2018-11-27 20:14:15 +00:00
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use if_chain::if_chain;
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use matches::matches;
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2019-12-03 23:16:03 +00:00
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use rustc::declare_lint_pass;
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2018-12-29 15:04:45 +00:00
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use rustc::hir::intravisit::FnKind;
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use rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
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use rustc::ty;
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use rustc_errors::Applicability;
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2020-01-06 16:39:50 +00:00
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use rustc_hir::*;
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2019-12-03 23:16:03 +00:00
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use rustc_session::declare_tool_lint;
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2020-01-04 10:00:00 +00:00
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use rustc_span::source_map::{ExpnKind, Span};
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2018-12-29 15:04:45 +00:00
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use syntax::ast::LitKind;
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2015-05-06 08:01:49 +00:00
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2019-01-31 01:15:29 +00:00
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use crate::consts::{constant, Constant};
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2019-03-10 21:12:26 +00:00
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use crate::utils::sugg::Sugg;
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2019-01-31 01:15:29 +00:00
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use crate::utils::{
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2019-09-09 15:01:01 +00:00
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get_item_name, get_parent_expr, implements_trait, in_constant, is_integer_const, iter_input_pats,
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2019-10-02 15:38:00 +00:00
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last_path_segment, match_qpath, match_trait_method, paths, snippet, snippet_opt, span_lint, span_lint_and_sugg,
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span_lint_and_then, span_lint_hir_and_then, walk_ptrs_ty, SpanlessEq,
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2019-01-31 01:15:29 +00:00
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};
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2018-03-28 13:24:26 +00:00
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declare_clippy_lint! {
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2019-03-05 16:50:33 +00:00
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/// **What it does:** Checks for function arguments and let bindings denoted as
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/// `ref`.
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///
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/// **Why is this bad?** The `ref` declaration makes the function take an owned
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/// value, but turns the argument into a reference (which means that the value
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/// is destroyed when exiting the function). This adds not much value: either
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/// take a reference type, or take an owned value and create references in the
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/// body.
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///
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/// For let bindings, `let x = &foo;` is preferred over `let ref x = foo`. The
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/// type of `x` is more obvious with the former.
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///
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/// **Known problems:** If the argument is dereferenced within the function,
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/// removing the `ref` will lead to errors. This can be fixed by removing the
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2019-01-31 01:15:29 +00:00
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/// dereferences, e.g., changing `*x` to `x` within the function.
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2019-03-05 16:50:33 +00:00
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///
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/// **Example:**
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2019-01-31 01:15:29 +00:00
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/// ```rust
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2019-03-05 16:50:33 +00:00
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/// fn foo(ref x: u8) -> bool {
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2019-03-10 22:01:56 +00:00
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/// true
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2019-03-05 16:50:33 +00:00
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/// }
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/// ```
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2016-08-06 08:18:36 +00:00
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pub TOPLEVEL_REF_ARG,
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2018-03-28 13:24:26 +00:00
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style,
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2016-08-06 08:18:36 +00:00
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"an entire binding declared as `ref`, in a function argument or a `let` statement"
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2016-02-05 23:13:29 +00:00
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}
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2014-12-24 23:15:22 +00:00
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2018-03-28 13:24:26 +00:00
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declare_clippy_lint! {
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2019-03-05 16:50:33 +00:00
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/// **What it does:** Checks for comparisons to NaN.
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///
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2019-08-19 19:38:33 +00:00
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/// **Why is this bad?** NaN does not compare meaningfully to anything – not
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/// even itself – so those comparisons are simply wrong.
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2019-03-05 16:50:33 +00:00
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///
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/// **Known problems:** None.
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///
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/// **Example:**
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2019-03-09 07:51:23 +00:00
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/// ```rust
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/// # use core::f32::NAN;
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/// # let x = 1.0;
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///
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/// if x == NAN { }
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2019-03-05 16:50:33 +00:00
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/// ```
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2016-08-24 19:47:46 +00:00
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pub CMP_NAN,
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2018-03-28 13:24:26 +00:00
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correctness,
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2016-08-24 19:47:46 +00:00
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"comparisons to NAN, which will always return false, probably not intended"
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}
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2018-03-28 13:24:26 +00:00
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declare_clippy_lint! {
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2019-03-05 16:50:33 +00:00
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/// **What it does:** Checks for (in-)equality comparisons on floating-point
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/// values (apart from zero), except in functions called `*eq*` (which probably
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/// implement equality for a type involving floats).
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///
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/// **Why is this bad?** Floating point calculations are usually imprecise, so
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/// asking if two values are *exactly* equal is asking for trouble. For a good
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/// guide on what to do, see [the floating point
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/// guide](http://www.floating-point-gui.de/errors/comparison).
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///
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/// **Known problems:** None.
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///
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/// **Example:**
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2019-03-09 07:51:23 +00:00
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/// ```rust
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/// let x = 1.2331f64;
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/// let y = 1.2332f64;
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/// if y == 1.23f64 { }
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/// if y != x {} // where both are floats
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2019-03-05 16:50:33 +00:00
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/// ```
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2016-08-24 19:47:46 +00:00
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pub FLOAT_CMP,
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2018-03-29 11:41:53 +00:00
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correctness,
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2016-08-24 19:47:46 +00:00
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"using `==` or `!=` on float values instead of comparing difference with an epsilon"
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}
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2018-03-28 13:24:26 +00:00
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declare_clippy_lint! {
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2019-03-05 16:50:33 +00:00
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/// **What it does:** Checks for conversions to owned values just for the sake
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/// of a comparison.
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///
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/// **Why is this bad?** The comparison can operate on a reference, so creating
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/// an owned value effectively throws it away directly afterwards, which is
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/// needlessly consuming code and heap space.
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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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2019-08-03 06:01:27 +00:00
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/// # let x = "foo";
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/// # let y = String::from("foo");
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/// if x.to_owned() == y {}
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2019-03-05 16:50:33 +00:00
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/// ```
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2019-08-20 14:23:53 +00:00
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/// Could be written as
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/// ```rust
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/// # let x = "foo";
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/// # let y = String::from("foo");
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/// if x == y {}
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/// ```
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2016-08-24 19:47:46 +00:00
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pub CMP_OWNED,
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2018-03-28 13:24:26 +00:00
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perf,
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2019-01-31 01:15:29 +00:00
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"creating owned instances for comparing with others, e.g., `x == \"foo\".to_string()`"
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2016-08-24 19:47:46 +00:00
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}
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2018-03-28 13:24:26 +00:00
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declare_clippy_lint! {
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2019-03-05 16:50:33 +00:00
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/// **What it does:** Checks for getting the remainder of a division by one.
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///
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/// **Why is this bad?** The result can only ever be zero. No one will write
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/// such code deliberately, unless trying to win an Underhanded Rust
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/// Contest. Even for that contest, it's probably a bad idea. Use something more
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/// underhanded.
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///
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/// **Known problems:** None.
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///
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/// **Example:**
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2019-03-09 07:51:23 +00:00
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/// ```rust
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/// # let x = 1;
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/// let a = x % 1;
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2019-03-05 16:50:33 +00:00
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/// ```
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2016-08-24 19:47:46 +00:00
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pub MODULO_ONE,
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2018-03-28 13:24:26 +00:00
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correctness,
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2016-08-24 19:47:46 +00:00
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"taking a number modulo 1, which always returns 0"
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}
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2018-03-28 13:24:26 +00:00
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declare_clippy_lint! {
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2019-03-05 16:50:33 +00:00
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/// **What it does:** Checks for the use of bindings with a single leading
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/// underscore.
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///
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/// **Why is this bad?** A single leading underscore is usually used to indicate
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/// that a binding will not be used. Using such a binding breaks this
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/// expectation.
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///
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/// **Known problems:** The lint does not work properly with desugaring and
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/// macro, it has been allowed in the mean time.
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///
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/// **Example:**
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/// ```rust
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/// let _x = 0;
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/// let y = _x + 1; // Here we are using `_x`, even though it has a leading
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/// // underscore. We should rename `_x` to `x`
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/// ```
|
2016-08-24 19:47:46 +00:00
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pub USED_UNDERSCORE_BINDING,
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2018-03-28 13:24:26 +00:00
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pedantic,
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2016-08-24 19:47:46 +00:00
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"using a binding which is prefixed with an underscore"
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}
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|
2018-03-28 13:24:26 +00:00
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declare_clippy_lint! {
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2019-03-05 16:50:33 +00:00
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/// **What it does:** Checks for the use of short circuit boolean conditions as
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/// a
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/// statement.
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///
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/// **Why is this bad?** Using a short circuit boolean condition as a statement
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/// may hide the fact that the second part is executed or not depending on the
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/// outcome of the first part.
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///
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/// **Known problems:** None.
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///
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/// **Example:**
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2019-08-02 06:13:54 +00:00
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/// ```rust,ignore
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2019-03-05 16:50:33 +00:00
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/// f() && g(); // We should write `if f() { g(); }`.
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/// ```
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2016-12-29 23:00:55 +00:00
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pub SHORT_CIRCUIT_STATEMENT,
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2018-03-28 13:24:26 +00:00
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complexity,
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2016-12-29 23:00:55 +00:00
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"using a short circuit boolean condition as a statement"
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}
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2018-03-28 13:24:26 +00:00
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declare_clippy_lint! {
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2019-03-05 16:50:33 +00:00
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/// **What it does:** Catch casts from `0` to some pointer type
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///
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/// **Why is this bad?** This generally means `null` and is better expressed as
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/// {`std`, `core`}`::ptr::`{`null`, `null_mut`}.
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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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2019-03-09 07:51:23 +00:00
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/// ```rust
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/// let a = 0 as *const u32;
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2019-03-05 16:50:33 +00:00
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/// ```
|
2017-03-07 11:58:07 +00:00
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pub ZERO_PTR,
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2018-03-28 13:24:26 +00:00
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style,
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2017-03-07 11:58:07 +00:00
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"using 0 as *{const, mut} T"
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}
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|
2018-03-28 13:24:26 +00:00
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declare_clippy_lint! {
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2019-03-05 16:50:33 +00:00
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/// **What it does:** Checks for (in-)equality comparisons on floating-point
|
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/// value and constant, except in functions called `*eq*` (which probably
|
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/// implement equality for a type involving floats).
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///
|
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|
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/// **Why is this bad?** Floating point calculations are usually imprecise, so
|
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|
|
|
/// asking if two values are *exactly* equal is asking for trouble. For a good
|
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|
|
|
/// guide on what to do, see [the floating point
|
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|
|
/// guide](http://www.floating-point-gui.de/errors/comparison).
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///
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/// **Known problems:** None.
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///
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|
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/// **Example:**
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|
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/// ```rust
|
2019-08-03 19:24:50 +00:00
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/// let x: f64 = 1.0;
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/// const ONE: f64 = 1.00;
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/// x == ONE; // where both are floats
|
2019-03-05 16:50:33 +00:00
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/// ```
|
2017-11-04 08:32:58 +00:00
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pub FLOAT_CMP_CONST,
|
2018-03-28 13:24:26 +00:00
|
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restriction,
|
2017-11-04 08:32:58 +00:00
|
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|
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"using `==` or `!=` on float constants instead of comparing difference with an epsilon"
|
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}
|
|
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|
2019-04-08 20:43:55 +00:00
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declare_lint_pass!(MiscLints => [
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TOPLEVEL_REF_ARG,
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CMP_NAN,
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FLOAT_CMP,
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CMP_OWNED,
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MODULO_ONE,
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USED_UNDERSCORE_BINDING,
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SHORT_CIRCUIT_STATEMENT,
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ZERO_PTR,
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FLOAT_CMP_CONST
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]);
|
2014-12-24 23:15:22 +00:00
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|
2019-04-08 20:43:55 +00:00
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|
impl<'a, 'tcx> LateLintPass<'a, 'tcx> for MiscLints {
|
2016-12-21 11:14:54 +00:00
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fn check_fn(
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|
&mut self,
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|
|
cx: &LateContext<'a, 'tcx>,
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|
|
k: FnKind<'tcx>,
|
2019-12-30 04:02:10 +00:00
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|
decl: &'tcx FnDecl<'_>,
|
2019-12-22 14:42:41 +00:00
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body: &'tcx Body<'_>,
|
2016-12-21 11:14:54 +00:00
|
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_: Span,
|
2019-02-20 10:11:11 +00:00
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_: HirId,
|
2016-12-21 11:14:54 +00:00
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) {
|
2016-03-23 15:11:24 +00:00
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|
if let FnKind::Closure(_) = k {
|
2015-08-16 11:54:03 +00:00
|
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|
|
// Does not apply to closures
|
2016-01-04 04:26:12 +00:00
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|
return;
|
2015-08-16 11:54:03 +00:00
|
|
|
|
}
|
2017-01-04 21:46:41 +00:00
|
|
|
|
for arg in iter_input_pats(decl, body) {
|
2019-09-27 15:16:06 +00:00
|
|
|
|
match arg.pat.kind {
|
2019-02-03 07:12:07 +00:00
|
|
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|
PatKind::Binding(BindingAnnotation::Ref, ..) | PatKind::Binding(BindingAnnotation::RefMut, ..) => {
|
2017-08-09 07:30:56 +00:00
|
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|
|
span_lint(
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|
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|
cx,
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|
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|
|
TOPLEVEL_REF_ARG,
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|
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|
|
arg.pat.span,
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|
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|
|
"`ref` directly on a function argument is ignored. Consider using a reference type \
|
2017-09-05 09:33:04 +00:00
|
|
|
|
instead.",
|
2017-08-09 07:30:56 +00:00
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|
|
);
|
2017-08-01 07:11:05 +00:00
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|
},
|
2017-08-01 08:19:49 +00:00
|
|
|
|
_ => {},
|
2014-12-24 23:15:22 +00:00
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
}
|
2016-08-24 19:47:46 +00:00
|
|
|
|
|
2019-12-27 07:12:26 +00:00
|
|
|
|
fn check_stmt(&mut self, cx: &LateContext<'a, 'tcx>, stmt: &'tcx Stmt<'_>) {
|
2017-10-23 19:18:02 +00:00
|
|
|
|
if_chain! {
|
2019-09-27 15:16:06 +00:00
|
|
|
|
if let StmtKind::Local(ref local) = stmt.kind;
|
|
|
|
|
if let PatKind::Binding(an, .., name, None) = local.pat.kind;
|
2019-09-26 01:46:51 +00:00
|
|
|
|
if let Some(ref init) = local.init;
|
2017-10-23 19:18:02 +00:00
|
|
|
|
then {
|
|
|
|
|
if an == BindingAnnotation::Ref || an == BindingAnnotation::RefMut {
|
2019-09-26 01:46:51 +00:00
|
|
|
|
let sugg_init = if init.span.from_expansion() {
|
|
|
|
|
Sugg::hir_with_macro_callsite(cx, init, "..")
|
|
|
|
|
} else {
|
|
|
|
|
Sugg::hir(cx, init, "..")
|
|
|
|
|
};
|
|
|
|
|
let (mutopt, initref) = if an == BindingAnnotation::RefMut {
|
2019-04-19 13:18:32 +00:00
|
|
|
|
("mut ", sugg_init.mut_addr())
|
2017-10-23 19:18:02 +00:00
|
|
|
|
} else {
|
2019-04-19 13:18:32 +00:00
|
|
|
|
("", sugg_init.addr())
|
2017-10-23 19:18:02 +00:00
|
|
|
|
};
|
2019-09-26 01:46:51 +00:00
|
|
|
|
let tyopt = if let Some(ref ty) = local.ty {
|
2017-10-23 19:18:02 +00:00
|
|
|
|
format!(": &{mutopt}{ty}", mutopt=mutopt, ty=snippet(cx, ty.span, "_"))
|
|
|
|
|
} else {
|
2018-08-21 10:46:18 +00:00
|
|
|
|
String::new()
|
2017-10-23 19:18:02 +00:00
|
|
|
|
};
|
2019-09-26 01:46:51 +00:00
|
|
|
|
span_lint_hir_and_then(
|
|
|
|
|
cx,
|
2017-10-23 19:18:02 +00:00
|
|
|
|
TOPLEVEL_REF_ARG,
|
2019-04-19 13:18:32 +00:00
|
|
|
|
init.hir_id,
|
2019-09-26 01:46:51 +00:00
|
|
|
|
local.pat.span,
|
2017-10-23 19:18:02 +00:00
|
|
|
|
"`ref` on an entire `let` pattern is discouraged, take a reference with `&` instead",
|
|
|
|
|
|db| {
|
2019-01-27 12:33:56 +00:00
|
|
|
|
db.span_suggestion(
|
2019-09-26 01:46:51 +00:00
|
|
|
|
stmt.span,
|
2018-09-18 15:07:54 +00:00
|
|
|
|
"try",
|
|
|
|
|
format!(
|
|
|
|
|
"let {name}{tyopt} = {initref};",
|
2019-09-26 01:46:51 +00:00
|
|
|
|
name=snippet(cx, name.span, "_"),
|
2018-09-18 15:07:54 +00:00
|
|
|
|
tyopt=tyopt,
|
|
|
|
|
initref=initref,
|
|
|
|
|
),
|
2019-09-26 01:46:51 +00:00
|
|
|
|
Applicability::MachineApplicable,
|
2018-09-18 15:07:54 +00:00
|
|
|
|
);
|
2017-10-23 19:18:02 +00:00
|
|
|
|
}
|
|
|
|
|
);
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
};
|
|
|
|
|
if_chain! {
|
2019-09-27 15:16:06 +00:00
|
|
|
|
if let StmtKind::Semi(ref expr) = stmt.kind;
|
|
|
|
|
if let ExprKind::Binary(ref binop, ref a, ref b) = expr.kind;
|
2018-07-12 07:50:09 +00:00
|
|
|
|
if binop.node == BinOpKind::And || binop.node == BinOpKind::Or;
|
2017-10-23 19:18:02 +00:00
|
|
|
|
if let Some(sugg) = Sugg::hir_opt(cx, a);
|
|
|
|
|
then {
|
2017-08-01 07:11:05 +00:00
|
|
|
|
span_lint_and_then(cx,
|
2017-10-23 19:18:02 +00:00
|
|
|
|
SHORT_CIRCUIT_STATEMENT,
|
2019-09-26 01:46:51 +00:00
|
|
|
|
stmt.span,
|
2017-10-23 19:18:02 +00:00
|
|
|
|
"boolean short circuit operator in statement may be clearer using an explicit test",
|
2017-08-01 07:11:05 +00:00
|
|
|
|
|db| {
|
2018-07-12 07:50:09 +00:00
|
|
|
|
let sugg = if binop.node == BinOpKind::Or { !sugg } else { sugg };
|
2019-01-27 12:33:56 +00:00
|
|
|
|
db.span_suggestion(
|
2019-09-26 01:46:51 +00:00
|
|
|
|
stmt.span,
|
2018-09-18 15:07:54 +00:00
|
|
|
|
"replace it with",
|
|
|
|
|
format!(
|
|
|
|
|
"if {} {{ {}; }}",
|
2018-10-09 02:04:29 +00:00
|
|
|
|
sugg,
|
2018-09-18 15:07:54 +00:00
|
|
|
|
&snippet(cx, b.span, ".."),
|
|
|
|
|
),
|
2018-09-18 17:01:17 +00:00
|
|
|
|
Applicability::MachineApplicable, // snippet
|
2018-09-18 15:07:54 +00:00
|
|
|
|
);
|
2017-10-23 19:18:02 +00:00
|
|
|
|
});
|
2017-08-01 07:11:05 +00:00
|
|
|
|
}
|
2017-10-23 19:18:02 +00:00
|
|
|
|
};
|
2015-09-22 07:08:42 +00:00
|
|
|
|
}
|
2015-05-04 12:11:15 +00:00
|
|
|
|
|
2019-12-27 07:12:26 +00:00
|
|
|
|
fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr<'_>) {
|
2019-09-27 15:16:06 +00:00
|
|
|
|
match expr.kind {
|
2018-07-12 07:30:57 +00:00
|
|
|
|
ExprKind::Cast(ref e, ref ty) => {
|
2017-03-07 11:58:07 +00:00
|
|
|
|
check_cast(cx, expr.span, e, ty);
|
|
|
|
|
return;
|
|
|
|
|
},
|
2018-07-12 07:30:57 +00:00
|
|
|
|
ExprKind::Binary(ref cmp, ref left, ref right) => {
|
2017-03-07 11:58:07 +00:00
|
|
|
|
let op = cmp.node;
|
|
|
|
|
if op.is_comparison() {
|
2019-12-18 03:18:42 +00:00
|
|
|
|
check_nan(cx, left, expr);
|
|
|
|
|
check_nan(cx, right, expr);
|
2017-05-11 16:59:36 +00:00
|
|
|
|
check_to_owned(cx, left, right);
|
|
|
|
|
check_to_owned(cx, right, left);
|
2016-01-04 04:26:12 +00:00
|
|
|
|
}
|
2018-07-12 07:50:09 +00:00
|
|
|
|
if (op == BinOpKind::Eq || op == BinOpKind::Ne) && (is_float(cx, left) || is_float(cx, right)) {
|
2017-03-07 11:58:07 +00:00
|
|
|
|
if is_allowed(cx, left) || is_allowed(cx, right) {
|
2015-09-06 19:03:09 +00:00
|
|
|
|
return;
|
|
|
|
|
}
|
2019-07-15 17:46:58 +00:00
|
|
|
|
|
|
|
|
|
// Allow comparing the results of signum()
|
|
|
|
|
if is_signum(cx, left) && is_signum(cx, right) {
|
|
|
|
|
return;
|
|
|
|
|
}
|
|
|
|
|
|
2017-03-07 11:58:07 +00:00
|
|
|
|
if let Some(name) = get_item_name(cx, expr) {
|
2017-03-30 08:21:13 +00:00
|
|
|
|
let name = name.as_str();
|
2018-11-27 20:14:15 +00:00
|
|
|
|
if name == "eq"
|
|
|
|
|
|| name == "ne"
|
|
|
|
|
|| name == "is_nan"
|
|
|
|
|
|| name.starts_with("eq_")
|
2017-11-04 19:55:56 +00:00
|
|
|
|
|| name.ends_with("_eq")
|
2017-08-09 07:30:56 +00:00
|
|
|
|
{
|
2017-03-07 11:58:07 +00:00
|
|
|
|
return;
|
|
|
|
|
}
|
|
|
|
|
}
|
2017-11-04 08:32:58 +00:00
|
|
|
|
let (lint, msg) = if is_named_constant(cx, left) || is_named_constant(cx, right) {
|
|
|
|
|
(FLOAT_CMP_CONST, "strict comparison of f32 or f64 constant")
|
|
|
|
|
} else {
|
|
|
|
|
(FLOAT_CMP, "strict comparison of f32 or f64")
|
|
|
|
|
};
|
|
|
|
|
span_lint_and_then(cx, lint, expr.span, msg, |db| {
|
2017-03-07 11:58:07 +00:00
|
|
|
|
let lhs = Sugg::hir(cx, left, "..");
|
|
|
|
|
let rhs = Sugg::hir(cx, right, "..");
|
|
|
|
|
|
2019-01-27 12:33:56 +00:00
|
|
|
|
db.span_suggestion(
|
2017-08-09 07:30:56 +00:00
|
|
|
|
expr.span,
|
|
|
|
|
"consider comparing them within some error",
|
2019-06-17 14:42:41 +00:00
|
|
|
|
format!(
|
|
|
|
|
"({}).abs() {} error",
|
|
|
|
|
lhs - rhs,
|
|
|
|
|
if op == BinOpKind::Eq { '<' } else { '>' }
|
|
|
|
|
),
|
2019-08-19 06:00:39 +00:00
|
|
|
|
Applicability::HasPlaceholders, // snippet
|
2017-08-09 07:30:56 +00:00
|
|
|
|
);
|
2017-03-07 11:58:07 +00:00
|
|
|
|
db.span_note(expr.span, "std::f32::EPSILON and std::f64::EPSILON are available.");
|
|
|
|
|
});
|
2019-09-09 15:01:01 +00:00
|
|
|
|
} else if op == BinOpKind::Rem && is_integer_const(cx, right, 1) {
|
2017-03-07 11:58:07 +00:00
|
|
|
|
span_lint(cx, MODULO_ONE, expr.span, "any number modulo 1 will be 0");
|
2015-09-02 08:30:11 +00:00
|
|
|
|
}
|
2017-03-07 11:58:07 +00:00
|
|
|
|
},
|
2017-03-13 10:32:58 +00:00
|
|
|
|
_ => {},
|
2016-08-24 19:47:46 +00:00
|
|
|
|
}
|
2017-03-31 22:14:04 +00:00
|
|
|
|
if in_attributes_expansion(expr) {
|
2016-08-24 19:47:46 +00:00
|
|
|
|
// Don't lint things expanded by #[derive(...)], etc
|
|
|
|
|
return;
|
|
|
|
|
}
|
2019-09-27 15:16:06 +00:00
|
|
|
|
let binding = match expr.kind {
|
2018-07-12 07:30:57 +00:00
|
|
|
|
ExprKind::Path(ref qpath) => {
|
2018-06-28 13:46:58 +00:00
|
|
|
|
let binding = last_path_segment(qpath).ident.as_str();
|
2016-12-02 16:38:31 +00:00
|
|
|
|
if binding.starts_with('_') &&
|
|
|
|
|
!binding.starts_with("__") &&
|
2017-03-09 09:58:31 +00:00
|
|
|
|
binding != "_result" && // FIXME: #944
|
2016-12-02 16:38:31 +00:00
|
|
|
|
is_used(cx, expr) &&
|
|
|
|
|
// don't lint if the declaration is in a macro
|
2019-05-04 00:03:12 +00:00
|
|
|
|
non_macro_local(cx, cx.tables.qpath_res(qpath, expr.hir_id))
|
2017-08-09 07:30:56 +00:00
|
|
|
|
{
|
2016-12-02 16:38:31 +00:00
|
|
|
|
Some(binding)
|
2016-08-24 19:47:46 +00:00
|
|
|
|
} else {
|
|
|
|
|
None
|
|
|
|
|
}
|
2016-12-20 17:21:30 +00:00
|
|
|
|
},
|
2018-07-12 07:30:57 +00:00
|
|
|
|
ExprKind::Field(_, ident) => {
|
2018-05-29 08:56:58 +00:00
|
|
|
|
let name = ident.as_str();
|
2016-08-24 19:47:46 +00:00
|
|
|
|
if name.starts_with('_') && !name.starts_with("__") {
|
|
|
|
|
Some(name)
|
|
|
|
|
} else {
|
|
|
|
|
None
|
|
|
|
|
}
|
2016-12-20 17:21:30 +00:00
|
|
|
|
},
|
2016-08-24 19:47:46 +00:00
|
|
|
|
_ => None,
|
|
|
|
|
};
|
|
|
|
|
if let Some(binding) = binding {
|
2017-08-09 07:30:56 +00:00
|
|
|
|
span_lint(
|
|
|
|
|
cx,
|
|
|
|
|
USED_UNDERSCORE_BINDING,
|
|
|
|
|
expr.span,
|
|
|
|
|
&format!(
|
|
|
|
|
"used binding `{}` which is prefixed with an underscore. A leading \
|
2017-09-05 09:33:04 +00:00
|
|
|
|
underscore signals that a binding will not be used.",
|
2017-08-09 07:30:56 +00:00
|
|
|
|
binding
|
|
|
|
|
),
|
|
|
|
|
);
|
2016-08-24 19:47:46 +00:00
|
|
|
|
}
|
|
|
|
|
}
|
2015-05-06 08:01:49 +00:00
|
|
|
|
}
|
|
|
|
|
|
2019-12-27 07:12:26 +00:00
|
|
|
|
fn check_nan(cx: &LateContext<'_, '_>, expr: &Expr<'_>, cmp_expr: &Expr<'_>) {
|
2019-12-18 03:18:42 +00:00
|
|
|
|
if_chain! {
|
|
|
|
|
if !in_constant(cx, cmp_expr.hir_id);
|
|
|
|
|
if let Some((value, _)) = constant(cx, cx.tables, expr);
|
|
|
|
|
then {
|
|
|
|
|
let needs_lint = match value {
|
|
|
|
|
Constant::F32(num) => num.is_nan(),
|
|
|
|
|
Constant::F64(num) => num.is_nan(),
|
|
|
|
|
_ => false,
|
|
|
|
|
};
|
2019-12-18 02:51:30 +00:00
|
|
|
|
|
2019-12-18 03:18:42 +00:00
|
|
|
|
if needs_lint {
|
|
|
|
|
span_lint(
|
|
|
|
|
cx,
|
|
|
|
|
CMP_NAN,
|
|
|
|
|
cmp_expr.span,
|
|
|
|
|
"doomed comparison with NAN, use `std::{f32,f64}::is_nan()` instead",
|
|
|
|
|
);
|
|
|
|
|
}
|
2017-01-23 01:57:17 +00:00
|
|
|
|
}
|
2017-03-07 11:58:07 +00:00
|
|
|
|
}
|
2016-08-24 19:47:46 +00:00
|
|
|
|
}
|
|
|
|
|
|
2019-12-27 07:12:26 +00:00
|
|
|
|
fn is_named_constant<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr<'_>) -> bool {
|
2018-05-13 11:16:31 +00:00
|
|
|
|
if let Some((_, res)) = constant(cx, cx.tables, expr) {
|
2017-11-04 08:32:58 +00:00
|
|
|
|
res
|
|
|
|
|
} else {
|
2018-11-27 20:14:15 +00:00
|
|
|
|
false
|
2017-11-04 08:32:58 +00:00
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
|
2019-12-27 07:12:26 +00:00
|
|
|
|
fn is_allowed<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr<'_>) -> bool {
|
2018-05-13 11:16:31 +00:00
|
|
|
|
match constant(cx, cx.tables, expr) {
|
2018-03-13 10:38:11 +00:00
|
|
|
|
Some((Constant::F32(f), _)) => f == 0.0 || f.is_infinite(),
|
|
|
|
|
Some((Constant::F64(f), _)) => f == 0.0 || f.is_infinite(),
|
|
|
|
|
_ => false,
|
2016-01-04 04:26:12 +00:00
|
|
|
|
}
|
2015-11-10 10:19:33 +00:00
|
|
|
|
}
|
|
|
|
|
|
2019-07-15 17:46:58 +00:00
|
|
|
|
// Return true if `expr` is the result of `signum()` invoked on a float value.
|
2019-12-27 07:12:26 +00:00
|
|
|
|
fn is_signum(cx: &LateContext<'_, '_>, expr: &Expr<'_>) -> bool {
|
2019-07-15 17:46:58 +00:00
|
|
|
|
// The negation of a signum is still a signum
|
2020-01-06 16:39:50 +00:00
|
|
|
|
if let ExprKind::Unary(UnOp::UnNeg, ref child_expr) = expr.kind {
|
2019-07-15 17:46:58 +00:00
|
|
|
|
return is_signum(cx, &child_expr);
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
if_chain! {
|
2019-09-27 15:16:06 +00:00
|
|
|
|
if let ExprKind::MethodCall(ref method_name, _, ref expressions) = expr.kind;
|
2019-07-15 17:46:58 +00:00
|
|
|
|
if sym!(signum) == method_name.ident.name;
|
|
|
|
|
// Check that the receiver of the signum() is a float (expressions[0] is the receiver of
|
|
|
|
|
// the method call)
|
|
|
|
|
then {
|
2019-07-15 19:00:07 +00:00
|
|
|
|
return is_float(cx, &expressions[0]);
|
2019-07-15 17:46:58 +00:00
|
|
|
|
}
|
|
|
|
|
}
|
2019-07-15 19:00:07 +00:00
|
|
|
|
false
|
2019-07-15 17:46:58 +00:00
|
|
|
|
}
|
|
|
|
|
|
2019-12-27 07:12:26 +00:00
|
|
|
|
fn is_float(cx: &LateContext<'_, '_>, expr: &Expr<'_>) -> bool {
|
2019-09-26 09:03:36 +00:00
|
|
|
|
matches!(walk_ptrs_ty(cx.tables.expr_ty(expr)).kind, ty::Float(_))
|
2015-05-06 08:01:49 +00:00
|
|
|
|
}
|
2015-05-06 10:59:08 +00:00
|
|
|
|
|
2019-12-27 07:12:26 +00:00
|
|
|
|
fn check_to_owned(cx: &LateContext<'_, '_>, expr: &Expr<'_>, other: &Expr<'_>) {
|
2019-09-27 15:16:06 +00:00
|
|
|
|
let (arg_ty, snip) = match expr.kind {
|
2018-07-12 07:30:57 +00:00
|
|
|
|
ExprKind::MethodCall(.., ref args) if args.len() == 1 => {
|
2019-05-17 21:53:54 +00:00
|
|
|
|
if match_trait_method(cx, expr, &paths::TO_STRING) || match_trait_method(cx, expr, &paths::TO_OWNED) {
|
2017-05-11 16:59:36 +00:00
|
|
|
|
(cx.tables.expr_ty_adjusted(&args[0]), snippet(cx, args[0].span, ".."))
|
2016-01-04 04:26:12 +00:00
|
|
|
|
} else {
|
|
|
|
|
return;
|
|
|
|
|
}
|
2016-12-20 17:21:30 +00:00
|
|
|
|
},
|
2018-11-27 20:14:15 +00:00
|
|
|
|
ExprKind::Call(ref path, ref v) if v.len() == 1 => {
|
2019-09-27 15:16:06 +00:00
|
|
|
|
if let ExprKind::Path(ref path) = path.kind {
|
2019-05-17 22:58:25 +00:00
|
|
|
|
if match_qpath(path, &["String", "from_str"]) || match_qpath(path, &["String", "from"]) {
|
2018-11-27 20:14:15 +00:00
|
|
|
|
(cx.tables.expr_ty_adjusted(&v[0]), snippet(cx, v[0].span, ".."))
|
|
|
|
|
} else {
|
|
|
|
|
return;
|
|
|
|
|
}
|
2015-10-12 22:46:05 +00:00
|
|
|
|
} else {
|
2016-01-04 04:26:12 +00:00
|
|
|
|
return;
|
2015-08-11 15:02:04 +00:00
|
|
|
|
}
|
2016-12-20 17:21:30 +00:00
|
|
|
|
},
|
2016-01-04 04:26:12 +00:00
|
|
|
|
_ => return,
|
2015-10-12 22:46:05 +00:00
|
|
|
|
};
|
2016-01-18 14:35:50 +00:00
|
|
|
|
|
2017-05-11 16:59:36 +00:00
|
|
|
|
let other_ty = cx.tables.expr_ty_adjusted(other);
|
2017-09-09 05:23:08 +00:00
|
|
|
|
let partial_eq_trait_id = match cx.tcx.lang_items().eq_trait() {
|
2016-01-18 14:35:50 +00:00
|
|
|
|
Some(id) => id,
|
|
|
|
|
None => return,
|
|
|
|
|
};
|
|
|
|
|
|
2018-11-27 20:14:15 +00:00
|
|
|
|
let deref_arg_impl_partial_eq_other = arg_ty.builtin_deref(true).map_or(false, |tam| {
|
|
|
|
|
implements_trait(cx, tam.ty, partial_eq_trait_id, &[other_ty.into()])
|
|
|
|
|
});
|
|
|
|
|
let arg_impl_partial_eq_deref_other = other_ty.builtin_deref(true).map_or(false, |tam| {
|
|
|
|
|
implements_trait(cx, arg_ty, partial_eq_trait_id, &[tam.ty.into()])
|
|
|
|
|
});
|
2018-10-09 02:04:29 +00:00
|
|
|
|
let arg_impl_partial_eq_other = implements_trait(cx, arg_ty, partial_eq_trait_id, &[other_ty.into()]);
|
|
|
|
|
|
2018-11-27 20:14:15 +00:00
|
|
|
|
if !deref_arg_impl_partial_eq_other && !arg_impl_partial_eq_deref_other && !arg_impl_partial_eq_other {
|
2016-01-18 14:35:50 +00:00
|
|
|
|
return;
|
|
|
|
|
}
|
|
|
|
|
|
2019-09-27 15:16:06 +00:00
|
|
|
|
let other_gets_derefed = match other.kind {
|
2020-01-06 16:39:50 +00:00
|
|
|
|
ExprKind::Unary(UnOp::UnDeref, _) => true,
|
2018-10-10 02:25:03 +00:00
|
|
|
|
_ => false,
|
|
|
|
|
};
|
|
|
|
|
|
2018-10-12 11:48:54 +00:00
|
|
|
|
let lint_span = if other_gets_derefed {
|
|
|
|
|
expr.span.to(other.span)
|
2018-10-10 02:25:03 +00:00
|
|
|
|
} else {
|
2018-10-12 11:48:54 +00:00
|
|
|
|
expr.span
|
2018-10-10 02:25:03 +00:00
|
|
|
|
};
|
|
|
|
|
|
2017-08-09 07:30:56 +00:00
|
|
|
|
span_lint_and_then(
|
|
|
|
|
cx,
|
|
|
|
|
CMP_OWNED,
|
2018-10-10 02:25:03 +00:00
|
|
|
|
lint_span,
|
2017-08-09 07:30:56 +00:00
|
|
|
|
"this creates an owned instance just for comparison",
|
|
|
|
|
|db| {
|
2019-01-31 01:15:29 +00:00
|
|
|
|
// This also catches `PartialEq` implementations that call `to_owned`.
|
2018-10-12 11:34:41 +00:00
|
|
|
|
if other_gets_derefed {
|
|
|
|
|
db.span_label(lint_span, "try implementing the comparison without allocating");
|
|
|
|
|
return;
|
|
|
|
|
}
|
2018-10-12 11:48:54 +00:00
|
|
|
|
|
|
|
|
|
let try_hint = if deref_arg_impl_partial_eq_other {
|
|
|
|
|
// suggest deref on the left
|
|
|
|
|
format!("*{}", snip)
|
|
|
|
|
} else {
|
|
|
|
|
// suggest dropping the to_owned on the left
|
|
|
|
|
snip.to_string()
|
|
|
|
|
};
|
|
|
|
|
|
2019-01-27 12:33:56 +00:00
|
|
|
|
db.span_suggestion(
|
2018-10-10 02:25:03 +00:00
|
|
|
|
lint_span,
|
2018-09-18 15:07:54 +00:00
|
|
|
|
"try",
|
2018-10-09 02:04:29 +00:00
|
|
|
|
try_hint,
|
2018-09-18 17:01:17 +00:00
|
|
|
|
Applicability::MachineApplicable, // snippet
|
2018-09-18 15:07:54 +00:00
|
|
|
|
);
|
2017-08-09 07:30:56 +00:00
|
|
|
|
},
|
|
|
|
|
);
|
2015-05-21 14:37:38 +00:00
|
|
|
|
}
|
2015-08-11 16:55:07 +00:00
|
|
|
|
|
2017-08-09 07:30:56 +00:00
|
|
|
|
/// Heuristic to see if an expression is used. Should be compatible with
|
|
|
|
|
/// `unused_variables`'s idea
|
2015-12-21 09:03:12 +00:00
|
|
|
|
/// of what it means for an expression to be "used".
|
2019-12-27 07:12:26 +00:00
|
|
|
|
fn is_used(cx: &LateContext<'_, '_>, expr: &Expr<'_>) -> bool {
|
2016-08-01 14:59:14 +00:00
|
|
|
|
if let Some(parent) = get_parent_expr(cx, expr) {
|
2019-09-27 15:16:06 +00:00
|
|
|
|
match parent.kind {
|
2019-12-24 04:16:04 +00:00
|
|
|
|
ExprKind::Assign(_, ref rhs, _) | ExprKind::AssignOp(_, _, ref rhs) => {
|
|
|
|
|
SpanlessEq::new(cx).eq_expr(rhs, expr)
|
|
|
|
|
},
|
2016-04-26 15:05:39 +00:00
|
|
|
|
_ => is_used(cx, parent),
|
2015-12-19 00:04:33 +00:00
|
|
|
|
}
|
2016-01-04 04:26:12 +00:00
|
|
|
|
} else {
|
2015-12-19 00:04:33 +00:00
|
|
|
|
true
|
|
|
|
|
}
|
|
|
|
|
}
|
2015-12-21 09:03:12 +00:00
|
|
|
|
|
2019-01-31 01:15:29 +00:00
|
|
|
|
/// Tests whether an expression is in a macro expansion (e.g., something
|
2019-03-10 17:19:47 +00:00
|
|
|
|
/// generated by `#[derive(...)]` or the like).
|
2019-12-27 07:12:26 +00:00
|
|
|
|
fn in_attributes_expansion(expr: &Expr<'_>) -> bool {
|
2019-12-31 00:17:56 +00:00
|
|
|
|
use rustc_span::hygiene::MacroKind;
|
2019-08-16 16:29:30 +00:00
|
|
|
|
if expr.span.from_expansion() {
|
|
|
|
|
let data = expr.span.ctxt().outer_expn_data();
|
|
|
|
|
|
|
|
|
|
if let ExpnKind::Macro(MacroKind::Attr, _) = data.kind {
|
2019-07-11 14:45:34 +00:00
|
|
|
|
true
|
|
|
|
|
} else {
|
|
|
|
|
false
|
|
|
|
|
}
|
2019-08-16 16:29:30 +00:00
|
|
|
|
} else {
|
|
|
|
|
false
|
|
|
|
|
}
|
2015-12-21 09:03:12 +00:00
|
|
|
|
}
|
2016-06-15 14:27:56 +00:00
|
|
|
|
|
2019-05-04 00:03:12 +00:00
|
|
|
|
/// Tests whether `res` is a variable defined outside a macro.
|
|
|
|
|
fn non_macro_local(cx: &LateContext<'_, '_>, res: def::Res) -> bool {
|
2019-06-02 16:30:40 +00:00
|
|
|
|
if let def::Res::Local(id) = res {
|
2019-08-19 16:30:32 +00:00
|
|
|
|
!cx.tcx.hir().span(id).from_expansion()
|
2019-06-02 16:30:40 +00:00
|
|
|
|
} else {
|
|
|
|
|
false
|
2016-06-15 14:27:56 +00:00
|
|
|
|
}
|
|
|
|
|
}
|
2017-03-07 11:58:07 +00:00
|
|
|
|
|
2019-12-30 04:02:10 +00:00
|
|
|
|
fn check_cast(cx: &LateContext<'_, '_>, span: Span, e: &Expr<'_>, ty: &Ty<'_>) {
|
2017-10-23 19:18:02 +00:00
|
|
|
|
if_chain! {
|
2019-10-02 15:38:00 +00:00
|
|
|
|
if let TyKind::Ptr(ref mut_ty) = ty.kind;
|
2019-09-27 15:16:06 +00:00
|
|
|
|
if let ExprKind::Lit(ref lit) = e.kind;
|
2019-10-02 15:38:00 +00:00
|
|
|
|
if let LitKind::Int(0, _) = lit.node;
|
2019-02-24 18:43:15 +00:00
|
|
|
|
if !in_constant(cx, e.hir_id);
|
2017-10-23 19:18:02 +00:00
|
|
|
|
then {
|
2019-10-02 15:38:00 +00:00
|
|
|
|
let (msg, sugg_fn) = match mut_ty.mutbl {
|
2019-12-21 18:38:45 +00:00
|
|
|
|
Mutability::Mut => ("`0 as *mut _` detected", "std::ptr::null_mut"),
|
|
|
|
|
Mutability::Not => ("`0 as *const _` detected", "std::ptr::null"),
|
2017-10-23 19:18:02 +00:00
|
|
|
|
};
|
2019-10-02 15:38:00 +00:00
|
|
|
|
|
|
|
|
|
let (sugg, appl) = if let TyKind::Infer = mut_ty.ty.kind {
|
|
|
|
|
(format!("{}()", sugg_fn), Applicability::MachineApplicable)
|
|
|
|
|
} else if let Some(mut_ty_snip) = snippet_opt(cx, mut_ty.ty.span) {
|
|
|
|
|
(format!("{}::<{}>()", sugg_fn, mut_ty_snip), Applicability::MachineApplicable)
|
|
|
|
|
} else {
|
|
|
|
|
// `MaybeIncorrect` as type inference may not work with the suggested code
|
|
|
|
|
(format!("{}()", sugg_fn), Applicability::MaybeIncorrect)
|
|
|
|
|
};
|
|
|
|
|
span_lint_and_sugg(cx, ZERO_PTR, span, msg, "try", sugg, appl);
|
2017-10-23 19:18:02 +00:00
|
|
|
|
}
|
|
|
|
|
}
|
2017-03-07 11:58:07 +00:00
|
|
|
|
}
|