, def_id: DefId, path: &QPath<'_>) -> bool {
+ let std_types_symbols = &[
+ sym::string_type,
+ sym::vec_type,
+ sym::vecdeque_type,
+ sym::LinkedList,
+ sym::hashmap_type,
+ sym::BTreeMap,
+ sym::hashset_type,
+ sym::BTreeSet,
+ sym::BinaryHeap,
+ ];
+
+ if let QPath::TypeRelative(_, method) = path {
+ if method.ident.name == sym::new {
+ if let Some(impl_did) = cx.tcx.impl_of_method(def_id) {
+ if let Some(adt) = cx.tcx.type_of(impl_did).ty_adt_def() {
+ return std_types_symbols
+ .iter()
+ .any(|&symbol| cx.tcx.is_diagnostic_item(symbol, adt.did));
+ }
}
}
}
+ false
+}
+
+fn check_replace_with_default(cx: &LateContext<'_>, src: &Expr<'_>, dest: &Expr<'_>, expr_span: Span) {
+ if_chain! {
+ if let ExprKind::Call(repl_func, _) = src.kind;
+ if !in_external_macro(cx.tcx.sess, expr_span);
+ if let ExprKind::Path(ref repl_func_qpath) = repl_func.kind;
+ if let Some(repl_def_id) = cx.qpath_res(repl_func_qpath, repl_func.hir_id).opt_def_id();
+ if is_diag_trait_item(cx, repl_def_id, sym::Default)
+ || is_default_equivalent_ctor(cx, repl_def_id, repl_func_qpath);
+
+ then {
+ span_lint_and_then(
+ cx,
+ MEM_REPLACE_WITH_DEFAULT,
+ expr_span,
+ "replacing a value of type `T` with `T::default()` is better expressed using `std::mem::take`",
+ |diag| {
+ if !in_macro(expr_span) {
+ let suggestion = format!("std::mem::take({})", snippet(cx, dest.span, ""));
+
+ diag.span_suggestion(
+ expr_span,
+ "consider using",
+ suggestion,
+ Applicability::MachineApplicable
+ );
+ }
+ }
+ );
+ }
+ }
+}
+
+pub struct MemReplace {
+ msrv: Option<RustcVersion>,
+}
+
+impl MemReplace {
+ #[must_use]
+ pub fn new(msrv: Option<RustcVersion>) -> Self {
+ Self { msrv }
+ }
}
-impl<'a, 'tcx> LateLintPass<'a, 'tcx> for MemReplace {
- fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr<'_>) {
+impl<'tcx> LateLintPass<'tcx> for MemReplace {
+ fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
if_chain! {
// Check that `expr` is a call to `mem::replace()`
- if let ExprKind::Call(ref func, ref func_args) = expr.kind;
+ if let ExprKind::Call(func, func_args) = expr.kind;
if let ExprKind::Path(ref func_qpath) = func.kind;
- if let Some(def_id) = cx.tables.qpath_res(func_qpath, func.hir_id).opt_def_id();
+ if let Some(def_id) = cx.qpath_res(func_qpath, func.hir_id).opt_def_id();
if match_def_path(cx, def_id, &paths::MEM_REPLACE);
- if let [dest, src] = &**func_args;
+ if let [dest, src] = func_args;
then {
check_replace_option_with_none(cx, src, dest, expr.span);
check_replace_with_uninit(cx, src, dest, expr.span);
- check_replace_with_default(cx, src, dest, expr.span);
+ if meets_msrv(self.msrv.as_ref(), &msrvs::MEM_TAKE) {
+ check_replace_with_default(cx, src, dest, expr.span);
+ }
}
}
}
+ extract_msrv_attr!(LateContext);
}
projects / rust.git / blobdiff