2207 lines
78 KiB
Rust
2207 lines
78 KiB
Rust
use matches::matches;
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use rustc::hir;
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use rustc::lint::*;
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use rustc::{declare_lint, lint_array};
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use if_chain::if_chain;
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use rustc::ty::{self, Ty};
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use rustc::hir::def::Def;
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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 syntax::ast;
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use syntax::codemap::{Span, BytePos};
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use crate::utils::{get_arg_name, get_trait_def_id, implements_trait, in_macro, is_copy, is_expn_of, is_self,
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is_self_ty, iter_input_pats, last_path_segment, match_def_path, match_path, match_qpath, match_trait_method,
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match_type, method_chain_args, match_var, return_ty, remove_blocks, same_tys, single_segment_path, snippet,
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span_lint, span_lint_and_sugg, span_lint_and_then, span_note_and_lint, walk_ptrs_ty, walk_ptrs_ty_depth, SpanlessEq};
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use crate::utils::paths;
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use crate::utils::sugg;
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use crate::consts::{constant, Constant};
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#[derive(Clone)]
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pub struct Pass;
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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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/// ```rust
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/// x.unwrap()
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/// ```
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declare_clippy_lint! {
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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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/// **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 `try!`.
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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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/// ```rust
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/// x.unwrap()
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/// ```
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declare_clippy_lint! {
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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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/// **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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/// ```
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declare_clippy_lint! {
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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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/// **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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/// impl X {
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/// fn as_str(self) -> &str { .. }
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/// }
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/// ```
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declare_clippy_lint! {
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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 \
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`self` with the wrong convention"
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}
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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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/// impl X {
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/// pub fn as_str(self) -> &str { .. }
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/// }
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/// ```
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declare_clippy_lint! {
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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 \
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`self` with the wrong convention"
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}
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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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/// x.ok().expect("why did I do this again?")
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/// ```
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declare_clippy_lint! {
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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 \
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calling `expect` directly on the Result"
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}
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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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/// x.map(|a| a + 1).unwrap_or(0)
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/// ```
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declare_clippy_lint! {
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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 \
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`map_or(a, f)`"
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}
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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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/// x.map(|a| a + 1).unwrap_or_else(some_function)
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/// ```
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declare_clippy_lint! {
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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 \
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`map_or_else(g, f)`"
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}
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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.ok().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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/// x.map(|a| a + 1).unwrap_or_else(some_function)
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/// ```
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declare_clippy_lint! {
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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 \
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`.ok().map_or_else(g, f)`"
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}
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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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/// opt.map_or(None, |a| a + 1)
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/// ```
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declare_clippy_lint! {
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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 \
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`and_then(f)`"
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}
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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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/// iter.filter(|x| x == 0).next()
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/// ```
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declare_clippy_lint! {
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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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/// **What it does:** Checks for usage of `_.filter(_).map(_)`,
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/// `_.filter(_).flat_map(_)`, `_.filter_map(_).flat_map(_)` and similar.
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///
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/// **Why is this bad?** Readability, this can be written more concisely as a
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/// single method call.
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///
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/// **Known problems:** Often requires a condition + Option/Iterator creation
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/// inside the closure.
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///
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/// **Example:**
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/// ```rust
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/// iter.filter(|x| x == 0).map(|x| x * 2)
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/// ```
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declare_clippy_lint! {
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pub FILTER_MAP,
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pedantic,
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"using combinations of `filter`, `map`, `filter_map` and `flat_map` which can \
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usually be written as a single method call"
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}
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/// **What it does:** Checks for an iterator search (such as `find()`,
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/// `position()`, or `rposition()`) followed by a call to `is_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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/// `_.any(_)`.
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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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/// iter.find(|x| x == 0).is_some()
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/// ```
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declare_clippy_lint! {
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pub SEARCH_IS_SOME,
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complexity,
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"using an iterator search followed by `is_some()`, which is more succinctly \
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expressed as a call to `any()`"
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}
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/// **What it does:** Checks for usage of `.chars().next()` on a `str` to check
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/// if it starts with a given char.
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///
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/// **Why is this bad?** Readability, this can be written more concisely as
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/// `_.starts_with(_)`.
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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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/// name.chars().next() == Some('_')
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/// ```
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declare_clippy_lint! {
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pub CHARS_NEXT_CMP,
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complexity,
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"using `.chars().next()` to check if a string starts with a char"
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}
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/// **What it does:** Checks for calls to `.or(foo(..))`, `.unwrap_or(foo(..))`,
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/// etc., and suggests to use `or_else`, `unwrap_or_else`, etc., or
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/// `unwrap_or_default` instead.
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///
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/// **Why is this bad?** The function will always be called and potentially
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/// allocate an object acting as the default.
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///
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/// **Known problems:** If the function has side-effects, not calling it will
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/// change the semantic of the program, but you shouldn't rely on that anyway.
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///
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/// **Example:**
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/// ```rust
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/// foo.unwrap_or(String::new())
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/// ```
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/// this can instead be written:
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/// ```rust
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/// foo.unwrap_or_else(String::new)
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/// ```
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/// or
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/// ```rust
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/// foo.unwrap_or_default()
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/// ```
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declare_clippy_lint! {
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pub OR_FUN_CALL,
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perf,
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"using any `*or` method with a function call, which suggests `*or_else`"
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}
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/// **What it does:** Checks for calls to `.expect(&format!(...))`, `.expect(foo(..))`,
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/// etc., and suggests to use `unwrap_or_else` instead
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///
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/// **Why is this bad?** The function will always be called.
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///
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/// **Known problems:** If the function has side-effects, not calling it will
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|
/// change the semantic of the program, but you shouldn't rely on that anyway.
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///
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/// **Example:**
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/// ```rust
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/// foo.expect(&format("Err {}: {}", err_code, err_msg))
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/// ```
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/// or
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/// ```rust
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/// foo.expect(format("Err {}: {}", err_code, err_msg).as_str())
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/// ```
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|
/// this can instead be written:
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/// ```rust
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/// foo.unwrap_or_else(|_| panic!("Err {}: {}", err_code, err_msg))
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/// ```
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/// or
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/// ```rust
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/// foo.unwrap_or_else(|_| panic!(format("Err {}: {}", err_code, err_msg).as_str()))
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/// ```
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declare_clippy_lint! {
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pub EXPECT_FUN_CALL,
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perf,
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"using any `expect` method with a function call"
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}
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|
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/// **What it does:** Checks for usage of `.clone()` on a `Copy` type.
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///
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/// **Why is this bad?** The only reason `Copy` types implement `Clone` is for
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/// generics, not for using the `clone` method on a concrete type.
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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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/// 42u64.clone()
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/// ```
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|
declare_clippy_lint! {
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|
pub CLONE_ON_COPY,
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|
complexity,
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|
"using `clone` on a `Copy` type"
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|
}
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|
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|
/// **What it does:** Checks for usage of `.clone()` on a ref-counted pointer,
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|
/// (`Rc`, `Arc`, `rc::Weak`, or `sync::Weak`), and suggests calling Clone via unified
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/// function syntax instead (e.g. `Rc::clone(foo)`).
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///
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|
/// **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
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/// data.
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|
///
|
|
/// **Example:**
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|
/// ```rust
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|
/// x.clone()
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/// ```
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|
declare_clippy_lint! {
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|
pub CLONE_ON_REF_PTR,
|
|
restriction,
|
|
"using 'clone' on a ref-counted pointer"
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|
}
|
|
|
|
/// **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
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|
/// fn main() {
|
|
/// let x = vec![1];
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|
/// let y = &&x;
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|
/// let z = y.clone();
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|
/// println!("{:p} {:p}",*y, z); // prints out the same pointer
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|
/// }
|
|
/// ```
|
|
declare_clippy_lint! {
|
|
pub CLONE_DOUBLE_REF,
|
|
correctness,
|
|
"using `clone` on `&&T`"
|
|
}
|
|
|
|
/// **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
|
|
/// impl Foo {
|
|
/// fn new(..) -> NotAFoo {
|
|
/// }
|
|
/// }
|
|
/// ```
|
|
declare_clippy_lint! {
|
|
pub NEW_RET_NO_SELF,
|
|
style,
|
|
"not returning `Self` in a `new` method"
|
|
}
|
|
|
|
/// **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')
|
|
declare_clippy_lint! {
|
|
pub SINGLE_CHAR_PATTERN,
|
|
perf,
|
|
"using a single-character str where a char could be used, e.g. \
|
|
`_.split(\"x\")`"
|
|
}
|
|
|
|
/// **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,ignore
|
|
/// 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,ignore
|
|
/// let c_str = CString::new("foo").unwrap();
|
|
/// unsafe {
|
|
/// call_some_ffi_func(c_str.as_ptr());
|
|
/// }
|
|
/// ```
|
|
declare_clippy_lint! {
|
|
pub TEMPORARY_CSTRING_AS_PTR,
|
|
correctness,
|
|
"getting the inner pointer of a temporary `CString`"
|
|
}
|
|
|
|
/// **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);
|
|
/// ```
|
|
declare_clippy_lint! {
|
|
pub ITER_NTH,
|
|
perf,
|
|
"using `.iter().nth()` on a standard library type with O(1) element access"
|
|
}
|
|
|
|
/// **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);
|
|
/// ```
|
|
declare_clippy_lint! {
|
|
pub ITER_SKIP_NEXT,
|
|
style,
|
|
"using `.skip(x).next()` on an iterator"
|
|
}
|
|
|
|
/// **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:** None.
|
|
///
|
|
/// **Example:**
|
|
/// ```rust
|
|
/// let 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 some_vec = vec![0, 1, 2, 3];
|
|
/// let last = some_vec[3];
|
|
/// some_vec[0] = 1;
|
|
/// ```
|
|
declare_clippy_lint! {
|
|
pub GET_UNWRAP,
|
|
style,
|
|
"using `.get().unwrap()` or `.get_mut().unwrap()` when using `[]` would work instead"
|
|
}
|
|
|
|
/// **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));
|
|
/// ```
|
|
declare_clippy_lint! {
|
|
pub STRING_EXTEND_CHARS,
|
|
style,
|
|
"using `x.extend(s.chars())` where s is a `&str` or `String`"
|
|
}
|
|
|
|
/// **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();
|
|
/// ```
|
|
declare_clippy_lint! {
|
|
pub ITER_CLONED_COLLECT,
|
|
style,
|
|
"using `.cloned().collect()` on slice to create a `Vec`"
|
|
}
|
|
|
|
/// **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
|
|
/// name.chars().last() == Some('_') || name.chars().next_back() == Some('-')
|
|
/// ```
|
|
declare_clippy_lint! {
|
|
pub CHARS_LAST_CMP,
|
|
style,
|
|
"using `.chars().last()` or `.chars().next_back()` to check if a string ends with a char"
|
|
}
|
|
|
|
/// **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
|
|
/// let x: &[i32] = &[1,2,3,4,5];
|
|
/// do_stuff(x.as_ref());
|
|
/// ```
|
|
/// The correct use would be:
|
|
/// ```rust
|
|
/// let x: &[i32] = &[1,2,3,4,5];
|
|
/// do_stuff(x);
|
|
/// ```
|
|
declare_clippy_lint! {
|
|
pub USELESS_ASREF,
|
|
complexity,
|
|
"using `as_ref` where the types before and after the call are the same"
|
|
}
|
|
|
|
|
|
/// **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:** None.
|
|
///
|
|
/// **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);
|
|
/// ```
|
|
declare_clippy_lint! {
|
|
pub UNNECESSARY_FOLD,
|
|
style,
|
|
"using `fold` when a more succinct alternative exists"
|
|
}
|
|
|
|
impl LintPass for Pass {
|
|
fn get_lints(&self) -> LintArray {
|
|
lint_array!(
|
|
OPTION_UNWRAP_USED,
|
|
RESULT_UNWRAP_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,
|
|
OPTION_MAP_OR_NONE,
|
|
OR_FUN_CALL,
|
|
EXPECT_FUN_CALL,
|
|
CHARS_NEXT_CMP,
|
|
CHARS_LAST_CMP,
|
|
CLONE_ON_COPY,
|
|
CLONE_ON_REF_PTR,
|
|
CLONE_DOUBLE_REF,
|
|
NEW_RET_NO_SELF,
|
|
SINGLE_CHAR_PATTERN,
|
|
SEARCH_IS_SOME,
|
|
TEMPORARY_CSTRING_AS_PTR,
|
|
FILTER_NEXT,
|
|
FILTER_MAP,
|
|
ITER_NTH,
|
|
ITER_SKIP_NEXT,
|
|
GET_UNWRAP,
|
|
STRING_EXTEND_CHARS,
|
|
ITER_CLONED_COLLECT,
|
|
USELESS_ASREF,
|
|
UNNECESSARY_FOLD
|
|
)
|
|
}
|
|
}
|
|
|
|
impl<'a, 'tcx> LateLintPass<'a, 'tcx> for Pass {
|
|
#[allow(cyclomatic_complexity)]
|
|
fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, expr: &'tcx hir::Expr) {
|
|
if in_macro(expr.span) {
|
|
return;
|
|
}
|
|
|
|
match expr.node {
|
|
hir::ExprKind::MethodCall(ref method_call, ref method_span, ref args) => {
|
|
// Chain calls
|
|
// GET_UNWRAP needs to be checked before general `UNWRAP` lints
|
|
if let Some(arglists) = method_chain_args(expr, &["get", "unwrap"]) {
|
|
lint_get_unwrap(cx, expr, arglists[0], false);
|
|
} else if let Some(arglists) = method_chain_args(expr, &["get_mut", "unwrap"]) {
|
|
lint_get_unwrap(cx, expr, arglists[0], true);
|
|
} else if let Some(arglists) = method_chain_args(expr, &["unwrap"]) {
|
|
lint_unwrap(cx, expr, arglists[0]);
|
|
} else if let Some(arglists) = method_chain_args(expr, &["ok", "expect"]) {
|
|
lint_ok_expect(cx, expr, arglists[0]);
|
|
} else if let Some(arglists) = method_chain_args(expr, &["map", "unwrap_or"]) {
|
|
lint_map_unwrap_or(cx, expr, arglists[0], arglists[1]);
|
|
} else if let Some(arglists) = method_chain_args(expr, &["map", "unwrap_or_else"]) {
|
|
lint_map_unwrap_or_else(cx, expr, arglists[0], arglists[1]);
|
|
} else if let Some(arglists) = method_chain_args(expr, &["map_or"]) {
|
|
lint_map_or_none(cx, expr, arglists[0]);
|
|
} else if let Some(arglists) = method_chain_args(expr, &["filter", "next"]) {
|
|
lint_filter_next(cx, expr, arglists[0]);
|
|
} else if let Some(arglists) = method_chain_args(expr, &["filter", "map"]) {
|
|
lint_filter_map(cx, expr, arglists[0], arglists[1]);
|
|
} else if let Some(arglists) = method_chain_args(expr, &["filter_map", "map"]) {
|
|
lint_filter_map_map(cx, expr, arglists[0], arglists[1]);
|
|
} else if let Some(arglists) = method_chain_args(expr, &["filter", "flat_map"]) {
|
|
lint_filter_flat_map(cx, expr, arglists[0], arglists[1]);
|
|
} else if let Some(arglists) = method_chain_args(expr, &["filter_map", "flat_map"]) {
|
|
lint_filter_map_flat_map(cx, expr, arglists[0], arglists[1]);
|
|
} else if let Some(arglists) = method_chain_args(expr, &["find", "is_some"]) {
|
|
lint_search_is_some(cx, expr, "find", arglists[0], arglists[1]);
|
|
} else if let Some(arglists) = method_chain_args(expr, &["position", "is_some"]) {
|
|
lint_search_is_some(cx, expr, "position", arglists[0], arglists[1]);
|
|
} else if let Some(arglists) = method_chain_args(expr, &["rposition", "is_some"]) {
|
|
lint_search_is_some(cx, expr, "rposition", arglists[0], arglists[1]);
|
|
} else if let Some(arglists) = method_chain_args(expr, &["extend"]) {
|
|
lint_extend(cx, expr, arglists[0]);
|
|
} else if let Some(arglists) = method_chain_args(expr, &["unwrap", "as_ptr"]) {
|
|
lint_cstring_as_ptr(cx, expr, &arglists[0][0], &arglists[1][0]);
|
|
} else if let Some(arglists) = method_chain_args(expr, &["iter", "nth"]) {
|
|
lint_iter_nth(cx, expr, arglists[0], false);
|
|
} else if let Some(arglists) = method_chain_args(expr, &["iter_mut", "nth"]) {
|
|
lint_iter_nth(cx, expr, arglists[0], true);
|
|
} else if method_chain_args(expr, &["skip", "next"]).is_some() {
|
|
lint_iter_skip_next(cx, expr);
|
|
} else if let Some(arglists) = method_chain_args(expr, &["cloned", "collect"]) {
|
|
lint_iter_cloned_collect(cx, expr, arglists[0]);
|
|
} else if let Some(arglists) = method_chain_args(expr, &["as_ref"]) {
|
|
lint_asref(cx, expr, "as_ref", arglists[0]);
|
|
} else if let Some(arglists) = method_chain_args(expr, &["as_mut"]) {
|
|
lint_asref(cx, expr, "as_mut", arglists[0]);
|
|
} else if let Some(arglists) = method_chain_args(expr, &["fold"]) {
|
|
lint_unnecessary_fold(cx, expr, arglists[0]);
|
|
}
|
|
|
|
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 == "clone" {
|
|
lint_clone_on_copy(cx, expr, &args[0], self_ty);
|
|
lint_clone_on_ref_ptr(cx, expr, &args[0]);
|
|
}
|
|
|
|
match self_ty.sty {
|
|
ty::TyRef(_, ty, _) if ty.sty == ty::TyStr => for &(method, pos) in &PATTERN_METHODS {
|
|
if method_call.ident.name == method && args.len() > pos {
|
|
lint_single_char_pattern(cx, expr, &args[pos]);
|
|
}
|
|
},
|
|
_ => (),
|
|
}
|
|
},
|
|
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>, implitem: &'tcx hir::ImplItem) {
|
|
if in_external_macro(cx.sess(), implitem.span) {
|
|
return;
|
|
}
|
|
let name = implitem.ident.name;
|
|
let parent = cx.tcx.hir.get_parent(implitem.id);
|
|
let item = cx.tcx.hir.expect_item(parent);
|
|
if_chain! {
|
|
if let hir::ImplItemKind::Method(ref sig, id) = implitem.node;
|
|
if let Some(first_arg_ty) = sig.decl.inputs.get(0);
|
|
if let Some(first_arg) = iter_input_pats(&sig.decl, cx.tcx.hir.body(id)).next();
|
|
if let hir::ItemKind::Impl(_, _, _, _, None, ref self_ty, _) = item.node;
|
|
then {
|
|
if cx.access_levels.is_exported(implitem.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, first_arg_ty, first_arg, self_ty, false, &implitem.generics) {
|
|
span_lint(cx, SHOULD_IMPLEMENT_TRAIT, implitem.span, &format!(
|
|
"defining a method called `{}` on this type; consider implementing \
|
|
the `{}` trait or choosing a less ambiguous name", name, trait_name));
|
|
}
|
|
}
|
|
}
|
|
|
|
// check conventions w.r.t. conversion method names and predicates
|
|
let def_id = cx.tcx.hir.local_def_id(item.id);
|
|
let ty = cx.tcx.type_of(def_id);
|
|
let is_copy = is_copy(cx, ty);
|
|
for &(ref conv, self_kinds) in &CONVENTIONS {
|
|
if_chain! {
|
|
if conv.check(&name.as_str());
|
|
if !self_kinds
|
|
.iter()
|
|
.any(|k| k.matches(cx, first_arg_ty, first_arg, self_ty, is_copy, &implitem.generics));
|
|
then {
|
|
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 ")));
|
|
}
|
|
}
|
|
}
|
|
|
|
let ret_ty = return_ty(cx, implitem.id);
|
|
if name == "new" &&
|
|
!ret_ty.walk().any(|t| same_tys(cx, t, ty)) {
|
|
span_lint(cx,
|
|
NEW_RET_NO_SELF,
|
|
implitem.span,
|
|
"methods called `new` usually return `Self`");
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/// Checks for the `OR_FUN_CALL` lint.
|
|
fn lint_or_fun_call(cx: &LateContext<'_, '_>, expr: &hir::Expr, method_span: Span, name: &str, args: &[hir::Expr]) {
|
|
/// Check 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 or_has_args {
|
|
return false;
|
|
}
|
|
|
|
if name == "unwrap_or" {
|
|
if let hir::ExprKind::Path(ref qpath) = fun.node {
|
|
let path = &*last_path_segment(qpath).ident.as_str();
|
|
|
|
if ["default", "new"].contains(&path) {
|
|
let arg_ty = cx.tables.expr_ty(arg);
|
|
let default_trait_id = if let Some(default_trait_id) = get_trait_def_id(cx, &paths::DEFAULT_TRAIT) {
|
|
default_trait_id
|
|
} else {
|
|
return false;
|
|
};
|
|
|
|
if implements_trait(cx, arg_ty, default_trait_id, &[]) {
|
|
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(cx, self_expr.span, "_")),
|
|
);
|
|
return true;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
false
|
|
}
|
|
|
|
/// Check for `*or(foo())`.
|
|
#[allow(too_many_arguments)]
|
|
fn check_general_case(
|
|
cx: &LateContext<'_, '_>,
|
|
name: &str,
|
|
method_span: Span,
|
|
fun_span: Span,
|
|
self_expr: &hir::Expr,
|
|
arg: &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"),
|
|
];
|
|
|
|
// early check if the name is one we care about
|
|
if know_types.iter().all(|k| !k.2.contains(&name)) {
|
|
return;
|
|
}
|
|
|
|
// don't lint for constant values
|
|
let owner_def = cx.tcx.hir.get_parent_did(arg.id);
|
|
let promotable = cx.tcx.rvalue_promotable_map(owner_def).contains(&arg.hir_id.local_id);
|
|
if promotable {
|
|
return;
|
|
}
|
|
|
|
let self_ty = cx.tables.expr_ty(self_expr);
|
|
|
|
let (fn_has_arguments, poss, suffix) = if let Some(&(_, fn_has_arguments, poss, suffix)) =
|
|
know_types.iter().find(|&&i| match_type(cx, self_ty, i.0))
|
|
{
|
|
(fn_has_arguments, poss, suffix)
|
|
} else {
|
|
return;
|
|
};
|
|
|
|
if !poss.contains(&name) {
|
|
return;
|
|
}
|
|
|
|
let sugg: Cow<'_, _> = match (fn_has_arguments, !or_has_args) {
|
|
(true, _) => format!("|_| {}", snippet(cx, arg.span, "..")).into(),
|
|
(false, false) => format!("|| {}", snippet(cx, arg.span, "..")).into(),
|
|
(false, true) => snippet(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),
|
|
);
|
|
}
|
|
|
|
if args.len() == 2 {
|
|
match args[1].node {
|
|
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.
|
|
fn lint_expect_fun_call(cx: &LateContext<'_, '_>, expr: &hir::Expr, method_span: Span, name: &str, args: &[hir::Expr]) {
|
|
fn extract_format_args(arg: &hir::Expr) -> Option<&hir::HirVec<hir::Expr>> {
|
|
if let hir::ExprKind::AddrOf(_, ref addr_of) = arg.node {
|
|
if let hir::ExprKind::Call(ref inner_fun, ref inner_args) = addr_of.node {
|
|
if is_expn_of(inner_fun.span, "format").is_some() && inner_args.len() == 1 {
|
|
if let hir::ExprKind::Call(_, ref format_args) = inner_args[0].node {
|
|
return Some(format_args);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
None
|
|
}
|
|
|
|
fn generate_format_arg_snippet(cx: &LateContext<'_, '_>, a: &hir::Expr) -> String {
|
|
if let hir::ExprKind::AddrOf(_, ref format_arg) = a.node {
|
|
if let hir::ExprKind::Match(ref format_arg_expr, _, _) = format_arg.node {
|
|
if let hir::ExprKind::Tup(ref format_arg_expr_tup) = format_arg_expr.node {
|
|
return snippet(cx, format_arg_expr_tup[0].span, "..").into_owned();
|
|
}
|
|
}
|
|
};
|
|
|
|
snippet(cx, a.span, "..").into_owned()
|
|
}
|
|
|
|
fn check_general_case(
|
|
cx: &LateContext<'_, '_>,
|
|
name: &str,
|
|
method_span: Span,
|
|
self_expr: &hir::Expr,
|
|
arg: &hir::Expr,
|
|
span: Span,
|
|
) {
|
|
if name != "expect" {
|
|
return;
|
|
}
|
|
|
|
let self_type = cx.tables.expr_ty(self_expr);
|
|
let known_types = &[&paths::OPTION, &paths::RESULT];
|
|
|
|
// if not a known type, return early
|
|
if known_types.iter().all(|&k| !match_type(cx, self_type, k)) {
|
|
return;
|
|
}
|
|
|
|
fn is_call(node: &hir::ExprKind) -> bool {
|
|
match node {
|
|
hir::ExprKind::AddrOf(_, expr) => {
|
|
is_call(&expr.node)
|
|
},
|
|
hir::ExprKind::Call(..)
|
|
| hir::ExprKind::MethodCall(..)
|
|
// These variants are debatable or require further examination
|
|
| hir::ExprKind::If(..)
|
|
| hir::ExprKind::Match(..) => true,
|
|
_ => false,
|
|
}
|
|
}
|
|
|
|
if !is_call(&arg.node) {
|
|
return;
|
|
}
|
|
|
|
let closure = if match_type(cx, self_type, &paths::OPTION) { "||" } else { "|_|" };
|
|
let span_replace_word = method_span.with_hi(span.hi());
|
|
|
|
if let Some(format_args) = extract_format_args(arg) {
|
|
let args_len = format_args.len();
|
|
let args: Vec<String> = format_args
|
|
.into_iter()
|
|
.take(args_len - 1)
|
|
.map(|a| generate_format_arg_snippet(cx, a))
|
|
.collect();
|
|
|
|
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, sugg),
|
|
);
|
|
|
|
return;
|
|
}
|
|
|
|
let sugg: Cow<'_, _> = snippet(cx, arg.span, "..");
|
|
|
|
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, sugg),
|
|
);
|
|
}
|
|
|
|
if args.len() == 2 {
|
|
match args[1].node {
|
|
hir::ExprKind::Lit(_) => {},
|
|
_ => check_general_case(cx, name, method_span, &args[0], &args[1], expr.span),
|
|
}
|
|
}
|
|
}
|
|
|
|
/// 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::TyRef(_, inner, _) = arg_ty.sty {
|
|
if let ty::TyRef(_, innermost, _) = inner.sty {
|
|
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::TyRef(_, inner, _) = ty.sty {
|
|
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()));
|
|
db.span_suggestion(expr.span, "or try being explicit about what type to clone", explicit);
|
|
},
|
|
);
|
|
return; // don't report clone_on_copy
|
|
}
|
|
}
|
|
|
|
if is_copy(cx, ty) {
|
|
let snip;
|
|
if let Some(snippet) = sugg::Sugg::hir_opt(cx, arg) {
|
|
if let ty::TyRef(..) = cx.tables.expr_ty(arg).sty {
|
|
let parent = cx.tcx.hir.get_parent_node(expr.id);
|
|
match cx.tcx.hir.get(parent) {
|
|
hir::map::NodeExpr(parent) => match parent.node {
|
|
// &*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::map::NodeStmt(stmt) => {
|
|
if let hir::StmtKind::Decl(ref decl, _) = stmt.node {
|
|
if let hir::DeclKind::Local(ref loc) = decl.node {
|
|
if let hir::PatKind::Ref(..) = loc.pat.node {
|
|
// let ref y = *x borrows x, let ref y = x.clone() does not
|
|
return;
|
|
}
|
|
}
|
|
}
|
|
},
|
|
_ => {},
|
|
}
|
|
snip = Some(("try dereferencing it", format!("{}", snippet.deref())));
|
|
} else {
|
|
snip = Some(("try removing the `clone` call", format!("{}", 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);
|
|
}
|
|
});
|
|
}
|
|
}
|
|
|
|
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::TyAdt(_, subst) = obj_ty.sty {
|
|
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, "_")),
|
|
);
|
|
}
|
|
}
|
|
|
|
|
|
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.sty == ty::TyStr {
|
|
""
|
|
} else if match_type(cx, self_ty, &paths::STRING) {
|
|
"&"
|
|
} else {
|
|
return;
|
|
};
|
|
|
|
span_lint_and_sugg(
|
|
cx,
|
|
STRING_EXTEND_CHARS,
|
|
expr.span,
|
|
"calling `.extend(_.chars())`",
|
|
"try this",
|
|
format!(
|
|
"{}.push_str({}{})",
|
|
snippet(cx, args[0].span, "_"),
|
|
ref_str,
|
|
snippet(cx, target.span, "_")
|
|
),
|
|
);
|
|
}
|
|
}
|
|
|
|
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, new: &hir::Expr, unwrap: &hir::Expr) {
|
|
if_chain! {
|
|
if let hir::ExprKind::Call(ref fun, ref args) = new.node;
|
|
if args.len() == 1;
|
|
if let hir::ExprKind::Path(ref path) = fun.node;
|
|
if let Def::Method(did) = cx.tables.qpath_def(path, fun.hir_id);
|
|
if match_def_path(cx.tcx, did, &paths::CSTRING_NEW);
|
|
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(cx: &LateContext<'_, '_>, expr: &hir::Expr, iter_args: &[hir::Expr]) {
|
|
if match_type(cx, cx.tables.expr_ty(expr), &paths::VEC)
|
|
&& derefs_to_slice(cx, &iter_args[0], cx.tables.expr_ty(&iter_args[0])).is_some()
|
|
{
|
|
span_lint(
|
|
cx,
|
|
ITER_CLONED_COLLECT,
|
|
expr.span,
|
|
"called `cloned().collect()` on a slice to create a `Vec`. Calling `to_vec()` is both faster and \
|
|
more readable",
|
|
);
|
|
}
|
|
}
|
|
|
|
fn lint_unnecessary_fold(cx: &LateContext<'_, '_>, expr: &hir::Expr, fold_args: &[hir::Expr]) {
|
|
// 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");
|
|
|
|
fn check_fold_with_op(
|
|
cx: &LateContext<'_, '_>,
|
|
fold_args: &[hir::Expr],
|
|
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].node;
|
|
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.node;
|
|
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.arguments[0].pat);
|
|
if let Some(second_arg_ident) = get_arg_name(&closure_body.arguments[1].pat);
|
|
|
|
if match_var(&*left_expr, first_arg_ident);
|
|
if replacement_has_args || match_var(&*right_expr, second_arg_ident);
|
|
|
|
then {
|
|
// Span containing `.fold(...)`
|
|
let next_point = cx.sess().codemap().next_point(fold_args[0].span);
|
|
let fold_span = next_point.with_hi(fold_args[2].span.hi() + BytePos(1));
|
|
|
|
let sugg = if replacement_has_args {
|
|
format!(
|
|
".{replacement}(|{s}| {r})",
|
|
replacement = replacement_method_name,
|
|
s = second_arg_ident,
|
|
r = snippet(cx, right_expr.span, "EXPR"),
|
|
)
|
|
} else {
|
|
format!(
|
|
".{replacement}()",
|
|
replacement = replacement_method_name,
|
|
)
|
|
};
|
|
|
|
span_lint_and_sugg(
|
|
cx,
|
|
UNNECESSARY_FOLD,
|
|
fold_span,
|
|
// 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,
|
|
);
|
|
}
|
|
}
|
|
}
|
|
|
|
// Check if the first argument to .fold is a suitable literal
|
|
match fold_args[1].node {
|
|
hir::ExprKind::Lit(ref lit) => {
|
|
match lit.node {
|
|
ast::LitKind::Bool(false) => check_fold_with_op(
|
|
cx, fold_args, hir::BinOpKind::Or, "any", true
|
|
),
|
|
ast::LitKind::Bool(true) => check_fold_with_op(
|
|
cx, fold_args, hir::BinOpKind::And, "all", true
|
|
),
|
|
ast::LitKind::Int(0, _) => check_fold_with_op(
|
|
cx, fold_args, hir::BinOpKind::Add, "sum", false
|
|
),
|
|
ast::LitKind::Int(1, _) => check_fold_with_op(
|
|
cx, fold_args, hir::BinOpKind::Mul, "product", false
|
|
),
|
|
_ => return
|
|
}
|
|
}
|
|
_ => return
|
|
};
|
|
}
|
|
|
|
fn lint_iter_nth(cx: &LateContext<'_, '_>, expr: &hir::Expr, iter_args: &[hir::Expr], is_mut: bool) {
|
|
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 match_type(cx, cx.tables.expr_ty(&iter_args[0]), &paths::VEC) {
|
|
"Vec"
|
|
} else if match_type(cx, cx.tables.expr_ty(&iter_args[0]), &paths::VEC_DEQUE) {
|
|
"VecDeque"
|
|
} else {
|
|
return; // caller is not a type that we want to lint
|
|
};
|
|
|
|
span_lint(
|
|
cx,
|
|
ITER_NTH,
|
|
expr.span,
|
|
&format!(
|
|
"called `.iter{0}().nth()` on a {1}. Calling `.get{0}()` is both faster and more readable",
|
|
mut_str,
|
|
caller_type
|
|
),
|
|
);
|
|
}
|
|
|
|
fn lint_get_unwrap(cx: &LateContext<'_, '_>, expr: &hir::Expr, get_args: &[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 expr_ty = cx.tables.expr_ty(&get_args[0]);
|
|
let caller_type = if derefs_to_slice(cx, &get_args[0], expr_ty).is_some() {
|
|
"slice"
|
|
} else if match_type(cx, expr_ty, &paths::VEC) {
|
|
"Vec"
|
|
} else if match_type(cx, expr_ty, &paths::VEC_DEQUE) {
|
|
"VecDeque"
|
|
} else if !is_mut && match_type(cx, expr_ty, &paths::HASHMAP) {
|
|
"HashMap"
|
|
} else if !is_mut && match_type(cx, expr_ty, &paths::BTREEMAP) {
|
|
"BTreeMap"
|
|
} else {
|
|
return; // caller is not a type that we want to lint
|
|
};
|
|
|
|
let mut_str = if is_mut { "_mut" } else { "" };
|
|
let borrow_str = if is_mut { "&mut " } else { "&" };
|
|
span_lint_and_sugg(
|
|
cx,
|
|
GET_UNWRAP,
|
|
expr.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(cx, get_args[0].span, "_"),
|
|
snippet(cx, get_args[1].span, "_")
|
|
),
|
|
);
|
|
}
|
|
|
|
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(
|
|
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(cx: &LateContext<'_, '_>, expr: &hir::Expr, ty: Ty<'_>) -> Option<sugg::Sugg<'static>> {
|
|
fn may_slice(cx: &LateContext<'_, '_>, ty: Ty<'_>) -> bool {
|
|
match ty.sty {
|
|
ty::TySlice(_) => true,
|
|
ty::TyAdt(def, _) if def.is_box() => may_slice(cx, ty.boxed_ty()),
|
|
ty::TyAdt(..) => match_type(cx, ty, &paths::VEC),
|
|
ty::TyArray(_, size) => size.assert_usize(cx.tcx).expect("array length") < 32,
|
|
ty::TyRef(_, inner, _) => may_slice(cx, inner),
|
|
_ => false,
|
|
}
|
|
}
|
|
|
|
if let hir::ExprKind::MethodCall(ref path, _, ref args) = expr.node {
|
|
if path.ident.name == "iter" && may_slice(cx, cx.tables.expr_ty(&args[0])) {
|
|
sugg::Sugg::hir_opt(cx, &args[0]).map(|sugg| sugg.addr())
|
|
} else {
|
|
None
|
|
}
|
|
} else {
|
|
match ty.sty {
|
|
ty::TySlice(_) => sugg::Sugg::hir_opt(cx, expr),
|
|
ty::TyAdt(def, _) if def.is_box() && may_slice(cx, ty.boxed_ty()) => sugg::Sugg::hir_opt(cx, expr),
|
|
ty::TyRef(_, inner, _) => if may_slice(cx, inner) {
|
|
sugg::Sugg::hir_opt(cx, 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(
|
|
cx,
|
|
lint,
|
|
expr.span,
|
|
&format!(
|
|
"used unwrap() on {} value. If you don't want to handle the {} case gracefully, consider \
|
|
using expect() to provide a better panic \
|
|
message",
|
|
kind,
|
|
none_value
|
|
),
|
|
);
|
|
}
|
|
}
|
|
|
|
/// lint use of `ok().expect()` for `Result`s
|
|
fn lint_ok_expect(cx: &LateContext<'_, '_>, expr: &hir::Expr, ok_args: &[hir::Expr]) {
|
|
// 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) {
|
|
span_lint(
|
|
cx,
|
|
OK_EXPECT,
|
|
expr.span,
|
|
"called `ok().expect()` on a Result value. You can call `expect` directly on the `Result`",
|
|
);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/// lint use of `map().unwrap_or()` for `Option`s
|
|
fn lint_map_unwrap_or(cx: &LateContext<'_, '_>, expr: &hir::Expr, map_args: &[hir::Expr], unwrap_args: &[hir::Expr]) {
|
|
// lint if the caller of `map()` is an `Option`
|
|
if match_type(cx, cx.tables.expr_ty(&map_args[0]), &paths::OPTION) {
|
|
// get snippets for args to map() and unwrap_or()
|
|
let map_snippet = snippet(cx, map_args[1].span, "..");
|
|
let unwrap_snippet = snippet(cx, unwrap_args[1].span, "..");
|
|
// lint message
|
|
// comparing the snippet from source to raw text ("None") below is safe
|
|
// because we already have checked the type.
|
|
let arg = if unwrap_snippet == "None" {
|
|
"None"
|
|
} else {
|
|
"a"
|
|
};
|
|
let suggest = if unwrap_snippet == "None" {
|
|
"and_then(f)"
|
|
} else {
|
|
"map_or(a, f)"
|
|
};
|
|
let msg = &format!(
|
|
"called `map(f).unwrap_or({})` on an Option value. \
|
|
This can be done more directly by calling `{}` instead",
|
|
arg,
|
|
suggest
|
|
);
|
|
// lint, with note if neither arg is > 1 line and both map() and
|
|
// unwrap_or() 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 {
|
|
let suggest = if unwrap_snippet == "None" {
|
|
format!("and_then({})", map_snippet)
|
|
} else {
|
|
format!("map_or({}, {})", unwrap_snippet, map_snippet)
|
|
};
|
|
let note = format!(
|
|
"replace `map({}).unwrap_or({})` with `{}`",
|
|
map_snippet,
|
|
unwrap_snippet,
|
|
suggest
|
|
);
|
|
span_note_and_lint(cx, OPTION_MAP_UNWRAP_OR, expr.span, msg, expr.span, ¬e);
|
|
} else if same_span && multiline {
|
|
span_lint(cx, OPTION_MAP_UNWRAP_OR, expr.span, msg);
|
|
};
|
|
}
|
|
}
|
|
|
|
/// 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 {
|
|
// 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 \
|
|
`ok().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_note_and_lint(
|
|
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 `{2}map_or_else({1}, {0})`",
|
|
map_snippet,
|
|
unwrap_snippet,
|
|
if is_result { "ok()." } else { "" }
|
|
),
|
|
);
|
|
} 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
|
|
fn lint_map_or_none<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, expr: &'tcx hir::Expr, map_or_args: &'tcx [hir::Expr]) {
|
|
if match_type(cx, cx.tables.expr_ty(&map_or_args[0]), &paths::OPTION) {
|
|
// check if the first non-self argument to map_or() is None
|
|
let map_or_arg_is_none = if let hir::ExprKind::Path(ref qpath) = map_or_args[1].node {
|
|
match_qpath(qpath, &paths::OPTION_NONE)
|
|
} else {
|
|
false
|
|
};
|
|
|
|
if map_or_arg_is_none {
|
|
// lint message
|
|
let msg = "called `map_or(None, f)` on an Option value. This can be done more directly by calling \
|
|
`and_then(f)` instead";
|
|
let map_or_self_snippet = snippet(cx, map_or_args[0].span, "..");
|
|
let map_or_func_snippet = snippet(cx, map_or_args[2].span, "..");
|
|
let hint = format!("{0}.and_then({1})", map_or_self_snippet, map_or_func_snippet);
|
|
span_lint_and_then(cx, OPTION_MAP_OR_NONE, expr.span, msg, |db| {
|
|
db.span_suggestion(expr.span, "try using and_then instead", hint);
|
|
});
|
|
}
|
|
}
|
|
}
|
|
|
|
/// 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_note_and_lint(
|
|
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 `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`. \
|
|
This is more succinctly expressed by calling `.filter_map(..)` instead.";
|
|
span_lint(cx, FILTER_MAP, expr.span, msg);
|
|
}
|
|
}
|
|
|
|
/// lint use of `filter().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`. \
|
|
This is more succinctly expressed by only calling `.filter_map(..)` instead.";
|
|
span_lint(cx, FILTER_MAP, expr.span, msg);
|
|
}
|
|
}
|
|
|
|
/// 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`. \
|
|
This is more succinctly expressed by calling `.flat_map(..)` \
|
|
and filtering by returning an empty Iterator.";
|
|
span_lint(cx, FILTER_MAP, expr.span, msg);
|
|
}
|
|
}
|
|
|
|
/// 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`. \
|
|
This is more succinctly expressed by calling `.flat_map(..)` \
|
|
and filtering by returning an empty Iterator.";
|
|
span_lint(cx, FILTER_MAP, expr.span, msg);
|
|
}
|
|
}
|
|
|
|
/// 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],
|
|
) {
|
|
// 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 {
|
|
// add note if not multi-line
|
|
span_note_and_lint(
|
|
cx,
|
|
SEARCH_IS_SOME,
|
|
expr.span,
|
|
&msg,
|
|
expr.span,
|
|
&format!("replace `{0}({1}).is_some()` with `any({1})`", search_method, search_snippet),
|
|
);
|
|
} 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,
|
|
chain: &'a hir::Expr,
|
|
other: &'a hir::Expr,
|
|
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_NEXT_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.node;
|
|
if arg_char.len() == 1;
|
|
if let hir::ExprKind::Path(ref qpath) = fun.node;
|
|
if let Some(segment) = single_segment_path(qpath);
|
|
if segment.ident.name == "Some";
|
|
then {
|
|
let self_ty = walk_ptrs_ty(cx.tables.expr_ty_adjusted(&args[0][0]));
|
|
|
|
if self_ty.sty != ty::TyStr {
|
|
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(cx, args[0][0].span, "_"),
|
|
suggest,
|
|
snippet(cx, arg_char[0].span, "_")));
|
|
|
|
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_NEXT_CMP, "ends_with") {
|
|
true
|
|
} else {
|
|
lint_chars_cmp(cx, info, &["chars", "next_back"], CHARS_NEXT_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.node;
|
|
if let ast::LitKind::Char(c) = lit.node;
|
|
then {
|
|
span_lint_and_sugg(
|
|
cx,
|
|
lint,
|
|
info.expr.span,
|
|
&format!("you should use the `{}` method", suggest),
|
|
"like this",
|
|
format!("{}{}.{}('{}')",
|
|
if info.eq { "" } else { "!" },
|
|
snippet(cx, args[0][0].span, "_"),
|
|
suggest,
|
|
c)
|
|
);
|
|
|
|
return true;
|
|
}
|
|
}
|
|
|
|
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 let Some((Constant::Str(r), _)) = constant(cx, cx.tables, arg) {
|
|
if r.len() == 1 {
|
|
let snip = snippet(cx, arg.span, "..");
|
|
let hint = format!("'{}'", &snip[1..snip.len() - 1]);
|
|
span_lint_and_sugg(
|
|
cx,
|
|
SINGLE_CHAR_PATTERN,
|
|
arg.span,
|
|
"single-character string constant used as pattern",
|
|
"try using a char instead",
|
|
hint,
|
|
);
|
|
}
|
|
}
|
|
}
|
|
|
|
/// 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 {
|
|
span_lint_and_sugg(
|
|
cx,
|
|
USELESS_ASREF,
|
|
expr.span,
|
|
&format!("this call to `{}` does nothing", call_name),
|
|
"try this",
|
|
snippet(cx, recvr.span, "_").into_owned(),
|
|
);
|
|
}
|
|
}
|
|
}
|
|
|
|
/// Given a `Result<T, E>` type, return its error type (`E`).
|
|
fn get_error_type<'a>(cx: &LateContext<'_, '_>, ty: Ty<'a>) -> Option<Ty<'a>> {
|
|
if let ty::TyAdt(_, substs) = ty.sty {
|
|
if match_type(cx, ty, &paths::RESULT) {
|
|
substs.types().nth(1)
|
|
} else {
|
|
None
|
|
}
|
|
} else {
|
|
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 {
|
|
match cx.tcx.lang_items().debug_trait() {
|
|
Some(debug) => implements_trait(cx, ty, debug, &[]),
|
|
None => false,
|
|
}
|
|
}
|
|
|
|
enum Convention {
|
|
Eq(&'static str),
|
|
StartsWith(&'static str),
|
|
}
|
|
|
|
#[rustfmt::skip]
|
|
const CONVENTIONS: [(Convention, &[SelfKind]); 6] = [
|
|
(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::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_left_matches", 1),
|
|
("trim_right_matches", 1),
|
|
];
|
|
|
|
|
|
#[derive(Clone, Copy, PartialEq, Debug)]
|
|
enum SelfKind {
|
|
Value,
|
|
Ref,
|
|
RefMut,
|
|
No,
|
|
}
|
|
|
|
impl SelfKind {
|
|
fn matches(
|
|
self,
|
|
cx: &LateContext<'_, '_>,
|
|
ty: &hir::Ty,
|
|
arg: &hir::Arg,
|
|
self_ty: &hir::Ty,
|
|
allow_value_for_ref: bool,
|
|
generics: &hir::Generics,
|
|
) -> bool {
|
|
// Self types in the HIR are desugared to explicit self types. So it will
|
|
// always be `self:
|
|
// SomeType`,
|
|
// where SomeType can be `Self` or an explicit impl self type (e.g. `Foo` if
|
|
// the impl is on `Foo`)
|
|
// Thus, we only need to test equality against the impl self type or if it is
|
|
// an explicit
|
|
// `Self`. Furthermore, the only possible types for `self: ` are `&Self`,
|
|
// `Self`, `&mut Self`,
|
|
// and `Box<Self>`, including the equivalent types with `Foo`.
|
|
|
|
let is_actually_self = |ty| is_self_ty(ty) || SpanlessEq::new(cx).eq_ty(ty, self_ty);
|
|
if is_self(arg) {
|
|
match self {
|
|
SelfKind::Value => is_actually_self(ty),
|
|
SelfKind::Ref | SelfKind::RefMut => {
|
|
if allow_value_for_ref && is_actually_self(ty) {
|
|
return true;
|
|
}
|
|
match ty.node {
|
|
hir::TyKind::Rptr(_, ref mt_ty) => {
|
|
let mutability_match = if self == SelfKind::Ref {
|
|
mt_ty.mutbl == hir::MutImmutable
|
|
} else {
|
|
mt_ty.mutbl == hir::MutMutable
|
|
};
|
|
is_actually_self(&mt_ty.ty) && mutability_match
|
|
},
|
|
_ => false,
|
|
}
|
|
},
|
|
_ => false,
|
|
}
|
|
} else {
|
|
match self {
|
|
SelfKind::Value => false,
|
|
SelfKind::Ref => is_as_ref_or_mut_trait(ty, self_ty, generics, &paths::ASREF_TRAIT),
|
|
SelfKind::RefMut => is_as_ref_or_mut_trait(ty, self_ty, generics, &paths::ASMUT_TRAIT),
|
|
SelfKind::No => true,
|
|
}
|
|
}
|
|
}
|
|
|
|
fn description(self) -> &'static str {
|
|
match self {
|
|
SelfKind::Value => "self by value",
|
|
SelfKind::Ref => "self by reference",
|
|
SelfKind::RefMut => "self by mutable reference",
|
|
SelfKind::No => "no self",
|
|
}
|
|
}
|
|
}
|
|
|
|
fn is_as_ref_or_mut_trait(ty: &hir::Ty, self_ty: &hir::Ty, generics: &hir::Generics, name: &[&str]) -> bool {
|
|
single_segment_ty(ty).map_or(false, |seg| {
|
|
generics.params.iter().any(|param| match param.kind {
|
|
hir::GenericParamKind::Type { .. } => {
|
|
param.name.ident().name == seg.ident.name && param.bounds.iter().any(|bound| {
|
|
if let hir::GenericBound::Trait(ref ptr, ..) = *bound {
|
|
let path = &ptr.trait_ref.path;
|
|
match_path(path, name) && path.segments.last().map_or(false, |s| {
|
|
if let Some(ref params) = s.args {
|
|
if params.parenthesized {
|
|
false
|
|
} else {
|
|
// FIXME(flip1995): messy, improve if there is a better option
|
|
// in the compiler
|
|
let types: Vec<_> = params.args.iter().filter_map(|arg| match arg {
|
|
hir::GenericArg::Type(ty) => Some(ty),
|
|
_ => None,
|
|
}).collect();
|
|
types.len() == 1
|
|
&& (is_self_ty(&types[0]) || is_ty(&*types[0], self_ty))
|
|
}
|
|
} else {
|
|
false
|
|
}
|
|
})
|
|
} else {
|
|
false
|
|
}
|
|
})
|
|
},
|
|
_ => false,
|
|
})
|
|
})
|
|
}
|
|
|
|
fn is_ty(ty: &hir::Ty, self_ty: &hir::Ty) -> bool {
|
|
match (&ty.node, &self_ty.node) {
|
|
(
|
|
&hir::TyKind::Path(hir::QPath::Resolved(_, ref ty_path)),
|
|
&hir::TyKind::Path(hir::QPath::Resolved(_, ref self_ty_path)),
|
|
) => ty_path
|
|
.segments
|
|
.iter()
|
|
.map(|seg| seg.ident.name)
|
|
.eq(self_ty_path.segments.iter().map(|seg| seg.ident.name)),
|
|
_ => false,
|
|
}
|
|
}
|
|
|
|
fn single_segment_ty(ty: &hir::Ty) -> Option<&hir::PathSegment> {
|
|
if let hir::TyKind::Path(ref path) = ty.node {
|
|
single_segment_path(path)
|
|
} else {
|
|
None
|
|
}
|
|
}
|
|
|
|
impl Convention {
|
|
fn check(&self, other: &str) -> bool {
|
|
match *self {
|
|
Convention::Eq(this) => this == other,
|
|
Convention::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 {
|
|
Convention::Eq(this) => this.fmt(f),
|
|
Convention::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::FunctionRetTy) -> bool {
|
|
let is_unit = |ty: &hir::Ty| SpanlessEq::new(cx).eq_ty_kind(&ty.node, &hir::TyKind::Tup(vec![].into()));
|
|
match (self, ty) {
|
|
(OutType::Unit, &hir::DefaultReturn(_)) => true,
|
|
(OutType::Unit, &hir::Return(ref ty)) if is_unit(ty) => true,
|
|
(OutType::Bool, &hir::Return(ref ty)) if is_bool(ty) => true,
|
|
(OutType::Any, &hir::Return(ref ty)) if !is_unit(ty) => true,
|
|
(OutType::Ref, &hir::Return(ref ty)) => matches!(ty.node, hir::TyKind::Rptr(_, _)),
|
|
_ => false,
|
|
}
|
|
}
|
|
}
|
|
|
|
fn is_bool(ty: &hir::Ty) -> bool {
|
|
if let hir::TyKind::Path(ref p) = ty.node {
|
|
match_qpath(p, &["bool"])
|
|
} else {
|
|
false
|
|
}
|
|
}
|