3561 lines
122 KiB
Rust
3561 lines
122 KiB
Rust
mod inefficient_to_string;
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mod manual_saturating_arithmetic;
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mod option_map_unwrap_or;
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mod unnecessary_filter_map;
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use std::borrow::Cow;
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use std::fmt;
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use std::iter;
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use if_chain::if_chain;
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use rustc_ast::ast;
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use rustc_errors::Applicability;
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use rustc_hir as hir;
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use rustc_hir::intravisit::{self, Visitor};
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use rustc_lint::{LateContext, LateLintPass, Lint, LintContext};
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use rustc_middle::hir::map::Map;
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use rustc_middle::lint::in_external_macro;
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use rustc_middle::ty::{self, Predicate, Ty};
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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::{sym, Symbol, SymbolStr};
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use crate::consts::{constant, Constant};
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use crate::utils::usage::mutated_variables;
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use crate::utils::{
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get_arg_name, get_parent_expr, get_trait_def_id, has_iter_method, implements_trait, in_macro, is_copy,
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is_ctor_or_promotable_const_function, is_expn_of, is_type_diagnostic_item, iter_input_pats, last_path_segment,
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match_def_path, match_qpath, match_trait_method, match_type, match_var, method_calls, method_chain_args, paths,
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remove_blocks, return_ty, same_tys, single_segment_path, snippet, snippet_with_applicability,
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snippet_with_macro_callsite, span_lint, span_lint_and_help, span_lint_and_note, span_lint_and_sugg,
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span_lint_and_then, sugg, walk_ptrs_ty, walk_ptrs_ty_depth, SpanlessEq,
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};
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declare_clippy_lint! {
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/// **What it does:** Checks for `.unwrap()` calls on `Option`s.
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///
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/// **Why is this bad?** Usually it is better to handle the `None` case, or to
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/// at least call `.expect(_)` with a more helpful message. Still, for a lot of
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/// quick-and-dirty code, `unwrap` is a good choice, which is why this lint is
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/// `Allow` by default.
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///
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/// **Known problems:** None.
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///
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/// **Example:**
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///
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/// Using unwrap on an `Option`:
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///
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/// ```rust
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/// let opt = Some(1);
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/// opt.unwrap();
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/// ```
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///
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/// Better:
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///
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/// ```rust
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/// let opt = Some(1);
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/// opt.expect("more helpful message");
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/// ```
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pub OPTION_UNWRAP_USED,
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restriction,
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"using `Option.unwrap()`, which should at least get a better message using `expect()`"
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}
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declare_clippy_lint! {
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/// **What it does:** Checks for `.unwrap()` calls on `Result`s.
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///
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/// **Why is this bad?** `result.unwrap()` will let the thread panic on `Err`
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/// values. Normally, you want to implement more sophisticated error handling,
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/// and propagate errors upwards with `?` operator.
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///
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/// Even if you want to panic on errors, not all `Error`s implement good
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/// messages on display. Therefore, it may be beneficial to look at the places
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/// where they may get displayed. Activate this lint to do just that.
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///
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/// **Known problems:** None.
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///
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/// **Example:**
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/// Using unwrap on an `Result`:
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///
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/// ```rust
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/// let res: Result<usize, ()> = Ok(1);
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/// res.unwrap();
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/// ```
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///
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/// Better:
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///
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/// ```rust
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/// let res: Result<usize, ()> = Ok(1);
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/// res.expect("more helpful message");
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/// ```
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pub RESULT_UNWRAP_USED,
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restriction,
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"using `Result.unwrap()`, which might be better handled"
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}
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declare_clippy_lint! {
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/// **What it does:** Checks for `.expect()` calls on `Option`s.
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///
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/// **Why is this bad?** Usually it is better to handle the `None` case. Still,
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/// for a lot of quick-and-dirty code, `expect` is a good choice, which is why
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/// this lint is `Allow` by default.
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///
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/// **Known problems:** None.
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///
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/// **Example:**
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///
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/// Using expect on an `Option`:
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///
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/// ```rust
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/// let opt = Some(1);
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/// opt.expect("one");
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/// ```
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///
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/// Better:
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///
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/// ```rust,ignore
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/// let opt = Some(1);
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/// opt?;
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/// ```
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pub OPTION_EXPECT_USED,
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restriction,
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"using `Option.expect()`, which might be better handled"
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}
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declare_clippy_lint! {
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/// **What it does:** Checks for `.expect()` calls on `Result`s.
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///
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/// **Why is this bad?** `result.expect()` will let the thread panic on `Err`
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/// values. Normally, you want to implement more sophisticated error handling,
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/// and propagate errors upwards with `?` operator.
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///
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/// **Known problems:** None.
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///
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/// **Example:**
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/// Using expect on an `Result`:
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///
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/// ```rust
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/// let res: Result<usize, ()> = Ok(1);
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/// res.expect("one");
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/// ```
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///
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/// Better:
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///
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/// ```rust
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/// let res: Result<usize, ()> = Ok(1);
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/// res?;
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/// # Ok::<(), ()>(())
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/// ```
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pub RESULT_EXPECT_USED,
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restriction,
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"using `Result.expect()`, which might be better handled"
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}
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declare_clippy_lint! {
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/// **What it does:** Checks for methods that should live in a trait
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/// implementation of a `std` trait (see [llogiq's blog
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/// post](http://llogiq.github.io/2015/07/30/traits.html) for further
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/// information) instead of an inherent implementation.
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///
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/// **Why is this bad?** Implementing the traits improve ergonomics for users of
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/// the code, often with very little cost. Also people seeing a `mul(...)`
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/// method
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/// may expect `*` to work equally, so you should have good reason to disappoint
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/// them.
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///
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/// **Known problems:** None.
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///
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/// **Example:**
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/// ```rust
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/// struct X;
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/// impl X {
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/// fn add(&self, other: &X) -> X {
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/// // ..
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/// # X
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/// }
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/// }
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/// ```
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pub SHOULD_IMPLEMENT_TRAIT,
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style,
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"defining a method that should be implementing a std trait"
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}
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declare_clippy_lint! {
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/// **What it does:** Checks for methods with certain name prefixes and which
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/// doesn't match how self is taken. The actual rules are:
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///
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/// |Prefix |`self` taken |
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/// |-------|----------------------|
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/// |`as_` |`&self` or `&mut self`|
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/// |`from_`| none |
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/// |`into_`|`self` |
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/// |`is_` |`&self` or none |
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/// |`to_` |`&self` |
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///
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/// **Why is this bad?** Consistency breeds readability. If you follow the
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/// conventions, your users won't be surprised that they, e.g., need to supply a
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/// mutable reference to a `as_..` function.
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///
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/// **Known problems:** None.
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///
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/// **Example:**
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/// ```rust
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/// # struct X;
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/// impl X {
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/// fn as_str(self) -> &'static str {
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/// // ..
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/// # ""
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/// }
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/// }
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/// ```
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pub WRONG_SELF_CONVENTION,
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style,
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"defining a method named with an established prefix (like \"into_\") that takes `self` with the wrong convention"
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}
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declare_clippy_lint! {
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/// **What it does:** This is the same as
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/// [`wrong_self_convention`](#wrong_self_convention), but for public items.
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///
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/// **Why is this bad?** See [`wrong_self_convention`](#wrong_self_convention).
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///
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/// **Known problems:** Actually *renaming* the function may break clients if
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/// the function is part of the public interface. In that case, be mindful of
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/// the stability guarantees you've given your users.
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///
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/// **Example:**
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/// ```rust
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/// # struct X;
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/// impl<'a> X {
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/// pub fn as_str(self) -> &'a str {
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/// "foo"
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/// }
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/// }
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/// ```
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pub WRONG_PUB_SELF_CONVENTION,
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restriction,
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"defining a public method named with an established prefix (like \"into_\") that takes `self` with the wrong convention"
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}
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declare_clippy_lint! {
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/// **What it does:** Checks for usage of `ok().expect(..)`.
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///
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/// **Why is this bad?** Because you usually call `expect()` on the `Result`
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/// directly to get a better error message.
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///
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/// **Known problems:** The error type needs to implement `Debug`
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///
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/// **Example:**
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/// ```rust
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/// # let x = Ok::<_, ()>(());
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/// x.ok().expect("why did I do this again?")
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/// ```
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pub OK_EXPECT,
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style,
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"using `ok().expect()`, which gives worse error messages than calling `expect` directly on the Result"
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}
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declare_clippy_lint! {
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/// **What it does:** Checks for usage of `_.map(_).unwrap_or(_)`.
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///
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/// **Why is this bad?** Readability, this can be written more concisely as
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/// `_.map_or(_, _)`.
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///
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/// **Known problems:** The order of the arguments is not in execution order
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///
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/// **Example:**
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/// ```rust
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/// # let x = Some(1);
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/// x.map(|a| a + 1).unwrap_or(0);
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/// ```
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pub OPTION_MAP_UNWRAP_OR,
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pedantic,
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"using `Option.map(f).unwrap_or(a)`, which is more succinctly expressed as `map_or(a, f)`"
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}
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declare_clippy_lint! {
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/// **What it does:** Checks for usage of `_.map(_).unwrap_or_else(_)`.
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///
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/// **Why is this bad?** Readability, this can be written more concisely as
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/// `_.map_or_else(_, _)`.
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///
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/// **Known problems:** The order of the arguments is not in execution order.
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///
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/// **Example:**
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/// ```rust
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/// # let x = Some(1);
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/// # fn some_function() -> usize { 1 }
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/// x.map(|a| a + 1).unwrap_or_else(some_function);
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/// ```
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pub OPTION_MAP_UNWRAP_OR_ELSE,
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pedantic,
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"using `Option.map(f).unwrap_or_else(g)`, which is more succinctly expressed as `map_or_else(g, f)`"
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}
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declare_clippy_lint! {
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/// **What it does:** Checks for usage of `result.map(_).unwrap_or_else(_)`.
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///
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/// **Why is this bad?** Readability, this can be written more concisely as
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/// `result.map_or_else(_, _)`.
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///
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/// **Known problems:** None.
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///
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/// **Example:**
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/// ```rust
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/// # let x: Result<usize, ()> = Ok(1);
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/// # fn some_function(foo: ()) -> usize { 1 }
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/// x.map(|a| a + 1).unwrap_or_else(some_function);
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/// ```
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pub RESULT_MAP_UNWRAP_OR_ELSE,
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pedantic,
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"using `Result.map(f).unwrap_or_else(g)`, which is more succinctly expressed as `.map_or_else(g, f)`"
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}
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declare_clippy_lint! {
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/// **What it does:** Checks for usage of `_.map_or(None, _)`.
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///
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/// **Why is this bad?** Readability, this can be written more concisely as
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/// `_.and_then(_)`.
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///
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/// **Known problems:** The order of the arguments is not in execution order.
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///
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/// **Example:**
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/// ```rust
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/// # let opt = Some(1);
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/// opt.map_or(None, |a| Some(a + 1))
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/// # ;
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/// ```
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pub OPTION_MAP_OR_NONE,
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style,
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"using `Option.map_or(None, f)`, which is more succinctly expressed as `and_then(f)`"
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}
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declare_clippy_lint! {
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/// **What it does:** Checks for usage of `_.map_or(None, Some)`.
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///
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/// **Why is this bad?** Readability, this can be written more concisely as
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/// `_.ok()`.
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///
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/// **Known problems:** None.
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///
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/// **Example:**
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/// ```rust
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/// # let opt = Some(1);
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/// # let r = opt.map_or(None, Some);
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/// ```
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pub RESULT_MAP_OR_INTO_OPTION,
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style,
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"using `Result.map_or(None, Some)`, which is more succinctly expressed as `ok()`"
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}
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declare_clippy_lint! {
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/// **What it does:** Checks for usage of `_.and_then(|x| Some(y))`.
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///
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/// **Why is this bad?** Readability, this can be written more concisely as
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/// `_.map(|x| y)`.
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///
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/// **Known problems:** None
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///
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/// **Example:**
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///
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/// ```rust
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/// let x = Some("foo");
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/// let _ = x.and_then(|s| Some(s.len()));
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/// ```
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///
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/// The correct use would be:
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///
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/// ```rust
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/// let x = Some("foo");
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/// let _ = x.map(|s| s.len());
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/// ```
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pub OPTION_AND_THEN_SOME,
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complexity,
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"using `Option.and_then(|x| Some(y))`, which is more succinctly expressed as `map(|x| y)`"
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}
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declare_clippy_lint! {
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/// **What it does:** Checks for usage of `_.filter(_).next()`.
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///
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/// **Why is this bad?** Readability, this can be written more concisely as
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/// `_.find(_)`.
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///
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/// **Known problems:** None.
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///
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/// **Example:**
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/// ```rust
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/// # let vec = vec![1];
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/// vec.iter().filter(|x| **x == 0).next();
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/// ```
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/// Could be written as
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/// ```rust
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/// # let vec = vec![1];
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/// vec.iter().find(|x| **x == 0);
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/// ```
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pub FILTER_NEXT,
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complexity,
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"using `filter(p).next()`, which is more succinctly expressed as `.find(p)`"
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}
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declare_clippy_lint! {
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/// **What it does:** Checks for usage of `_.skip_while(condition).next()`.
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///
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|
/// **Why is this bad?** Readability, this can be written more concisely as
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/// `_.find(!condition)`.
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///
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|
/// **Known problems:** None.
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|
///
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/// **Example:**
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/// ```rust
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/// # let vec = vec![1];
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/// vec.iter().skip_while(|x| **x == 0).next();
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/// ```
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|
/// Could be written as
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/// ```rust
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/// # let vec = vec![1];
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/// vec.iter().find(|x| **x != 0);
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/// ```
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pub SKIP_WHILE_NEXT,
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complexity,
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|
"using `skip_while(p).next()`, which is more succinctly expressed as `.find(!p)`"
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}
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|
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|
declare_clippy_lint! {
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|
/// **What it does:** Checks for usage of `_.map(_).flatten(_)`,
|
|
///
|
|
/// **Why is this bad?** Readability, this can be written more concisely as a
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|
/// single method call.
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|
///
|
|
/// **Known problems:**
|
|
///
|
|
/// **Example:**
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|
/// ```rust
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|
/// let vec = vec![vec![1]];
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|
/// vec.iter().map(|x| x.iter()).flatten();
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/// ```
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|
pub MAP_FLATTEN,
|
|
pedantic,
|
|
"using combinations of `flatten` and `map` which can usually be written as a single method call"
|
|
}
|
|
|
|
declare_clippy_lint! {
|
|
/// **What it does:** Checks for usage of `_.filter(_).map(_)`,
|
|
/// `_.filter(_).flat_map(_)`, `_.filter_map(_).flat_map(_)` and similar.
|
|
///
|
|
/// **Why is this bad?** Readability, this can be written more concisely as a
|
|
/// single method call.
|
|
///
|
|
/// **Known problems:** Often requires a condition + Option/Iterator creation
|
|
/// inside the closure.
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|
///
|
|
/// **Example:**
|
|
/// ```rust
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|
/// let vec = vec![1];
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|
/// vec.iter().filter(|x| **x == 0).map(|x| *x * 2);
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|
/// ```
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|
pub FILTER_MAP,
|
|
pedantic,
|
|
"using combinations of `filter`, `map`, `filter_map` and `flat_map` which can usually be written as a single method call"
|
|
}
|
|
|
|
declare_clippy_lint! {
|
|
/// **What it does:** Checks for usage of `_.filter_map(_).next()`.
|
|
///
|
|
/// **Why is this bad?** Readability, this can be written more concisely as a
|
|
/// single method call.
|
|
///
|
|
/// **Known problems:** None
|
|
///
|
|
/// **Example:**
|
|
/// ```rust
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|
/// (0..3).filter_map(|x| if x == 2 { Some(x) } else { None }).next();
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/// ```
|
|
/// Can be written as
|
|
///
|
|
/// ```rust
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|
/// (0..3).find_map(|x| if x == 2 { Some(x) } else { None });
|
|
/// ```
|
|
pub FILTER_MAP_NEXT,
|
|
pedantic,
|
|
"using combination of `filter_map` and `next` which can usually be written as a single method call"
|
|
}
|
|
|
|
declare_clippy_lint! {
|
|
/// **What it does:** Checks for usage of `flat_map(|x| x)`.
|
|
///
|
|
/// **Why is this bad?** Readability, this can be written more concisely by using `flatten`.
|
|
///
|
|
/// **Known problems:** None
|
|
///
|
|
/// **Example:**
|
|
/// ```rust
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|
/// # let iter = vec![vec![0]].into_iter();
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|
/// iter.flat_map(|x| x);
|
|
/// ```
|
|
/// Can be written as
|
|
/// ```rust
|
|
/// # let iter = vec![vec![0]].into_iter();
|
|
/// iter.flatten();
|
|
/// ```
|
|
pub FLAT_MAP_IDENTITY,
|
|
complexity,
|
|
"call to `flat_map` where `flatten` is sufficient"
|
|
}
|
|
|
|
declare_clippy_lint! {
|
|
/// **What it does:** Checks for usage of `_.find(_).map(_)`.
|
|
///
|
|
/// **Why is this bad?** Readability, this can be written more concisely as a
|
|
/// single method call.
|
|
///
|
|
/// **Known problems:** Often requires a condition + Option/Iterator creation
|
|
/// inside the closure.
|
|
///
|
|
/// **Example:**
|
|
/// ```rust
|
|
/// (0..3).find(|x| *x == 2).map(|x| x * 2);
|
|
/// ```
|
|
/// Can be written as
|
|
/// ```rust
|
|
/// (0..3).find_map(|x| if x == 2 { Some(x * 2) } else { None });
|
|
/// ```
|
|
pub FIND_MAP,
|
|
pedantic,
|
|
"using a combination of `find` and `map` can usually be written as a single method call"
|
|
}
|
|
|
|
declare_clippy_lint! {
|
|
/// **What it does:** Checks for an iterator search (such as `find()`,
|
|
/// `position()`, or `rposition()`) followed by a call to `is_some()`.
|
|
///
|
|
/// **Why is this bad?** Readability, this can be written more concisely as
|
|
/// `_.any(_)`.
|
|
///
|
|
/// **Known problems:** None.
|
|
///
|
|
/// **Example:**
|
|
/// ```rust
|
|
/// # let vec = vec![1];
|
|
/// vec.iter().find(|x| **x == 0).is_some();
|
|
/// ```
|
|
/// Could be written as
|
|
/// ```rust
|
|
/// # let vec = vec![1];
|
|
/// vec.iter().any(|x| *x == 0);
|
|
/// ```
|
|
pub SEARCH_IS_SOME,
|
|
complexity,
|
|
"using an iterator search followed by `is_some()`, which is more succinctly expressed as a call to `any()`"
|
|
}
|
|
|
|
declare_clippy_lint! {
|
|
/// **What it does:** Checks for usage of `.chars().next()` on a `str` to check
|
|
/// if it starts with a given char.
|
|
///
|
|
/// **Why is this bad?** Readability, this can be written more concisely as
|
|
/// `_.starts_with(_)`.
|
|
///
|
|
/// **Known problems:** None.
|
|
///
|
|
/// **Example:**
|
|
/// ```rust
|
|
/// let name = "foo";
|
|
/// if name.chars().next() == Some('_') {};
|
|
/// ```
|
|
/// Could be written as
|
|
/// ```rust
|
|
/// let name = "foo";
|
|
/// if name.starts_with('_') {};
|
|
/// ```
|
|
pub CHARS_NEXT_CMP,
|
|
style,
|
|
"using `.chars().next()` to check if a string starts with a char"
|
|
}
|
|
|
|
declare_clippy_lint! {
|
|
/// **What it does:** Checks for calls to `.or(foo(..))`, `.unwrap_or(foo(..))`,
|
|
/// etc., and suggests to use `or_else`, `unwrap_or_else`, etc., or
|
|
/// `unwrap_or_default` instead.
|
|
///
|
|
/// **Why is this bad?** The function will always be called and potentially
|
|
/// allocate an object acting as the default.
|
|
///
|
|
/// **Known problems:** If the function has side-effects, not calling it will
|
|
/// change the semantic of the program, but you shouldn't rely on that anyway.
|
|
///
|
|
/// **Example:**
|
|
/// ```rust
|
|
/// # let foo = Some(String::new());
|
|
/// foo.unwrap_or(String::new());
|
|
/// ```
|
|
/// this can instead be written:
|
|
/// ```rust
|
|
/// # let foo = Some(String::new());
|
|
/// foo.unwrap_or_else(String::new);
|
|
/// ```
|
|
/// or
|
|
/// ```rust
|
|
/// # let foo = Some(String::new());
|
|
/// foo.unwrap_or_default();
|
|
/// ```
|
|
pub OR_FUN_CALL,
|
|
perf,
|
|
"using any `*or` method with a function call, which suggests `*or_else`"
|
|
}
|
|
|
|
declare_clippy_lint! {
|
|
/// **What it does:** Checks for calls to `.expect(&format!(...))`, `.expect(foo(..))`,
|
|
/// etc., and suggests to use `unwrap_or_else` instead
|
|
///
|
|
/// **Why is this bad?** The function will always be called.
|
|
///
|
|
/// **Known problems:** If the function has side-effects, not calling it will
|
|
/// change the semantics of the program, but you shouldn't rely on that anyway.
|
|
///
|
|
/// **Example:**
|
|
/// ```rust
|
|
/// # let foo = Some(String::new());
|
|
/// # let err_code = "418";
|
|
/// # let err_msg = "I'm a teapot";
|
|
/// foo.expect(&format!("Err {}: {}", err_code, err_msg));
|
|
/// ```
|
|
/// or
|
|
/// ```rust
|
|
/// # let foo = Some(String::new());
|
|
/// # let err_code = "418";
|
|
/// # let err_msg = "I'm a teapot";
|
|
/// foo.expect(format!("Err {}: {}", err_code, err_msg).as_str());
|
|
/// ```
|
|
/// this can instead be written:
|
|
/// ```rust
|
|
/// # let foo = Some(String::new());
|
|
/// # let err_code = "418";
|
|
/// # let err_msg = "I'm a teapot";
|
|
/// foo.unwrap_or_else(|| panic!("Err {}: {}", err_code, err_msg));
|
|
/// ```
|
|
pub EXPECT_FUN_CALL,
|
|
perf,
|
|
"using any `expect` method with a function call"
|
|
}
|
|
|
|
declare_clippy_lint! {
|
|
/// **What it does:** Checks for usage of `.clone()` on a `Copy` type.
|
|
///
|
|
/// **Why is this bad?** The only reason `Copy` types implement `Clone` is for
|
|
/// generics, not for using the `clone` method on a concrete type.
|
|
///
|
|
/// **Known problems:** None.
|
|
///
|
|
/// **Example:**
|
|
/// ```rust
|
|
/// 42u64.clone();
|
|
/// ```
|
|
pub CLONE_ON_COPY,
|
|
complexity,
|
|
"using `clone` on a `Copy` type"
|
|
}
|
|
|
|
declare_clippy_lint! {
|
|
/// **What it does:** Checks for usage of `.clone()` on a ref-counted pointer,
|
|
/// (`Rc`, `Arc`, `rc::Weak`, or `sync::Weak`), and suggests calling Clone via unified
|
|
/// function syntax instead (e.g., `Rc::clone(foo)`).
|
|
///
|
|
/// **Why is this bad?** Calling '.clone()' on an Rc, Arc, or Weak
|
|
/// can obscure the fact that only the pointer is being cloned, not the underlying
|
|
/// data.
|
|
///
|
|
/// **Example:**
|
|
/// ```rust
|
|
/// # use std::rc::Rc;
|
|
/// let x = Rc::new(1);
|
|
/// x.clone();
|
|
/// ```
|
|
pub CLONE_ON_REF_PTR,
|
|
restriction,
|
|
"using 'clone' on a ref-counted pointer"
|
|
}
|
|
|
|
declare_clippy_lint! {
|
|
/// **What it does:** Checks for usage of `.clone()` on an `&&T`.
|
|
///
|
|
/// **Why is this bad?** Cloning an `&&T` copies the inner `&T`, instead of
|
|
/// cloning the underlying `T`.
|
|
///
|
|
/// **Known problems:** None.
|
|
///
|
|
/// **Example:**
|
|
/// ```rust
|
|
/// fn main() {
|
|
/// let x = vec![1];
|
|
/// let y = &&x;
|
|
/// let z = y.clone();
|
|
/// println!("{:p} {:p}", *y, z); // prints out the same pointer
|
|
/// }
|
|
/// ```
|
|
pub CLONE_DOUBLE_REF,
|
|
correctness,
|
|
"using `clone` on `&&T`"
|
|
}
|
|
|
|
declare_clippy_lint! {
|
|
/// **What it does:** Checks for usage of `.to_string()` on an `&&T` where
|
|
/// `T` implements `ToString` directly (like `&&str` or `&&String`).
|
|
///
|
|
/// **Why is this bad?** This bypasses the specialized implementation of
|
|
/// `ToString` and instead goes through the more expensive string formatting
|
|
/// facilities.
|
|
///
|
|
/// **Known problems:** None.
|
|
///
|
|
/// **Example:**
|
|
/// ```rust
|
|
/// // Generic implementation for `T: Display` is used (slow)
|
|
/// ["foo", "bar"].iter().map(|s| s.to_string());
|
|
///
|
|
/// // OK, the specialized impl is used
|
|
/// ["foo", "bar"].iter().map(|&s| s.to_string());
|
|
/// ```
|
|
pub INEFFICIENT_TO_STRING,
|
|
perf,
|
|
"using `to_string` on `&&T` where `T: ToString`"
|
|
}
|
|
|
|
declare_clippy_lint! {
|
|
/// **What it does:** Checks for `new` not returning `Self`.
|
|
///
|
|
/// **Why is this bad?** As a convention, `new` methods are used to make a new
|
|
/// instance of a type.
|
|
///
|
|
/// **Known problems:** None.
|
|
///
|
|
/// **Example:**
|
|
/// ```rust
|
|
/// # struct Foo;
|
|
/// # struct NotAFoo;
|
|
/// impl Foo {
|
|
/// fn new() -> NotAFoo {
|
|
/// # NotAFoo
|
|
/// }
|
|
/// }
|
|
/// ```
|
|
pub NEW_RET_NO_SELF,
|
|
style,
|
|
"not returning `Self` in a `new` method"
|
|
}
|
|
|
|
declare_clippy_lint! {
|
|
/// **What it does:** Checks for string methods that receive a single-character
|
|
/// `str` as an argument, e.g., `_.split("x")`.
|
|
///
|
|
/// **Why is this bad?** Performing these methods using a `char` is faster than
|
|
/// using a `str`.
|
|
///
|
|
/// **Known problems:** Does not catch multi-byte unicode characters.
|
|
///
|
|
/// **Example:**
|
|
/// `_.split("x")` could be `_.split('x')`
|
|
pub SINGLE_CHAR_PATTERN,
|
|
perf,
|
|
"using a single-character str where a char could be used, e.g., `_.split(\"x\")`"
|
|
}
|
|
|
|
declare_clippy_lint! {
|
|
/// **What it does:** Checks for getting the inner pointer of a temporary
|
|
/// `CString`.
|
|
///
|
|
/// **Why is this bad?** The inner pointer of a `CString` is only valid as long
|
|
/// as the `CString` is alive.
|
|
///
|
|
/// **Known problems:** None.
|
|
///
|
|
/// **Example:**
|
|
/// ```rust
|
|
/// # use std::ffi::CString;
|
|
/// # fn call_some_ffi_func(_: *const i8) {}
|
|
/// #
|
|
/// let c_str = CString::new("foo").unwrap().as_ptr();
|
|
/// unsafe {
|
|
/// call_some_ffi_func(c_str);
|
|
/// }
|
|
/// ```
|
|
/// Here `c_str` point to a freed address. The correct use would be:
|
|
/// ```rust
|
|
/// # use std::ffi::CString;
|
|
/// # fn call_some_ffi_func(_: *const i8) {}
|
|
/// #
|
|
/// let c_str = CString::new("foo").unwrap();
|
|
/// unsafe {
|
|
/// call_some_ffi_func(c_str.as_ptr());
|
|
/// }
|
|
/// ```
|
|
pub TEMPORARY_CSTRING_AS_PTR,
|
|
correctness,
|
|
"getting the inner pointer of a temporary `CString`"
|
|
}
|
|
|
|
declare_clippy_lint! {
|
|
/// **What it does:** Checks for calling `.step_by(0)` on iterators which panics.
|
|
///
|
|
/// **Why is this bad?** This very much looks like an oversight. Use `panic!()` instead if you
|
|
/// actually intend to panic.
|
|
///
|
|
/// **Known problems:** None.
|
|
///
|
|
/// **Example:**
|
|
/// ```rust,should_panic
|
|
/// for x in (0..100).step_by(0) {
|
|
/// //..
|
|
/// }
|
|
/// ```
|
|
pub ITERATOR_STEP_BY_ZERO,
|
|
correctness,
|
|
"using `Iterator::step_by(0)`, which will panic at runtime"
|
|
}
|
|
|
|
declare_clippy_lint! {
|
|
/// **What it does:** Checks for the use of `iter.nth(0)`.
|
|
///
|
|
/// **Why is this bad?** `iter.next()` is equivalent to
|
|
/// `iter.nth(0)`, as they both consume the next element,
|
|
/// but is more readable.
|
|
///
|
|
/// **Known problems:** None.
|
|
///
|
|
/// **Example:**
|
|
///
|
|
/// ```rust
|
|
/// # use std::collections::HashSet;
|
|
/// // Bad
|
|
/// # let mut s = HashSet::new();
|
|
/// # s.insert(1);
|
|
/// let x = s.iter().nth(0);
|
|
///
|
|
/// // Good
|
|
/// # let mut s = HashSet::new();
|
|
/// # s.insert(1);
|
|
/// let x = s.iter().next();
|
|
/// ```
|
|
pub ITER_NTH_ZERO,
|
|
style,
|
|
"replace `iter.nth(0)` with `iter.next()`"
|
|
}
|
|
|
|
declare_clippy_lint! {
|
|
/// **What it does:** Checks for use of `.iter().nth()` (and the related
|
|
/// `.iter_mut().nth()`) on standard library types with O(1) element access.
|
|
///
|
|
/// **Why is this bad?** `.get()` and `.get_mut()` are more efficient and more
|
|
/// readable.
|
|
///
|
|
/// **Known problems:** None.
|
|
///
|
|
/// **Example:**
|
|
/// ```rust
|
|
/// let some_vec = vec![0, 1, 2, 3];
|
|
/// let bad_vec = some_vec.iter().nth(3);
|
|
/// let bad_slice = &some_vec[..].iter().nth(3);
|
|
/// ```
|
|
/// The correct use would be:
|
|
/// ```rust
|
|
/// let some_vec = vec![0, 1, 2, 3];
|
|
/// let bad_vec = some_vec.get(3);
|
|
/// let bad_slice = &some_vec[..].get(3);
|
|
/// ```
|
|
pub ITER_NTH,
|
|
perf,
|
|
"using `.iter().nth()` on a standard library type with O(1) element access"
|
|
}
|
|
|
|
declare_clippy_lint! {
|
|
/// **What it does:** Checks for use of `.skip(x).next()` on iterators.
|
|
///
|
|
/// **Why is this bad?** `.nth(x)` is cleaner
|
|
///
|
|
/// **Known problems:** None.
|
|
///
|
|
/// **Example:**
|
|
/// ```rust
|
|
/// let some_vec = vec![0, 1, 2, 3];
|
|
/// let bad_vec = some_vec.iter().skip(3).next();
|
|
/// let bad_slice = &some_vec[..].iter().skip(3).next();
|
|
/// ```
|
|
/// The correct use would be:
|
|
/// ```rust
|
|
/// let some_vec = vec![0, 1, 2, 3];
|
|
/// let bad_vec = some_vec.iter().nth(3);
|
|
/// let bad_slice = &some_vec[..].iter().nth(3);
|
|
/// ```
|
|
pub ITER_SKIP_NEXT,
|
|
style,
|
|
"using `.skip(x).next()` on an iterator"
|
|
}
|
|
|
|
declare_clippy_lint! {
|
|
/// **What it does:** Checks for use of `.get().unwrap()` (or
|
|
/// `.get_mut().unwrap`) on a standard library type which implements `Index`
|
|
///
|
|
/// **Why is this bad?** Using the Index trait (`[]`) is more clear and more
|
|
/// concise.
|
|
///
|
|
/// **Known problems:** Not a replacement for error handling: Using either
|
|
/// `.unwrap()` or the Index trait (`[]`) carries the risk of causing a `panic`
|
|
/// if the value being accessed is `None`. If the use of `.get().unwrap()` is a
|
|
/// temporary placeholder for dealing with the `Option` type, then this does
|
|
/// not mitigate the need for error handling. If there is a chance that `.get()`
|
|
/// will be `None` in your program, then it is advisable that the `None` case
|
|
/// is handled in a future refactor instead of using `.unwrap()` or the Index
|
|
/// trait.
|
|
///
|
|
/// **Example:**
|
|
/// ```rust
|
|
/// let mut some_vec = vec![0, 1, 2, 3];
|
|
/// let last = some_vec.get(3).unwrap();
|
|
/// *some_vec.get_mut(0).unwrap() = 1;
|
|
/// ```
|
|
/// The correct use would be:
|
|
/// ```rust
|
|
/// let mut some_vec = vec![0, 1, 2, 3];
|
|
/// let last = some_vec[3];
|
|
/// some_vec[0] = 1;
|
|
/// ```
|
|
pub GET_UNWRAP,
|
|
restriction,
|
|
"using `.get().unwrap()` or `.get_mut().unwrap()` when using `[]` would work instead"
|
|
}
|
|
|
|
declare_clippy_lint! {
|
|
/// **What it does:** Checks for the use of `.extend(s.chars())` where s is a
|
|
/// `&str` or `String`.
|
|
///
|
|
/// **Why is this bad?** `.push_str(s)` is clearer
|
|
///
|
|
/// **Known problems:** None.
|
|
///
|
|
/// **Example:**
|
|
/// ```rust
|
|
/// let abc = "abc";
|
|
/// let def = String::from("def");
|
|
/// let mut s = String::new();
|
|
/// s.extend(abc.chars());
|
|
/// s.extend(def.chars());
|
|
/// ```
|
|
/// The correct use would be:
|
|
/// ```rust
|
|
/// let abc = "abc";
|
|
/// let def = String::from("def");
|
|
/// let mut s = String::new();
|
|
/// s.push_str(abc);
|
|
/// s.push_str(&def);
|
|
/// ```
|
|
pub STRING_EXTEND_CHARS,
|
|
style,
|
|
"using `x.extend(s.chars())` where s is a `&str` or `String`"
|
|
}
|
|
|
|
declare_clippy_lint! {
|
|
/// **What it does:** Checks for the use of `.cloned().collect()` on slice to
|
|
/// create a `Vec`.
|
|
///
|
|
/// **Why is this bad?** `.to_vec()` is clearer
|
|
///
|
|
/// **Known problems:** None.
|
|
///
|
|
/// **Example:**
|
|
/// ```rust
|
|
/// let s = [1, 2, 3, 4, 5];
|
|
/// let s2: Vec<isize> = s[..].iter().cloned().collect();
|
|
/// ```
|
|
/// The better use would be:
|
|
/// ```rust
|
|
/// let s = [1, 2, 3, 4, 5];
|
|
/// let s2: Vec<isize> = s.to_vec();
|
|
/// ```
|
|
pub ITER_CLONED_COLLECT,
|
|
style,
|
|
"using `.cloned().collect()` on slice to create a `Vec`"
|
|
}
|
|
|
|
declare_clippy_lint! {
|
|
/// **What it does:** Checks for usage of `.chars().last()` or
|
|
/// `.chars().next_back()` on a `str` to check if it ends with a given char.
|
|
///
|
|
/// **Why is this bad?** Readability, this can be written more concisely as
|
|
/// `_.ends_with(_)`.
|
|
///
|
|
/// **Known problems:** None.
|
|
///
|
|
/// **Example:**
|
|
/// ```rust
|
|
/// # let name = "_";
|
|
/// name.chars().last() == Some('_') || name.chars().next_back() == Some('-')
|
|
/// # ;
|
|
/// ```
|
|
pub CHARS_LAST_CMP,
|
|
style,
|
|
"using `.chars().last()` or `.chars().next_back()` to check if a string ends with a char"
|
|
}
|
|
|
|
declare_clippy_lint! {
|
|
/// **What it does:** Checks for usage of `.as_ref()` or `.as_mut()` where the
|
|
/// types before and after the call are the same.
|
|
///
|
|
/// **Why is this bad?** The call is unnecessary.
|
|
///
|
|
/// **Known problems:** None.
|
|
///
|
|
/// **Example:**
|
|
/// ```rust
|
|
/// # fn do_stuff(x: &[i32]) {}
|
|
/// let x: &[i32] = &[1, 2, 3, 4, 5];
|
|
/// do_stuff(x.as_ref());
|
|
/// ```
|
|
/// The correct use would be:
|
|
/// ```rust
|
|
/// # fn do_stuff(x: &[i32]) {}
|
|
/// let x: &[i32] = &[1, 2, 3, 4, 5];
|
|
/// do_stuff(x);
|
|
/// ```
|
|
pub USELESS_ASREF,
|
|
complexity,
|
|
"using `as_ref` where the types before and after the call are the same"
|
|
}
|
|
|
|
declare_clippy_lint! {
|
|
/// **What it does:** Checks for using `fold` when a more succinct alternative exists.
|
|
/// Specifically, this checks for `fold`s which could be replaced by `any`, `all`,
|
|
/// `sum` or `product`.
|
|
///
|
|
/// **Why is this bad?** Readability.
|
|
///
|
|
/// **Known problems:** False positive in pattern guards. Will be resolved once
|
|
/// non-lexical lifetimes are stable.
|
|
///
|
|
/// **Example:**
|
|
/// ```rust
|
|
/// let _ = (0..3).fold(false, |acc, x| acc || x > 2);
|
|
/// ```
|
|
/// This could be written as:
|
|
/// ```rust
|
|
/// let _ = (0..3).any(|x| x > 2);
|
|
/// ```
|
|
pub UNNECESSARY_FOLD,
|
|
style,
|
|
"using `fold` when a more succinct alternative exists"
|
|
}
|
|
|
|
declare_clippy_lint! {
|
|
/// **What it does:** Checks for `filter_map` calls which could be replaced by `filter` or `map`.
|
|
/// More specifically it checks if the closure provided is only performing one of the
|
|
/// filter or map operations and suggests the appropriate option.
|
|
///
|
|
/// **Why is this bad?** Complexity. The intent is also clearer if only a single
|
|
/// operation is being performed.
|
|
///
|
|
/// **Known problems:** None
|
|
///
|
|
/// **Example:**
|
|
/// ```rust
|
|
/// let _ = (0..3).filter_map(|x| if x > 2 { Some(x) } else { None });
|
|
/// ```
|
|
/// As there is no transformation of the argument this could be written as:
|
|
/// ```rust
|
|
/// let _ = (0..3).filter(|&x| x > 2);
|
|
/// ```
|
|
///
|
|
/// ```rust
|
|
/// let _ = (0..4).filter_map(|x| Some(x + 1));
|
|
/// ```
|
|
/// As there is no conditional check on the argument this could be written as:
|
|
/// ```rust
|
|
/// let _ = (0..4).map(|x| x + 1);
|
|
/// ```
|
|
pub UNNECESSARY_FILTER_MAP,
|
|
complexity,
|
|
"using `filter_map` when a more succinct alternative exists"
|
|
}
|
|
|
|
declare_clippy_lint! {
|
|
/// **What it does:** Checks for `into_iter` calls on references which should be replaced by `iter`
|
|
/// or `iter_mut`.
|
|
///
|
|
/// **Why is this bad?** Readability. Calling `into_iter` on a reference will not move out its
|
|
/// content into the resulting iterator, which is confusing. It is better just call `iter` or
|
|
/// `iter_mut` directly.
|
|
///
|
|
/// **Known problems:** None
|
|
///
|
|
/// **Example:**
|
|
///
|
|
/// ```rust
|
|
/// let _ = (&vec![3, 4, 5]).into_iter();
|
|
/// ```
|
|
pub INTO_ITER_ON_REF,
|
|
style,
|
|
"using `.into_iter()` on a reference"
|
|
}
|
|
|
|
declare_clippy_lint! {
|
|
/// **What it does:** Checks for calls to `map` followed by a `count`.
|
|
///
|
|
/// **Why is this bad?** It looks suspicious. Maybe `map` was confused with `filter`.
|
|
/// If the `map` call is intentional, this should be rewritten. Or, if you intend to
|
|
/// drive the iterator to completion, you can just use `for_each` instead.
|
|
///
|
|
/// **Known problems:** None
|
|
///
|
|
/// **Example:**
|
|
///
|
|
/// ```rust
|
|
/// let _ = (0..3).map(|x| x + 2).count();
|
|
/// ```
|
|
pub SUSPICIOUS_MAP,
|
|
complexity,
|
|
"suspicious usage of map"
|
|
}
|
|
|
|
declare_clippy_lint! {
|
|
/// **What it does:** Checks for `MaybeUninit::uninit().assume_init()`.
|
|
///
|
|
/// **Why is this bad?** For most types, this is undefined behavior.
|
|
///
|
|
/// **Known problems:** For now, we accept empty tuples and tuples / arrays
|
|
/// of `MaybeUninit`. There may be other types that allow uninitialized
|
|
/// data, but those are not yet rigorously defined.
|
|
///
|
|
/// **Example:**
|
|
///
|
|
/// ```rust
|
|
/// // Beware the UB
|
|
/// use std::mem::MaybeUninit;
|
|
///
|
|
/// let _: usize = unsafe { MaybeUninit::uninit().assume_init() };
|
|
/// ```
|
|
///
|
|
/// Note that the following is OK:
|
|
///
|
|
/// ```rust
|
|
/// use std::mem::MaybeUninit;
|
|
///
|
|
/// let _: [MaybeUninit<bool>; 5] = unsafe {
|
|
/// MaybeUninit::uninit().assume_init()
|
|
/// };
|
|
/// ```
|
|
pub UNINIT_ASSUMED_INIT,
|
|
correctness,
|
|
"`MaybeUninit::uninit().assume_init()`"
|
|
}
|
|
|
|
declare_clippy_lint! {
|
|
/// **What it does:** Checks for `.checked_add/sub(x).unwrap_or(MAX/MIN)`.
|
|
///
|
|
/// **Why is this bad?** These can be written simply with `saturating_add/sub` methods.
|
|
///
|
|
/// **Example:**
|
|
///
|
|
/// ```rust
|
|
/// # let y: u32 = 0;
|
|
/// # let x: u32 = 100;
|
|
/// let add = x.checked_add(y).unwrap_or(u32::max_value());
|
|
/// let sub = x.checked_sub(y).unwrap_or(u32::min_value());
|
|
/// ```
|
|
///
|
|
/// can be written using dedicated methods for saturating addition/subtraction as:
|
|
///
|
|
/// ```rust
|
|
/// # let y: u32 = 0;
|
|
/// # let x: u32 = 100;
|
|
/// let add = x.saturating_add(y);
|
|
/// let sub = x.saturating_sub(y);
|
|
/// ```
|
|
pub MANUAL_SATURATING_ARITHMETIC,
|
|
style,
|
|
"`.chcked_add/sub(x).unwrap_or(MAX/MIN)`"
|
|
}
|
|
|
|
declare_clippy_lint! {
|
|
/// **What it does:** Checks for `offset(_)`, `wrapping_`{`add`, `sub`}, etc. on raw pointers to
|
|
/// zero-sized types
|
|
///
|
|
/// **Why is this bad?** This is a no-op, and likely unintended
|
|
///
|
|
/// **Known problems:** None
|
|
///
|
|
/// **Example:**
|
|
/// ```rust
|
|
/// unsafe { (&() as *const ()).offset(1) };
|
|
/// ```
|
|
pub ZST_OFFSET,
|
|
correctness,
|
|
"Check for offset calculations on raw pointers to zero-sized types"
|
|
}
|
|
|
|
declare_clippy_lint! {
|
|
/// **What it does:** Checks for `FileType::is_file()`.
|
|
///
|
|
/// **Why is this bad?** When people testing a file type with `FileType::is_file`
|
|
/// they are testing whether a path is something they can get bytes from. But
|
|
/// `is_file` doesn't cover special file types in unix-like systems, and doesn't cover
|
|
/// symlink in windows. Using `!FileType::is_dir()` is a better way to that intention.
|
|
///
|
|
/// **Example:**
|
|
///
|
|
/// ```rust
|
|
/// # || {
|
|
/// let metadata = std::fs::metadata("foo.txt")?;
|
|
/// let filetype = metadata.file_type();
|
|
///
|
|
/// if filetype.is_file() {
|
|
/// // read file
|
|
/// }
|
|
/// # Ok::<_, std::io::Error>(())
|
|
/// # };
|
|
/// ```
|
|
///
|
|
/// should be written as:
|
|
///
|
|
/// ```rust
|
|
/// # || {
|
|
/// let metadata = std::fs::metadata("foo.txt")?;
|
|
/// let filetype = metadata.file_type();
|
|
///
|
|
/// if !filetype.is_dir() {
|
|
/// // read file
|
|
/// }
|
|
/// # Ok::<_, std::io::Error>(())
|
|
/// # };
|
|
/// ```
|
|
pub FILETYPE_IS_FILE,
|
|
restriction,
|
|
"`FileType::is_file` is not recommended to test for readable file type"
|
|
}
|
|
|
|
declare_clippy_lint! {
|
|
/// **What it does:** Checks for usage of `_.as_ref().map(Deref::deref)` or it's aliases (such as String::as_str).
|
|
///
|
|
/// **Why is this bad?** Readability, this can be written more concisely as a
|
|
/// single method call.
|
|
///
|
|
/// **Known problems:** None.
|
|
///
|
|
/// **Example:**
|
|
/// ```rust
|
|
/// # let opt = Some("".to_string());
|
|
/// opt.as_ref().map(String::as_str)
|
|
/// # ;
|
|
/// ```
|
|
/// Can be written as
|
|
/// ```rust
|
|
/// # let opt = Some("".to_string());
|
|
/// opt.as_deref()
|
|
/// # ;
|
|
/// ```
|
|
pub OPTION_AS_REF_DEREF,
|
|
complexity,
|
|
"using `as_ref().map(Deref::deref)`, which is more succinctly expressed as `as_deref()`"
|
|
}
|
|
|
|
declare_lint_pass!(Methods => [
|
|
OPTION_UNWRAP_USED,
|
|
RESULT_UNWRAP_USED,
|
|
OPTION_EXPECT_USED,
|
|
RESULT_EXPECT_USED,
|
|
SHOULD_IMPLEMENT_TRAIT,
|
|
WRONG_SELF_CONVENTION,
|
|
WRONG_PUB_SELF_CONVENTION,
|
|
OK_EXPECT,
|
|
OPTION_MAP_UNWRAP_OR,
|
|
OPTION_MAP_UNWRAP_OR_ELSE,
|
|
RESULT_MAP_UNWRAP_OR_ELSE,
|
|
RESULT_MAP_OR_INTO_OPTION,
|
|
OPTION_MAP_OR_NONE,
|
|
OPTION_AND_THEN_SOME,
|
|
OR_FUN_CALL,
|
|
EXPECT_FUN_CALL,
|
|
CHARS_NEXT_CMP,
|
|
CHARS_LAST_CMP,
|
|
CLONE_ON_COPY,
|
|
CLONE_ON_REF_PTR,
|
|
CLONE_DOUBLE_REF,
|
|
INEFFICIENT_TO_STRING,
|
|
NEW_RET_NO_SELF,
|
|
SINGLE_CHAR_PATTERN,
|
|
SEARCH_IS_SOME,
|
|
TEMPORARY_CSTRING_AS_PTR,
|
|
FILTER_NEXT,
|
|
SKIP_WHILE_NEXT,
|
|
FILTER_MAP,
|
|
FILTER_MAP_NEXT,
|
|
FLAT_MAP_IDENTITY,
|
|
FIND_MAP,
|
|
MAP_FLATTEN,
|
|
ITERATOR_STEP_BY_ZERO,
|
|
ITER_NTH,
|
|
ITER_NTH_ZERO,
|
|
ITER_SKIP_NEXT,
|
|
GET_UNWRAP,
|
|
STRING_EXTEND_CHARS,
|
|
ITER_CLONED_COLLECT,
|
|
USELESS_ASREF,
|
|
UNNECESSARY_FOLD,
|
|
UNNECESSARY_FILTER_MAP,
|
|
INTO_ITER_ON_REF,
|
|
SUSPICIOUS_MAP,
|
|
UNINIT_ASSUMED_INIT,
|
|
MANUAL_SATURATING_ARITHMETIC,
|
|
ZST_OFFSET,
|
|
FILETYPE_IS_FILE,
|
|
OPTION_AS_REF_DEREF,
|
|
]);
|
|
|
|
impl<'a, 'tcx> LateLintPass<'a, 'tcx> for Methods {
|
|
#[allow(clippy::cognitive_complexity, clippy::too_many_lines)]
|
|
fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, expr: &'tcx hir::Expr<'_>) {
|
|
if in_macro(expr.span) {
|
|
return;
|
|
}
|
|
|
|
let (method_names, arg_lists, method_spans) = method_calls(expr, 2);
|
|
let method_names: Vec<SymbolStr> = method_names.iter().map(|s| s.as_str()).collect();
|
|
let method_names: Vec<&str> = method_names.iter().map(|s| &**s).collect();
|
|
|
|
match method_names.as_slice() {
|
|
["unwrap", "get"] => lint_get_unwrap(cx, expr, arg_lists[1], false),
|
|
["unwrap", "get_mut"] => lint_get_unwrap(cx, expr, arg_lists[1], true),
|
|
["unwrap", ..] => lint_unwrap(cx, expr, arg_lists[0]),
|
|
["expect", "ok"] => lint_ok_expect(cx, expr, arg_lists[1]),
|
|
["expect", ..] => lint_expect(cx, expr, arg_lists[0]),
|
|
["unwrap_or", "map"] => option_map_unwrap_or::lint(cx, expr, arg_lists[1], arg_lists[0], method_spans[1]),
|
|
["unwrap_or_else", "map"] => lint_map_unwrap_or_else(cx, expr, arg_lists[1], arg_lists[0]),
|
|
["map_or", ..] => lint_map_or_none(cx, expr, arg_lists[0]),
|
|
["and_then", ..] => lint_option_and_then_some(cx, expr, arg_lists[0]),
|
|
["next", "filter"] => lint_filter_next(cx, expr, arg_lists[1]),
|
|
["next", "skip_while"] => lint_skip_while_next(cx, expr, arg_lists[1]),
|
|
["map", "filter"] => lint_filter_map(cx, expr, arg_lists[1], arg_lists[0]),
|
|
["map", "filter_map"] => lint_filter_map_map(cx, expr, arg_lists[1], arg_lists[0]),
|
|
["next", "filter_map"] => lint_filter_map_next(cx, expr, arg_lists[1]),
|
|
["map", "find"] => lint_find_map(cx, expr, arg_lists[1], arg_lists[0]),
|
|
["flat_map", "filter"] => lint_filter_flat_map(cx, expr, arg_lists[1], arg_lists[0]),
|
|
["flat_map", "filter_map"] => lint_filter_map_flat_map(cx, expr, arg_lists[1], arg_lists[0]),
|
|
["flat_map", ..] => lint_flat_map_identity(cx, expr, arg_lists[0], method_spans[0]),
|
|
["flatten", "map"] => lint_map_flatten(cx, expr, arg_lists[1]),
|
|
["is_some", "find"] => lint_search_is_some(cx, expr, "find", arg_lists[1], arg_lists[0], method_spans[1]),
|
|
["is_some", "position"] => {
|
|
lint_search_is_some(cx, expr, "position", arg_lists[1], arg_lists[0], method_spans[1])
|
|
},
|
|
["is_some", "rposition"] => {
|
|
lint_search_is_some(cx, expr, "rposition", arg_lists[1], arg_lists[0], method_spans[1])
|
|
},
|
|
["extend", ..] => lint_extend(cx, expr, arg_lists[0]),
|
|
["as_ptr", "unwrap"] | ["as_ptr", "expect"] => {
|
|
lint_cstring_as_ptr(cx, expr, &arg_lists[1][0], &arg_lists[0][0])
|
|
},
|
|
["nth", "iter"] => lint_iter_nth(cx, expr, &arg_lists, false),
|
|
["nth", "iter_mut"] => lint_iter_nth(cx, expr, &arg_lists, true),
|
|
["nth", ..] => lint_iter_nth_zero(cx, expr, arg_lists[0]),
|
|
["step_by", ..] => lint_step_by(cx, expr, arg_lists[0]),
|
|
["next", "skip"] => lint_iter_skip_next(cx, expr),
|
|
["collect", "cloned"] => lint_iter_cloned_collect(cx, expr, arg_lists[1]),
|
|
["as_ref"] => lint_asref(cx, expr, "as_ref", arg_lists[0]),
|
|
["as_mut"] => lint_asref(cx, expr, "as_mut", arg_lists[0]),
|
|
["fold", ..] => lint_unnecessary_fold(cx, expr, arg_lists[0], method_spans[0]),
|
|
["filter_map", ..] => unnecessary_filter_map::lint(cx, expr, arg_lists[0]),
|
|
["count", "map"] => lint_suspicious_map(cx, expr),
|
|
["assume_init"] => lint_maybe_uninit(cx, &arg_lists[0][0], expr),
|
|
["unwrap_or", arith @ "checked_add"]
|
|
| ["unwrap_or", arith @ "checked_sub"]
|
|
| ["unwrap_or", arith @ "checked_mul"] => {
|
|
manual_saturating_arithmetic::lint(cx, expr, &arg_lists, &arith["checked_".len()..])
|
|
},
|
|
["add"] | ["offset"] | ["sub"] | ["wrapping_offset"] | ["wrapping_add"] | ["wrapping_sub"] => {
|
|
check_pointer_offset(cx, expr, arg_lists[0])
|
|
},
|
|
["is_file", ..] => lint_filetype_is_file(cx, expr, arg_lists[0]),
|
|
["map", "as_ref"] => lint_option_as_ref_deref(cx, expr, arg_lists[1], arg_lists[0], false),
|
|
["map", "as_mut"] => lint_option_as_ref_deref(cx, expr, arg_lists[1], arg_lists[0], true),
|
|
_ => {},
|
|
}
|
|
|
|
match expr.kind {
|
|
hir::ExprKind::MethodCall(ref method_call, ref method_span, ref args) => {
|
|
lint_or_fun_call(cx, expr, *method_span, &method_call.ident.as_str(), args);
|
|
lint_expect_fun_call(cx, expr, *method_span, &method_call.ident.as_str(), args);
|
|
|
|
let self_ty = cx.tables.expr_ty_adjusted(&args[0]);
|
|
if args.len() == 1 && method_call.ident.name == sym!(clone) {
|
|
lint_clone_on_copy(cx, expr, &args[0], self_ty);
|
|
lint_clone_on_ref_ptr(cx, expr, &args[0]);
|
|
}
|
|
if args.len() == 1 && method_call.ident.name == sym!(to_string) {
|
|
inefficient_to_string::lint(cx, expr, &args[0], self_ty);
|
|
}
|
|
|
|
match self_ty.kind {
|
|
ty::Ref(_, ty, _) if ty.kind == ty::Str => {
|
|
for &(method, pos) in &PATTERN_METHODS {
|
|
if method_call.ident.name.as_str() == method && args.len() > pos {
|
|
lint_single_char_pattern(cx, expr, &args[pos]);
|
|
}
|
|
}
|
|
},
|
|
ty::Ref(..) if method_call.ident.name == sym!(into_iter) => {
|
|
lint_into_iter(cx, expr, self_ty, *method_span);
|
|
},
|
|
_ => (),
|
|
}
|
|
},
|
|
hir::ExprKind::Binary(op, ref lhs, ref rhs)
|
|
if op.node == hir::BinOpKind::Eq || op.node == hir::BinOpKind::Ne =>
|
|
{
|
|
let mut info = BinaryExprInfo {
|
|
expr,
|
|
chain: lhs,
|
|
other: rhs,
|
|
eq: op.node == hir::BinOpKind::Eq,
|
|
};
|
|
lint_binary_expr_with_method_call(cx, &mut info);
|
|
}
|
|
_ => (),
|
|
}
|
|
}
|
|
|
|
fn check_impl_item(&mut self, cx: &LateContext<'a, 'tcx>, impl_item: &'tcx hir::ImplItem<'_>) {
|
|
if in_external_macro(cx.sess(), impl_item.span) {
|
|
return;
|
|
}
|
|
let name = impl_item.ident.name.as_str();
|
|
let parent = cx.tcx.hir().get_parent_item(impl_item.hir_id);
|
|
let item = cx.tcx.hir().expect_item(parent);
|
|
let def_id = cx.tcx.hir().local_def_id(item.hir_id);
|
|
let ty = cx.tcx.type_of(def_id);
|
|
if_chain! {
|
|
if let hir::ImplItemKind::Fn(ref sig, id) = impl_item.kind;
|
|
if let Some(first_arg) = iter_input_pats(&sig.decl, cx.tcx.hir().body(id)).next();
|
|
if let hir::ItemKind::Impl{ of_trait: None, .. } = item.kind;
|
|
|
|
let method_def_id = cx.tcx.hir().local_def_id(impl_item.hir_id);
|
|
let method_sig = cx.tcx.fn_sig(method_def_id);
|
|
let method_sig = cx.tcx.erase_late_bound_regions(&method_sig);
|
|
|
|
let first_arg_ty = &method_sig.inputs().iter().next();
|
|
|
|
// check conventions w.r.t. conversion method names and predicates
|
|
if let Some(first_arg_ty) = first_arg_ty;
|
|
|
|
then {
|
|
if cx.access_levels.is_exported(impl_item.hir_id) {
|
|
// check missing trait implementations
|
|
for &(method_name, n_args, self_kind, out_type, trait_name) in &TRAIT_METHODS {
|
|
if name == method_name &&
|
|
sig.decl.inputs.len() == n_args &&
|
|
out_type.matches(cx, &sig.decl.output) &&
|
|
self_kind.matches(cx, ty, first_arg_ty) {
|
|
span_lint(cx, SHOULD_IMPLEMENT_TRAIT, impl_item.span, &format!(
|
|
"defining a method called `{}` on this type; consider implementing \
|
|
the `{}` trait or choosing a less ambiguous name", name, trait_name));
|
|
}
|
|
}
|
|
}
|
|
|
|
if let Some((ref conv, self_kinds)) = &CONVENTIONS
|
|
.iter()
|
|
.find(|(ref conv, _)| conv.check(&name))
|
|
{
|
|
if !self_kinds.iter().any(|k| k.matches(cx, ty, first_arg_ty)) {
|
|
let lint = if item.vis.node.is_pub() {
|
|
WRONG_PUB_SELF_CONVENTION
|
|
} else {
|
|
WRONG_SELF_CONVENTION
|
|
};
|
|
|
|
span_lint(
|
|
cx,
|
|
lint,
|
|
first_arg.pat.span,
|
|
&format!(
|
|
"methods called `{}` usually take {}; consider choosing a less \
|
|
ambiguous name",
|
|
conv,
|
|
&self_kinds
|
|
.iter()
|
|
.map(|k| k.description())
|
|
.collect::<Vec<_>>()
|
|
.join(" or ")
|
|
),
|
|
);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
if let hir::ImplItemKind::Fn(_, _) = impl_item.kind {
|
|
let ret_ty = return_ty(cx, impl_item.hir_id);
|
|
|
|
// walk the return type and check for Self (this does not check associated types)
|
|
if ret_ty.walk().any(|inner_type| same_tys(cx, ty, inner_type)) {
|
|
return;
|
|
}
|
|
|
|
// if return type is impl trait, check the associated types
|
|
if let ty::Opaque(def_id, _) = ret_ty.kind {
|
|
// one of the associated types must be Self
|
|
for predicate in cx.tcx.predicates_of(def_id).predicates {
|
|
match predicate {
|
|
(Predicate::Projection(poly_projection_predicate), _) => {
|
|
let binder = poly_projection_predicate.ty();
|
|
let associated_type = binder.skip_binder();
|
|
|
|
// walk the associated type and check for Self
|
|
for inner_type in associated_type.walk() {
|
|
if same_tys(cx, ty, inner_type) {
|
|
return;
|
|
}
|
|
}
|
|
},
|
|
(_, _) => {},
|
|
}
|
|
}
|
|
}
|
|
|
|
if name == "new" && !same_tys(cx, ret_ty, ty) {
|
|
span_lint(
|
|
cx,
|
|
NEW_RET_NO_SELF,
|
|
impl_item.span,
|
|
"methods called `new` usually return `Self`",
|
|
);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/// Checks for the `OR_FUN_CALL` lint.
|
|
#[allow(clippy::too_many_lines)]
|
|
fn lint_or_fun_call<'a, 'tcx>(
|
|
cx: &LateContext<'a, 'tcx>,
|
|
expr: &hir::Expr<'_>,
|
|
method_span: Span,
|
|
name: &str,
|
|
args: &'tcx [hir::Expr<'_>],
|
|
) {
|
|
// Searches an expression for method calls or function calls that aren't ctors
|
|
struct FunCallFinder<'a, 'tcx> {
|
|
cx: &'a LateContext<'a, 'tcx>,
|
|
found: bool,
|
|
}
|
|
|
|
impl<'a, 'tcx> intravisit::Visitor<'tcx> for FunCallFinder<'a, 'tcx> {
|
|
type Map = Map<'tcx>;
|
|
|
|
fn visit_expr(&mut self, expr: &'tcx hir::Expr<'_>) {
|
|
let call_found = match &expr.kind {
|
|
// ignore enum and struct constructors
|
|
hir::ExprKind::Call(..) => !is_ctor_or_promotable_const_function(self.cx, expr),
|
|
hir::ExprKind::MethodCall(..) => true,
|
|
_ => false,
|
|
};
|
|
|
|
if call_found {
|
|
self.found |= true;
|
|
}
|
|
|
|
if !self.found {
|
|
intravisit::walk_expr(self, expr);
|
|
}
|
|
}
|
|
|
|
fn nested_visit_map(&mut self) -> intravisit::NestedVisitorMap<Self::Map> {
|
|
intravisit::NestedVisitorMap::None
|
|
}
|
|
}
|
|
|
|
/// Checks for `unwrap_or(T::new())` or `unwrap_or(T::default())`.
|
|
fn check_unwrap_or_default(
|
|
cx: &LateContext<'_, '_>,
|
|
name: &str,
|
|
fun: &hir::Expr<'_>,
|
|
self_expr: &hir::Expr<'_>,
|
|
arg: &hir::Expr<'_>,
|
|
or_has_args: bool,
|
|
span: Span,
|
|
) -> bool {
|
|
if_chain! {
|
|
if !or_has_args;
|
|
if name == "unwrap_or";
|
|
if let hir::ExprKind::Path(ref qpath) = fun.kind;
|
|
let path = &*last_path_segment(qpath).ident.as_str();
|
|
if ["default", "new"].contains(&path);
|
|
let arg_ty = cx.tables.expr_ty(arg);
|
|
if let Some(default_trait_id) = get_trait_def_id(cx, &paths::DEFAULT_TRAIT);
|
|
if implements_trait(cx, arg_ty, default_trait_id, &[]);
|
|
|
|
then {
|
|
let mut applicability = Applicability::MachineApplicable;
|
|
span_lint_and_sugg(
|
|
cx,
|
|
OR_FUN_CALL,
|
|
span,
|
|
&format!("use of `{}` followed by a call to `{}`", name, path),
|
|
"try this",
|
|
format!(
|
|
"{}.unwrap_or_default()",
|
|
snippet_with_applicability(cx, self_expr.span, "_", &mut applicability)
|
|
),
|
|
applicability,
|
|
);
|
|
|
|
true
|
|
} else {
|
|
false
|
|
}
|
|
}
|
|
}
|
|
|
|
/// Checks for `*or(foo())`.
|
|
#[allow(clippy::too_many_arguments)]
|
|
fn check_general_case<'a, 'tcx>(
|
|
cx: &LateContext<'a, 'tcx>,
|
|
name: &str,
|
|
method_span: Span,
|
|
fun_span: Span,
|
|
self_expr: &hir::Expr<'_>,
|
|
arg: &'tcx hir::Expr<'_>,
|
|
or_has_args: bool,
|
|
span: Span,
|
|
) {
|
|
// (path, fn_has_argument, methods, suffix)
|
|
let know_types: &[(&[_], _, &[_], _)] = &[
|
|
(&paths::BTREEMAP_ENTRY, false, &["or_insert"], "with"),
|
|
(&paths::HASHMAP_ENTRY, false, &["or_insert"], "with"),
|
|
(&paths::OPTION, false, &["map_or", "ok_or", "or", "unwrap_or"], "else"),
|
|
(&paths::RESULT, true, &["or", "unwrap_or"], "else"),
|
|
];
|
|
|
|
if_chain! {
|
|
if know_types.iter().any(|k| k.2.contains(&name));
|
|
|
|
let mut finder = FunCallFinder { cx: &cx, found: false };
|
|
if { finder.visit_expr(&arg); finder.found };
|
|
if !contains_return(&arg);
|
|
|
|
let self_ty = cx.tables.expr_ty(self_expr);
|
|
|
|
if let Some(&(_, fn_has_arguments, poss, suffix)) =
|
|
know_types.iter().find(|&&i| match_type(cx, self_ty, i.0));
|
|
|
|
if poss.contains(&name);
|
|
|
|
then {
|
|
let sugg: Cow<'_, _> = match (fn_has_arguments, !or_has_args) {
|
|
(true, _) => format!("|_| {}", snippet_with_macro_callsite(cx, arg.span, "..")).into(),
|
|
(false, false) => format!("|| {}", snippet_with_macro_callsite(cx, arg.span, "..")).into(),
|
|
(false, true) => snippet_with_macro_callsite(cx, fun_span, ".."),
|
|
};
|
|
let span_replace_word = method_span.with_hi(span.hi());
|
|
span_lint_and_sugg(
|
|
cx,
|
|
OR_FUN_CALL,
|
|
span_replace_word,
|
|
&format!("use of `{}` followed by a function call", name),
|
|
"try this",
|
|
format!("{}_{}({})", name, suffix, sugg),
|
|
Applicability::HasPlaceholders,
|
|
);
|
|
}
|
|
}
|
|
}
|
|
|
|
if args.len() == 2 {
|
|
match args[1].kind {
|
|
hir::ExprKind::Call(ref fun, ref or_args) => {
|
|
let or_has_args = !or_args.is_empty();
|
|
if !check_unwrap_or_default(cx, name, fun, &args[0], &args[1], or_has_args, expr.span) {
|
|
check_general_case(
|
|
cx,
|
|
name,
|
|
method_span,
|
|
fun.span,
|
|
&args[0],
|
|
&args[1],
|
|
or_has_args,
|
|
expr.span,
|
|
);
|
|
}
|
|
},
|
|
hir::ExprKind::MethodCall(_, span, ref or_args) => check_general_case(
|
|
cx,
|
|
name,
|
|
method_span,
|
|
span,
|
|
&args[0],
|
|
&args[1],
|
|
!or_args.is_empty(),
|
|
expr.span,
|
|
),
|
|
_ => {},
|
|
}
|
|
}
|
|
}
|
|
|
|
/// Checks for the `EXPECT_FUN_CALL` lint.
|
|
#[allow(clippy::too_many_lines)]
|
|
fn lint_expect_fun_call(
|
|
cx: &LateContext<'_, '_>,
|
|
expr: &hir::Expr<'_>,
|
|
method_span: Span,
|
|
name: &str,
|
|
args: &[hir::Expr<'_>],
|
|
) {
|
|
// Strip `&`, `as_ref()` and `as_str()` off `arg` until we're left with either a `String` or
|
|
// `&str`
|
|
fn get_arg_root<'a>(cx: &LateContext<'_, '_>, arg: &'a hir::Expr<'a>) -> &'a hir::Expr<'a> {
|
|
let mut arg_root = arg;
|
|
loop {
|
|
arg_root = match &arg_root.kind {
|
|
hir::ExprKind::AddrOf(hir::BorrowKind::Ref, _, expr) => expr,
|
|
hir::ExprKind::MethodCall(method_name, _, call_args) => {
|
|
if call_args.len() == 1
|
|
&& (method_name.ident.name == sym!(as_str) || method_name.ident.name == sym!(as_ref))
|
|
&& {
|
|
let arg_type = cx.tables.expr_ty(&call_args[0]);
|
|
let base_type = walk_ptrs_ty(arg_type);
|
|
base_type.kind == ty::Str || match_type(cx, base_type, &paths::STRING)
|
|
}
|
|
{
|
|
&call_args[0]
|
|
} else {
|
|
break;
|
|
}
|
|
},
|
|
_ => break,
|
|
};
|
|
}
|
|
arg_root
|
|
}
|
|
|
|
// Only `&'static str` or `String` can be used directly in the `panic!`. Other types should be
|
|
// converted to string.
|
|
fn requires_to_string(cx: &LateContext<'_, '_>, arg: &hir::Expr<'_>) -> bool {
|
|
let arg_ty = cx.tables.expr_ty(arg);
|
|
if match_type(cx, arg_ty, &paths::STRING) {
|
|
return false;
|
|
}
|
|
if let ty::Ref(_, ty, ..) = arg_ty.kind {
|
|
if ty.kind == ty::Str && can_be_static_str(cx, arg) {
|
|
return false;
|
|
}
|
|
};
|
|
true
|
|
}
|
|
|
|
// Check if an expression could have type `&'static str`, knowing that it
|
|
// has type `&str` for some lifetime.
|
|
fn can_be_static_str(cx: &LateContext<'_, '_>, arg: &hir::Expr<'_>) -> bool {
|
|
match arg.kind {
|
|
hir::ExprKind::Lit(_) => true,
|
|
hir::ExprKind::Call(fun, _) => {
|
|
if let hir::ExprKind::Path(ref p) = fun.kind {
|
|
match cx.tables.qpath_res(p, fun.hir_id) {
|
|
hir::def::Res::Def(hir::def::DefKind::Fn, def_id)
|
|
| hir::def::Res::Def(hir::def::DefKind::AssocFn, def_id) => matches!(
|
|
cx.tcx.fn_sig(def_id).output().skip_binder().kind,
|
|
ty::Ref(ty::ReStatic, ..)
|
|
),
|
|
_ => false,
|
|
}
|
|
} else {
|
|
false
|
|
}
|
|
},
|
|
hir::ExprKind::MethodCall(..) => cx.tables.type_dependent_def_id(arg.hir_id).map_or(false, |method_id| {
|
|
matches!(
|
|
cx.tcx.fn_sig(method_id).output().skip_binder().kind,
|
|
ty::Ref(ty::ReStatic, ..)
|
|
)
|
|
}),
|
|
hir::ExprKind::Path(ref p) => match cx.tables.qpath_res(p, arg.hir_id) {
|
|
hir::def::Res::Def(hir::def::DefKind::Const | hir::def::DefKind::Static, _) => true,
|
|
_ => false,
|
|
},
|
|
_ => false,
|
|
}
|
|
}
|
|
|
|
fn generate_format_arg_snippet(
|
|
cx: &LateContext<'_, '_>,
|
|
a: &hir::Expr<'_>,
|
|
applicability: &mut Applicability,
|
|
) -> Vec<String> {
|
|
if_chain! {
|
|
if let hir::ExprKind::AddrOf(hir::BorrowKind::Ref, _, ref format_arg) = a.kind;
|
|
if let hir::ExprKind::Match(ref format_arg_expr, _, _) = format_arg.kind;
|
|
if let hir::ExprKind::Tup(ref format_arg_expr_tup) = format_arg_expr.kind;
|
|
|
|
then {
|
|
format_arg_expr_tup
|
|
.iter()
|
|
.map(|a| snippet_with_applicability(cx, a.span, "..", applicability).into_owned())
|
|
.collect()
|
|
} else {
|
|
unreachable!()
|
|
}
|
|
}
|
|
}
|
|
|
|
fn is_call(node: &hir::ExprKind<'_>) -> bool {
|
|
match node {
|
|
hir::ExprKind::AddrOf(hir::BorrowKind::Ref, _, expr) => {
|
|
is_call(&expr.kind)
|
|
},
|
|
hir::ExprKind::Call(..)
|
|
| hir::ExprKind::MethodCall(..)
|
|
// These variants are debatable or require further examination
|
|
| hir::ExprKind::Match(..)
|
|
| hir::ExprKind::Block{ .. } => true,
|
|
_ => false,
|
|
}
|
|
}
|
|
|
|
if args.len() != 2 || name != "expect" || !is_call(&args[1].kind) {
|
|
return;
|
|
}
|
|
|
|
let receiver_type = cx.tables.expr_ty_adjusted(&args[0]);
|
|
let closure_args = if match_type(cx, receiver_type, &paths::OPTION) {
|
|
"||"
|
|
} else if match_type(cx, receiver_type, &paths::RESULT) {
|
|
"|_|"
|
|
} else {
|
|
return;
|
|
};
|
|
|
|
let arg_root = get_arg_root(cx, &args[1]);
|
|
|
|
let span_replace_word = method_span.with_hi(expr.span.hi());
|
|
|
|
let mut applicability = Applicability::MachineApplicable;
|
|
|
|
//Special handling for `format!` as arg_root
|
|
if_chain! {
|
|
if let hir::ExprKind::Block(block, None) = &arg_root.kind;
|
|
if block.stmts.len() == 1;
|
|
if let hir::StmtKind::Local(local) = &block.stmts[0].kind;
|
|
if let Some(arg_root) = &local.init;
|
|
if let hir::ExprKind::Call(ref inner_fun, ref inner_args) = arg_root.kind;
|
|
if is_expn_of(inner_fun.span, "format").is_some() && inner_args.len() == 1;
|
|
if let hir::ExprKind::Call(_, format_args) = &inner_args[0].kind;
|
|
then {
|
|
let fmt_spec = &format_args[0];
|
|
let fmt_args = &format_args[1];
|
|
|
|
let mut args = vec![snippet(cx, fmt_spec.span, "..").into_owned()];
|
|
|
|
args.extend(generate_format_arg_snippet(cx, fmt_args, &mut applicability));
|
|
|
|
let sugg = args.join(", ");
|
|
|
|
span_lint_and_sugg(
|
|
cx,
|
|
EXPECT_FUN_CALL,
|
|
span_replace_word,
|
|
&format!("use of `{}` followed by a function call", name),
|
|
"try this",
|
|
format!("unwrap_or_else({} panic!({}))", closure_args, sugg),
|
|
applicability,
|
|
);
|
|
|
|
return;
|
|
}
|
|
}
|
|
|
|
let mut arg_root_snippet: Cow<'_, _> = snippet_with_applicability(cx, arg_root.span, "..", &mut applicability);
|
|
if requires_to_string(cx, arg_root) {
|
|
arg_root_snippet.to_mut().push_str(".to_string()");
|
|
}
|
|
|
|
span_lint_and_sugg(
|
|
cx,
|
|
EXPECT_FUN_CALL,
|
|
span_replace_word,
|
|
&format!("use of `{}` followed by a function call", name),
|
|
"try this",
|
|
format!("unwrap_or_else({} {{ panic!({}) }})", closure_args, arg_root_snippet),
|
|
applicability,
|
|
);
|
|
}
|
|
|
|
/// Checks for the `CLONE_ON_COPY` lint.
|
|
fn lint_clone_on_copy(cx: &LateContext<'_, '_>, expr: &hir::Expr<'_>, arg: &hir::Expr<'_>, arg_ty: Ty<'_>) {
|
|
let ty = cx.tables.expr_ty(expr);
|
|
if let ty::Ref(_, inner, _) = arg_ty.kind {
|
|
if let ty::Ref(_, innermost, _) = inner.kind {
|
|
span_lint_and_then(
|
|
cx,
|
|
CLONE_DOUBLE_REF,
|
|
expr.span,
|
|
"using `clone` on a double-reference; \
|
|
this will copy the reference instead of cloning the inner type",
|
|
|db| {
|
|
if let Some(snip) = sugg::Sugg::hir_opt(cx, arg) {
|
|
let mut ty = innermost;
|
|
let mut n = 0;
|
|
while let ty::Ref(_, inner, _) = ty.kind {
|
|
ty = inner;
|
|
n += 1;
|
|
}
|
|
let refs: String = iter::repeat('&').take(n + 1).collect();
|
|
let derefs: String = iter::repeat('*').take(n).collect();
|
|
let explicit = format!("{}{}::clone({})", refs, ty, snip);
|
|
db.span_suggestion(
|
|
expr.span,
|
|
"try dereferencing it",
|
|
format!("{}({}{}).clone()", refs, derefs, snip.deref()),
|
|
Applicability::MaybeIncorrect,
|
|
);
|
|
db.span_suggestion(
|
|
expr.span,
|
|
"or try being explicit about what type to clone",
|
|
explicit,
|
|
Applicability::MaybeIncorrect,
|
|
);
|
|
}
|
|
},
|
|
);
|
|
return; // don't report clone_on_copy
|
|
}
|
|
}
|
|
|
|
if is_copy(cx, ty) {
|
|
let snip;
|
|
if let Some(snippet) = sugg::Sugg::hir_opt(cx, arg) {
|
|
let parent = cx.tcx.hir().get_parent_node(expr.hir_id);
|
|
match &cx.tcx.hir().get(parent) {
|
|
hir::Node::Expr(parent) => match parent.kind {
|
|
// &*x is a nop, &x.clone() is not
|
|
hir::ExprKind::AddrOf(..) |
|
|
// (*x).func() is useless, x.clone().func() can work in case func borrows mutably
|
|
hir::ExprKind::MethodCall(..) => return,
|
|
_ => {},
|
|
},
|
|
hir::Node::Stmt(stmt) => {
|
|
if let hir::StmtKind::Local(ref loc) = stmt.kind {
|
|
if let hir::PatKind::Ref(..) = loc.pat.kind {
|
|
// let ref y = *x borrows x, let ref y = x.clone() does not
|
|
return;
|
|
}
|
|
}
|
|
},
|
|
_ => {},
|
|
}
|
|
|
|
// x.clone() might have dereferenced x, possibly through Deref impls
|
|
if cx.tables.expr_ty(arg) == ty {
|
|
snip = Some(("try removing the `clone` call", format!("{}", snippet)));
|
|
} else {
|
|
let deref_count = cx
|
|
.tables
|
|
.expr_adjustments(arg)
|
|
.iter()
|
|
.filter(|adj| {
|
|
if let ty::adjustment::Adjust::Deref(_) = adj.kind {
|
|
true
|
|
} else {
|
|
false
|
|
}
|
|
})
|
|
.count();
|
|
let derefs: String = iter::repeat('*').take(deref_count).collect();
|
|
snip = Some(("try dereferencing it", format!("{}{}", derefs, snippet)));
|
|
}
|
|
} else {
|
|
snip = None;
|
|
}
|
|
span_lint_and_then(cx, CLONE_ON_COPY, expr.span, "using `clone` on a `Copy` type", |db| {
|
|
if let Some((text, snip)) = snip {
|
|
db.span_suggestion(expr.span, text, snip, Applicability::Unspecified);
|
|
}
|
|
});
|
|
}
|
|
}
|
|
|
|
fn lint_clone_on_ref_ptr(cx: &LateContext<'_, '_>, expr: &hir::Expr<'_>, arg: &hir::Expr<'_>) {
|
|
let obj_ty = walk_ptrs_ty(cx.tables.expr_ty(arg));
|
|
|
|
if let ty::Adt(_, subst) = obj_ty.kind {
|
|
let caller_type = if match_type(cx, obj_ty, &paths::RC) {
|
|
"Rc"
|
|
} else if match_type(cx, obj_ty, &paths::ARC) {
|
|
"Arc"
|
|
} else if match_type(cx, obj_ty, &paths::WEAK_RC) || match_type(cx, obj_ty, &paths::WEAK_ARC) {
|
|
"Weak"
|
|
} else {
|
|
return;
|
|
};
|
|
|
|
span_lint_and_sugg(
|
|
cx,
|
|
CLONE_ON_REF_PTR,
|
|
expr.span,
|
|
"using `.clone()` on a ref-counted pointer",
|
|
"try this",
|
|
format!(
|
|
"{}::<{}>::clone(&{})",
|
|
caller_type,
|
|
subst.type_at(0),
|
|
snippet(cx, arg.span, "_")
|
|
),
|
|
Applicability::Unspecified, // Sometimes unnecessary ::<_> after Rc/Arc/Weak
|
|
);
|
|
}
|
|
}
|
|
|
|
fn lint_string_extend(cx: &LateContext<'_, '_>, expr: &hir::Expr<'_>, args: &[hir::Expr<'_>]) {
|
|
let arg = &args[1];
|
|
if let Some(arglists) = method_chain_args(arg, &["chars"]) {
|
|
let target = &arglists[0][0];
|
|
let self_ty = walk_ptrs_ty(cx.tables.expr_ty(target));
|
|
let ref_str = if self_ty.kind == ty::Str {
|
|
""
|
|
} else if match_type(cx, self_ty, &paths::STRING) {
|
|
"&"
|
|
} else {
|
|
return;
|
|
};
|
|
|
|
let mut applicability = Applicability::MachineApplicable;
|
|
span_lint_and_sugg(
|
|
cx,
|
|
STRING_EXTEND_CHARS,
|
|
expr.span,
|
|
"calling `.extend(_.chars())`",
|
|
"try this",
|
|
format!(
|
|
"{}.push_str({}{})",
|
|
snippet_with_applicability(cx, args[0].span, "_", &mut applicability),
|
|
ref_str,
|
|
snippet_with_applicability(cx, target.span, "_", &mut applicability)
|
|
),
|
|
applicability,
|
|
);
|
|
}
|
|
}
|
|
|
|
fn lint_extend(cx: &LateContext<'_, '_>, expr: &hir::Expr<'_>, args: &[hir::Expr<'_>]) {
|
|
let obj_ty = walk_ptrs_ty(cx.tables.expr_ty(&args[0]));
|
|
if match_type(cx, obj_ty, &paths::STRING) {
|
|
lint_string_extend(cx, expr, args);
|
|
}
|
|
}
|
|
|
|
fn lint_cstring_as_ptr(cx: &LateContext<'_, '_>, expr: &hir::Expr<'_>, source: &hir::Expr<'_>, unwrap: &hir::Expr<'_>) {
|
|
if_chain! {
|
|
let source_type = cx.tables.expr_ty(source);
|
|
if let ty::Adt(def, substs) = source_type.kind;
|
|
if match_def_path(cx, def.did, &paths::RESULT);
|
|
if match_type(cx, substs.type_at(0), &paths::CSTRING);
|
|
then {
|
|
span_lint_and_then(
|
|
cx,
|
|
TEMPORARY_CSTRING_AS_PTR,
|
|
expr.span,
|
|
"you are getting the inner pointer of a temporary `CString`",
|
|
|db| {
|
|
db.note("that pointer will be invalid outside this expression");
|
|
db.span_help(unwrap.span, "assign the `CString` to a variable to extend its lifetime");
|
|
});
|
|
}
|
|
}
|
|
}
|
|
|
|
fn lint_iter_cloned_collect<'a, 'tcx>(
|
|
cx: &LateContext<'a, 'tcx>,
|
|
expr: &hir::Expr<'_>,
|
|
iter_args: &'tcx [hir::Expr<'_>],
|
|
) {
|
|
if_chain! {
|
|
if is_type_diagnostic_item(cx, cx.tables.expr_ty(expr), Symbol::intern("vec_type"));
|
|
if let Some(slice) = derefs_to_slice(cx, &iter_args[0], cx.tables.expr_ty(&iter_args[0]));
|
|
if let Some(to_replace) = expr.span.trim_start(slice.span.source_callsite());
|
|
|
|
then {
|
|
span_lint_and_sugg(
|
|
cx,
|
|
ITER_CLONED_COLLECT,
|
|
to_replace,
|
|
"called `iter().cloned().collect()` on a slice to create a `Vec`. Calling `to_vec()` is both faster and \
|
|
more readable",
|
|
"try",
|
|
".to_vec()".to_string(),
|
|
Applicability::MachineApplicable,
|
|
);
|
|
}
|
|
}
|
|
}
|
|
|
|
fn lint_unnecessary_fold(cx: &LateContext<'_, '_>, expr: &hir::Expr<'_>, fold_args: &[hir::Expr<'_>], fold_span: Span) {
|
|
fn check_fold_with_op(
|
|
cx: &LateContext<'_, '_>,
|
|
expr: &hir::Expr<'_>,
|
|
fold_args: &[hir::Expr<'_>],
|
|
fold_span: Span,
|
|
op: hir::BinOpKind,
|
|
replacement_method_name: &str,
|
|
replacement_has_args: bool,
|
|
) {
|
|
if_chain! {
|
|
// Extract the body of the closure passed to fold
|
|
if let hir::ExprKind::Closure(_, _, body_id, _, _) = fold_args[2].kind;
|
|
let closure_body = cx.tcx.hir().body(body_id);
|
|
let closure_expr = remove_blocks(&closure_body.value);
|
|
|
|
// Check if the closure body is of the form `acc <op> some_expr(x)`
|
|
if let hir::ExprKind::Binary(ref bin_op, ref left_expr, ref right_expr) = closure_expr.kind;
|
|
if bin_op.node == op;
|
|
|
|
// Extract the names of the two arguments to the closure
|
|
if let Some(first_arg_ident) = get_arg_name(&closure_body.params[0].pat);
|
|
if let Some(second_arg_ident) = get_arg_name(&closure_body.params[1].pat);
|
|
|
|
if match_var(&*left_expr, first_arg_ident);
|
|
if replacement_has_args || match_var(&*right_expr, second_arg_ident);
|
|
|
|
then {
|
|
let mut applicability = Applicability::MachineApplicable;
|
|
let sugg = if replacement_has_args {
|
|
format!(
|
|
"{replacement}(|{s}| {r})",
|
|
replacement = replacement_method_name,
|
|
s = second_arg_ident,
|
|
r = snippet_with_applicability(cx, right_expr.span, "EXPR", &mut applicability),
|
|
)
|
|
} else {
|
|
format!(
|
|
"{replacement}()",
|
|
replacement = replacement_method_name,
|
|
)
|
|
};
|
|
|
|
span_lint_and_sugg(
|
|
cx,
|
|
UNNECESSARY_FOLD,
|
|
fold_span.with_hi(expr.span.hi()),
|
|
// TODO #2371 don't suggest e.g., .any(|x| f(x)) if we can suggest .any(f)
|
|
"this `.fold` can be written more succinctly using another method",
|
|
"try",
|
|
sugg,
|
|
applicability,
|
|
);
|
|
}
|
|
}
|
|
}
|
|
|
|
// Check that this is a call to Iterator::fold rather than just some function called fold
|
|
if !match_trait_method(cx, expr, &paths::ITERATOR) {
|
|
return;
|
|
}
|
|
|
|
assert!(
|
|
fold_args.len() == 3,
|
|
"Expected fold_args to have three entries - the receiver, the initial value and the closure"
|
|
);
|
|
|
|
// Check if the first argument to .fold is a suitable literal
|
|
if let hir::ExprKind::Lit(ref lit) = fold_args[1].kind {
|
|
match lit.node {
|
|
ast::LitKind::Bool(false) => {
|
|
check_fold_with_op(cx, expr, fold_args, fold_span, hir::BinOpKind::Or, "any", true)
|
|
},
|
|
ast::LitKind::Bool(true) => {
|
|
check_fold_with_op(cx, expr, fold_args, fold_span, hir::BinOpKind::And, "all", true)
|
|
},
|
|
ast::LitKind::Int(0, _) => {
|
|
check_fold_with_op(cx, expr, fold_args, fold_span, hir::BinOpKind::Add, "sum", false)
|
|
},
|
|
ast::LitKind::Int(1, _) => {
|
|
check_fold_with_op(cx, expr, fold_args, fold_span, hir::BinOpKind::Mul, "product", false)
|
|
},
|
|
_ => (),
|
|
}
|
|
}
|
|
}
|
|
|
|
fn lint_step_by<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, expr: &hir::Expr<'_>, args: &'tcx [hir::Expr<'_>]) {
|
|
if match_trait_method(cx, expr, &paths::ITERATOR) {
|
|
if let Some((Constant::Int(0), _)) = constant(cx, cx.tables, &args[1]) {
|
|
span_lint(
|
|
cx,
|
|
ITERATOR_STEP_BY_ZERO,
|
|
expr.span,
|
|
"Iterator::step_by(0) will panic at runtime",
|
|
);
|
|
}
|
|
}
|
|
}
|
|
|
|
fn lint_iter_nth<'a, 'tcx>(
|
|
cx: &LateContext<'a, 'tcx>,
|
|
expr: &hir::Expr<'_>,
|
|
nth_and_iter_args: &[&'tcx [hir::Expr<'tcx>]],
|
|
is_mut: bool,
|
|
) {
|
|
let iter_args = nth_and_iter_args[1];
|
|
let mut_str = if is_mut { "_mut" } else { "" };
|
|
let caller_type = if derefs_to_slice(cx, &iter_args[0], cx.tables.expr_ty(&iter_args[0])).is_some() {
|
|
"slice"
|
|
} else if is_type_diagnostic_item(cx, cx.tables.expr_ty(&iter_args[0]), Symbol::intern("vec_type")) {
|
|
"Vec"
|
|
} else if match_type(cx, cx.tables.expr_ty(&iter_args[0]), &paths::VEC_DEQUE) {
|
|
"VecDeque"
|
|
} else {
|
|
let nth_args = nth_and_iter_args[0];
|
|
lint_iter_nth_zero(cx, expr, &nth_args);
|
|
return; // caller is not a type that we want to lint
|
|
};
|
|
|
|
span_lint_and_help(
|
|
cx,
|
|
ITER_NTH,
|
|
expr.span,
|
|
&format!("called `.iter{0}().nth()` on a {1}", mut_str, caller_type),
|
|
&format!("calling `.get{}()` is both faster and more readable", mut_str),
|
|
);
|
|
}
|
|
|
|
fn lint_iter_nth_zero<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, expr: &hir::Expr<'_>, nth_args: &'tcx [hir::Expr<'_>]) {
|
|
if_chain! {
|
|
if match_trait_method(cx, expr, &paths::ITERATOR);
|
|
if let Some((Constant::Int(0), _)) = constant(cx, cx.tables, &nth_args[1]);
|
|
then {
|
|
let mut applicability = Applicability::MachineApplicable;
|
|
span_lint_and_sugg(
|
|
cx,
|
|
ITER_NTH_ZERO,
|
|
expr.span,
|
|
"called `.nth(0)` on a `std::iter::Iterator`",
|
|
"try calling",
|
|
format!("{}.next()", snippet_with_applicability(cx, nth_args[0].span, "..", &mut applicability)),
|
|
applicability,
|
|
);
|
|
}
|
|
}
|
|
}
|
|
|
|
fn lint_get_unwrap<'a, 'tcx>(
|
|
cx: &LateContext<'a, 'tcx>,
|
|
expr: &hir::Expr<'_>,
|
|
get_args: &'tcx [hir::Expr<'_>],
|
|
is_mut: bool,
|
|
) {
|
|
// Note: we don't want to lint `get_mut().unwrap` for `HashMap` or `BTreeMap`,
|
|
// because they do not implement `IndexMut`
|
|
let mut applicability = Applicability::MachineApplicable;
|
|
let expr_ty = cx.tables.expr_ty(&get_args[0]);
|
|
let get_args_str = if get_args.len() > 1 {
|
|
snippet_with_applicability(cx, get_args[1].span, "_", &mut applicability)
|
|
} else {
|
|
return; // not linting on a .get().unwrap() chain or variant
|
|
};
|
|
let mut needs_ref;
|
|
let caller_type = if derefs_to_slice(cx, &get_args[0], expr_ty).is_some() {
|
|
needs_ref = get_args_str.parse::<usize>().is_ok();
|
|
"slice"
|
|
} else if is_type_diagnostic_item(cx, expr_ty, Symbol::intern("vec_type")) {
|
|
needs_ref = get_args_str.parse::<usize>().is_ok();
|
|
"Vec"
|
|
} else if match_type(cx, expr_ty, &paths::VEC_DEQUE) {
|
|
needs_ref = get_args_str.parse::<usize>().is_ok();
|
|
"VecDeque"
|
|
} else if !is_mut && match_type(cx, expr_ty, &paths::HASHMAP) {
|
|
needs_ref = true;
|
|
"HashMap"
|
|
} else if !is_mut && match_type(cx, expr_ty, &paths::BTREEMAP) {
|
|
needs_ref = true;
|
|
"BTreeMap"
|
|
} else {
|
|
return; // caller is not a type that we want to lint
|
|
};
|
|
|
|
let mut span = expr.span;
|
|
|
|
// Handle the case where the result is immediately dereferenced
|
|
// by not requiring ref and pulling the dereference into the
|
|
// suggestion.
|
|
if_chain! {
|
|
if needs_ref;
|
|
if let Some(parent) = get_parent_expr(cx, expr);
|
|
if let hir::ExprKind::Unary(hir::UnOp::UnDeref, _) = parent.kind;
|
|
then {
|
|
needs_ref = false;
|
|
span = parent.span;
|
|
}
|
|
}
|
|
|
|
let mut_str = if is_mut { "_mut" } else { "" };
|
|
let borrow_str = if !needs_ref {
|
|
""
|
|
} else if is_mut {
|
|
"&mut "
|
|
} else {
|
|
"&"
|
|
};
|
|
|
|
span_lint_and_sugg(
|
|
cx,
|
|
GET_UNWRAP,
|
|
span,
|
|
&format!(
|
|
"called `.get{0}().unwrap()` on a {1}. Using `[]` is more clear and more concise",
|
|
mut_str, caller_type
|
|
),
|
|
"try this",
|
|
format!(
|
|
"{}{}[{}]",
|
|
borrow_str,
|
|
snippet_with_applicability(cx, get_args[0].span, "_", &mut applicability),
|
|
get_args_str
|
|
),
|
|
applicability,
|
|
);
|
|
}
|
|
|
|
fn lint_iter_skip_next(cx: &LateContext<'_, '_>, expr: &hir::Expr<'_>) {
|
|
// lint if caller of skip is an Iterator
|
|
if match_trait_method(cx, expr, &paths::ITERATOR) {
|
|
span_lint_and_help(
|
|
cx,
|
|
ITER_SKIP_NEXT,
|
|
expr.span,
|
|
"called `skip(x).next()` on an iterator",
|
|
"this is more succinctly expressed by calling `nth(x)`",
|
|
);
|
|
}
|
|
}
|
|
|
|
fn derefs_to_slice<'a, 'tcx>(
|
|
cx: &LateContext<'a, 'tcx>,
|
|
expr: &'tcx hir::Expr<'tcx>,
|
|
ty: Ty<'tcx>,
|
|
) -> Option<&'tcx hir::Expr<'tcx>> {
|
|
fn may_slice<'a>(cx: &LateContext<'_, 'a>, ty: Ty<'a>) -> bool {
|
|
match ty.kind {
|
|
ty::Slice(_) => true,
|
|
ty::Adt(def, _) if def.is_box() => may_slice(cx, ty.boxed_ty()),
|
|
ty::Adt(..) => is_type_diagnostic_item(cx, ty, Symbol::intern("vec_type")),
|
|
ty::Array(_, size) => {
|
|
if let Some(size) = size.try_eval_usize(cx.tcx, cx.param_env) {
|
|
size < 32
|
|
} else {
|
|
false
|
|
}
|
|
},
|
|
ty::Ref(_, inner, _) => may_slice(cx, inner),
|
|
_ => false,
|
|
}
|
|
}
|
|
|
|
if let hir::ExprKind::MethodCall(ref path, _, ref args) = expr.kind {
|
|
if path.ident.name == sym!(iter) && may_slice(cx, cx.tables.expr_ty(&args[0])) {
|
|
Some(&args[0])
|
|
} else {
|
|
None
|
|
}
|
|
} else {
|
|
match ty.kind {
|
|
ty::Slice(_) => Some(expr),
|
|
ty::Adt(def, _) if def.is_box() && may_slice(cx, ty.boxed_ty()) => Some(expr),
|
|
ty::Ref(_, inner, _) => {
|
|
if may_slice(cx, inner) {
|
|
Some(expr)
|
|
} else {
|
|
None
|
|
}
|
|
},
|
|
_ => None,
|
|
}
|
|
}
|
|
}
|
|
|
|
/// lint use of `unwrap()` for `Option`s and `Result`s
|
|
fn lint_unwrap(cx: &LateContext<'_, '_>, expr: &hir::Expr<'_>, unwrap_args: &[hir::Expr<'_>]) {
|
|
let obj_ty = walk_ptrs_ty(cx.tables.expr_ty(&unwrap_args[0]));
|
|
|
|
let mess = if match_type(cx, obj_ty, &paths::OPTION) {
|
|
Some((OPTION_UNWRAP_USED, "an Option", "None"))
|
|
} else if match_type(cx, obj_ty, &paths::RESULT) {
|
|
Some((RESULT_UNWRAP_USED, "a Result", "Err"))
|
|
} else {
|
|
None
|
|
};
|
|
|
|
if let Some((lint, kind, none_value)) = mess {
|
|
span_lint_and_help(
|
|
cx,
|
|
lint,
|
|
expr.span,
|
|
&format!("used `unwrap()` on `{}` value", kind,),
|
|
&format!(
|
|
"if you don't want to handle the `{}` case gracefully, consider \
|
|
using `expect()` to provide a better panic message",
|
|
none_value,
|
|
),
|
|
);
|
|
}
|
|
}
|
|
|
|
/// lint use of `expect()` for `Option`s and `Result`s
|
|
fn lint_expect(cx: &LateContext<'_, '_>, expr: &hir::Expr<'_>, expect_args: &[hir::Expr<'_>]) {
|
|
let obj_ty = walk_ptrs_ty(cx.tables.expr_ty(&expect_args[0]));
|
|
|
|
let mess = if match_type(cx, obj_ty, &paths::OPTION) {
|
|
Some((OPTION_EXPECT_USED, "an Option", "None"))
|
|
} else if match_type(cx, obj_ty, &paths::RESULT) {
|
|
Some((RESULT_EXPECT_USED, "a Result", "Err"))
|
|
} else {
|
|
None
|
|
};
|
|
|
|
if let Some((lint, kind, none_value)) = mess {
|
|
span_lint_and_help(
|
|
cx,
|
|
lint,
|
|
expr.span,
|
|
&format!("used `expect()` on `{}` value", kind,),
|
|
&format!("if this value is an `{}`, it will panic", none_value,),
|
|
);
|
|
}
|
|
}
|
|
|
|
/// lint use of `ok().expect()` for `Result`s
|
|
fn lint_ok_expect(cx: &LateContext<'_, '_>, expr: &hir::Expr<'_>, ok_args: &[hir::Expr<'_>]) {
|
|
if_chain! {
|
|
// lint if the caller of `ok()` is a `Result`
|
|
if match_type(cx, cx.tables.expr_ty(&ok_args[0]), &paths::RESULT);
|
|
let result_type = cx.tables.expr_ty(&ok_args[0]);
|
|
if let Some(error_type) = get_error_type(cx, result_type);
|
|
if has_debug_impl(error_type, cx);
|
|
|
|
then {
|
|
span_lint_and_help(
|
|
cx,
|
|
OK_EXPECT,
|
|
expr.span,
|
|
"called `ok().expect()` on a `Result` value",
|
|
"you can call `expect()` directly on the `Result`",
|
|
);
|
|
}
|
|
}
|
|
}
|
|
|
|
/// lint use of `map().flatten()` for `Iterators`
|
|
fn lint_map_flatten<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, expr: &'tcx hir::Expr<'_>, map_args: &'tcx [hir::Expr<'_>]) {
|
|
// lint if caller of `.map().flatten()` is an Iterator
|
|
if match_trait_method(cx, expr, &paths::ITERATOR) {
|
|
let msg = "called `map(..).flatten()` on an `Iterator`. \
|
|
This is more succinctly expressed by calling `.flat_map(..)`";
|
|
let self_snippet = snippet(cx, map_args[0].span, "..");
|
|
let func_snippet = snippet(cx, map_args[1].span, "..");
|
|
let hint = format!("{0}.flat_map({1})", self_snippet, func_snippet);
|
|
span_lint_and_sugg(
|
|
cx,
|
|
MAP_FLATTEN,
|
|
expr.span,
|
|
msg,
|
|
"try using `flat_map` instead",
|
|
hint,
|
|
Applicability::MachineApplicable,
|
|
);
|
|
}
|
|
}
|
|
|
|
/// lint use of `map().unwrap_or_else()` for `Option`s and `Result`s
|
|
fn lint_map_unwrap_or_else<'a, 'tcx>(
|
|
cx: &LateContext<'a, 'tcx>,
|
|
expr: &'tcx hir::Expr<'_>,
|
|
map_args: &'tcx [hir::Expr<'_>],
|
|
unwrap_args: &'tcx [hir::Expr<'_>],
|
|
) {
|
|
// lint if the caller of `map()` is an `Option`
|
|
let is_option = match_type(cx, cx.tables.expr_ty(&map_args[0]), &paths::OPTION);
|
|
let is_result = match_type(cx, cx.tables.expr_ty(&map_args[0]), &paths::RESULT);
|
|
|
|
if is_option || is_result {
|
|
// Don't make a suggestion that may fail to compile due to mutably borrowing
|
|
// the same variable twice.
|
|
let map_mutated_vars = mutated_variables(&map_args[0], cx);
|
|
let unwrap_mutated_vars = mutated_variables(&unwrap_args[1], cx);
|
|
if let (Some(map_mutated_vars), Some(unwrap_mutated_vars)) = (map_mutated_vars, unwrap_mutated_vars) {
|
|
if map_mutated_vars.intersection(&unwrap_mutated_vars).next().is_some() {
|
|
return;
|
|
}
|
|
} else {
|
|
return;
|
|
}
|
|
|
|
// lint message
|
|
let msg = if is_option {
|
|
"called `map(f).unwrap_or_else(g)` on an `Option` value. This can be done more directly by calling \
|
|
`map_or_else(g, f)` instead"
|
|
} else {
|
|
"called `map(f).unwrap_or_else(g)` on a `Result` value. This can be done more directly by calling \
|
|
`.map_or_else(g, f)` instead"
|
|
};
|
|
// get snippets for args to map() and unwrap_or_else()
|
|
let map_snippet = snippet(cx, map_args[1].span, "..");
|
|
let unwrap_snippet = snippet(cx, unwrap_args[1].span, "..");
|
|
// lint, with note if neither arg is > 1 line and both map() and
|
|
// unwrap_or_else() have the same span
|
|
let multiline = map_snippet.lines().count() > 1 || unwrap_snippet.lines().count() > 1;
|
|
let same_span = map_args[1].span.ctxt() == unwrap_args[1].span.ctxt();
|
|
if same_span && !multiline {
|
|
span_lint_and_note(
|
|
cx,
|
|
if is_option {
|
|
OPTION_MAP_UNWRAP_OR_ELSE
|
|
} else {
|
|
RESULT_MAP_UNWRAP_OR_ELSE
|
|
},
|
|
expr.span,
|
|
msg,
|
|
expr.span,
|
|
&format!(
|
|
"replace `map({0}).unwrap_or_else({1})` with `map_or_else({1}, {0})`",
|
|
map_snippet, unwrap_snippet,
|
|
),
|
|
);
|
|
} else if same_span && multiline {
|
|
span_lint(
|
|
cx,
|
|
if is_option {
|
|
OPTION_MAP_UNWRAP_OR_ELSE
|
|
} else {
|
|
RESULT_MAP_UNWRAP_OR_ELSE
|
|
},
|
|
expr.span,
|
|
msg,
|
|
);
|
|
};
|
|
}
|
|
}
|
|
|
|
/// lint use of `_.map_or(None, _)` for `Option`s and `Result`s
|
|
fn lint_map_or_none<'a, 'tcx>(
|
|
cx: &LateContext<'a, 'tcx>,
|
|
expr: &'tcx hir::Expr<'_>,
|
|
map_or_args: &'tcx [hir::Expr<'_>],
|
|
) {
|
|
let is_option = match_type(cx, cx.tables.expr_ty(&map_or_args[0]), &paths::OPTION);
|
|
let is_result = match_type(cx, cx.tables.expr_ty(&map_or_args[0]), &paths::RESULT);
|
|
|
|
// There are two variants of this `map_or` lint:
|
|
// (1) using `map_or` as an adapter from `Result<T,E>` to `Option<T>`
|
|
// (2) using `map_or` as a combinator instead of `and_then`
|
|
//
|
|
// (For this lint) we don't care if any other type calls `map_or`
|
|
if !is_option && !is_result {
|
|
return;
|
|
}
|
|
|
|
let default_arg_is_none = if let hir::ExprKind::Path(ref qpath) = map_or_args[1].kind {
|
|
match_qpath(qpath, &paths::OPTION_NONE)
|
|
} else {
|
|
false
|
|
};
|
|
|
|
// This is really only needed if `is_result` holds. Computing it here
|
|
// makes `mess`'s assignment a bit easier, so just compute it here.
|
|
let f_arg_is_some = if let hir::ExprKind::Path(ref qpath) = map_or_args[2].kind {
|
|
match_qpath(qpath, &paths::OPTION_SOME)
|
|
} else {
|
|
false
|
|
};
|
|
|
|
let mess = if is_option && default_arg_is_none {
|
|
let self_snippet = snippet(cx, map_or_args[0].span, "..");
|
|
let func_snippet = snippet(cx, map_or_args[2].span, "..");
|
|
let msg = "called `map_or(None, f)` on an `Option` value. This can be done more directly by calling \
|
|
`and_then(f)` instead";
|
|
Some((
|
|
OPTION_MAP_OR_NONE,
|
|
msg,
|
|
"try using `and_then` instead",
|
|
format!("{0}.and_then({1})", self_snippet, func_snippet),
|
|
))
|
|
} else if is_result && f_arg_is_some {
|
|
let msg = "called `map_or(None, Some)` on a `Result` value. This can be done more directly by calling \
|
|
`ok()` instead";
|
|
let self_snippet = snippet(cx, map_or_args[0].span, "..");
|
|
Some((
|
|
RESULT_MAP_OR_INTO_OPTION,
|
|
msg,
|
|
"try using `ok` instead",
|
|
format!("{0}.ok()", self_snippet),
|
|
))
|
|
} else {
|
|
None
|
|
};
|
|
|
|
if let Some((lint, msg, instead, hint)) = mess {
|
|
span_lint_and_sugg(
|
|
cx,
|
|
lint,
|
|
expr.span,
|
|
msg,
|
|
instead,
|
|
hint,
|
|
Applicability::MachineApplicable,
|
|
);
|
|
}
|
|
}
|
|
|
|
/// Lint use of `_.and_then(|x| Some(y))` for `Option`s
|
|
fn lint_option_and_then_some(cx: &LateContext<'_, '_>, expr: &hir::Expr<'_>, args: &[hir::Expr<'_>]) {
|
|
const LINT_MSG: &str = "using `Option.and_then(|x| Some(y))`, which is more succinctly expressed as `map(|x| y)`";
|
|
const NO_OP_MSG: &str = "using `Option.and_then(Some)`, which is a no-op";
|
|
|
|
let ty = cx.tables.expr_ty(&args[0]);
|
|
if !match_type(cx, ty, &paths::OPTION) {
|
|
return;
|
|
}
|
|
|
|
match args[1].kind {
|
|
hir::ExprKind::Closure(_, _, body_id, closure_args_span, _) => {
|
|
let closure_body = cx.tcx.hir().body(body_id);
|
|
let closure_expr = remove_blocks(&closure_body.value);
|
|
if_chain! {
|
|
if let hir::ExprKind::Call(ref some_expr, ref some_args) = closure_expr.kind;
|
|
if let hir::ExprKind::Path(ref qpath) = some_expr.kind;
|
|
if match_qpath(qpath, &paths::OPTION_SOME);
|
|
if some_args.len() == 1;
|
|
then {
|
|
let inner_expr = &some_args[0];
|
|
|
|
if contains_return(inner_expr) {
|
|
return;
|
|
}
|
|
|
|
let some_inner_snip = if inner_expr.span.from_expansion() {
|
|
snippet_with_macro_callsite(cx, inner_expr.span, "_")
|
|
} else {
|
|
snippet(cx, inner_expr.span, "_")
|
|
};
|
|
|
|
let closure_args_snip = snippet(cx, closure_args_span, "..");
|
|
let option_snip = snippet(cx, args[0].span, "..");
|
|
let note = format!("{}.map({} {})", option_snip, closure_args_snip, some_inner_snip);
|
|
span_lint_and_sugg(
|
|
cx,
|
|
OPTION_AND_THEN_SOME,
|
|
expr.span,
|
|
LINT_MSG,
|
|
"try this",
|
|
note,
|
|
Applicability::MachineApplicable,
|
|
);
|
|
}
|
|
}
|
|
},
|
|
// `_.and_then(Some)` case, which is no-op.
|
|
hir::ExprKind::Path(ref qpath) => {
|
|
if match_qpath(qpath, &paths::OPTION_SOME) {
|
|
let option_snip = snippet(cx, args[0].span, "..");
|
|
let note = format!("{}", option_snip);
|
|
span_lint_and_sugg(
|
|
cx,
|
|
OPTION_AND_THEN_SOME,
|
|
expr.span,
|
|
NO_OP_MSG,
|
|
"use the expression directly",
|
|
note,
|
|
Applicability::MachineApplicable,
|
|
);
|
|
}
|
|
},
|
|
_ => {},
|
|
}
|
|
}
|
|
|
|
/// lint use of `filter().next()` for `Iterators`
|
|
fn lint_filter_next<'a, 'tcx>(
|
|
cx: &LateContext<'a, 'tcx>,
|
|
expr: &'tcx hir::Expr<'_>,
|
|
filter_args: &'tcx [hir::Expr<'_>],
|
|
) {
|
|
// lint if caller of `.filter().next()` is an Iterator
|
|
if match_trait_method(cx, expr, &paths::ITERATOR) {
|
|
let msg = "called `filter(p).next()` on an `Iterator`. This is more succinctly expressed by calling \
|
|
`.find(p)` instead.";
|
|
let filter_snippet = snippet(cx, filter_args[1].span, "..");
|
|
if filter_snippet.lines().count() <= 1 {
|
|
// add note if not multi-line
|
|
span_lint_and_note(
|
|
cx,
|
|
FILTER_NEXT,
|
|
expr.span,
|
|
msg,
|
|
expr.span,
|
|
&format!("replace `filter({0}).next()` with `find({0})`", filter_snippet),
|
|
);
|
|
} else {
|
|
span_lint(cx, FILTER_NEXT, expr.span, msg);
|
|
}
|
|
}
|
|
}
|
|
|
|
/// lint use of `skip_while().next()` for `Iterators`
|
|
fn lint_skip_while_next<'a, 'tcx>(
|
|
cx: &LateContext<'a, 'tcx>,
|
|
expr: &'tcx hir::Expr<'_>,
|
|
_skip_while_args: &'tcx [hir::Expr<'_>],
|
|
) {
|
|
// lint if caller of `.skip_while().next()` is an Iterator
|
|
if match_trait_method(cx, expr, &paths::ITERATOR) {
|
|
span_lint_and_help(
|
|
cx,
|
|
SKIP_WHILE_NEXT,
|
|
expr.span,
|
|
"called `skip_while(p).next()` on an `Iterator`",
|
|
"this is more succinctly expressed by calling `.find(!p)` instead",
|
|
);
|
|
}
|
|
}
|
|
|
|
/// lint use of `filter().map()` for `Iterators`
|
|
fn lint_filter_map<'a, 'tcx>(
|
|
cx: &LateContext<'a, 'tcx>,
|
|
expr: &'tcx hir::Expr<'_>,
|
|
_filter_args: &'tcx [hir::Expr<'_>],
|
|
_map_args: &'tcx [hir::Expr<'_>],
|
|
) {
|
|
// lint if caller of `.filter().map()` is an Iterator
|
|
if match_trait_method(cx, expr, &paths::ITERATOR) {
|
|
let msg = "called `filter(p).map(q)` on an `Iterator`";
|
|
let hint = "this is more succinctly expressed by calling `.filter_map(..)` instead";
|
|
span_lint_and_help(cx, FILTER_MAP, expr.span, msg, hint);
|
|
}
|
|
}
|
|
|
|
/// lint use of `filter_map().next()` for `Iterators`
|
|
fn lint_filter_map_next<'a, 'tcx>(
|
|
cx: &LateContext<'a, 'tcx>,
|
|
expr: &'tcx hir::Expr<'_>,
|
|
filter_args: &'tcx [hir::Expr<'_>],
|
|
) {
|
|
if match_trait_method(cx, expr, &paths::ITERATOR) {
|
|
let msg = "called `filter_map(p).next()` on an `Iterator`. This is more succinctly expressed by calling \
|
|
`.find_map(p)` instead.";
|
|
let filter_snippet = snippet(cx, filter_args[1].span, "..");
|
|
if filter_snippet.lines().count() <= 1 {
|
|
span_lint_and_note(
|
|
cx,
|
|
FILTER_MAP_NEXT,
|
|
expr.span,
|
|
msg,
|
|
expr.span,
|
|
&format!("replace `filter_map({0}).next()` with `find_map({0})`", filter_snippet),
|
|
);
|
|
} else {
|
|
span_lint(cx, FILTER_MAP_NEXT, expr.span, msg);
|
|
}
|
|
}
|
|
}
|
|
|
|
/// lint use of `find().map()` for `Iterators`
|
|
fn lint_find_map<'a, 'tcx>(
|
|
cx: &LateContext<'a, 'tcx>,
|
|
expr: &'tcx hir::Expr<'_>,
|
|
_find_args: &'tcx [hir::Expr<'_>],
|
|
map_args: &'tcx [hir::Expr<'_>],
|
|
) {
|
|
// lint if caller of `.filter().map()` is an Iterator
|
|
if match_trait_method(cx, &map_args[0], &paths::ITERATOR) {
|
|
let msg = "called `find(p).map(q)` on an `Iterator`";
|
|
let hint = "this is more succinctly expressed by calling `.find_map(..)` instead";
|
|
span_lint_and_help(cx, FIND_MAP, expr.span, msg, hint);
|
|
}
|
|
}
|
|
|
|
/// lint use of `filter_map().map()` for `Iterators`
|
|
fn lint_filter_map_map<'a, 'tcx>(
|
|
cx: &LateContext<'a, 'tcx>,
|
|
expr: &'tcx hir::Expr<'_>,
|
|
_filter_args: &'tcx [hir::Expr<'_>],
|
|
_map_args: &'tcx [hir::Expr<'_>],
|
|
) {
|
|
// lint if caller of `.filter().map()` is an Iterator
|
|
if match_trait_method(cx, expr, &paths::ITERATOR) {
|
|
let msg = "called `filter_map(p).map(q)` on an `Iterator`";
|
|
let hint = "this is more succinctly expressed by only calling `.filter_map(..)` instead";
|
|
span_lint_and_help(cx, FILTER_MAP, expr.span, msg, hint);
|
|
}
|
|
}
|
|
|
|
/// lint use of `filter().flat_map()` for `Iterators`
|
|
fn lint_filter_flat_map<'a, 'tcx>(
|
|
cx: &LateContext<'a, 'tcx>,
|
|
expr: &'tcx hir::Expr<'_>,
|
|
_filter_args: &'tcx [hir::Expr<'_>],
|
|
_map_args: &'tcx [hir::Expr<'_>],
|
|
) {
|
|
// lint if caller of `.filter().flat_map()` is an Iterator
|
|
if match_trait_method(cx, expr, &paths::ITERATOR) {
|
|
let msg = "called `filter(p).flat_map(q)` on an `Iterator`";
|
|
let hint = "this is more succinctly expressed by calling `.flat_map(..)` \
|
|
and filtering by returning `iter::empty()`";
|
|
span_lint_and_help(cx, FILTER_MAP, expr.span, msg, hint);
|
|
}
|
|
}
|
|
|
|
/// lint use of `filter_map().flat_map()` for `Iterators`
|
|
fn lint_filter_map_flat_map<'a, 'tcx>(
|
|
cx: &LateContext<'a, 'tcx>,
|
|
expr: &'tcx hir::Expr<'_>,
|
|
_filter_args: &'tcx [hir::Expr<'_>],
|
|
_map_args: &'tcx [hir::Expr<'_>],
|
|
) {
|
|
// lint if caller of `.filter_map().flat_map()` is an Iterator
|
|
if match_trait_method(cx, expr, &paths::ITERATOR) {
|
|
let msg = "called `filter_map(p).flat_map(q)` on an `Iterator`";
|
|
let hint = "this is more succinctly expressed by calling `.flat_map(..)` \
|
|
and filtering by returning `iter::empty()`";
|
|
span_lint_and_help(cx, FILTER_MAP, expr.span, msg, hint);
|
|
}
|
|
}
|
|
|
|
/// lint use of `flat_map` for `Iterators` where `flatten` would be sufficient
|
|
fn lint_flat_map_identity<'a, 'tcx>(
|
|
cx: &LateContext<'a, 'tcx>,
|
|
expr: &'tcx hir::Expr<'_>,
|
|
flat_map_args: &'tcx [hir::Expr<'_>],
|
|
flat_map_span: Span,
|
|
) {
|
|
if match_trait_method(cx, expr, &paths::ITERATOR) {
|
|
let arg_node = &flat_map_args[1].kind;
|
|
|
|
let apply_lint = |message: &str| {
|
|
span_lint_and_sugg(
|
|
cx,
|
|
FLAT_MAP_IDENTITY,
|
|
flat_map_span.with_hi(expr.span.hi()),
|
|
message,
|
|
"try",
|
|
"flatten()".to_string(),
|
|
Applicability::MachineApplicable,
|
|
);
|
|
};
|
|
|
|
if_chain! {
|
|
if let hir::ExprKind::Closure(_, _, body_id, _, _) = arg_node;
|
|
let body = cx.tcx.hir().body(*body_id);
|
|
|
|
if let hir::PatKind::Binding(_, _, binding_ident, _) = body.params[0].pat.kind;
|
|
if let hir::ExprKind::Path(hir::QPath::Resolved(_, ref path)) = body.value.kind;
|
|
|
|
if path.segments.len() == 1;
|
|
if path.segments[0].ident.as_str() == binding_ident.as_str();
|
|
|
|
then {
|
|
apply_lint("called `flat_map(|x| x)` on an `Iterator`");
|
|
}
|
|
}
|
|
|
|
if_chain! {
|
|
if let hir::ExprKind::Path(ref qpath) = arg_node;
|
|
|
|
if match_qpath(qpath, &paths::STD_CONVERT_IDENTITY);
|
|
|
|
then {
|
|
apply_lint("called `flat_map(std::convert::identity)` on an `Iterator`");
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/// lint searching an Iterator followed by `is_some()`
|
|
fn lint_search_is_some<'a, 'tcx>(
|
|
cx: &LateContext<'a, 'tcx>,
|
|
expr: &'tcx hir::Expr<'_>,
|
|
search_method: &str,
|
|
search_args: &'tcx [hir::Expr<'_>],
|
|
is_some_args: &'tcx [hir::Expr<'_>],
|
|
method_span: Span,
|
|
) {
|
|
// lint if caller of search is an Iterator
|
|
if match_trait_method(cx, &is_some_args[0], &paths::ITERATOR) {
|
|
let msg = format!(
|
|
"called `is_some()` after searching an `Iterator` with {}. This is more succinctly \
|
|
expressed by calling `any()`.",
|
|
search_method
|
|
);
|
|
let search_snippet = snippet(cx, search_args[1].span, "..");
|
|
if search_snippet.lines().count() <= 1 {
|
|
// suggest `any(|x| ..)` instead of `any(|&x| ..)` for `find(|&x| ..).is_some()`
|
|
// suggest `any(|..| *..)` instead of `any(|..| **..)` for `find(|..| **..).is_some()`
|
|
let any_search_snippet = if_chain! {
|
|
if search_method == "find";
|
|
if let hir::ExprKind::Closure(_, _, body_id, ..) = search_args[1].kind;
|
|
let closure_body = cx.tcx.hir().body(body_id);
|
|
if let Some(closure_arg) = closure_body.params.get(0);
|
|
then {
|
|
if let hir::PatKind::Ref(..) = closure_arg.pat.kind {
|
|
Some(search_snippet.replacen('&', "", 1))
|
|
} else if let Some(name) = get_arg_name(&closure_arg.pat) {
|
|
Some(search_snippet.replace(&format!("*{}", name), &name.as_str()))
|
|
} else {
|
|
None
|
|
}
|
|
} else {
|
|
None
|
|
}
|
|
};
|
|
// add note if not multi-line
|
|
span_lint_and_sugg(
|
|
cx,
|
|
SEARCH_IS_SOME,
|
|
method_span.with_hi(expr.span.hi()),
|
|
&msg,
|
|
"try this",
|
|
format!(
|
|
"any({})",
|
|
any_search_snippet.as_ref().map_or(&*search_snippet, String::as_str)
|
|
),
|
|
Applicability::MachineApplicable,
|
|
);
|
|
} else {
|
|
span_lint(cx, SEARCH_IS_SOME, expr.span, &msg);
|
|
}
|
|
}
|
|
}
|
|
|
|
/// Used for `lint_binary_expr_with_method_call`.
|
|
#[derive(Copy, Clone)]
|
|
struct BinaryExprInfo<'a> {
|
|
expr: &'a hir::Expr<'a>,
|
|
chain: &'a hir::Expr<'a>,
|
|
other: &'a hir::Expr<'a>,
|
|
eq: bool,
|
|
}
|
|
|
|
/// Checks for the `CHARS_NEXT_CMP` and `CHARS_LAST_CMP` lints.
|
|
fn lint_binary_expr_with_method_call(cx: &LateContext<'_, '_>, info: &mut BinaryExprInfo<'_>) {
|
|
macro_rules! lint_with_both_lhs_and_rhs {
|
|
($func:ident, $cx:expr, $info:ident) => {
|
|
if !$func($cx, $info) {
|
|
::std::mem::swap(&mut $info.chain, &mut $info.other);
|
|
if $func($cx, $info) {
|
|
return;
|
|
}
|
|
}
|
|
};
|
|
}
|
|
|
|
lint_with_both_lhs_and_rhs!(lint_chars_next_cmp, cx, info);
|
|
lint_with_both_lhs_and_rhs!(lint_chars_last_cmp, cx, info);
|
|
lint_with_both_lhs_and_rhs!(lint_chars_next_cmp_with_unwrap, cx, info);
|
|
lint_with_both_lhs_and_rhs!(lint_chars_last_cmp_with_unwrap, cx, info);
|
|
}
|
|
|
|
/// Wrapper fn for `CHARS_NEXT_CMP` and `CHARS_LAST_CMP` lints.
|
|
fn lint_chars_cmp(
|
|
cx: &LateContext<'_, '_>,
|
|
info: &BinaryExprInfo<'_>,
|
|
chain_methods: &[&str],
|
|
lint: &'static Lint,
|
|
suggest: &str,
|
|
) -> bool {
|
|
if_chain! {
|
|
if let Some(args) = method_chain_args(info.chain, chain_methods);
|
|
if let hir::ExprKind::Call(ref fun, ref arg_char) = info.other.kind;
|
|
if arg_char.len() == 1;
|
|
if let hir::ExprKind::Path(ref qpath) = fun.kind;
|
|
if let Some(segment) = single_segment_path(qpath);
|
|
if segment.ident.name == sym!(Some);
|
|
then {
|
|
let mut applicability = Applicability::MachineApplicable;
|
|
let self_ty = walk_ptrs_ty(cx.tables.expr_ty_adjusted(&args[0][0]));
|
|
|
|
if self_ty.kind != ty::Str {
|
|
return false;
|
|
}
|
|
|
|
span_lint_and_sugg(
|
|
cx,
|
|
lint,
|
|
info.expr.span,
|
|
&format!("you should use the `{}` method", suggest),
|
|
"like this",
|
|
format!("{}{}.{}({})",
|
|
if info.eq { "" } else { "!" },
|
|
snippet_with_applicability(cx, args[0][0].span, "_", &mut applicability),
|
|
suggest,
|
|
snippet_with_applicability(cx, arg_char[0].span, "_", &mut applicability)),
|
|
applicability,
|
|
);
|
|
|
|
return true;
|
|
}
|
|
}
|
|
|
|
false
|
|
}
|
|
|
|
/// Checks for the `CHARS_NEXT_CMP` lint.
|
|
fn lint_chars_next_cmp<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, info: &BinaryExprInfo<'_>) -> bool {
|
|
lint_chars_cmp(cx, info, &["chars", "next"], CHARS_NEXT_CMP, "starts_with")
|
|
}
|
|
|
|
/// Checks for the `CHARS_LAST_CMP` lint.
|
|
fn lint_chars_last_cmp<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, info: &BinaryExprInfo<'_>) -> bool {
|
|
if lint_chars_cmp(cx, info, &["chars", "last"], CHARS_LAST_CMP, "ends_with") {
|
|
true
|
|
} else {
|
|
lint_chars_cmp(cx, info, &["chars", "next_back"], CHARS_LAST_CMP, "ends_with")
|
|
}
|
|
}
|
|
|
|
/// Wrapper fn for `CHARS_NEXT_CMP` and `CHARS_LAST_CMP` lints with `unwrap()`.
|
|
fn lint_chars_cmp_with_unwrap<'a, 'tcx>(
|
|
cx: &LateContext<'a, 'tcx>,
|
|
info: &BinaryExprInfo<'_>,
|
|
chain_methods: &[&str],
|
|
lint: &'static Lint,
|
|
suggest: &str,
|
|
) -> bool {
|
|
if_chain! {
|
|
if let Some(args) = method_chain_args(info.chain, chain_methods);
|
|
if let hir::ExprKind::Lit(ref lit) = info.other.kind;
|
|
if let ast::LitKind::Char(c) = lit.node;
|
|
then {
|
|
let mut applicability = Applicability::MachineApplicable;
|
|
span_lint_and_sugg(
|
|
cx,
|
|
lint,
|
|
info.expr.span,
|
|
&format!("you should use the `{}` method", suggest),
|
|
"like this",
|
|
format!("{}{}.{}('{}')",
|
|
if info.eq { "" } else { "!" },
|
|
snippet_with_applicability(cx, args[0][0].span, "_", &mut applicability),
|
|
suggest,
|
|
c),
|
|
applicability,
|
|
);
|
|
|
|
true
|
|
} else {
|
|
false
|
|
}
|
|
}
|
|
}
|
|
|
|
/// Checks for the `CHARS_NEXT_CMP` lint with `unwrap()`.
|
|
fn lint_chars_next_cmp_with_unwrap<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, info: &BinaryExprInfo<'_>) -> bool {
|
|
lint_chars_cmp_with_unwrap(cx, info, &["chars", "next", "unwrap"], CHARS_NEXT_CMP, "starts_with")
|
|
}
|
|
|
|
/// Checks for the `CHARS_LAST_CMP` lint with `unwrap()`.
|
|
fn lint_chars_last_cmp_with_unwrap<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, info: &BinaryExprInfo<'_>) -> bool {
|
|
if lint_chars_cmp_with_unwrap(cx, info, &["chars", "last", "unwrap"], CHARS_LAST_CMP, "ends_with") {
|
|
true
|
|
} else {
|
|
lint_chars_cmp_with_unwrap(cx, info, &["chars", "next_back", "unwrap"], CHARS_LAST_CMP, "ends_with")
|
|
}
|
|
}
|
|
|
|
/// lint for length-1 `str`s for methods in `PATTERN_METHODS`
|
|
fn lint_single_char_pattern<'a, 'tcx>(
|
|
cx: &LateContext<'a, 'tcx>,
|
|
_expr: &'tcx hir::Expr<'_>,
|
|
arg: &'tcx hir::Expr<'_>,
|
|
) {
|
|
if_chain! {
|
|
if let hir::ExprKind::Lit(lit) = &arg.kind;
|
|
if let ast::LitKind::Str(r, style) = lit.node;
|
|
if r.as_str().len() == 1;
|
|
then {
|
|
let mut applicability = Applicability::MachineApplicable;
|
|
let snip = snippet_with_applicability(cx, arg.span, "..", &mut applicability);
|
|
let ch = if let ast::StrStyle::Raw(nhash) = style {
|
|
let nhash = nhash as usize;
|
|
// for raw string: r##"a"##
|
|
&snip[(nhash + 2)..(snip.len() - 1 - nhash)]
|
|
} else {
|
|
// for regular string: "a"
|
|
&snip[1..(snip.len() - 1)]
|
|
};
|
|
let hint = format!("'{}'", if ch == "'" { "\\'" } else { ch });
|
|
span_lint_and_sugg(
|
|
cx,
|
|
SINGLE_CHAR_PATTERN,
|
|
arg.span,
|
|
"single-character string constant used as pattern",
|
|
"try using a `char` instead",
|
|
hint,
|
|
applicability,
|
|
);
|
|
}
|
|
}
|
|
}
|
|
|
|
/// Checks for the `USELESS_ASREF` lint.
|
|
fn lint_asref(cx: &LateContext<'_, '_>, expr: &hir::Expr<'_>, call_name: &str, as_ref_args: &[hir::Expr<'_>]) {
|
|
// when we get here, we've already checked that the call name is "as_ref" or "as_mut"
|
|
// check if the call is to the actual `AsRef` or `AsMut` trait
|
|
if match_trait_method(cx, expr, &paths::ASREF_TRAIT) || match_trait_method(cx, expr, &paths::ASMUT_TRAIT) {
|
|
// check if the type after `as_ref` or `as_mut` is the same as before
|
|
let recvr = &as_ref_args[0];
|
|
let rcv_ty = cx.tables.expr_ty(recvr);
|
|
let res_ty = cx.tables.expr_ty(expr);
|
|
let (base_res_ty, res_depth) = walk_ptrs_ty_depth(res_ty);
|
|
let (base_rcv_ty, rcv_depth) = walk_ptrs_ty_depth(rcv_ty);
|
|
if base_rcv_ty == base_res_ty && rcv_depth >= res_depth {
|
|
// allow the `as_ref` or `as_mut` if it is followed by another method call
|
|
if_chain! {
|
|
if let Some(parent) = get_parent_expr(cx, expr);
|
|
if let hir::ExprKind::MethodCall(_, ref span, _) = parent.kind;
|
|
if span != &expr.span;
|
|
then {
|
|
return;
|
|
}
|
|
}
|
|
|
|
let mut applicability = Applicability::MachineApplicable;
|
|
span_lint_and_sugg(
|
|
cx,
|
|
USELESS_ASREF,
|
|
expr.span,
|
|
&format!("this call to `{}` does nothing", call_name),
|
|
"try this",
|
|
snippet_with_applicability(cx, recvr.span, "_", &mut applicability).to_string(),
|
|
applicability,
|
|
);
|
|
}
|
|
}
|
|
}
|
|
|
|
fn ty_has_iter_method(cx: &LateContext<'_, '_>, self_ref_ty: Ty<'_>) -> Option<(&'static str, &'static str)> {
|
|
has_iter_method(cx, self_ref_ty).map(|ty_name| {
|
|
let mutbl = match self_ref_ty.kind {
|
|
ty::Ref(_, _, mutbl) => mutbl,
|
|
_ => unreachable!(),
|
|
};
|
|
let method_name = match mutbl {
|
|
hir::Mutability::Not => "iter",
|
|
hir::Mutability::Mut => "iter_mut",
|
|
};
|
|
(ty_name, method_name)
|
|
})
|
|
}
|
|
|
|
fn lint_into_iter(cx: &LateContext<'_, '_>, expr: &hir::Expr<'_>, self_ref_ty: Ty<'_>, method_span: Span) {
|
|
if !match_trait_method(cx, expr, &paths::INTO_ITERATOR) {
|
|
return;
|
|
}
|
|
if let Some((kind, method_name)) = ty_has_iter_method(cx, self_ref_ty) {
|
|
span_lint_and_sugg(
|
|
cx,
|
|
INTO_ITER_ON_REF,
|
|
method_span,
|
|
&format!(
|
|
"this `.into_iter()` call is equivalent to `.{}()` and will not move the `{}`",
|
|
method_name, kind,
|
|
),
|
|
"call directly",
|
|
method_name.to_string(),
|
|
Applicability::MachineApplicable,
|
|
);
|
|
}
|
|
}
|
|
|
|
/// lint for `MaybeUninit::uninit().assume_init()` (we already have the latter)
|
|
fn lint_maybe_uninit(cx: &LateContext<'_, '_>, expr: &hir::Expr<'_>, outer: &hir::Expr<'_>) {
|
|
if_chain! {
|
|
if let hir::ExprKind::Call(ref callee, ref args) = expr.kind;
|
|
if args.is_empty();
|
|
if let hir::ExprKind::Path(ref path) = callee.kind;
|
|
if match_qpath(path, &paths::MEM_MAYBEUNINIT_UNINIT);
|
|
if !is_maybe_uninit_ty_valid(cx, cx.tables.expr_ty_adjusted(outer));
|
|
then {
|
|
span_lint(
|
|
cx,
|
|
UNINIT_ASSUMED_INIT,
|
|
outer.span,
|
|
"this call for this type may be undefined behavior"
|
|
);
|
|
}
|
|
}
|
|
}
|
|
|
|
fn is_maybe_uninit_ty_valid(cx: &LateContext<'_, '_>, ty: Ty<'_>) -> bool {
|
|
match ty.kind {
|
|
ty::Array(ref component, _) => is_maybe_uninit_ty_valid(cx, component),
|
|
ty::Tuple(ref types) => types.types().all(|ty| is_maybe_uninit_ty_valid(cx, ty)),
|
|
ty::Adt(ref adt, _) => {
|
|
// needs to be a MaybeUninit
|
|
match_def_path(cx, adt.did, &paths::MEM_MAYBEUNINIT)
|
|
},
|
|
_ => false,
|
|
}
|
|
}
|
|
|
|
fn lint_suspicious_map(cx: &LateContext<'_, '_>, expr: &hir::Expr<'_>) {
|
|
span_lint_and_help(
|
|
cx,
|
|
SUSPICIOUS_MAP,
|
|
expr.span,
|
|
"this call to `map()` won't have an effect on the call to `count()`",
|
|
"make sure you did not confuse `map` with `filter` or `for_each`",
|
|
);
|
|
}
|
|
|
|
/// lint use of `_.as_ref().map(Deref::deref)` for `Option`s
|
|
fn lint_option_as_ref_deref<'a, 'tcx>(
|
|
cx: &LateContext<'a, 'tcx>,
|
|
expr: &hir::Expr<'_>,
|
|
as_ref_args: &[hir::Expr<'_>],
|
|
map_args: &[hir::Expr<'_>],
|
|
is_mut: bool,
|
|
) {
|
|
let option_ty = cx.tables.expr_ty(&as_ref_args[0]);
|
|
if !match_type(cx, option_ty, &paths::OPTION) {
|
|
return;
|
|
}
|
|
|
|
let deref_aliases: [&[&str]; 9] = [
|
|
&paths::DEREF_TRAIT_METHOD,
|
|
&paths::DEREF_MUT_TRAIT_METHOD,
|
|
&paths::CSTRING_AS_C_STR,
|
|
&paths::OS_STRING_AS_OS_STR,
|
|
&paths::PATH_BUF_AS_PATH,
|
|
&paths::STRING_AS_STR,
|
|
&paths::STRING_AS_MUT_STR,
|
|
&paths::VEC_AS_SLICE,
|
|
&paths::VEC_AS_MUT_SLICE,
|
|
];
|
|
|
|
let is_deref = match map_args[1].kind {
|
|
hir::ExprKind::Path(ref expr_qpath) => deref_aliases.iter().any(|path| match_qpath(expr_qpath, path)),
|
|
hir::ExprKind::Closure(_, _, body_id, _, _) => {
|
|
let closure_body = cx.tcx.hir().body(body_id);
|
|
let closure_expr = remove_blocks(&closure_body.value);
|
|
if_chain! {
|
|
if let hir::ExprKind::MethodCall(_, _, args) = &closure_expr.kind;
|
|
if args.len() == 1;
|
|
if let hir::ExprKind::Path(qpath) = &args[0].kind;
|
|
if let hir::def::Res::Local(local_id) = cx.tables.qpath_res(qpath, args[0].hir_id);
|
|
if closure_body.params[0].pat.hir_id == local_id;
|
|
let adj = cx.tables.expr_adjustments(&args[0]).iter().map(|x| &x.kind).collect::<Box<[_]>>();
|
|
if let [ty::adjustment::Adjust::Deref(None), ty::adjustment::Adjust::Borrow(_)] = *adj;
|
|
then {
|
|
let method_did = cx.tables.type_dependent_def_id(closure_expr.hir_id).unwrap();
|
|
deref_aliases.iter().any(|path| match_def_path(cx, method_did, path))
|
|
} else {
|
|
false
|
|
}
|
|
}
|
|
},
|
|
|
|
_ => false,
|
|
};
|
|
|
|
if is_deref {
|
|
let current_method = if is_mut {
|
|
".as_mut().map(DerefMut::deref_mut)"
|
|
} else {
|
|
".as_ref().map(Deref::deref)"
|
|
};
|
|
let method_hint = if is_mut { "as_deref_mut" } else { "as_deref" };
|
|
let hint = format!("{}.{}()", snippet(cx, as_ref_args[0].span, ".."), method_hint);
|
|
let suggestion = format!("try using {} instead", method_hint);
|
|
|
|
let msg = format!(
|
|
"called `{0}` (or with one of deref aliases) on an Option value. \
|
|
This can be done more directly by calling `{1}` instead",
|
|
current_method, hint
|
|
);
|
|
span_lint_and_sugg(
|
|
cx,
|
|
OPTION_AS_REF_DEREF,
|
|
expr.span,
|
|
&msg,
|
|
&suggestion,
|
|
hint,
|
|
Applicability::MachineApplicable,
|
|
);
|
|
}
|
|
}
|
|
|
|
/// Given a `Result<T, E>` type, return its error type (`E`).
|
|
fn get_error_type<'a>(cx: &LateContext<'_, '_>, ty: Ty<'a>) -> Option<Ty<'a>> {
|
|
match ty.kind {
|
|
ty::Adt(_, substs) if match_type(cx, ty, &paths::RESULT) => substs.types().nth(1),
|
|
_ => None,
|
|
}
|
|
}
|
|
|
|
/// This checks whether a given type is known to implement Debug.
|
|
fn has_debug_impl<'a, 'b>(ty: Ty<'a>, cx: &LateContext<'b, 'a>) -> bool {
|
|
cx.tcx
|
|
.get_diagnostic_item(sym::debug_trait)
|
|
.map_or(false, |debug| implements_trait(cx, ty, debug, &[]))
|
|
}
|
|
|
|
enum Convention {
|
|
Eq(&'static str),
|
|
StartsWith(&'static str),
|
|
}
|
|
|
|
#[rustfmt::skip]
|
|
const CONVENTIONS: [(Convention, &[SelfKind]); 7] = [
|
|
(Convention::Eq("new"), &[SelfKind::No]),
|
|
(Convention::StartsWith("as_"), &[SelfKind::Ref, SelfKind::RefMut]),
|
|
(Convention::StartsWith("from_"), &[SelfKind::No]),
|
|
(Convention::StartsWith("into_"), &[SelfKind::Value]),
|
|
(Convention::StartsWith("is_"), &[SelfKind::Ref, SelfKind::No]),
|
|
(Convention::Eq("to_mut"), &[SelfKind::RefMut]),
|
|
(Convention::StartsWith("to_"), &[SelfKind::Ref]),
|
|
];
|
|
|
|
#[rustfmt::skip]
|
|
const TRAIT_METHODS: [(&str, usize, SelfKind, OutType, &str); 30] = [
|
|
("add", 2, SelfKind::Value, OutType::Any, "std::ops::Add"),
|
|
("as_mut", 1, SelfKind::RefMut, OutType::Ref, "std::convert::AsMut"),
|
|
("as_ref", 1, SelfKind::Ref, OutType::Ref, "std::convert::AsRef"),
|
|
("bitand", 2, SelfKind::Value, OutType::Any, "std::ops::BitAnd"),
|
|
("bitor", 2, SelfKind::Value, OutType::Any, "std::ops::BitOr"),
|
|
("bitxor", 2, SelfKind::Value, OutType::Any, "std::ops::BitXor"),
|
|
("borrow", 1, SelfKind::Ref, OutType::Ref, "std::borrow::Borrow"),
|
|
("borrow_mut", 1, SelfKind::RefMut, OutType::Ref, "std::borrow::BorrowMut"),
|
|
("clone", 1, SelfKind::Ref, OutType::Any, "std::clone::Clone"),
|
|
("cmp", 2, SelfKind::Ref, OutType::Any, "std::cmp::Ord"),
|
|
("default", 0, SelfKind::No, OutType::Any, "std::default::Default"),
|
|
("deref", 1, SelfKind::Ref, OutType::Ref, "std::ops::Deref"),
|
|
("deref_mut", 1, SelfKind::RefMut, OutType::Ref, "std::ops::DerefMut"),
|
|
("div", 2, SelfKind::Value, OutType::Any, "std::ops::Div"),
|
|
("drop", 1, SelfKind::RefMut, OutType::Unit, "std::ops::Drop"),
|
|
("eq", 2, SelfKind::Ref, OutType::Bool, "std::cmp::PartialEq"),
|
|
("from_iter", 1, SelfKind::No, OutType::Any, "std::iter::FromIterator"),
|
|
("from_str", 1, SelfKind::No, OutType::Any, "std::str::FromStr"),
|
|
("hash", 2, SelfKind::Ref, OutType::Unit, "std::hash::Hash"),
|
|
("index", 2, SelfKind::Ref, OutType::Ref, "std::ops::Index"),
|
|
("index_mut", 2, SelfKind::RefMut, OutType::Ref, "std::ops::IndexMut"),
|
|
("into_iter", 1, SelfKind::Value, OutType::Any, "std::iter::IntoIterator"),
|
|
("mul", 2, SelfKind::Value, OutType::Any, "std::ops::Mul"),
|
|
("neg", 1, SelfKind::Value, OutType::Any, "std::ops::Neg"),
|
|
("next", 1, SelfKind::RefMut, OutType::Any, "std::iter::Iterator"),
|
|
("not", 1, SelfKind::Value, OutType::Any, "std::ops::Not"),
|
|
("rem", 2, SelfKind::Value, OutType::Any, "std::ops::Rem"),
|
|
("shl", 2, SelfKind::Value, OutType::Any, "std::ops::Shl"),
|
|
("shr", 2, SelfKind::Value, OutType::Any, "std::ops::Shr"),
|
|
("sub", 2, SelfKind::Value, OutType::Any, "std::ops::Sub"),
|
|
];
|
|
|
|
#[rustfmt::skip]
|
|
const PATTERN_METHODS: [(&str, usize); 17] = [
|
|
("contains", 1),
|
|
("starts_with", 1),
|
|
("ends_with", 1),
|
|
("find", 1),
|
|
("rfind", 1),
|
|
("split", 1),
|
|
("rsplit", 1),
|
|
("split_terminator", 1),
|
|
("rsplit_terminator", 1),
|
|
("splitn", 2),
|
|
("rsplitn", 2),
|
|
("matches", 1),
|
|
("rmatches", 1),
|
|
("match_indices", 1),
|
|
("rmatch_indices", 1),
|
|
("trim_start_matches", 1),
|
|
("trim_end_matches", 1),
|
|
];
|
|
|
|
#[derive(Clone, Copy, PartialEq, Debug)]
|
|
enum SelfKind {
|
|
Value,
|
|
Ref,
|
|
RefMut,
|
|
No,
|
|
}
|
|
|
|
impl SelfKind {
|
|
fn matches<'a>(self, cx: &LateContext<'_, 'a>, parent_ty: Ty<'a>, ty: Ty<'a>) -> bool {
|
|
fn matches_value(parent_ty: Ty<'_>, ty: Ty<'_>) -> bool {
|
|
if ty == parent_ty {
|
|
true
|
|
} else if ty.is_box() {
|
|
ty.boxed_ty() == parent_ty
|
|
} else if ty.is_rc() || ty.is_arc() {
|
|
if let ty::Adt(_, substs) = ty.kind {
|
|
substs.types().next().map_or(false, |t| t == parent_ty)
|
|
} else {
|
|
false
|
|
}
|
|
} else {
|
|
false
|
|
}
|
|
}
|
|
|
|
fn matches_ref<'a>(
|
|
cx: &LateContext<'_, 'a>,
|
|
mutability: hir::Mutability,
|
|
parent_ty: Ty<'a>,
|
|
ty: Ty<'a>,
|
|
) -> bool {
|
|
if let ty::Ref(_, t, m) = ty.kind {
|
|
return m == mutability && t == parent_ty;
|
|
}
|
|
|
|
let trait_path = match mutability {
|
|
hir::Mutability::Not => &paths::ASREF_TRAIT,
|
|
hir::Mutability::Mut => &paths::ASMUT_TRAIT,
|
|
};
|
|
|
|
let trait_def_id = match get_trait_def_id(cx, trait_path) {
|
|
Some(did) => did,
|
|
None => return false,
|
|
};
|
|
implements_trait(cx, ty, trait_def_id, &[parent_ty.into()])
|
|
}
|
|
|
|
match self {
|
|
Self::Value => matches_value(parent_ty, ty),
|
|
Self::Ref => matches_ref(cx, hir::Mutability::Not, parent_ty, ty) || ty == parent_ty && is_copy(cx, ty),
|
|
Self::RefMut => matches_ref(cx, hir::Mutability::Mut, parent_ty, ty),
|
|
Self::No => ty != parent_ty,
|
|
}
|
|
}
|
|
|
|
#[must_use]
|
|
fn description(self) -> &'static str {
|
|
match self {
|
|
Self::Value => "self by value",
|
|
Self::Ref => "self by reference",
|
|
Self::RefMut => "self by mutable reference",
|
|
Self::No => "no self",
|
|
}
|
|
}
|
|
}
|
|
|
|
impl Convention {
|
|
#[must_use]
|
|
fn check(&self, other: &str) -> bool {
|
|
match *self {
|
|
Self::Eq(this) => this == other,
|
|
Self::StartsWith(this) => other.starts_with(this) && this != other,
|
|
}
|
|
}
|
|
}
|
|
|
|
impl fmt::Display for Convention {
|
|
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> Result<(), fmt::Error> {
|
|
match *self {
|
|
Self::Eq(this) => this.fmt(f),
|
|
Self::StartsWith(this) => this.fmt(f).and_then(|_| '*'.fmt(f)),
|
|
}
|
|
}
|
|
}
|
|
|
|
#[derive(Clone, Copy)]
|
|
enum OutType {
|
|
Unit,
|
|
Bool,
|
|
Any,
|
|
Ref,
|
|
}
|
|
|
|
impl OutType {
|
|
fn matches(self, cx: &LateContext<'_, '_>, ty: &hir::FnRetTy<'_>) -> bool {
|
|
let is_unit = |ty: &hir::Ty<'_>| SpanlessEq::new(cx).eq_ty_kind(&ty.kind, &hir::TyKind::Tup(&[]));
|
|
match (self, ty) {
|
|
(Self::Unit, &hir::FnRetTy::DefaultReturn(_)) => true,
|
|
(Self::Unit, &hir::FnRetTy::Return(ref ty)) if is_unit(ty) => true,
|
|
(Self::Bool, &hir::FnRetTy::Return(ref ty)) if is_bool(ty) => true,
|
|
(Self::Any, &hir::FnRetTy::Return(ref ty)) if !is_unit(ty) => true,
|
|
(Self::Ref, &hir::FnRetTy::Return(ref ty)) => matches!(ty.kind, hir::TyKind::Rptr(_, _)),
|
|
_ => false,
|
|
}
|
|
}
|
|
}
|
|
|
|
fn is_bool(ty: &hir::Ty<'_>) -> bool {
|
|
if let hir::TyKind::Path(ref p) = ty.kind {
|
|
match_qpath(p, &["bool"])
|
|
} else {
|
|
false
|
|
}
|
|
}
|
|
|
|
// Returns `true` if `expr` contains a return expression
|
|
fn contains_return(expr: &hir::Expr<'_>) -> bool {
|
|
struct RetCallFinder {
|
|
found: bool,
|
|
}
|
|
|
|
impl<'tcx> intravisit::Visitor<'tcx> for RetCallFinder {
|
|
type Map = Map<'tcx>;
|
|
|
|
fn visit_expr(&mut self, expr: &'tcx hir::Expr<'_>) {
|
|
if self.found {
|
|
return;
|
|
}
|
|
if let hir::ExprKind::Ret(..) = &expr.kind {
|
|
self.found = true;
|
|
} else {
|
|
intravisit::walk_expr(self, expr);
|
|
}
|
|
}
|
|
|
|
fn nested_visit_map(&mut self) -> intravisit::NestedVisitorMap<Self::Map> {
|
|
intravisit::NestedVisitorMap::None
|
|
}
|
|
}
|
|
|
|
let mut visitor = RetCallFinder { found: false };
|
|
visitor.visit_expr(expr);
|
|
visitor.found
|
|
}
|
|
|
|
fn check_pointer_offset(cx: &LateContext<'_, '_>, expr: &hir::Expr<'_>, args: &[hir::Expr<'_>]) {
|
|
if_chain! {
|
|
if args.len() == 2;
|
|
if let ty::RawPtr(ty::TypeAndMut { ref ty, .. }) = cx.tables.expr_ty(&args[0]).kind;
|
|
if let Ok(layout) = cx.tcx.layout_of(cx.param_env.and(ty));
|
|
if layout.is_zst();
|
|
then {
|
|
span_lint(cx, ZST_OFFSET, expr.span, "offset calculation on zero-sized value");
|
|
}
|
|
}
|
|
}
|
|
|
|
fn lint_filetype_is_file(cx: &LateContext<'_, '_>, expr: &hir::Expr<'_>, args: &[hir::Expr<'_>]) {
|
|
let ty = cx.tables.expr_ty(&args[0]);
|
|
|
|
if !match_type(cx, ty, &paths::FILE_TYPE) {
|
|
return;
|
|
}
|
|
|
|
let span: Span;
|
|
let verb: &str;
|
|
let lint_unary: &str;
|
|
let help_unary: &str;
|
|
if_chain! {
|
|
if let Some(parent) = get_parent_expr(cx, expr);
|
|
if let hir::ExprKind::Unary(op, _) = parent.kind;
|
|
if op == hir::UnOp::UnNot;
|
|
then {
|
|
lint_unary = "!";
|
|
verb = "denies";
|
|
help_unary = "";
|
|
span = parent.span;
|
|
} else {
|
|
lint_unary = "";
|
|
verb = "covers";
|
|
help_unary = "!";
|
|
span = expr.span;
|
|
}
|
|
}
|
|
let lint_msg = format!("`{}FileType::is_file()` only {} regular files", lint_unary, verb);
|
|
let help_msg = format!("use `{}FileType::is_dir()` instead", help_unary);
|
|
span_lint_and_help(cx, FILETYPE_IS_FILE, span, &lint_msg, &help_msg);
|
|
}
|