d647696c1f
So, some context for this, well, more a story. I'm not used to scripting, I've never really scripted anything, even if it's a valuable skill. I just never really needed it. Now, `@flip1995` correctly suggested using a script for this in `rust-clippy#7813`... And I decided to write a script using nushell because why not? This was a mistake... I spend way more time on this than I would like to admit. It has definitely been more than 4 hours. It shouldn't take that long, but me being new to scripting and nushell just wasn't a good mixture... Anyway, here is the script that creates another script which adds the versions. Fun... Just execute this on the `gh-pages` branch and the resulting `replacer.sh` in `clippy_lints` and it should all work. ```nu mv v0.0.212 rust-1.00.0; mv beta rust-1.57.0; mv master rust-1.58.0; let paths = (open ./rust-1.58.0/lints.json | select id id_span | flatten | select id path); let versions = ( ls | where name =~ "rust-" | select name | format {name}/lints.json | each { open $it | select id | insert version $it | str substring "5,11" version} | group-by id | rotate counter-clockwise id version | update version {get version | first 1} | flatten | select id version); $paths | each { |row| let version = ($versions | where id == ($row.id) | format {version}) let idu = ($row.id | str upcase) $"sed -i '0,/($idu),/{s/pub ($idu),/#[clippy::version = "($version)"]\n pub ($idu),/}' ($row.path)" } | str collect ";" | str find-replace --all '1.00.0' 'pre 1.29.0' | save "replacer.sh"; ``` And this still has some problems, but at this point I just want to be done -.-
450 lines
17 KiB
Rust
450 lines
17 KiB
Rust
//! Checks for usage of `&Vec[_]` and `&String`.
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use clippy_utils::diagnostics::{span_lint, span_lint_and_sugg, span_lint_and_then};
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use clippy_utils::ptr::get_spans;
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use clippy_utils::source::snippet_opt;
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use clippy_utils::ty::walk_ptrs_hir_ty;
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use clippy_utils::{expr_path_res, is_lint_allowed, match_any_diagnostic_items, paths};
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use if_chain::if_chain;
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use rustc_errors::Applicability;
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use rustc_hir::def::Res;
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use rustc_hir::{
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BinOpKind, BodyId, Expr, ExprKind, FnDecl, FnRetTy, GenericArg, Impl, ImplItem, ImplItemKind, Item, ItemKind,
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Lifetime, MutTy, Mutability, Node, PathSegment, QPath, TraitFn, TraitItem, TraitItemKind, Ty, TyKind,
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};
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use rustc_lint::{LateContext, LateLintPass};
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use rustc_session::{declare_lint_pass, declare_tool_lint};
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use rustc_span::source_map::Span;
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use rustc_span::symbol::Symbol;
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use rustc_span::{sym, MultiSpan};
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use std::borrow::Cow;
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declare_clippy_lint! {
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/// ### What it does
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/// This lint checks for function arguments of type `&String`
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/// or `&Vec` unless the references are mutable. It will also suggest you
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/// replace `.clone()` calls with the appropriate `.to_owned()`/`to_string()`
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/// calls.
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///
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/// ### Why is this bad?
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/// Requiring the argument to be of the specific size
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/// makes the function less useful for no benefit; slices in the form of `&[T]`
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/// or `&str` usually suffice and can be obtained from other types, too.
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///
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/// ### Known problems
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/// The lint does not follow data. So if you have an
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/// argument `x` and write `let y = x; y.clone()` the lint will not suggest
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/// changing that `.clone()` to `.to_owned()`.
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///
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/// Other functions called from this function taking a `&String` or `&Vec`
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/// argument may also fail to compile if you change the argument. Applying
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/// this lint on them will fix the problem, but they may be in other crates.
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///
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/// One notable example of a function that may cause issues, and which cannot
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/// easily be changed due to being in the standard library is `Vec::contains`.
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/// when called on a `Vec<Vec<T>>`. If a `&Vec` is passed to that method then
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/// it will compile, but if a `&[T]` is passed then it will not compile.
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///
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/// ```ignore
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/// fn cannot_take_a_slice(v: &Vec<u8>) -> bool {
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/// let vec_of_vecs: Vec<Vec<u8>> = some_other_fn();
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///
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/// vec_of_vecs.contains(v)
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/// }
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/// ```
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///
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/// Also there may be `fn(&Vec)`-typed references pointing to your function.
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/// If you have them, you will get a compiler error after applying this lint's
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/// suggestions. You then have the choice to undo your changes or change the
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/// type of the reference.
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///
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/// Note that if the function is part of your public interface, there may be
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/// other crates referencing it, of which you may not be aware. Carefully
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/// deprecate the function before applying the lint suggestions in this case.
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///
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/// ### Example
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/// ```ignore
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/// // Bad
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/// fn foo(&Vec<u32>) { .. }
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///
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/// // Good
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/// fn foo(&[u32]) { .. }
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/// ```
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#[clippy::version = "pre 1.29.0"]
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pub PTR_ARG,
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style,
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"fn arguments of the type `&Vec<...>` or `&String`, suggesting to use `&[...]` or `&str` instead, respectively"
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}
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declare_clippy_lint! {
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/// ### What it does
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/// This lint checks for equality comparisons with `ptr::null`
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///
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/// ### Why is this bad?
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/// It's easier and more readable to use the inherent
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/// `.is_null()`
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/// method instead
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///
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/// ### Example
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/// ```ignore
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/// // Bad
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/// if x == ptr::null {
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/// ..
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/// }
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///
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/// // Good
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/// if x.is_null() {
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/// ..
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/// }
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/// ```
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#[clippy::version = "pre 1.29.0"]
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pub CMP_NULL,
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style,
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"comparing a pointer to a null pointer, suggesting to use `.is_null()` instead"
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}
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declare_clippy_lint! {
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/// ### What it does
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/// This lint checks for functions that take immutable
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/// references and return mutable ones.
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///
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/// ### Why is this bad?
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/// This is trivially unsound, as one can create two
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/// mutable references from the same (immutable!) source.
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/// This [error](https://github.com/rust-lang/rust/issues/39465)
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/// actually lead to an interim Rust release 1.15.1.
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///
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/// ### Known problems
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/// To be on the conservative side, if there's at least one
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/// mutable reference with the output lifetime, this lint will not trigger.
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/// In practice, this case is unlikely anyway.
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///
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/// ### Example
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/// ```ignore
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/// fn foo(&Foo) -> &mut Bar { .. }
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/// ```
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#[clippy::version = "pre 1.29.0"]
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pub MUT_FROM_REF,
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correctness,
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"fns that create mutable refs from immutable ref args"
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}
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declare_clippy_lint! {
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/// ### What it does
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/// This lint checks for invalid usages of `ptr::null`.
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///
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/// ### Why is this bad?
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/// This causes undefined behavior.
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///
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/// ### Example
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/// ```ignore
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/// // Bad. Undefined behavior
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/// unsafe { std::slice::from_raw_parts(ptr::null(), 0); }
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/// ```
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///
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/// ```ignore
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/// // Good
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/// unsafe { std::slice::from_raw_parts(NonNull::dangling().as_ptr(), 0); }
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/// ```
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#[clippy::version = "1.53.0"]
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pub INVALID_NULL_PTR_USAGE,
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correctness,
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"invalid usage of a null pointer, suggesting `NonNull::dangling()` instead"
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}
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declare_lint_pass!(Ptr => [PTR_ARG, CMP_NULL, MUT_FROM_REF, INVALID_NULL_PTR_USAGE]);
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impl<'tcx> LateLintPass<'tcx> for Ptr {
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fn check_item(&mut self, cx: &LateContext<'tcx>, item: &'tcx Item<'_>) {
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if let ItemKind::Fn(ref sig, _, body_id) = item.kind {
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check_fn(cx, sig.decl, Some(body_id));
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}
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}
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fn check_impl_item(&mut self, cx: &LateContext<'tcx>, item: &'tcx ImplItem<'_>) {
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if let ImplItemKind::Fn(ref sig, body_id) = item.kind {
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let parent_item = cx.tcx.hir().get_parent_item(item.hir_id());
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if let Some(Node::Item(it)) = cx.tcx.hir().find(parent_item) {
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if let ItemKind::Impl(Impl { of_trait: Some(_), .. }) = it.kind {
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return; // ignore trait impls
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}
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}
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check_fn(cx, sig.decl, Some(body_id));
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}
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}
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fn check_trait_item(&mut self, cx: &LateContext<'tcx>, item: &'tcx TraitItem<'_>) {
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if let TraitItemKind::Fn(ref sig, ref trait_method) = item.kind {
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let body_id = if let TraitFn::Provided(b) = *trait_method {
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Some(b)
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} else {
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None
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};
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check_fn(cx, sig.decl, body_id);
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}
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}
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fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
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if let ExprKind::Binary(ref op, l, r) = expr.kind {
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if (op.node == BinOpKind::Eq || op.node == BinOpKind::Ne) && (is_null_path(cx, l) || is_null_path(cx, r)) {
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span_lint(
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cx,
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CMP_NULL,
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expr.span,
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"comparing with null is better expressed by the `.is_null()` method",
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);
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}
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} else {
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check_invalid_ptr_usage(cx, expr);
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}
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}
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}
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fn check_invalid_ptr_usage<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
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// (fn_path, arg_indices) - `arg_indices` are the `arg` positions where null would cause U.B.
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const INVALID_NULL_PTR_USAGE_TABLE: [(&[&str], &[usize]); 16] = [
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(&paths::SLICE_FROM_RAW_PARTS, &[0]),
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(&paths::SLICE_FROM_RAW_PARTS_MUT, &[0]),
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(&paths::PTR_COPY, &[0, 1]),
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(&paths::PTR_COPY_NONOVERLAPPING, &[0, 1]),
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(&paths::PTR_READ, &[0]),
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(&paths::PTR_READ_UNALIGNED, &[0]),
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(&paths::PTR_READ_VOLATILE, &[0]),
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(&paths::PTR_REPLACE, &[0]),
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(&paths::PTR_SLICE_FROM_RAW_PARTS, &[0]),
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(&paths::PTR_SLICE_FROM_RAW_PARTS_MUT, &[0]),
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(&paths::PTR_SWAP, &[0, 1]),
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(&paths::PTR_SWAP_NONOVERLAPPING, &[0, 1]),
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(&paths::PTR_WRITE, &[0]),
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(&paths::PTR_WRITE_UNALIGNED, &[0]),
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(&paths::PTR_WRITE_VOLATILE, &[0]),
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(&paths::PTR_WRITE_BYTES, &[0]),
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];
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if_chain! {
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if let ExprKind::Call(fun, args) = expr.kind;
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if let ExprKind::Path(ref qpath) = fun.kind;
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if let Some(fun_def_id) = cx.qpath_res(qpath, fun.hir_id).opt_def_id();
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let fun_def_path = cx.get_def_path(fun_def_id).into_iter().map(Symbol::to_ident_string).collect::<Vec<_>>();
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if let Some(&(_, arg_indices)) = INVALID_NULL_PTR_USAGE_TABLE
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.iter()
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.find(|&&(fn_path, _)| fn_path == fun_def_path);
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then {
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for &arg_idx in arg_indices {
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if let Some(arg) = args.get(arg_idx).filter(|arg| is_null_path(cx, arg)) {
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span_lint_and_sugg(
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cx,
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INVALID_NULL_PTR_USAGE,
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arg.span,
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"pointer must be non-null",
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"change this to",
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"core::ptr::NonNull::dangling().as_ptr()".to_string(),
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Applicability::MachineApplicable,
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);
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}
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}
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}
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}
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}
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#[allow(clippy::too_many_lines)]
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fn check_fn(cx: &LateContext<'_>, decl: &FnDecl<'_>, opt_body_id: Option<BodyId>) {
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let body = opt_body_id.map(|id| cx.tcx.hir().body(id));
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for (idx, arg) in decl.inputs.iter().enumerate() {
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// Honor the allow attribute on parameters. See issue 5644.
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if let Some(body) = &body {
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if is_lint_allowed(cx, PTR_ARG, body.params[idx].hir_id) {
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continue;
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}
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}
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let (item_name, path) = if_chain! {
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if let TyKind::Rptr(_, MutTy { ty, mutbl: Mutability::Not }) = arg.kind;
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if let TyKind::Path(QPath::Resolved(_, path)) = ty.kind;
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if let Res::Def(_, did) = path.res;
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if let Some(item_name) = cx.tcx.get_diagnostic_name(did);
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then {
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(item_name, path)
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} else {
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continue
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}
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};
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match item_name {
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sym::Vec => {
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if let Some(spans) = get_spans(cx, opt_body_id, idx, &[("clone", ".to_owned()")]) {
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span_lint_and_then(
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cx,
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PTR_ARG,
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arg.span,
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"writing `&Vec<_>` instead of `&[_]` involves one more reference and cannot be used \
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with non-Vec-based slices",
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|diag| {
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if let Some(ref snippet) = get_only_generic_arg_snippet(cx, arg) {
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diag.span_suggestion(
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arg.span,
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"change this to",
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format!("&[{}]", snippet),
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Applicability::Unspecified,
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);
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}
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for (clonespan, suggestion) in spans {
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diag.span_suggestion(
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clonespan,
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&snippet_opt(cx, clonespan).map_or("change the call to".into(), |x| {
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Cow::Owned(format!("change `{}` to", x))
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}),
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suggestion.into(),
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Applicability::Unspecified,
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);
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}
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},
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);
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}
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},
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sym::String => {
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if let Some(spans) = get_spans(cx, opt_body_id, idx, &[("clone", ".to_string()"), ("as_str", "")]) {
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span_lint_and_then(
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cx,
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PTR_ARG,
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arg.span,
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"writing `&String` instead of `&str` involves a new object where a slice will do",
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|diag| {
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diag.span_suggestion(arg.span, "change this to", "&str".into(), Applicability::Unspecified);
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for (clonespan, suggestion) in spans {
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diag.span_suggestion_short(
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clonespan,
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&snippet_opt(cx, clonespan).map_or("change the call to".into(), |x| {
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Cow::Owned(format!("change `{}` to", x))
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}),
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suggestion.into(),
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Applicability::Unspecified,
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);
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}
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},
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);
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}
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},
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sym::PathBuf => {
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if let Some(spans) = get_spans(cx, opt_body_id, idx, &[("clone", ".to_path_buf()"), ("as_path", "")]) {
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span_lint_and_then(
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cx,
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PTR_ARG,
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arg.span,
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"writing `&PathBuf` instead of `&Path` involves a new object where a slice will do",
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|diag| {
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diag.span_suggestion(
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arg.span,
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"change this to",
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"&Path".into(),
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Applicability::Unspecified,
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);
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for (clonespan, suggestion) in spans {
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diag.span_suggestion_short(
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clonespan,
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&snippet_opt(cx, clonespan).map_or("change the call to".into(), |x| {
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Cow::Owned(format!("change `{}` to", x))
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}),
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suggestion.into(),
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Applicability::Unspecified,
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);
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}
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},
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);
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}
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},
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sym::Cow => {
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if_chain! {
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if let [ref bx] = *path.segments;
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if let Some(params) = bx.args;
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if !params.parenthesized;
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if let Some(inner) = params.args.iter().find_map(|arg| match arg {
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GenericArg::Type(ty) => Some(ty),
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_ => None,
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});
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let replacement = snippet_opt(cx, inner.span);
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if let Some(r) = replacement;
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then {
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span_lint_and_sugg(
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cx,
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PTR_ARG,
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arg.span,
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"using a reference to `Cow` is not recommended",
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"change this to",
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"&".to_owned() + &r,
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Applicability::Unspecified,
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);
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}
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}
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},
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_ => {},
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}
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}
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|
|
if let FnRetTy::Return(ty) = decl.output {
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|
if let Some((out, Mutability::Mut, _)) = get_rptr_lm(ty) {
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|
let mut immutables = vec![];
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|
for (_, ref mutbl, ref argspan) in decl
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.inputs
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.iter()
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.filter_map(get_rptr_lm)
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.filter(|&(lt, _, _)| lt.name == out.name)
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{
|
|
if *mutbl == Mutability::Mut {
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return;
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}
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immutables.push(*argspan);
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}
|
|
if immutables.is_empty() {
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|
return;
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|
}
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|
span_lint_and_then(
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|
cx,
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MUT_FROM_REF,
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ty.span,
|
|
"mutable borrow from immutable input(s)",
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|
|diag| {
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let ms = MultiSpan::from_spans(immutables);
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diag.span_note(ms, "immutable borrow here");
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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 get_only_generic_arg_snippet(cx: &LateContext<'_>, arg: &Ty<'_>) -> Option<String> {
|
|
if_chain! {
|
|
if let TyKind::Path(QPath::Resolved(_, path)) = walk_ptrs_hir_ty(arg).kind;
|
|
if let Some(&PathSegment{args: Some(parameters), ..}) = path.segments.last();
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|
let types: Vec<_> = parameters.args.iter().filter_map(|arg| match arg {
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|
GenericArg::Type(ty) => Some(ty),
|
|
_ => None,
|
|
}).collect();
|
|
if types.len() == 1;
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|
then {
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|
snippet_opt(cx, types[0].span)
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|
} else {
|
|
None
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|
}
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|
}
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|
}
|
|
|
|
fn get_rptr_lm<'tcx>(ty: &'tcx Ty<'tcx>) -> Option<(&'tcx Lifetime, Mutability, Span)> {
|
|
if let TyKind::Rptr(ref lt, ref m) = ty.kind {
|
|
Some((lt, m.mutbl, ty.span))
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|
} else {
|
|
None
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|
}
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|
}
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|
|
fn is_null_path(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
|
|
if let ExprKind::Call(pathexp, []) = expr.kind {
|
|
expr_path_res(cx, pathexp).opt_def_id().map_or(false, |id| {
|
|
match_any_diagnostic_items(cx, id, &[sym::ptr_null, sym::ptr_null_mut]).is_some()
|
|
})
|
|
} else {
|
|
false
|
|
}
|
|
}
|