2020-01-11 10:39:43 +00:00
|
|
|
|
use crate::consts::{constant, miri_to_const, Constant};
|
2018-05-30 08:15:50 +00:00
|
|
|
|
use crate::utils::sugg::Sugg;
|
2020-01-10 16:14:17 +00:00
|
|
|
|
use crate::utils::usage::is_unused;
|
2018-11-27 20:14:15 +00:00
|
|
|
|
use crate::utils::{
|
2021-01-11 04:32:23 +00:00
|
|
|
|
expr_block, get_arg_name, get_parent_expr, implements_trait, in_macro, indent_of, is_allowed, is_expn_of,
|
|
|
|
|
is_refutable, is_type_diagnostic_item, is_wild, match_qpath, match_type, match_var, meets_msrv, multispan_sugg,
|
2021-01-14 19:26:26 +00:00
|
|
|
|
peel_hir_pat_refs, peel_mid_ty_refs, peeln_hir_expr_refs, remove_blocks, snippet, snippet_block, snippet_opt,
|
|
|
|
|
snippet_with_applicability, span_lint_and_help, span_lint_and_note, span_lint_and_sugg, span_lint_and_then,
|
2018-11-27 20:14:15 +00:00
|
|
|
|
};
|
2020-10-24 15:06:07 +00:00
|
|
|
|
use crate::utils::{paths, search_same, SpanlessEq, SpanlessHash};
|
2018-11-27 20:14:15 +00:00
|
|
|
|
use if_chain::if_chain;
|
2020-11-25 10:50:13 +00:00
|
|
|
|
use rustc_ast::ast::LitKind;
|
2020-10-24 15:06:07 +00:00
|
|
|
|
use rustc_data_structures::fx::FxHashMap;
|
2018-12-29 15:04:45 +00:00
|
|
|
|
use rustc_errors::Applicability;
|
2020-01-06 16:39:50 +00:00
|
|
|
|
use rustc_hir::def::CtorKind;
|
2020-02-21 08:39:38 +00:00
|
|
|
|
use rustc_hir::{
|
2020-07-14 12:59:59 +00:00
|
|
|
|
Arm, BindingAnnotation, Block, BorrowKind, Expr, ExprKind, Guard, Local, MatchSource, Mutability, Node, Pat,
|
|
|
|
|
PatKind, QPath, RangeEnd,
|
2020-02-21 08:39:38 +00:00
|
|
|
|
};
|
2020-01-12 06:08:41 +00:00
|
|
|
|
use rustc_lint::{LateContext, LateLintPass, LintContext};
|
2020-03-30 09:02:14 +00:00
|
|
|
|
use rustc_middle::lint::in_external_macro;
|
2020-10-24 15:06:07 +00:00
|
|
|
|
use rustc_middle::ty::{self, Ty, TyS};
|
2020-11-28 14:11:27 +00:00
|
|
|
|
use rustc_semver::RustcVersion;
|
2020-01-19 10:07:13 +00:00
|
|
|
|
use rustc_session::{declare_tool_lint, impl_lint_pass};
|
2020-07-14 12:59:59 +00:00
|
|
|
|
use rustc_span::source_map::{Span, Spanned};
|
2020-11-02 16:32:55 +00:00
|
|
|
|
use rustc_span::{sym, Symbol};
|
2018-11-27 20:14:15 +00:00
|
|
|
|
use std::cmp::Ordering;
|
2020-10-24 15:06:07 +00:00
|
|
|
|
use std::collections::hash_map::Entry;
|
2018-11-27 20:14:15 +00:00
|
|
|
|
use std::collections::Bound;
|
2015-08-21 17:32:21 +00:00
|
|
|
|
|
2018-03-28 13:24:26 +00:00
|
|
|
|
declare_clippy_lint! {
|
2019-03-05 16:50:33 +00:00
|
|
|
|
/// **What it does:** Checks for matches with a single arm where an `if let`
|
|
|
|
|
/// will usually suffice.
|
|
|
|
|
///
|
|
|
|
|
/// **Why is this bad?** Just readability – `if let` nests less than a `match`.
|
|
|
|
|
///
|
|
|
|
|
/// **Known problems:** None.
|
|
|
|
|
///
|
|
|
|
|
/// **Example:**
|
2019-03-09 07:51:23 +00:00
|
|
|
|
/// ```rust
|
|
|
|
|
/// # fn bar(stool: &str) {}
|
|
|
|
|
/// # let x = Some("abc");
|
2020-06-09 14:36:01 +00:00
|
|
|
|
/// // Bad
|
2019-03-05 16:50:33 +00:00
|
|
|
|
/// match x {
|
|
|
|
|
/// Some(ref foo) => bar(foo),
|
|
|
|
|
/// _ => (),
|
|
|
|
|
/// }
|
2020-06-09 14:36:01 +00:00
|
|
|
|
///
|
|
|
|
|
/// // Good
|
|
|
|
|
/// if let Some(ref foo) = x {
|
|
|
|
|
/// bar(foo);
|
|
|
|
|
/// }
|
2019-03-05 16:50:33 +00:00
|
|
|
|
/// ```
|
2018-11-27 20:49:09 +00:00
|
|
|
|
pub SINGLE_MATCH,
|
|
|
|
|
style,
|
2020-01-06 06:30:43 +00:00
|
|
|
|
"a `match` statement with a single nontrivial arm (i.e., where the other arm is `_ => {}`) instead of `if let`"
|
2016-02-05 23:13:29 +00:00
|
|
|
|
}
|
2015-12-23 00:14:10 +00:00
|
|
|
|
|
2018-03-28 13:24:26 +00:00
|
|
|
|
declare_clippy_lint! {
|
2019-08-16 12:41:35 +00:00
|
|
|
|
/// **What it does:** Checks for matches with two arms where an `if let else` will
|
2019-03-05 16:50:33 +00:00
|
|
|
|
/// usually suffice.
|
|
|
|
|
///
|
|
|
|
|
/// **Why is this bad?** Just readability – `if let` nests less than a `match`.
|
|
|
|
|
///
|
|
|
|
|
/// **Known problems:** Personal style preferences may differ.
|
|
|
|
|
///
|
|
|
|
|
/// **Example:**
|
|
|
|
|
///
|
|
|
|
|
/// Using `match`:
|
|
|
|
|
///
|
|
|
|
|
/// ```rust
|
2019-08-03 16:42:05 +00:00
|
|
|
|
/// # fn bar(foo: &usize) {}
|
|
|
|
|
/// # let other_ref: usize = 1;
|
|
|
|
|
/// # let x: Option<&usize> = Some(&1);
|
2019-03-05 16:50:33 +00:00
|
|
|
|
/// match x {
|
|
|
|
|
/// Some(ref foo) => bar(foo),
|
2019-08-03 16:42:05 +00:00
|
|
|
|
/// _ => bar(&other_ref),
|
2019-03-05 16:50:33 +00:00
|
|
|
|
/// }
|
|
|
|
|
/// ```
|
|
|
|
|
///
|
|
|
|
|
/// Using `if let` with `else`:
|
|
|
|
|
///
|
2019-03-09 07:51:23 +00:00
|
|
|
|
/// ```rust
|
2019-08-03 16:42:05 +00:00
|
|
|
|
/// # fn bar(foo: &usize) {}
|
|
|
|
|
/// # let other_ref: usize = 1;
|
|
|
|
|
/// # let x: Option<&usize> = Some(&1);
|
2019-03-05 16:50:33 +00:00
|
|
|
|
/// if let Some(ref foo) = x {
|
|
|
|
|
/// bar(foo);
|
|
|
|
|
/// } else {
|
2019-08-03 16:42:05 +00:00
|
|
|
|
/// bar(&other_ref);
|
2019-03-05 16:50:33 +00:00
|
|
|
|
/// }
|
|
|
|
|
/// ```
|
2018-11-27 20:49:09 +00:00
|
|
|
|
pub SINGLE_MATCH_ELSE,
|
|
|
|
|
pedantic,
|
2020-01-06 06:30:43 +00:00
|
|
|
|
"a `match` statement with two arms where the second arm's pattern is a placeholder instead of a specific match pattern"
|
2016-02-05 23:13:29 +00:00
|
|
|
|
}
|
2016-01-24 11:24:16 +00:00
|
|
|
|
|
2018-03-28 13:24:26 +00:00
|
|
|
|
declare_clippy_lint! {
|
2019-03-05 16:50:33 +00:00
|
|
|
|
/// **What it does:** Checks for matches where all arms match a reference,
|
|
|
|
|
/// suggesting to remove the reference and deref the matched expression
|
|
|
|
|
/// instead. It also checks for `if let &foo = bar` blocks.
|
|
|
|
|
///
|
|
|
|
|
/// **Why is this bad?** It just makes the code less readable. That reference
|
|
|
|
|
/// destructuring adds nothing to the code.
|
|
|
|
|
///
|
|
|
|
|
/// **Known problems:** None.
|
|
|
|
|
///
|
|
|
|
|
/// **Example:**
|
2019-03-09 07:51:23 +00:00
|
|
|
|
/// ```rust,ignore
|
2020-06-09 14:36:01 +00:00
|
|
|
|
/// // Bad
|
2019-03-05 16:50:33 +00:00
|
|
|
|
/// match x {
|
|
|
|
|
/// &A(ref y) => foo(y),
|
|
|
|
|
/// &B => bar(),
|
|
|
|
|
/// _ => frob(&x),
|
|
|
|
|
/// }
|
2020-06-09 14:36:01 +00:00
|
|
|
|
///
|
|
|
|
|
/// // Good
|
|
|
|
|
/// match *x {
|
|
|
|
|
/// A(ref y) => foo(y),
|
|
|
|
|
/// B => bar(),
|
|
|
|
|
/// _ => frob(x),
|
|
|
|
|
/// }
|
2019-03-05 16:50:33 +00:00
|
|
|
|
/// ```
|
2016-08-06 08:18:36 +00:00
|
|
|
|
pub MATCH_REF_PATS,
|
2018-03-28 13:24:26 +00:00
|
|
|
|
style,
|
2020-01-06 06:30:43 +00:00
|
|
|
|
"a `match` or `if let` with all arms prefixed with `&` instead of deref-ing the match expression"
|
2016-02-05 23:13:29 +00:00
|
|
|
|
}
|
2015-12-23 00:14:10 +00:00
|
|
|
|
|
2018-03-28 13:24:26 +00:00
|
|
|
|
declare_clippy_lint! {
|
2019-03-05 16:50:33 +00:00
|
|
|
|
/// **What it does:** Checks for matches where match expression is a `bool`. It
|
|
|
|
|
/// suggests to replace the expression with an `if...else` block.
|
|
|
|
|
///
|
|
|
|
|
/// **Why is this bad?** It makes the code less readable.
|
|
|
|
|
///
|
|
|
|
|
/// **Known problems:** None.
|
|
|
|
|
///
|
|
|
|
|
/// **Example:**
|
2019-03-09 07:51:23 +00:00
|
|
|
|
/// ```rust
|
|
|
|
|
/// # fn foo() {}
|
|
|
|
|
/// # fn bar() {}
|
2019-03-05 16:50:33 +00:00
|
|
|
|
/// let condition: bool = true;
|
|
|
|
|
/// match condition {
|
|
|
|
|
/// true => foo(),
|
|
|
|
|
/// false => bar(),
|
|
|
|
|
/// }
|
|
|
|
|
/// ```
|
|
|
|
|
/// Use if/else instead:
|
2019-03-09 07:51:23 +00:00
|
|
|
|
/// ```rust
|
|
|
|
|
/// # fn foo() {}
|
|
|
|
|
/// # fn bar() {}
|
2019-03-05 16:50:33 +00:00
|
|
|
|
/// let condition: bool = true;
|
|
|
|
|
/// if condition {
|
|
|
|
|
/// foo();
|
|
|
|
|
/// } else {
|
|
|
|
|
/// bar();
|
|
|
|
|
/// }
|
|
|
|
|
/// ```
|
2016-08-06 08:18:36 +00:00
|
|
|
|
pub MATCH_BOOL,
|
2020-04-03 00:36:49 +00:00
|
|
|
|
pedantic,
|
2020-01-06 06:30:43 +00:00
|
|
|
|
"a `match` on a boolean expression instead of an `if..else` block"
|
2016-02-05 23:13:29 +00:00
|
|
|
|
}
|
2015-08-21 17:32:21 +00:00
|
|
|
|
|
2018-03-28 13:24:26 +00:00
|
|
|
|
declare_clippy_lint! {
|
2019-03-05 16:50:33 +00:00
|
|
|
|
/// **What it does:** Checks for overlapping match arms.
|
|
|
|
|
///
|
|
|
|
|
/// **Why is this bad?** It is likely to be an error and if not, makes the code
|
|
|
|
|
/// less obvious.
|
|
|
|
|
///
|
|
|
|
|
/// **Known problems:** None.
|
|
|
|
|
///
|
|
|
|
|
/// **Example:**
|
|
|
|
|
/// ```rust
|
|
|
|
|
/// let x = 5;
|
|
|
|
|
/// match x {
|
|
|
|
|
/// 1...10 => println!("1 ... 10"),
|
|
|
|
|
/// 5...15 => println!("5 ... 15"),
|
|
|
|
|
/// _ => (),
|
|
|
|
|
/// }
|
|
|
|
|
/// ```
|
2016-08-06 08:18:36 +00:00
|
|
|
|
pub MATCH_OVERLAPPING_ARM,
|
2018-03-28 13:24:26 +00:00
|
|
|
|
style,
|
2020-01-06 06:30:43 +00:00
|
|
|
|
"a `match` with overlapping arms"
|
2016-02-05 23:13:29 +00:00
|
|
|
|
}
|
2015-12-23 00:14:10 +00:00
|
|
|
|
|
2018-03-28 13:24:26 +00:00
|
|
|
|
declare_clippy_lint! {
|
2019-03-05 16:50:33 +00:00
|
|
|
|
/// **What it does:** Checks for arm which matches all errors with `Err(_)`
|
|
|
|
|
/// and take drastic actions like `panic!`.
|
|
|
|
|
///
|
2020-05-28 13:45:24 +00:00
|
|
|
|
/// **Why is this bad?** It is generally a bad practice, similar to
|
2019-03-05 16:50:33 +00:00
|
|
|
|
/// catching all exceptions in java with `catch(Exception)`
|
|
|
|
|
///
|
|
|
|
|
/// **Known problems:** None.
|
|
|
|
|
///
|
|
|
|
|
/// **Example:**
|
|
|
|
|
/// ```rust
|
2019-03-05 22:23:50 +00:00
|
|
|
|
/// let x: Result<i32, &str> = Ok(3);
|
2019-03-05 16:50:33 +00:00
|
|
|
|
/// match x {
|
|
|
|
|
/// Ok(_) => println!("ok"),
|
|
|
|
|
/// Err(_) => panic!("err"),
|
|
|
|
|
/// }
|
|
|
|
|
/// ```
|
2017-02-11 06:57:50 +00:00
|
|
|
|
pub MATCH_WILD_ERR_ARM,
|
2020-05-28 13:45:24 +00:00
|
|
|
|
pedantic,
|
2020-01-06 06:30:43 +00:00
|
|
|
|
"a `match` with `Err(_)` arm and take drastic actions"
|
2017-02-11 06:57:50 +00:00
|
|
|
|
}
|
|
|
|
|
|
2018-03-28 13:24:26 +00:00
|
|
|
|
declare_clippy_lint! {
|
2019-03-05 16:50:33 +00:00
|
|
|
|
/// **What it does:** Checks for match which is used to add a reference to an
|
|
|
|
|
/// `Option` value.
|
|
|
|
|
///
|
|
|
|
|
/// **Why is this bad?** Using `as_ref()` or `as_mut()` instead is shorter.
|
|
|
|
|
///
|
|
|
|
|
/// **Known problems:** None.
|
|
|
|
|
///
|
|
|
|
|
/// **Example:**
|
|
|
|
|
/// ```rust
|
|
|
|
|
/// let x: Option<()> = None;
|
2020-06-09 14:36:01 +00:00
|
|
|
|
///
|
|
|
|
|
/// // Bad
|
2019-03-05 16:50:33 +00:00
|
|
|
|
/// let r: Option<&()> = match x {
|
|
|
|
|
/// None => None,
|
|
|
|
|
/// Some(ref v) => Some(v),
|
|
|
|
|
/// };
|
2020-06-09 14:36:01 +00:00
|
|
|
|
///
|
|
|
|
|
/// // Good
|
|
|
|
|
/// let r: Option<&()> = x.as_ref();
|
2019-03-05 16:50:33 +00:00
|
|
|
|
/// ```
|
2017-12-19 22:22:16 +00:00
|
|
|
|
pub MATCH_AS_REF,
|
2018-03-28 13:24:26 +00:00
|
|
|
|
complexity,
|
2020-01-06 06:30:43 +00:00
|
|
|
|
"a `match` on an Option value instead of using `as_ref()` or `as_mut`"
|
2017-12-19 22:22:16 +00:00
|
|
|
|
}
|
|
|
|
|
|
2019-01-10 20:56:28 +00:00
|
|
|
|
declare_clippy_lint! {
|
2019-03-05 16:50:33 +00:00
|
|
|
|
/// **What it does:** Checks for wildcard enum matches using `_`.
|
|
|
|
|
///
|
|
|
|
|
/// **Why is this bad?** New enum variants added by library updates can be missed.
|
|
|
|
|
///
|
|
|
|
|
/// **Known problems:** Suggested replacements may be incorrect if guards exhaustively cover some
|
|
|
|
|
/// variants, and also may not use correct path to enum if it's not present in the current scope.
|
|
|
|
|
///
|
|
|
|
|
/// **Example:**
|
|
|
|
|
/// ```rust
|
2019-08-03 19:24:50 +00:00
|
|
|
|
/// # enum Foo { A(usize), B(usize) }
|
|
|
|
|
/// # let x = Foo::B(1);
|
2020-06-09 14:36:01 +00:00
|
|
|
|
/// // Bad
|
2019-03-05 16:50:33 +00:00
|
|
|
|
/// match x {
|
2020-05-28 13:45:24 +00:00
|
|
|
|
/// Foo::A(_) => {},
|
2019-03-05 16:50:33 +00:00
|
|
|
|
/// _ => {},
|
|
|
|
|
/// }
|
2020-06-09 14:36:01 +00:00
|
|
|
|
///
|
|
|
|
|
/// // Good
|
|
|
|
|
/// match x {
|
|
|
|
|
/// Foo::A(_) => {},
|
|
|
|
|
/// Foo::B(_) => {},
|
|
|
|
|
/// }
|
2019-03-05 16:50:33 +00:00
|
|
|
|
/// ```
|
2019-01-29 20:25:40 +00:00
|
|
|
|
pub WILDCARD_ENUM_MATCH_ARM,
|
2019-01-10 20:56:28 +00:00
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restriction,
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2019-01-29 20:25:40 +00:00
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"a wildcard enum match arm using `_`"
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2019-01-10 20:56:28 +00:00
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}
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2020-05-28 13:45:24 +00:00
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declare_clippy_lint! {
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/// **What it does:** Checks for wildcard enum matches for a single variant.
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///
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/// **Why is this bad?** New enum variants added by library updates can be missed.
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///
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/// **Known problems:** Suggested replacements may not use correct path to enum
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/// if it's not present in the current scope.
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///
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/// **Example:**
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///
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/// ```rust
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/// # enum Foo { A, B, C }
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/// # let x = Foo::B;
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2020-06-09 14:36:01 +00:00
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/// // Bad
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2020-05-28 13:45:24 +00:00
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/// match x {
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/// Foo::A => {},
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/// Foo::B => {},
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/// _ => {},
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/// }
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2020-06-09 14:36:01 +00:00
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///
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/// // Good
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2020-05-28 13:45:24 +00:00
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/// match x {
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/// Foo::A => {},
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/// Foo::B => {},
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/// Foo::C => {},
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/// }
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/// ```
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pub MATCH_WILDCARD_FOR_SINGLE_VARIANTS,
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pedantic,
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"a wildcard enum match for a single variant"
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}
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2019-12-24 15:42:09 +00:00
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declare_clippy_lint! {
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/// **What it does:** Checks for wildcard pattern used with others patterns in same match arm.
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///
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/// **Why is this bad?** Wildcard pattern already covers any other pattern as it will match anyway.
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/// It makes the code less readable, especially to spot wildcard pattern use in match arm.
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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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2020-06-09 14:36:01 +00:00
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/// // Bad
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2019-12-24 15:42:09 +00:00
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/// match "foo" {
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/// "a" => {},
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/// "bar" | _ => {},
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/// }
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2020-06-09 14:36:01 +00:00
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///
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/// // Good
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/// match "foo" {
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/// "a" => {},
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/// _ => {},
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/// }
|
2019-12-24 15:42:09 +00:00
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/// ```
|
2020-01-05 14:05:16 +00:00
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pub WILDCARD_IN_OR_PATTERNS,
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2019-12-27 01:03:16 +00:00
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complexity,
|
2019-12-24 15:42:09 +00:00
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"a wildcard pattern used with others patterns in same match arm"
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}
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2020-01-19 10:07:13 +00:00
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declare_clippy_lint! {
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/// **What it does:** Checks for matches being used to destructure a single-variant enum
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/// or tuple struct where a `let` will suffice.
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///
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/// **Why is this bad?** Just readability – `let` doesn't nest, whereas a `match` does.
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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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/// enum Wrapper {
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/// Data(i32),
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/// }
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///
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/// let wrapper = Wrapper::Data(42);
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///
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/// let data = match wrapper {
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/// Wrapper::Data(i) => i,
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/// };
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/// ```
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///
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/// The correct use would be:
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/// ```rust
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/// enum Wrapper {
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/// Data(i32),
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/// }
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///
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/// let wrapper = Wrapper::Data(42);
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/// let Wrapper::Data(data) = wrapper;
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/// ```
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pub INFALLIBLE_DESTRUCTURING_MATCH,
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style,
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"a `match` statement with a single infallible arm instead of a `let`"
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}
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2020-01-15 06:56:56 +00:00
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declare_clippy_lint! {
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/// **What it does:** Checks for useless match that binds to only one value.
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///
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/// **Why is this bad?** Readability and needless complexity.
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///
|
2020-02-04 19:19:20 +00:00
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/// **Known problems:** Suggested replacements may be incorrect when `match`
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/// is actually binding temporary value, bringing a 'dropped while borrowed' error.
|
2020-01-15 06:56:56 +00:00
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///
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/// **Example:**
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/// ```rust
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/// # let a = 1;
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/// # let b = 2;
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///
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/// // Bad
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/// match (a, b) {
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/// (c, d) => {
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/// // useless match
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/// }
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/// }
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///
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/// // Good
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/// let (c, d) = (a, b);
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/// ```
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pub MATCH_SINGLE_BINDING,
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complexity,
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"a match with a single binding instead of using `let` statement"
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}
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|
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|
|
2020-03-01 16:36:14 +00:00
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|
declare_clippy_lint! {
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/// **What it does:** Checks for unnecessary '..' pattern binding on struct when all fields are explicitly matched.
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///
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/// **Why is this bad?** Correctness and readability. It's like having a wildcard pattern after
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/// matching all enum variants explicitly.
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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 A { a: i32 }
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/// let a = A { a: 5 };
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///
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/// // Bad
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/// match a {
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/// A { a: 5, .. } => {},
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/// _ => {},
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/// }
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///
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/// // Good
|
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|
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/// match a {
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/// A { a: 5 } => {},
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/// _ => {},
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/// }
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/// ```
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pub REST_PAT_IN_FULLY_BOUND_STRUCTS,
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restriction,
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"a match on a struct that binds all fields but still uses the wildcard pattern"
|
|
|
|
|
}
|
|
|
|
|
|
2020-07-14 12:59:59 +00:00
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|
|
declare_clippy_lint! {
|
2020-11-25 01:01:05 +00:00
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|
/// **What it does:** Lint for redundant pattern matching over `Result`, `Option`,
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/// `std::task::Poll` or `std::net::IpAddr`
|
2020-07-14 12:59:59 +00:00
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///
|
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/// **Why is this bad?** It's more concise and clear to just use the proper
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/// utility function
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///
|
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/// **Known problems:** None.
|
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///
|
|
|
|
|
/// **Example:**
|
|
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|
|
///
|
|
|
|
|
/// ```rust
|
2020-11-17 21:34:39 +00:00
|
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|
|
/// # use std::task::Poll;
|
2020-11-25 01:01:05 +00:00
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/// # use std::net::{IpAddr, Ipv4Addr, Ipv6Addr};
|
2020-07-14 12:59:59 +00:00
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/// if let Ok(_) = Ok::<i32, i32>(42) {}
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/// if let Err(_) = Err::<i32, i32>(42) {}
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/// if let None = None::<()> {}
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/// if let Some(_) = Some(42) {}
|
2020-11-17 21:34:39 +00:00
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/// if let Poll::Pending = Poll::Pending::<()> {}
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/// if let Poll::Ready(_) = Poll::Ready(42) {}
|
2020-11-25 01:01:05 +00:00
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/// if let IpAddr::V4(_) = IpAddr::V4(Ipv4Addr::LOCALHOST) {}
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/// if let IpAddr::V6(_) = IpAddr::V6(Ipv6Addr::LOCALHOST) {}
|
2020-07-14 12:59:59 +00:00
|
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/// match Ok::<i32, i32>(42) {
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|
/// Ok(_) => true,
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/// Err(_) => false,
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|
/// };
|
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|
|
/// ```
|
|
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|
|
///
|
|
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|
|
/// The more idiomatic use would be:
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///
|
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|
/// ```rust
|
2020-11-17 21:34:39 +00:00
|
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|
|
/// # use std::task::Poll;
|
2020-11-25 01:01:05 +00:00
|
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|
/// # use std::net::{IpAddr, Ipv4Addr, Ipv6Addr};
|
2020-07-14 12:59:59 +00:00
|
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|
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/// if Ok::<i32, i32>(42).is_ok() {}
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/// if Err::<i32, i32>(42).is_err() {}
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/// if None::<()>.is_none() {}
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|
/// if Some(42).is_some() {}
|
2020-11-17 21:34:39 +00:00
|
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/// if Poll::Pending::<()>.is_pending() {}
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/// if Poll::Ready(42).is_ready() {}
|
2020-11-25 01:01:05 +00:00
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/// if IpAddr::V4(Ipv4Addr::LOCALHOST).is_ipv4() {}
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/// if IpAddr::V6(Ipv6Addr::LOCALHOST).is_ipv6() {}
|
2020-07-14 12:59:59 +00:00
|
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|
/// Ok::<i32, i32>(42).is_ok();
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|
/// ```
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|
pub REDUNDANT_PATTERN_MATCHING,
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style,
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"use the proper utility function avoiding an `if let`"
|
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|
|
}
|
|
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|
|
|
|
|
|
|
declare_clippy_lint! {
|
|
|
|
|
/// **What it does:** Checks for `match` or `if let` expressions producing a
|
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|
/// `bool` that could be written using `matches!`
|
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|
///
|
|
|
|
|
/// **Why is this bad?** Readability and needless complexity.
|
|
|
|
|
///
|
2020-11-28 17:58:53 +00:00
|
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|
|
/// **Known problems:** This lint falsely triggers, if there are arms with
|
2020-11-28 21:40:46 +00:00
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|
/// `cfg` attributes that remove an arm evaluating to `false`.
|
2020-07-14 12:59:59 +00:00
|
|
|
|
///
|
|
|
|
|
/// **Example:**
|
|
|
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|
/// ```rust
|
|
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|
|
/// let x = Some(5);
|
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|
|
///
|
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|
|
/// // Bad
|
|
|
|
|
/// let a = match x {
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|
|
/// Some(0) => true,
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/// _ => false,
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/// };
|
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|
///
|
|
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|
|
/// let a = if let Some(0) = x {
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|
|
/// true
|
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|
|
/// } else {
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|
/// false
|
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|
|
/// };
|
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|
|
///
|
|
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|
|
/// // Good
|
|
|
|
|
/// let a = matches!(x, Some(0));
|
|
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|
|
/// ```
|
|
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|
|
pub MATCH_LIKE_MATCHES_MACRO,
|
|
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|
|
style,
|
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|
|
"a match that could be written with the matches! macro"
|
|
|
|
|
}
|
|
|
|
|
|
2020-10-24 15:06:07 +00:00
|
|
|
|
declare_clippy_lint! {
|
|
|
|
|
/// **What it does:** Checks for `match` with identical arm bodies.
|
|
|
|
|
///
|
|
|
|
|
/// **Why is this bad?** This is probably a copy & paste error. If arm bodies
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|
|
/// are the same on purpose, you can factor them
|
|
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|
|
/// [using `|`](https://doc.rust-lang.org/book/patterns.html#multiple-patterns).
|
|
|
|
|
///
|
|
|
|
|
/// **Known problems:** False positive possible with order dependent `match`
|
|
|
|
|
/// (see issue
|
|
|
|
|
/// [#860](https://github.com/rust-lang/rust-clippy/issues/860)).
|
|
|
|
|
///
|
|
|
|
|
/// **Example:**
|
|
|
|
|
/// ```rust,ignore
|
|
|
|
|
/// match foo {
|
|
|
|
|
/// Bar => bar(),
|
|
|
|
|
/// Quz => quz(),
|
|
|
|
|
/// Baz => bar(), // <= oops
|
|
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|
|
/// }
|
|
|
|
|
/// ```
|
|
|
|
|
///
|
|
|
|
|
/// This should probably be
|
|
|
|
|
/// ```rust,ignore
|
|
|
|
|
/// match foo {
|
|
|
|
|
/// Bar => bar(),
|
|
|
|
|
/// Quz => quz(),
|
|
|
|
|
/// Baz => baz(), // <= fixed
|
|
|
|
|
/// }
|
|
|
|
|
/// ```
|
|
|
|
|
///
|
|
|
|
|
/// or if the original code was not a typo:
|
|
|
|
|
/// ```rust,ignore
|
|
|
|
|
/// match foo {
|
|
|
|
|
/// Bar | Baz => bar(), // <= shows the intent better
|
|
|
|
|
/// Quz => quz(),
|
|
|
|
|
/// }
|
|
|
|
|
/// ```
|
|
|
|
|
pub MATCH_SAME_ARMS,
|
|
|
|
|
pedantic,
|
|
|
|
|
"`match` with identical arm bodies"
|
|
|
|
|
}
|
|
|
|
|
|
2020-01-19 10:07:13 +00:00
|
|
|
|
#[derive(Default)]
|
|
|
|
|
pub struct Matches {
|
2020-11-28 14:11:27 +00:00
|
|
|
|
msrv: Option<RustcVersion>,
|
2020-01-19 10:07:13 +00:00
|
|
|
|
infallible_destructuring_match_linted: bool,
|
|
|
|
|
}
|
|
|
|
|
|
2020-10-21 12:47:34 +00:00
|
|
|
|
impl Matches {
|
|
|
|
|
#[must_use]
|
2020-11-28 14:11:27 +00:00
|
|
|
|
pub fn new(msrv: Option<RustcVersion>) -> Self {
|
2020-10-21 12:47:34 +00:00
|
|
|
|
Self {
|
|
|
|
|
msrv,
|
|
|
|
|
..Matches::default()
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
|
2020-01-19 10:07:13 +00:00
|
|
|
|
impl_lint_pass!(Matches => [
|
2019-04-08 20:43:55 +00:00
|
|
|
|
SINGLE_MATCH,
|
|
|
|
|
MATCH_REF_PATS,
|
|
|
|
|
MATCH_BOOL,
|
|
|
|
|
SINGLE_MATCH_ELSE,
|
|
|
|
|
MATCH_OVERLAPPING_ARM,
|
|
|
|
|
MATCH_WILD_ERR_ARM,
|
|
|
|
|
MATCH_AS_REF,
|
2019-12-24 15:42:09 +00:00
|
|
|
|
WILDCARD_ENUM_MATCH_ARM,
|
2020-05-28 13:45:24 +00:00
|
|
|
|
MATCH_WILDCARD_FOR_SINGLE_VARIANTS,
|
2020-01-15 06:56:56 +00:00
|
|
|
|
WILDCARD_IN_OR_PATTERNS,
|
|
|
|
|
MATCH_SINGLE_BINDING,
|
2020-03-01 16:36:14 +00:00
|
|
|
|
INFALLIBLE_DESTRUCTURING_MATCH,
|
2020-07-14 12:59:59 +00:00
|
|
|
|
REST_PAT_IN_FULLY_BOUND_STRUCTS,
|
|
|
|
|
REDUNDANT_PATTERN_MATCHING,
|
2020-10-24 15:06:07 +00:00
|
|
|
|
MATCH_LIKE_MATCHES_MACRO,
|
|
|
|
|
MATCH_SAME_ARMS,
|
2019-04-08 20:43:55 +00:00
|
|
|
|
]);
|
2015-08-21 17:32:21 +00:00
|
|
|
|
|
2020-11-28 14:11:27 +00:00
|
|
|
|
const MATCH_LIKE_MATCHES_MACRO_MSRV: RustcVersion = RustcVersion::new(1, 42, 0);
|
2020-10-21 12:47:34 +00:00
|
|
|
|
|
2020-06-25 20:41:36 +00:00
|
|
|
|
impl<'tcx> LateLintPass<'tcx> for Matches {
|
|
|
|
|
fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
|
2020-09-20 09:38:23 +00:00
|
|
|
|
if in_external_macro(cx.sess(), expr.span) || in_macro(expr.span) {
|
2016-01-04 04:26:12 +00:00
|
|
|
|
return;
|
|
|
|
|
}
|
2020-07-14 12:59:59 +00:00
|
|
|
|
|
|
|
|
|
redundant_pattern_match::check(cx, expr);
|
2020-10-21 12:47:34 +00:00
|
|
|
|
|
|
|
|
|
if meets_msrv(self.msrv.as_ref(), &MATCH_LIKE_MATCHES_MACRO_MSRV) {
|
|
|
|
|
if !check_match_like_matches(cx, expr) {
|
|
|
|
|
lint_match_arms(cx, expr);
|
|
|
|
|
}
|
|
|
|
|
} else {
|
2020-10-24 15:06:07 +00:00
|
|
|
|
lint_match_arms(cx, expr);
|
|
|
|
|
}
|
2020-07-14 12:59:59 +00:00
|
|
|
|
|
2019-09-27 15:16:06 +00:00
|
|
|
|
if let ExprKind::Match(ref ex, ref arms, MatchSource::Normal) = expr.kind {
|
2015-12-23 01:19:32 +00:00
|
|
|
|
check_single_match(cx, ex, arms, expr);
|
|
|
|
|
check_match_bool(cx, ex, arms, expr);
|
2015-12-23 10:25:44 +00:00
|
|
|
|
check_overlapping_arms(cx, ex, arms);
|
2017-02-11 06:57:50 +00:00
|
|
|
|
check_wild_err_arm(cx, ex, arms);
|
2019-01-29 20:25:40 +00:00
|
|
|
|
check_wild_enum_match(cx, ex, arms);
|
2017-12-19 22:22:16 +00:00
|
|
|
|
check_match_as_ref(cx, ex, arms, expr);
|
2020-01-07 17:13:31 +00:00
|
|
|
|
check_wild_in_or_pats(cx, arms);
|
2020-01-19 10:07:13 +00:00
|
|
|
|
|
|
|
|
|
if self.infallible_destructuring_match_linted {
|
|
|
|
|
self.infallible_destructuring_match_linted = false;
|
|
|
|
|
} else {
|
|
|
|
|
check_match_single_binding(cx, ex, arms, expr);
|
|
|
|
|
}
|
2015-12-23 01:19:32 +00:00
|
|
|
|
}
|
2019-09-27 15:16:06 +00:00
|
|
|
|
if let ExprKind::Match(ref ex, ref arms, _) = expr.kind {
|
2018-02-04 12:41:54 +00:00
|
|
|
|
check_match_ref_pats(cx, ex, arms, expr);
|
2015-12-23 01:19:32 +00:00
|
|
|
|
}
|
|
|
|
|
}
|
2020-01-19 10:07:13 +00:00
|
|
|
|
|
2020-06-25 20:41:36 +00:00
|
|
|
|
fn check_local(&mut self, cx: &LateContext<'tcx>, local: &'tcx Local<'_>) {
|
2020-01-19 10:07:13 +00:00
|
|
|
|
if_chain! {
|
2020-03-27 19:36:00 +00:00
|
|
|
|
if !in_external_macro(cx.sess(), local.span);
|
|
|
|
|
if !in_macro(local.span);
|
2020-01-19 10:07:13 +00:00
|
|
|
|
if let Some(ref expr) = local.init;
|
|
|
|
|
if let ExprKind::Match(ref target, ref arms, MatchSource::Normal) = expr.kind;
|
|
|
|
|
if arms.len() == 1 && arms[0].guard.is_none();
|
|
|
|
|
if let PatKind::TupleStruct(
|
|
|
|
|
QPath::Resolved(None, ref variant_name), ref args, _) = arms[0].pat.kind;
|
|
|
|
|
if args.len() == 1;
|
|
|
|
|
if let Some(arg) = get_arg_name(&args[0]);
|
|
|
|
|
let body = remove_blocks(&arms[0].body);
|
|
|
|
|
if match_var(body, arg);
|
|
|
|
|
|
|
|
|
|
then {
|
|
|
|
|
let mut applicability = Applicability::MachineApplicable;
|
|
|
|
|
self.infallible_destructuring_match_linted = true;
|
|
|
|
|
span_lint_and_sugg(
|
|
|
|
|
cx,
|
|
|
|
|
INFALLIBLE_DESTRUCTURING_MATCH,
|
|
|
|
|
local.span,
|
|
|
|
|
"you seem to be trying to use `match` to destructure a single infallible pattern. \
|
|
|
|
|
Consider using `let`",
|
|
|
|
|
"try this",
|
|
|
|
|
format!(
|
|
|
|
|
"let {}({}) = {};",
|
|
|
|
|
snippet_with_applicability(cx, variant_name.span, "..", &mut applicability),
|
|
|
|
|
snippet_with_applicability(cx, local.pat.span, "..", &mut applicability),
|
|
|
|
|
snippet_with_applicability(cx, target.span, "..", &mut applicability),
|
|
|
|
|
),
|
|
|
|
|
applicability,
|
|
|
|
|
);
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
}
|
2020-03-01 16:36:14 +00:00
|
|
|
|
|
2020-06-25 20:41:36 +00:00
|
|
|
|
fn check_pat(&mut self, cx: &LateContext<'tcx>, pat: &'tcx Pat<'_>) {
|
2020-03-01 16:36:14 +00:00
|
|
|
|
if_chain! {
|
2020-03-27 19:36:00 +00:00
|
|
|
|
if !in_external_macro(cx.sess(), pat.span);
|
|
|
|
|
if !in_macro(pat.span);
|
2020-11-25 02:57:09 +00:00
|
|
|
|
if let PatKind::Struct(QPath::Resolved(_, ref path), fields, true) = pat.kind;
|
2020-03-01 16:36:14 +00:00
|
|
|
|
if let Some(def_id) = path.res.opt_def_id();
|
|
|
|
|
let ty = cx.tcx.type_of(def_id);
|
2020-08-03 22:18:29 +00:00
|
|
|
|
if let ty::Adt(def, _) = ty.kind();
|
2020-03-01 16:36:14 +00:00
|
|
|
|
if def.is_struct() || def.is_union();
|
|
|
|
|
if fields.len() == def.non_enum_variant().fields.len();
|
|
|
|
|
|
|
|
|
|
then {
|
|
|
|
|
span_lint_and_help(
|
|
|
|
|
cx,
|
|
|
|
|
REST_PAT_IN_FULLY_BOUND_STRUCTS,
|
|
|
|
|
pat.span,
|
|
|
|
|
"unnecessary use of `..` pattern in struct binding. All fields were already bound",
|
2020-04-18 10:28:29 +00:00
|
|
|
|
None,
|
2020-03-01 16:36:14 +00:00
|
|
|
|
"consider removing `..` from this binding",
|
|
|
|
|
);
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
}
|
2020-10-21 12:47:34 +00:00
|
|
|
|
|
|
|
|
|
extract_msrv_attr!(LateContext);
|
2015-12-23 01:19:32 +00:00
|
|
|
|
}
|
2015-08-21 17:49:00 +00:00
|
|
|
|
|
2018-05-30 16:24:44 +00:00
|
|
|
|
#[rustfmt::skip]
|
2020-06-25 20:41:36 +00:00
|
|
|
|
fn check_single_match(cx: &LateContext<'_>, ex: &Expr<'_>, arms: &[Arm<'_>], expr: &Expr<'_>) {
|
2019-09-25 19:00:17 +00:00
|
|
|
|
if arms.len() == 2 && arms[0].guard.is_none() && arms[1].guard.is_none() {
|
2020-03-31 10:20:15 +00:00
|
|
|
|
if in_macro(expr.span) {
|
|
|
|
|
// Don't lint match expressions present in
|
|
|
|
|
// macro_rules! block
|
|
|
|
|
return;
|
|
|
|
|
}
|
2019-09-27 15:16:06 +00:00
|
|
|
|
if let PatKind::Or(..) = arms[0].pat.kind {
|
2019-09-25 20:34:55 +00:00
|
|
|
|
// don't lint for or patterns for now, this makes
|
|
|
|
|
// the lint noisy in unnecessary situations
|
|
|
|
|
return;
|
|
|
|
|
}
|
2020-07-14 12:59:59 +00:00
|
|
|
|
let els = arms[1].body;
|
|
|
|
|
let els = if is_unit_expr(remove_blocks(els)) {
|
2016-02-24 16:38:57 +00:00
|
|
|
|
None
|
2020-07-14 12:59:59 +00:00
|
|
|
|
} else if let ExprKind::Block(Block { stmts, expr: block_expr, .. }, _) = els.kind {
|
|
|
|
|
if stmts.len() == 1 && block_expr.is_none() || stmts.is_empty() && block_expr.is_some() {
|
|
|
|
|
// single statement/expr "else" block, don't lint
|
|
|
|
|
return;
|
|
|
|
|
}
|
2020-11-13 18:46:37 +00:00
|
|
|
|
// block with 2+ statements or 1 expr and 1+ statement
|
|
|
|
|
Some(els)
|
2016-02-24 16:38:57 +00:00
|
|
|
|
} else {
|
2020-07-14 12:59:59 +00:00
|
|
|
|
// not a block, don't lint
|
2020-11-02 16:32:55 +00:00
|
|
|
|
return;
|
2016-02-24 16:38:57 +00:00
|
|
|
|
};
|
2020-07-14 12:59:59 +00:00
|
|
|
|
|
2020-07-17 08:47:04 +00:00
|
|
|
|
let ty = cx.typeck_results().expr_ty(ex);
|
2020-08-03 22:18:29 +00:00
|
|
|
|
if *ty.kind() != ty::Bool || is_allowed(cx, MATCH_BOOL, ex.hir_id) {
|
2016-02-24 16:38:57 +00:00
|
|
|
|
check_single_match_single_pattern(cx, ex, arms, expr, els);
|
|
|
|
|
check_single_match_opt_like(cx, ex, arms, expr, ty, els);
|
|
|
|
|
}
|
2016-01-13 00:19:27 +00:00
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
|
2018-11-27 20:14:15 +00:00
|
|
|
|
fn check_single_match_single_pattern(
|
2020-06-25 20:41:36 +00:00
|
|
|
|
cx: &LateContext<'_>,
|
2019-12-27 07:12:26 +00:00
|
|
|
|
ex: &Expr<'_>,
|
|
|
|
|
arms: &[Arm<'_>],
|
|
|
|
|
expr: &Expr<'_>,
|
|
|
|
|
els: Option<&Expr<'_>>,
|
2018-11-27 20:14:15 +00:00
|
|
|
|
) {
|
2019-09-25 19:00:17 +00:00
|
|
|
|
if is_wild(&arms[1].pat) {
|
2017-03-03 14:44:23 +00:00
|
|
|
|
report_single_match_single_pattern(cx, ex, arms, expr, els);
|
2015-12-23 01:19:32 +00:00
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
|
2018-11-27 20:14:15 +00:00
|
|
|
|
fn report_single_match_single_pattern(
|
2020-06-25 20:41:36 +00:00
|
|
|
|
cx: &LateContext<'_>,
|
2019-12-27 07:12:26 +00:00
|
|
|
|
ex: &Expr<'_>,
|
|
|
|
|
arms: &[Arm<'_>],
|
|
|
|
|
expr: &Expr<'_>,
|
|
|
|
|
els: Option<&Expr<'_>>,
|
2018-11-27 20:14:15 +00:00
|
|
|
|
) {
|
|
|
|
|
let lint = if els.is_some() { SINGLE_MATCH_ELSE } else { SINGLE_MATCH };
|
|
|
|
|
let els_str = els.map_or(String::new(), |els| {
|
2020-02-04 15:07:09 +00:00
|
|
|
|
format!(" else {}", expr_block(cx, els, None, "..", Some(expr.span)))
|
2018-11-27 20:14:15 +00:00
|
|
|
|
});
|
2021-01-11 04:32:23 +00:00
|
|
|
|
|
|
|
|
|
let (msg, sugg) = if_chain! {
|
2021-01-14 19:26:26 +00:00
|
|
|
|
let (pat, pat_ref_count) = peel_hir_pat_refs(arms[0].pat);
|
2021-01-11 04:32:23 +00:00
|
|
|
|
if let PatKind::Path(_) | PatKind::Lit(_) = pat.kind;
|
2021-01-14 19:26:26 +00:00
|
|
|
|
let (ty, ty_ref_count) = peel_mid_ty_refs(cx.typeck_results().expr_ty(ex));
|
2021-01-11 04:32:23 +00:00
|
|
|
|
if let Some(trait_id) = cx.tcx.lang_items().structural_peq_trait();
|
|
|
|
|
if ty.is_integral() || ty.is_char() || ty.is_str() || implements_trait(cx, ty, trait_id, &[]);
|
|
|
|
|
then {
|
|
|
|
|
// scrutinee derives PartialEq and the pattern is a constant.
|
|
|
|
|
let pat_ref_count = match pat.kind {
|
|
|
|
|
// string literals are already a reference.
|
|
|
|
|
PatKind::Lit(Expr { kind: ExprKind::Lit(lit), .. }) if lit.node.is_str() => pat_ref_count + 1,
|
|
|
|
|
_ => pat_ref_count,
|
|
|
|
|
};
|
2021-01-14 19:26:26 +00:00
|
|
|
|
// References are only implicitly added to the pattern, so no overflow here.
|
|
|
|
|
// e.g. will work: match &Some(_) { Some(_) => () }
|
|
|
|
|
// will not: match Some(_) { &Some(_) => () }
|
|
|
|
|
let ref_count_diff = ty_ref_count - pat_ref_count;
|
|
|
|
|
|
|
|
|
|
// Try to remove address of expressions first.
|
|
|
|
|
let (ex, removed) = peeln_hir_expr_refs(ex, ref_count_diff);
|
|
|
|
|
let ref_count_diff = ref_count_diff - removed;
|
|
|
|
|
|
|
|
|
|
let msg = "you seem to be trying to use `match` for an equality check. Consider using `if`";
|
2021-01-11 04:32:23 +00:00
|
|
|
|
let sugg = format!(
|
|
|
|
|
"if {} == {}{} {}{}",
|
|
|
|
|
snippet(cx, ex.span, ".."),
|
|
|
|
|
// PartialEq for different reference counts may not exist.
|
2021-01-14 19:26:26 +00:00
|
|
|
|
"&".repeat(ref_count_diff),
|
2021-01-11 04:32:23 +00:00
|
|
|
|
snippet(cx, arms[0].pat.span, ".."),
|
|
|
|
|
expr_block(cx, &arms[0].body, None, "..", Some(expr.span)),
|
|
|
|
|
els_str,
|
|
|
|
|
);
|
|
|
|
|
(msg, sugg)
|
|
|
|
|
} else {
|
2021-01-14 19:26:26 +00:00
|
|
|
|
let msg = "you seem to be trying to use `match` for destructuring a single pattern. Consider using `if let`";
|
2021-01-11 04:32:23 +00:00
|
|
|
|
let sugg = format!(
|
|
|
|
|
"if let {} = {} {}{}",
|
|
|
|
|
snippet(cx, arms[0].pat.span, ".."),
|
|
|
|
|
snippet(cx, ex.span, ".."),
|
|
|
|
|
expr_block(cx, &arms[0].body, None, "..", Some(expr.span)),
|
|
|
|
|
els_str,
|
|
|
|
|
);
|
|
|
|
|
(msg, sugg)
|
|
|
|
|
}
|
|
|
|
|
};
|
|
|
|
|
|
2017-08-09 07:30:56 +00:00
|
|
|
|
span_lint_and_sugg(
|
|
|
|
|
cx,
|
|
|
|
|
lint,
|
|
|
|
|
expr.span,
|
2021-01-11 04:32:23 +00:00
|
|
|
|
msg,
|
2017-08-09 07:30:56 +00:00
|
|
|
|
"try this",
|
2021-01-11 04:32:23 +00:00
|
|
|
|
sugg,
|
2018-11-27 14:13:57 +00:00
|
|
|
|
Applicability::HasPlaceholders,
|
2017-08-09 07:30:56 +00:00
|
|
|
|
);
|
2017-03-03 14:44:23 +00:00
|
|
|
|
}
|
|
|
|
|
|
2018-11-27 20:14:15 +00:00
|
|
|
|
fn check_single_match_opt_like(
|
2020-06-25 20:41:36 +00:00
|
|
|
|
cx: &LateContext<'_>,
|
2019-12-27 07:12:26 +00:00
|
|
|
|
ex: &Expr<'_>,
|
|
|
|
|
arms: &[Arm<'_>],
|
|
|
|
|
expr: &Expr<'_>,
|
2018-11-27 20:14:15 +00:00
|
|
|
|
ty: Ty<'_>,
|
2019-12-27 07:12:26 +00:00
|
|
|
|
els: Option<&Expr<'_>>,
|
2018-11-27 20:14:15 +00:00
|
|
|
|
) {
|
2019-03-10 17:19:47 +00:00
|
|
|
|
// list of candidate `Enum`s we know will never get any more members
|
2017-08-09 07:30:56 +00:00
|
|
|
|
let candidates = &[
|
2019-05-17 21:53:54 +00:00
|
|
|
|
(&paths::COW, "Borrowed"),
|
|
|
|
|
(&paths::COW, "Cow::Borrowed"),
|
|
|
|
|
(&paths::COW, "Cow::Owned"),
|
|
|
|
|
(&paths::COW, "Owned"),
|
|
|
|
|
(&paths::OPTION, "None"),
|
|
|
|
|
(&paths::RESULT, "Err"),
|
|
|
|
|
(&paths::RESULT, "Ok"),
|
2017-08-09 07:30:56 +00:00
|
|
|
|
];
|
2016-01-13 00:19:27 +00:00
|
|
|
|
|
2019-09-27 15:16:06 +00:00
|
|
|
|
let path = match arms[1].pat.kind {
|
2016-05-27 12:24:28 +00:00
|
|
|
|
PatKind::TupleStruct(ref path, ref inner, _) => {
|
2019-03-10 17:19:47 +00:00
|
|
|
|
// Contains any non wildcard patterns (e.g., `Err(err)`)?
|
2018-07-14 22:00:27 +00:00
|
|
|
|
if !inner.iter().all(is_wild) {
|
2016-01-24 11:24:16 +00:00
|
|
|
|
return;
|
|
|
|
|
}
|
2020-03-27 14:34:29 +00:00
|
|
|
|
rustc_hir_pretty::to_string(rustc_hir_pretty::NO_ANN, |s| s.print_qpath(path, false))
|
2016-12-20 17:21:30 +00:00
|
|
|
|
},
|
2019-02-03 07:12:07 +00:00
|
|
|
|
PatKind::Binding(BindingAnnotation::Unannotated, .., ident, None) => ident.to_string(),
|
2020-03-27 14:34:29 +00:00
|
|
|
|
PatKind::Path(ref path) => {
|
|
|
|
|
rustc_hir_pretty::to_string(rustc_hir_pretty::NO_ANN, |s| s.print_qpath(path, false))
|
|
|
|
|
},
|
2016-01-30 12:48:39 +00:00
|
|
|
|
_ => return,
|
2016-01-13 00:19:27 +00:00
|
|
|
|
};
|
|
|
|
|
|
|
|
|
|
for &(ty_path, pat_path) in candidates {
|
2017-03-09 09:58:31 +00:00
|
|
|
|
if path == *pat_path && match_type(cx, ty, ty_path) {
|
2017-03-03 14:44:23 +00:00
|
|
|
|
report_single_match_single_pattern(cx, ex, arms, expr, els);
|
2016-01-13 00:19:27 +00:00
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
|
2020-06-25 20:41:36 +00:00
|
|
|
|
fn check_match_bool(cx: &LateContext<'_>, ex: &Expr<'_>, arms: &[Arm<'_>], expr: &Expr<'_>) {
|
2019-03-10 17:19:47 +00:00
|
|
|
|
// Type of expression is `bool`.
|
2020-08-03 22:18:29 +00:00
|
|
|
|
if *cx.typeck_results().expr_ty(ex).kind() == ty::Bool {
|
2017-08-09 07:30:56 +00:00
|
|
|
|
span_lint_and_then(
|
|
|
|
|
cx,
|
|
|
|
|
MATCH_BOOL,
|
|
|
|
|
expr.span,
|
|
|
|
|
"you seem to be trying to match on a boolean expression",
|
2020-04-17 06:08:00 +00:00
|
|
|
|
move |diag| {
|
2019-09-25 19:00:17 +00:00
|
|
|
|
if arms.len() == 2 {
|
2017-08-09 07:30:56 +00:00
|
|
|
|
// no guards
|
2019-09-27 15:16:06 +00:00
|
|
|
|
let exprs = if let PatKind::Lit(ref arm_bool) = arms[0].pat.kind {
|
|
|
|
|
if let ExprKind::Lit(ref lit) = arm_bool.kind {
|
2017-08-09 07:30:56 +00:00
|
|
|
|
match lit.node {
|
|
|
|
|
LitKind::Bool(true) => Some((&*arms[0].body, &*arms[1].body)),
|
|
|
|
|
LitKind::Bool(false) => Some((&*arms[1].body, &*arms[0].body)),
|
|
|
|
|
_ => None,
|
|
|
|
|
}
|
|
|
|
|
} else {
|
|
|
|
|
None
|
2016-07-03 17:13:01 +00:00
|
|
|
|
}
|
|
|
|
|
} else {
|
|
|
|
|
None
|
|
|
|
|
};
|
|
|
|
|
|
2017-08-09 07:30:56 +00:00
|
|
|
|
if let Some((true_expr, false_expr)) = exprs {
|
|
|
|
|
let sugg = match (is_unit_expr(true_expr), is_unit_expr(false_expr)) {
|
2017-09-05 09:33:04 +00:00
|
|
|
|
(false, false) => Some(format!(
|
|
|
|
|
"if {} {} else {}",
|
|
|
|
|
snippet(cx, ex.span, "b"),
|
2020-02-04 15:07:09 +00:00
|
|
|
|
expr_block(cx, true_expr, None, "..", Some(expr.span)),
|
|
|
|
|
expr_block(cx, false_expr, None, "..", Some(expr.span))
|
2017-09-05 09:33:04 +00:00
|
|
|
|
)),
|
|
|
|
|
(false, true) => Some(format!(
|
|
|
|
|
"if {} {}",
|
|
|
|
|
snippet(cx, ex.span, "b"),
|
2020-02-04 15:07:09 +00:00
|
|
|
|
expr_block(cx, true_expr, None, "..", Some(expr.span))
|
2017-09-05 09:33:04 +00:00
|
|
|
|
)),
|
2017-08-09 07:30:56 +00:00
|
|
|
|
(true, false) => {
|
|
|
|
|
let test = Sugg::hir(cx, ex, "..");
|
2020-02-04 15:07:09 +00:00
|
|
|
|
Some(format!(
|
|
|
|
|
"if {} {}",
|
|
|
|
|
!test,
|
|
|
|
|
expr_block(cx, false_expr, None, "..", Some(expr.span))
|
|
|
|
|
))
|
2017-08-09 07:30:56 +00:00
|
|
|
|
},
|
|
|
|
|
(true, true) => None,
|
|
|
|
|
};
|
|
|
|
|
|
|
|
|
|
if let Some(sugg) = sugg {
|
2020-04-17 06:08:00 +00:00
|
|
|
|
diag.span_suggestion(
|
2018-09-18 15:07:54 +00:00
|
|
|
|
expr.span,
|
2020-01-06 06:30:43 +00:00
|
|
|
|
"consider using an `if`/`else` expression",
|
2018-09-18 15:07:54 +00:00
|
|
|
|
sugg,
|
2018-09-18 19:43:52 +00:00
|
|
|
|
Applicability::HasPlaceholders,
|
2018-09-18 15:07:54 +00:00
|
|
|
|
);
|
2017-08-09 07:30:56 +00:00
|
|
|
|
}
|
2016-04-14 18:14:03 +00:00
|
|
|
|
}
|
2015-10-21 06:24:56 +00:00
|
|
|
|
}
|
2017-08-09 07:30:56 +00:00
|
|
|
|
},
|
|
|
|
|
);
|
2015-12-23 01:19:32 +00:00
|
|
|
|
}
|
|
|
|
|
}
|
2015-12-23 00:14:10 +00:00
|
|
|
|
|
2020-06-25 20:41:36 +00:00
|
|
|
|
fn check_overlapping_arms<'tcx>(cx: &LateContext<'tcx>, ex: &'tcx Expr<'_>, arms: &'tcx [Arm<'_>]) {
|
2020-07-17 08:47:04 +00:00
|
|
|
|
if arms.len() >= 2 && cx.typeck_results().expr_ty(ex).is_integral() {
|
|
|
|
|
let ranges = all_ranges(cx, arms, cx.typeck_results().expr_ty(ex));
|
2016-03-15 19:09:53 +00:00
|
|
|
|
let type_ranges = type_ranges(&ranges);
|
|
|
|
|
if !type_ranges.is_empty() {
|
|
|
|
|
if let Some((start, end)) = overlapping(&type_ranges) {
|
2020-01-27 02:26:42 +00:00
|
|
|
|
span_lint_and_note(
|
2017-08-09 07:30:56 +00:00
|
|
|
|
cx,
|
|
|
|
|
MATCH_OVERLAPPING_ARM,
|
|
|
|
|
start.span,
|
|
|
|
|
"some ranges overlap",
|
2020-04-18 10:29:36 +00:00
|
|
|
|
Some(end.span),
|
2017-08-09 07:30:56 +00:00
|
|
|
|
"overlaps with this",
|
|
|
|
|
);
|
2016-03-15 19:09:53 +00:00
|
|
|
|
}
|
2015-08-21 17:32:21 +00:00
|
|
|
|
}
|
2015-12-23 01:19:32 +00:00
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
|
2020-06-25 20:41:36 +00:00
|
|
|
|
fn check_wild_err_arm(cx: &LateContext<'_>, ex: &Expr<'_>, arms: &[Arm<'_>]) {
|
2020-09-11 03:06:49 +00:00
|
|
|
|
let ex_ty = cx.typeck_results().expr_ty(ex).peel_refs();
|
2020-11-02 16:32:55 +00:00
|
|
|
|
if is_type_diagnostic_item(cx, ex_ty, sym::result_type) {
|
2017-02-11 06:57:50 +00:00
|
|
|
|
for arm in arms {
|
2019-09-27 15:16:06 +00:00
|
|
|
|
if let PatKind::TupleStruct(ref path, ref inner, _) = arm.pat.kind {
|
2020-03-27 14:34:29 +00:00
|
|
|
|
let path_str = rustc_hir_pretty::to_string(rustc_hir_pretty::NO_ANN, |s| s.print_qpath(path, false));
|
2020-01-10 09:56:09 +00:00
|
|
|
|
if path_str == "Err" {
|
|
|
|
|
let mut matching_wild = inner.iter().any(is_wild);
|
|
|
|
|
let mut ident_bind_name = String::from("_");
|
|
|
|
|
if !matching_wild {
|
|
|
|
|
// Looking for unused bindings (i.e.: `_e`)
|
|
|
|
|
inner.iter().for_each(|pat| {
|
|
|
|
|
if let PatKind::Binding(.., ident, None) = &pat.kind {
|
|
|
|
|
if ident.as_str().starts_with('_') && is_unused(ident, arm.body) {
|
|
|
|
|
ident_bind_name = (&ident.name.as_str()).to_string();
|
|
|
|
|
matching_wild = true;
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
});
|
|
|
|
|
}
|
|
|
|
|
if_chain! {
|
|
|
|
|
if matching_wild;
|
|
|
|
|
if let ExprKind::Block(ref block, _) = arm.body.kind;
|
|
|
|
|
if is_panic_block(block);
|
|
|
|
|
then {
|
|
|
|
|
// `Err(_)` or `Err(_e)` arm with `panic!` found
|
2020-01-27 02:26:42 +00:00
|
|
|
|
span_lint_and_note(cx,
|
2020-01-10 14:09:37 +00:00
|
|
|
|
MATCH_WILD_ERR_ARM,
|
|
|
|
|
arm.pat.span,
|
2020-01-10 14:12:21 +00:00
|
|
|
|
&format!("`Err({})` matches all errors", &ident_bind_name),
|
2020-04-18 10:29:36 +00:00
|
|
|
|
None,
|
2020-05-28 13:45:24 +00:00
|
|
|
|
"match each error separately or use the error output, or use `.except(msg)` if the error case is unreachable",
|
2020-01-10 14:09:37 +00:00
|
|
|
|
);
|
2020-01-10 09:56:09 +00:00
|
|
|
|
}
|
2017-10-23 19:18:02 +00:00
|
|
|
|
}
|
|
|
|
|
}
|
2017-02-11 06:57:50 +00:00
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
|
2020-06-25 20:41:36 +00:00
|
|
|
|
fn check_wild_enum_match(cx: &LateContext<'_>, ex: &Expr<'_>, arms: &[Arm<'_>]) {
|
2020-07-17 08:47:04 +00:00
|
|
|
|
let ty = cx.typeck_results().expr_ty(ex);
|
2019-01-31 22:01:23 +00:00
|
|
|
|
if !ty.is_enum() {
|
|
|
|
|
// If there isn't a nice closed set of possible values that can be conveniently enumerated,
|
|
|
|
|
// don't complain about not enumerating the mall.
|
|
|
|
|
return;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
// First pass - check for violation, but don't do much book-keeping because this is hopefully
|
|
|
|
|
// the uncommon case, and the book-keeping is slightly expensive.
|
|
|
|
|
let mut wildcard_span = None;
|
|
|
|
|
let mut wildcard_ident = None;
|
|
|
|
|
for arm in arms {
|
2019-09-27 15:16:06 +00:00
|
|
|
|
if let PatKind::Wild = arm.pat.kind {
|
2019-09-25 19:00:17 +00:00
|
|
|
|
wildcard_span = Some(arm.pat.span);
|
2019-09-27 15:16:06 +00:00
|
|
|
|
} else if let PatKind::Binding(_, _, ident, None) = arm.pat.kind {
|
2019-09-25 19:00:17 +00:00
|
|
|
|
wildcard_span = Some(arm.pat.span);
|
|
|
|
|
wildcard_ident = Some(ident);
|
2019-01-31 22:01:23 +00:00
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
if let Some(wildcard_span) = wildcard_span {
|
|
|
|
|
// Accumulate the variants which should be put in place of the wildcard because they're not
|
|
|
|
|
// already covered.
|
|
|
|
|
|
|
|
|
|
let mut missing_variants = vec![];
|
2020-08-03 22:18:29 +00:00
|
|
|
|
if let ty::Adt(def, _) = ty.kind() {
|
2019-01-31 22:01:23 +00:00
|
|
|
|
for variant in &def.variants {
|
|
|
|
|
missing_variants.push(variant);
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
|
2019-01-29 20:25:40 +00:00
|
|
|
|
for arm in arms {
|
2019-01-31 22:01:23 +00:00
|
|
|
|
if arm.guard.is_some() {
|
|
|
|
|
// Guards mean that this case probably isn't exhaustively covered. Technically
|
|
|
|
|
// this is incorrect, as we should really check whether each variant is exhaustively
|
|
|
|
|
// covered by the set of guards that cover it, but that's really hard to do.
|
|
|
|
|
continue;
|
|
|
|
|
}
|
2019-09-27 15:16:06 +00:00
|
|
|
|
if let PatKind::Path(ref path) = arm.pat.kind {
|
2019-09-25 19:00:17 +00:00
|
|
|
|
if let QPath::Resolved(_, p) = path {
|
|
|
|
|
missing_variants.retain(|e| e.ctor_def_id != Some(p.res.def_id()));
|
|
|
|
|
}
|
2020-11-25 02:57:09 +00:00
|
|
|
|
} else if let PatKind::TupleStruct(QPath::Resolved(_, p), ref patterns, ..) = arm.pat.kind {
|
|
|
|
|
// Some simple checks for exhaustive patterns.
|
|
|
|
|
// There is a room for improvements to detect more cases,
|
|
|
|
|
// but it can be more expensive to do so.
|
|
|
|
|
let is_pattern_exhaustive =
|
|
|
|
|
|pat: &&Pat<'_>| matches!(pat.kind, PatKind::Wild | PatKind::Binding(.., None));
|
|
|
|
|
if patterns.iter().all(is_pattern_exhaustive) {
|
|
|
|
|
missing_variants.retain(|e| e.ctor_def_id != Some(p.res.def_id()));
|
2019-01-31 22:01:23 +00:00
|
|
|
|
}
|
2019-01-29 20:25:40 +00:00
|
|
|
|
}
|
2019-01-10 20:56:28 +00:00
|
|
|
|
}
|
2019-01-31 22:01:23 +00:00
|
|
|
|
|
2019-12-22 02:13:39 +00:00
|
|
|
|
let mut suggestion: Vec<String> = missing_variants
|
2019-01-31 22:01:23 +00:00
|
|
|
|
.iter()
|
|
|
|
|
.map(|v| {
|
|
|
|
|
let suffix = match v.ctor_kind {
|
|
|
|
|
CtorKind::Fn => "(..)",
|
|
|
|
|
CtorKind::Const | CtorKind::Fictive => "",
|
|
|
|
|
};
|
|
|
|
|
let ident_str = if let Some(ident) = wildcard_ident {
|
|
|
|
|
format!("{} @ ", ident.name)
|
|
|
|
|
} else {
|
|
|
|
|
String::new()
|
|
|
|
|
};
|
|
|
|
|
// This path assumes that the enum type is imported into scope.
|
2019-03-26 09:55:03 +00:00
|
|
|
|
format!("{}{}{}", ident_str, cx.tcx.def_path_str(v.def_id), suffix)
|
2019-01-31 22:01:23 +00:00
|
|
|
|
})
|
|
|
|
|
.collect();
|
|
|
|
|
|
2019-02-18 22:55:16 +00:00
|
|
|
|
if suggestion.is_empty() {
|
|
|
|
|
return;
|
|
|
|
|
}
|
|
|
|
|
|
2019-12-22 11:51:39 +00:00
|
|
|
|
let mut message = "wildcard match will miss any future added variants";
|
2019-12-22 02:13:39 +00:00
|
|
|
|
|
2020-08-03 22:18:29 +00:00
|
|
|
|
if let ty::Adt(def, _) = ty.kind() {
|
2019-12-22 02:13:39 +00:00
|
|
|
|
if def.is_variant_list_non_exhaustive() {
|
2019-12-22 11:51:39 +00:00
|
|
|
|
message = "match on non-exhaustive enum doesn't explicitly match all known variants";
|
2019-12-22 02:13:39 +00:00
|
|
|
|
suggestion.push(String::from("_"));
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
|
2020-05-28 13:45:24 +00:00
|
|
|
|
if suggestion.len() == 1 {
|
|
|
|
|
// No need to check for non-exhaustive enum as in that case len would be greater than 1
|
|
|
|
|
span_lint_and_sugg(
|
|
|
|
|
cx,
|
|
|
|
|
MATCH_WILDCARD_FOR_SINGLE_VARIANTS,
|
|
|
|
|
wildcard_span,
|
|
|
|
|
message,
|
|
|
|
|
"try this",
|
|
|
|
|
suggestion[0].clone(),
|
|
|
|
|
Applicability::MaybeIncorrect,
|
|
|
|
|
)
|
|
|
|
|
};
|
|
|
|
|
|
2019-01-31 22:01:23 +00:00
|
|
|
|
span_lint_and_sugg(
|
|
|
|
|
cx,
|
|
|
|
|
WILDCARD_ENUM_MATCH_ARM,
|
|
|
|
|
wildcard_span,
|
2019-12-22 02:13:39 +00:00
|
|
|
|
message,
|
2019-01-31 22:01:23 +00:00
|
|
|
|
"try this",
|
|
|
|
|
suggestion.join(" | "),
|
2020-05-28 13:45:24 +00:00
|
|
|
|
Applicability::MaybeIncorrect,
|
2019-01-31 22:01:23 +00:00
|
|
|
|
)
|
2019-01-10 20:56:28 +00:00
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
|
2017-02-11 13:42:42 +00:00
|
|
|
|
// If the block contains only a `panic!` macro (as expression or statement)
|
2019-12-27 07:12:26 +00:00
|
|
|
|
fn is_panic_block(block: &Block<'_>) -> bool {
|
2017-02-11 06:57:50 +00:00
|
|
|
|
match (&block.expr, block.stmts.len(), block.stmts.first()) {
|
2017-02-11 13:47:26 +00:00
|
|
|
|
(&Some(ref exp), 0, _) => {
|
2019-05-17 21:53:54 +00:00
|
|
|
|
is_expn_of(exp.span, "panic").is_some() && is_expn_of(exp.span, "unreachable").is_none()
|
2017-02-11 13:47:26 +00:00
|
|
|
|
},
|
2017-02-12 01:16:37 +00:00
|
|
|
|
(&None, 1, Some(stmt)) => {
|
2019-05-17 21:53:54 +00:00
|
|
|
|
is_expn_of(stmt.span, "panic").is_some() && is_expn_of(stmt.span, "unreachable").is_none()
|
2017-02-11 13:47:26 +00:00
|
|
|
|
},
|
|
|
|
|
_ => false,
|
2017-02-11 06:57:50 +00:00
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
|
2020-06-25 20:41:36 +00:00
|
|
|
|
fn check_match_ref_pats(cx: &LateContext<'_>, ex: &Expr<'_>, arms: &[Arm<'_>], expr: &Expr<'_>) {
|
2015-12-23 01:19:32 +00:00
|
|
|
|
if has_only_ref_pats(arms) {
|
2020-02-18 11:50:10 +00:00
|
|
|
|
let mut suggs = Vec::with_capacity(arms.len() + 1);
|
2019-12-21 18:38:45 +00:00
|
|
|
|
let (title, msg) = if let ExprKind::AddrOf(BorrowKind::Ref, Mutability::Not, ref inner) = ex.kind {
|
2019-02-16 18:35:15 +00:00
|
|
|
|
let span = ex.span.source_callsite();
|
|
|
|
|
suggs.push((span, Sugg::hir_with_macro_callsite(cx, inner, "..").to_string()));
|
2018-02-04 12:41:54 +00:00
|
|
|
|
(
|
2017-09-05 09:33:04 +00:00
|
|
|
|
"you don't need to add `&` to both the expression and the patterns",
|
2018-02-04 12:41:54 +00:00
|
|
|
|
"try",
|
|
|
|
|
)
|
2015-12-23 01:19:32 +00:00
|
|
|
|
} else {
|
2019-02-16 18:35:15 +00:00
|
|
|
|
let span = ex.span.source_callsite();
|
|
|
|
|
suggs.push((span, Sugg::hir_with_macro_callsite(cx, ex, "..").deref().to_string()));
|
2018-02-04 12:41:54 +00:00
|
|
|
|
(
|
2017-08-09 07:30:56 +00:00
|
|
|
|
"you don't need to add `&` to all patterns",
|
2018-02-04 12:41:54 +00:00
|
|
|
|
"instead of prefixing all patterns with `&`, you can dereference the expression",
|
|
|
|
|
)
|
|
|
|
|
};
|
|
|
|
|
|
2019-09-25 19:00:17 +00:00
|
|
|
|
suggs.extend(arms.iter().filter_map(|a| {
|
2019-09-27 15:16:06 +00:00
|
|
|
|
if let PatKind::Ref(ref refp, _) = a.pat.kind {
|
2019-09-25 19:00:17 +00:00
|
|
|
|
Some((a.pat.span, snippet(cx, refp.span, "..").to_string()))
|
2018-02-04 12:41:54 +00:00
|
|
|
|
} else {
|
|
|
|
|
None
|
|
|
|
|
}
|
|
|
|
|
}));
|
|
|
|
|
|
2020-04-17 06:08:00 +00:00
|
|
|
|
span_lint_and_then(cx, MATCH_REF_PATS, expr.span, title, |diag| {
|
2019-08-19 16:30:32 +00:00
|
|
|
|
if !expr.span.from_expansion() {
|
2020-05-17 15:36:26 +00:00
|
|
|
|
multispan_sugg(diag, msg, suggs);
|
2018-11-15 16:03:17 +00:00
|
|
|
|
}
|
2018-02-04 12:41:54 +00:00
|
|
|
|
});
|
2015-08-21 17:32:21 +00:00
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
|
2020-06-25 20:41:36 +00:00
|
|
|
|
fn check_match_as_ref(cx: &LateContext<'_>, ex: &Expr<'_>, arms: &[Arm<'_>], expr: &Expr<'_>) {
|
2019-09-25 19:00:17 +00:00
|
|
|
|
if arms.len() == 2 && arms[0].guard.is_none() && arms[1].guard.is_none() {
|
2017-12-20 09:39:48 +00:00
|
|
|
|
let arm_ref: Option<BindingAnnotation> = if is_none_arm(&arms[0]) {
|
|
|
|
|
is_ref_some_arm(&arms[1])
|
|
|
|
|
} else if is_none_arm(&arms[1]) {
|
|
|
|
|
is_ref_some_arm(&arms[0])
|
|
|
|
|
} else {
|
|
|
|
|
None
|
|
|
|
|
};
|
|
|
|
|
if let Some(rb) = arm_ref {
|
2018-11-27 20:14:15 +00:00
|
|
|
|
let suggestion = if rb == BindingAnnotation::Ref {
|
|
|
|
|
"as_ref"
|
|
|
|
|
} else {
|
|
|
|
|
"as_mut"
|
|
|
|
|
};
|
2019-08-25 05:10:45 +00:00
|
|
|
|
|
2020-07-17 08:47:04 +00:00
|
|
|
|
let output_ty = cx.typeck_results().expr_ty(expr);
|
|
|
|
|
let input_ty = cx.typeck_results().expr_ty(ex);
|
2019-08-25 05:10:45 +00:00
|
|
|
|
|
|
|
|
|
let cast = if_chain! {
|
2020-08-03 22:18:29 +00:00
|
|
|
|
if let ty::Adt(_, substs) = input_ty.kind();
|
2019-08-25 05:10:45 +00:00
|
|
|
|
let input_ty = substs.type_at(0);
|
2020-08-03 22:18:29 +00:00
|
|
|
|
if let ty::Adt(_, substs) = output_ty.kind();
|
2019-08-25 05:10:45 +00:00
|
|
|
|
let output_ty = substs.type_at(0);
|
2020-08-03 22:18:29 +00:00
|
|
|
|
if let ty::Ref(_, output_ty, _) = *output_ty.kind();
|
2019-08-25 05:10:45 +00:00
|
|
|
|
if input_ty != output_ty;
|
|
|
|
|
then {
|
|
|
|
|
".map(|x| x as _)"
|
|
|
|
|
} else {
|
|
|
|
|
""
|
|
|
|
|
}
|
|
|
|
|
};
|
|
|
|
|
|
2018-11-27 14:13:57 +00:00
|
|
|
|
let mut applicability = Applicability::MachineApplicable;
|
2017-12-19 22:22:16 +00:00
|
|
|
|
span_lint_and_sugg(
|
|
|
|
|
cx,
|
|
|
|
|
MATCH_AS_REF,
|
|
|
|
|
expr.span,
|
2020-01-06 06:30:43 +00:00
|
|
|
|
&format!("use `{}()` instead", suggestion),
|
2017-12-19 22:22:16 +00:00
|
|
|
|
"try this",
|
2018-11-27 20:14:15 +00:00
|
|
|
|
format!(
|
2019-08-25 05:10:45 +00:00
|
|
|
|
"{}.{}(){}",
|
2018-11-27 20:14:15 +00:00
|
|
|
|
snippet_with_applicability(cx, ex.span, "_", &mut applicability),
|
2019-08-25 05:10:45 +00:00
|
|
|
|
suggestion,
|
|
|
|
|
cast,
|
2018-11-27 20:14:15 +00:00
|
|
|
|
),
|
2018-11-27 14:13:57 +00:00
|
|
|
|
applicability,
|
2017-12-19 22:22:16 +00:00
|
|
|
|
)
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
|
2020-06-25 20:41:36 +00:00
|
|
|
|
fn check_wild_in_or_pats(cx: &LateContext<'_>, arms: &[Arm<'_>]) {
|
2019-12-24 15:42:09 +00:00
|
|
|
|
for arm in arms {
|
|
|
|
|
if let PatKind::Or(ref fields) = arm.pat.kind {
|
2020-01-02 19:00:27 +00:00
|
|
|
|
// look for multiple fields in this arm that contains at least one Wild pattern
|
|
|
|
|
if fields.len() > 1 && fields.iter().any(is_wild) {
|
2020-01-27 01:56:22 +00:00
|
|
|
|
span_lint_and_help(
|
2019-12-24 15:42:09 +00:00
|
|
|
|
cx,
|
2020-01-05 14:05:16 +00:00
|
|
|
|
WILDCARD_IN_OR_PATTERNS,
|
2019-12-24 15:42:09 +00:00
|
|
|
|
arm.pat.span,
|
2020-01-02 19:00:27 +00:00
|
|
|
|
"wildcard pattern covers any other pattern as it will match anyway.",
|
2020-04-18 10:28:29 +00:00
|
|
|
|
None,
|
2020-01-07 17:13:31 +00:00
|
|
|
|
"Consider handling `_` separately.",
|
2020-01-02 19:00:27 +00:00
|
|
|
|
);
|
2019-12-24 15:42:09 +00:00
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
|
2020-07-14 12:59:59 +00:00
|
|
|
|
/// Lint a `match` or `if let .. { .. } else { .. }` expr that could be replaced by `matches!`
|
2020-10-24 15:06:07 +00:00
|
|
|
|
fn check_match_like_matches<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) -> bool {
|
2020-07-14 12:59:59 +00:00
|
|
|
|
if let ExprKind::Match(ex, arms, ref match_source) = &expr.kind {
|
|
|
|
|
match match_source {
|
|
|
|
|
MatchSource::Normal => find_matches_sugg(cx, ex, arms, expr, false),
|
|
|
|
|
MatchSource::IfLetDesugar { .. } => find_matches_sugg(cx, ex, arms, expr, true),
|
2020-10-24 15:06:07 +00:00
|
|
|
|
_ => false,
|
2020-07-14 12:59:59 +00:00
|
|
|
|
}
|
2020-10-24 15:06:07 +00:00
|
|
|
|
} else {
|
|
|
|
|
false
|
2020-07-14 12:59:59 +00:00
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
/// Lint a `match` or desugared `if let` for replacement by `matches!`
|
2020-10-24 15:06:07 +00:00
|
|
|
|
fn find_matches_sugg(cx: &LateContext<'_>, ex: &Expr<'_>, arms: &[Arm<'_>], expr: &Expr<'_>, desugared: bool) -> bool {
|
2020-07-14 12:59:59 +00:00
|
|
|
|
if_chain! {
|
2020-10-24 15:06:07 +00:00
|
|
|
|
if arms.len() >= 2;
|
2020-07-17 08:47:04 +00:00
|
|
|
|
if cx.typeck_results().expr_ty(expr).is_bool();
|
2020-10-24 15:06:07 +00:00
|
|
|
|
if let Some((b1_arm, b0_arms)) = arms.split_last();
|
|
|
|
|
if let Some(b0) = find_bool_lit(&b0_arms[0].body.kind, desugared);
|
|
|
|
|
if let Some(b1) = find_bool_lit(&b1_arm.body.kind, desugared);
|
|
|
|
|
if is_wild(&b1_arm.pat);
|
|
|
|
|
if b0 != b1;
|
|
|
|
|
let if_guard = &b0_arms[0].guard;
|
|
|
|
|
if if_guard.is_none() || b0_arms.len() == 1;
|
2020-11-04 18:16:25 +00:00
|
|
|
|
if b0_arms[0].attrs.is_empty();
|
2020-10-24 15:06:07 +00:00
|
|
|
|
if b0_arms[1..].iter()
|
|
|
|
|
.all(|arm| {
|
|
|
|
|
find_bool_lit(&arm.body.kind, desugared).map_or(false, |b| b == b0) &&
|
2020-11-04 18:16:25 +00:00
|
|
|
|
arm.guard.is_none() && arm.attrs.is_empty()
|
2020-10-24 15:06:07 +00:00
|
|
|
|
});
|
2020-07-14 12:59:59 +00:00
|
|
|
|
then {
|
2020-11-04 18:16:25 +00:00
|
|
|
|
// The suggestion may be incorrect, because some arms can have `cfg` attributes
|
|
|
|
|
// evaluated into `false` and so such arms will be stripped before.
|
|
|
|
|
let mut applicability = Applicability::MaybeIncorrect;
|
2020-10-24 15:06:07 +00:00
|
|
|
|
let pat = {
|
|
|
|
|
use itertools::Itertools as _;
|
|
|
|
|
b0_arms.iter()
|
|
|
|
|
.map(|arm| snippet_with_applicability(cx, arm.pat.span, "..", &mut applicability))
|
|
|
|
|
.join(" | ")
|
|
|
|
|
};
|
|
|
|
|
let pat_and_guard = if let Some(Guard::If(g)) = if_guard {
|
|
|
|
|
format!("{} if {}", pat, snippet_with_applicability(cx, g.span, "..", &mut applicability))
|
2020-07-14 12:59:59 +00:00
|
|
|
|
} else {
|
2020-10-24 15:06:07 +00:00
|
|
|
|
pat
|
2020-07-14 12:59:59 +00:00
|
|
|
|
};
|
|
|
|
|
span_lint_and_sugg(
|
|
|
|
|
cx,
|
|
|
|
|
MATCH_LIKE_MATCHES_MACRO,
|
|
|
|
|
expr.span,
|
|
|
|
|
&format!("{} expression looks like `matches!` macro", if desugared { "if let .. else" } else { "match" }),
|
|
|
|
|
"try this",
|
|
|
|
|
format!(
|
|
|
|
|
"{}matches!({}, {})",
|
2020-10-24 15:06:07 +00:00
|
|
|
|
if b0 { "" } else { "!" },
|
2020-07-14 12:59:59 +00:00
|
|
|
|
snippet_with_applicability(cx, ex.span, "..", &mut applicability),
|
|
|
|
|
pat_and_guard,
|
|
|
|
|
),
|
|
|
|
|
applicability,
|
2020-10-24 15:06:07 +00:00
|
|
|
|
);
|
|
|
|
|
true
|
|
|
|
|
} else {
|
|
|
|
|
false
|
2020-07-14 12:59:59 +00:00
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
/// Extract a `bool` or `{ bool }`
|
|
|
|
|
fn find_bool_lit(ex: &ExprKind<'_>, desugared: bool) -> Option<bool> {
|
|
|
|
|
match ex {
|
|
|
|
|
ExprKind::Lit(Spanned {
|
|
|
|
|
node: LitKind::Bool(b), ..
|
|
|
|
|
}) => Some(*b),
|
|
|
|
|
ExprKind::Block(
|
|
|
|
|
rustc_hir::Block {
|
|
|
|
|
stmts: &[],
|
|
|
|
|
expr: Some(exp),
|
|
|
|
|
..
|
|
|
|
|
},
|
|
|
|
|
_,
|
|
|
|
|
) if desugared => {
|
|
|
|
|
if let ExprKind::Lit(Spanned {
|
|
|
|
|
node: LitKind::Bool(b), ..
|
|
|
|
|
}) = exp.kind
|
|
|
|
|
{
|
|
|
|
|
Some(b)
|
|
|
|
|
} else {
|
|
|
|
|
None
|
|
|
|
|
}
|
|
|
|
|
},
|
|
|
|
|
_ => None,
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
|
2020-06-25 20:41:36 +00:00
|
|
|
|
fn check_match_single_binding<'a>(cx: &LateContext<'a>, ex: &Expr<'a>, arms: &[Arm<'_>], expr: &Expr<'_>) {
|
2020-01-26 16:03:39 +00:00
|
|
|
|
if in_macro(expr.span) || arms.len() != 1 || is_refutable(cx, arms[0].pat) {
|
2020-01-15 06:56:56 +00:00
|
|
|
|
return;
|
|
|
|
|
}
|
2020-12-09 12:25:45 +00:00
|
|
|
|
|
|
|
|
|
// HACK:
|
|
|
|
|
// This is a hack to deal with arms that are excluded by macros like `#[cfg]`. It is only used here
|
|
|
|
|
// to prevent false positives as there is currently no better way to detect if code was excluded by
|
|
|
|
|
// a macro. See PR #6435
|
|
|
|
|
if_chain! {
|
|
|
|
|
if let Some(match_snippet) = snippet_opt(cx, expr.span);
|
|
|
|
|
if let Some(arm_snippet) = snippet_opt(cx, arms[0].span);
|
|
|
|
|
if let Some(ex_snippet) = snippet_opt(cx, ex.span);
|
|
|
|
|
let rest_snippet = match_snippet.replace(&arm_snippet, "").replace(&ex_snippet, "");
|
|
|
|
|
if rest_snippet.contains("=>");
|
|
|
|
|
then {
|
|
|
|
|
// The code it self contains another thick arrow "=>"
|
|
|
|
|
// -> Either another arm or a comment
|
|
|
|
|
return;
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
|
2020-01-26 16:03:39 +00:00
|
|
|
|
let matched_vars = ex.span;
|
|
|
|
|
let bind_names = arms[0].pat.span;
|
|
|
|
|
let match_body = remove_blocks(&arms[0].body);
|
|
|
|
|
let mut snippet_body = if match_body.span.from_expansion() {
|
|
|
|
|
Sugg::hir_with_macro_callsite(cx, match_body, "..").to_string()
|
|
|
|
|
} else {
|
2020-02-05 08:55:48 +00:00
|
|
|
|
snippet_block(cx, match_body.span, "..", Some(expr.span)).to_string()
|
2020-01-26 16:03:39 +00:00
|
|
|
|
};
|
|
|
|
|
|
|
|
|
|
// Do we need to add ';' to suggestion ?
|
2020-02-04 19:19:20 +00:00
|
|
|
|
match match_body.kind {
|
|
|
|
|
ExprKind::Block(block, _) => {
|
|
|
|
|
// macro + expr_ty(body) == ()
|
2020-07-17 08:47:04 +00:00
|
|
|
|
if block.span.from_expansion() && cx.typeck_results().expr_ty(&match_body).is_unit() {
|
2020-02-04 19:19:20 +00:00
|
|
|
|
snippet_body.push(';');
|
2020-01-26 16:03:39 +00:00
|
|
|
|
}
|
2020-02-04 19:19:20 +00:00
|
|
|
|
},
|
|
|
|
|
_ => {
|
|
|
|
|
// expr_ty(body) == ()
|
2020-07-17 08:47:04 +00:00
|
|
|
|
if cx.typeck_results().expr_ty(&match_body).is_unit() {
|
2020-02-04 19:19:20 +00:00
|
|
|
|
snippet_body.push(';');
|
|
|
|
|
}
|
|
|
|
|
},
|
2020-01-15 06:56:56 +00:00
|
|
|
|
}
|
2020-01-26 16:03:39 +00:00
|
|
|
|
|
2020-02-04 19:19:20 +00:00
|
|
|
|
let mut applicability = Applicability::MaybeIncorrect;
|
2020-01-26 16:03:39 +00:00
|
|
|
|
match arms[0].pat.kind {
|
|
|
|
|
PatKind::Binding(..) | PatKind::Tuple(_, _) | PatKind::Struct(..) => {
|
2020-03-08 21:57:35 +00:00
|
|
|
|
// If this match is in a local (`let`) stmt
|
|
|
|
|
let (target_span, sugg) = if let Some(parent_let_node) = opt_parent_let(cx, ex) {
|
|
|
|
|
(
|
|
|
|
|
parent_let_node.span,
|
|
|
|
|
format!(
|
|
|
|
|
"let {} = {};\n{}let {} = {};",
|
|
|
|
|
snippet_with_applicability(cx, bind_names, "..", &mut applicability),
|
|
|
|
|
snippet_with_applicability(cx, matched_vars, "..", &mut applicability),
|
|
|
|
|
" ".repeat(indent_of(cx, expr.span).unwrap_or(0)),
|
|
|
|
|
snippet_with_applicability(cx, parent_let_node.pat.span, "..", &mut applicability),
|
|
|
|
|
snippet_body
|
|
|
|
|
),
|
|
|
|
|
)
|
|
|
|
|
} else {
|
2020-03-21 19:26:55 +00:00
|
|
|
|
// If we are in closure, we need curly braces around suggestion
|
|
|
|
|
let mut indent = " ".repeat(indent_of(cx, ex.span).unwrap_or(0));
|
|
|
|
|
let (mut cbrace_start, mut cbrace_end) = ("".to_string(), "".to_string());
|
|
|
|
|
if let Some(parent_expr) = get_parent_expr(cx, expr) {
|
|
|
|
|
if let ExprKind::Closure(..) = parent_expr.kind {
|
|
|
|
|
cbrace_end = format!("\n{}}}", indent);
|
|
|
|
|
// Fix body indent due to the closure
|
|
|
|
|
indent = " ".repeat(indent_of(cx, bind_names).unwrap_or(0));
|
|
|
|
|
cbrace_start = format!("{{\n{}", indent);
|
|
|
|
|
}
|
|
|
|
|
};
|
2020-03-08 21:57:35 +00:00
|
|
|
|
(
|
|
|
|
|
expr.span,
|
|
|
|
|
format!(
|
2020-03-21 19:26:55 +00:00
|
|
|
|
"{}let {} = {};\n{}{}{}",
|
|
|
|
|
cbrace_start,
|
2020-03-08 21:57:35 +00:00
|
|
|
|
snippet_with_applicability(cx, bind_names, "..", &mut applicability),
|
|
|
|
|
snippet_with_applicability(cx, matched_vars, "..", &mut applicability),
|
2020-03-21 19:26:55 +00:00
|
|
|
|
indent,
|
|
|
|
|
snippet_body,
|
|
|
|
|
cbrace_end
|
2020-03-08 21:57:35 +00:00
|
|
|
|
),
|
|
|
|
|
)
|
|
|
|
|
};
|
2020-01-26 16:03:39 +00:00
|
|
|
|
span_lint_and_sugg(
|
|
|
|
|
cx,
|
|
|
|
|
MATCH_SINGLE_BINDING,
|
2020-03-08 21:57:35 +00:00
|
|
|
|
target_span,
|
2020-01-26 16:03:39 +00:00
|
|
|
|
"this match could be written as a `let` statement",
|
|
|
|
|
"consider using `let` statement",
|
2020-03-08 21:57:35 +00:00
|
|
|
|
sugg,
|
2020-02-04 19:19:20 +00:00
|
|
|
|
applicability,
|
2020-01-26 16:03:39 +00:00
|
|
|
|
);
|
|
|
|
|
},
|
|
|
|
|
PatKind::Wild => {
|
|
|
|
|
span_lint_and_sugg(
|
|
|
|
|
cx,
|
|
|
|
|
MATCH_SINGLE_BINDING,
|
|
|
|
|
expr.span,
|
|
|
|
|
"this match could be replaced by its body itself",
|
|
|
|
|
"consider using the match body instead",
|
|
|
|
|
snippet_body,
|
|
|
|
|
Applicability::MachineApplicable,
|
|
|
|
|
);
|
|
|
|
|
},
|
|
|
|
|
_ => (),
|
|
|
|
|
}
|
2020-01-15 06:56:56 +00:00
|
|
|
|
}
|
|
|
|
|
|
2020-03-08 21:57:35 +00:00
|
|
|
|
/// Returns true if the `ex` match expression is in a local (`let`) statement
|
2020-06-25 20:41:36 +00:00
|
|
|
|
fn opt_parent_let<'a>(cx: &LateContext<'a>, ex: &Expr<'a>) -> Option<&'a Local<'a>> {
|
2020-03-08 21:57:35 +00:00
|
|
|
|
if_chain! {
|
|
|
|
|
let map = &cx.tcx.hir();
|
|
|
|
|
if let Some(Node::Expr(parent_arm_expr)) = map.find(map.get_parent_node(ex.hir_id));
|
|
|
|
|
if let Some(Node::Local(parent_let_expr)) = map.find(map.get_parent_node(parent_arm_expr.hir_id));
|
|
|
|
|
then {
|
|
|
|
|
return Some(parent_let_expr);
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
None
|
|
|
|
|
}
|
|
|
|
|
|
2019-01-31 01:15:29 +00:00
|
|
|
|
/// Gets all arms that are unbounded `PatRange`s.
|
2020-06-25 20:41:36 +00:00
|
|
|
|
fn all_ranges<'tcx>(cx: &LateContext<'tcx>, arms: &'tcx [Arm<'_>], ty: Ty<'tcx>) -> Vec<SpannedRange<Constant>> {
|
2015-12-23 00:14:10 +00:00
|
|
|
|
arms.iter()
|
2016-06-21 11:51:44 +00:00
|
|
|
|
.flat_map(|arm| {
|
2017-08-09 07:30:56 +00:00
|
|
|
|
if let Arm {
|
2019-09-25 19:00:17 +00:00
|
|
|
|
ref pat, guard: None, ..
|
2017-08-09 07:30:56 +00:00
|
|
|
|
} = *arm
|
|
|
|
|
{
|
2020-01-11 10:39:43 +00:00
|
|
|
|
if let PatKind::Range(ref lhs, ref rhs, range_end) = pat.kind {
|
2020-01-11 14:21:09 +00:00
|
|
|
|
let lhs = match lhs {
|
2020-07-17 08:47:04 +00:00
|
|
|
|
Some(lhs) => constant(cx, cx.typeck_results(), lhs)?.0,
|
2020-01-11 14:21:09 +00:00
|
|
|
|
None => miri_to_const(ty.numeric_min_val(cx.tcx)?)?,
|
|
|
|
|
};
|
|
|
|
|
let rhs = match rhs {
|
2020-07-17 08:47:04 +00:00
|
|
|
|
Some(rhs) => constant(cx, cx.typeck_results(), rhs)?.0,
|
2020-01-11 14:21:09 +00:00
|
|
|
|
None => miri_to_const(ty.numeric_max_val(cx.tcx)?)?,
|
|
|
|
|
};
|
|
|
|
|
let rhs = match range_end {
|
|
|
|
|
RangeEnd::Included => Bound::Included(rhs),
|
|
|
|
|
RangeEnd::Excluded => Bound::Excluded(rhs),
|
|
|
|
|
};
|
|
|
|
|
return Some(SpannedRange {
|
|
|
|
|
span: pat.span,
|
|
|
|
|
node: (lhs, rhs),
|
|
|
|
|
});
|
2017-10-23 19:18:02 +00:00
|
|
|
|
}
|
2015-12-23 00:14:10 +00:00
|
|
|
|
|
2019-09-27 15:16:06 +00:00
|
|
|
|
if let PatKind::Lit(ref value) = pat.kind {
|
2020-07-17 08:47:04 +00:00
|
|
|
|
let value = constant(cx, cx.typeck_results(), value)?.0;
|
2018-11-27 20:14:15 +00:00
|
|
|
|
return Some(SpannedRange {
|
|
|
|
|
span: pat.span,
|
|
|
|
|
node: (value.clone(), Bound::Included(value)),
|
|
|
|
|
});
|
2017-10-23 19:18:02 +00:00
|
|
|
|
}
|
2019-09-25 19:00:17 +00:00
|
|
|
|
}
|
|
|
|
|
None
|
2015-12-23 00:14:10 +00:00
|
|
|
|
})
|
|
|
|
|
.collect()
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
#[derive(Debug, Eq, PartialEq)]
|
2015-12-23 16:48:30 +00:00
|
|
|
|
pub struct SpannedRange<T> {
|
|
|
|
|
pub span: Span,
|
2017-01-30 11:30:16 +00:00
|
|
|
|
pub node: (T, Bound<T>),
|
2015-12-23 00:14:10 +00:00
|
|
|
|
}
|
|
|
|
|
|
2018-03-13 10:38:11 +00:00
|
|
|
|
type TypedRanges = Vec<SpannedRange<u128>>;
|
2015-12-23 00:14:10 +00:00
|
|
|
|
|
2019-01-31 01:15:29 +00:00
|
|
|
|
/// Gets all `Int` ranges or all `Uint` ranges. Mixed types are an error anyway
|
2017-08-09 07:30:56 +00:00
|
|
|
|
/// and other types than
|
2015-12-23 00:14:10 +00:00
|
|
|
|
/// `Uint` and `Int` probably don't make sense.
|
2018-03-13 10:38:11 +00:00
|
|
|
|
fn type_ranges(ranges: &[SpannedRange<Constant>]) -> TypedRanges {
|
2017-08-09 07:30:56 +00:00
|
|
|
|
ranges
|
|
|
|
|
.iter()
|
2017-01-30 11:30:16 +00:00
|
|
|
|
.filter_map(|range| match range.node {
|
2018-11-27 20:14:15 +00:00
|
|
|
|
(Constant::Int(start), Bound::Included(Constant::Int(end))) => Some(SpannedRange {
|
2017-09-05 09:33:04 +00:00
|
|
|
|
span: range.span,
|
|
|
|
|
node: (start, Bound::Included(end)),
|
|
|
|
|
}),
|
2018-11-27 20:14:15 +00:00
|
|
|
|
(Constant::Int(start), Bound::Excluded(Constant::Int(end))) => Some(SpannedRange {
|
2017-09-05 09:33:04 +00:00
|
|
|
|
span: range.span,
|
|
|
|
|
node: (start, Bound::Excluded(end)),
|
|
|
|
|
}),
|
2018-11-27 20:14:15 +00:00
|
|
|
|
(Constant::Int(start), Bound::Unbounded) => Some(SpannedRange {
|
2017-09-05 09:33:04 +00:00
|
|
|
|
span: range.span,
|
|
|
|
|
node: (start, Bound::Unbounded),
|
|
|
|
|
}),
|
2017-01-30 11:30:16 +00:00
|
|
|
|
_ => None,
|
2016-12-20 17:21:30 +00:00
|
|
|
|
})
|
|
|
|
|
.collect()
|
2015-12-23 00:14:10 +00:00
|
|
|
|
}
|
|
|
|
|
|
2019-12-27 07:12:26 +00:00
|
|
|
|
fn is_unit_expr(expr: &Expr<'_>) -> bool {
|
2019-09-27 15:16:06 +00:00
|
|
|
|
match expr.kind {
|
2018-07-12 07:30:57 +00:00
|
|
|
|
ExprKind::Tup(ref v) if v.is_empty() => true,
|
|
|
|
|
ExprKind::Block(ref b, _) if b.stmts.is_empty() && b.expr.is_none() => true,
|
2015-08-21 17:32:21 +00:00
|
|
|
|
_ => false,
|
|
|
|
|
}
|
|
|
|
|
}
|
2015-08-21 17:49:00 +00:00
|
|
|
|
|
2017-12-19 22:22:16 +00:00
|
|
|
|
// Checks if arm has the form `None => None`
|
2019-12-27 07:12:26 +00:00
|
|
|
|
fn is_none_arm(arm: &Arm<'_>) -> bool {
|
2020-07-14 12:59:59 +00:00
|
|
|
|
matches!(arm.pat.kind, PatKind::Path(ref path) if match_qpath(path, &paths::OPTION_NONE))
|
2017-12-19 22:22:16 +00:00
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
// Checks if arm has the form `Some(ref v) => Some(v)` (checks for `ref` and `ref mut`)
|
2019-12-27 07:12:26 +00:00
|
|
|
|
fn is_ref_some_arm(arm: &Arm<'_>) -> Option<BindingAnnotation> {
|
2017-12-19 22:22:16 +00:00
|
|
|
|
if_chain! {
|
2019-09-27 15:16:06 +00:00
|
|
|
|
if let PatKind::TupleStruct(ref path, ref pats, _) = arm.pat.kind;
|
2019-05-17 21:53:54 +00:00
|
|
|
|
if pats.len() == 1 && match_qpath(path, &paths::OPTION_SOME);
|
2019-09-27 15:16:06 +00:00
|
|
|
|
if let PatKind::Binding(rb, .., ident, _) = pats[0].kind;
|
2017-12-19 22:22:16 +00:00
|
|
|
|
if rb == BindingAnnotation::Ref || rb == BindingAnnotation::RefMut;
|
2019-09-27 15:16:06 +00:00
|
|
|
|
if let ExprKind::Call(ref e, ref args) = remove_blocks(&arm.body).kind;
|
|
|
|
|
if let ExprKind::Path(ref some_path) = e.kind;
|
2019-05-17 21:53:54 +00:00
|
|
|
|
if match_qpath(some_path, &paths::OPTION_SOME) && args.len() == 1;
|
2020-11-25 02:57:09 +00:00
|
|
|
|
if let ExprKind::Path(QPath::Resolved(_, ref path2)) = args[0].kind;
|
2018-06-28 13:46:58 +00:00
|
|
|
|
if path2.segments.len() == 1 && ident.name == path2.segments[0].ident.name;
|
2017-12-19 22:22:16 +00:00
|
|
|
|
then {
|
2017-12-20 09:39:48 +00:00
|
|
|
|
return Some(rb)
|
2017-12-19 22:22:16 +00:00
|
|
|
|
}
|
|
|
|
|
}
|
2017-12-20 09:39:48 +00:00
|
|
|
|
None
|
2017-12-19 22:22:16 +00:00
|
|
|
|
}
|
|
|
|
|
|
2019-12-27 07:12:26 +00:00
|
|
|
|
fn has_only_ref_pats(arms: &[Arm<'_>]) -> bool {
|
2018-11-27 20:14:15 +00:00
|
|
|
|
let mapped = arms
|
|
|
|
|
.iter()
|
2019-09-25 19:00:17 +00:00
|
|
|
|
.map(|a| {
|
2019-09-27 15:16:06 +00:00
|
|
|
|
match a.pat.kind {
|
2017-09-05 09:33:04 +00:00
|
|
|
|
PatKind::Ref(..) => Some(true), // &-patterns
|
2016-12-20 17:21:30 +00:00
|
|
|
|
PatKind::Wild => Some(false), // an "anything" wildcard is also fine
|
2017-09-05 09:33:04 +00:00
|
|
|
|
_ => None, // any other pattern is not fine
|
2016-12-20 17:21:30 +00:00
|
|
|
|
}
|
|
|
|
|
})
|
|
|
|
|
.collect::<Option<Vec<bool>>>();
|
2015-09-17 05:24:11 +00:00
|
|
|
|
// look for Some(v) where there's at least one true element
|
|
|
|
|
mapped.map_or(false, |v| v.iter().any(|el| *el))
|
2015-08-21 17:49:00 +00:00
|
|
|
|
}
|
2015-11-24 17:47:17 +00:00
|
|
|
|
|
2015-12-23 16:48:30 +00:00
|
|
|
|
pub fn overlapping<T>(ranges: &[SpannedRange<T>]) -> Option<(&SpannedRange<T>, &SpannedRange<T>)>
|
2017-08-09 07:30:56 +00:00
|
|
|
|
where
|
|
|
|
|
T: Copy + Ord,
|
2016-01-04 04:26:12 +00:00
|
|
|
|
{
|
2015-12-23 00:14:10 +00:00
|
|
|
|
#[derive(Copy, Clone, Debug, Eq, PartialEq)]
|
2019-06-19 18:36:23 +00:00
|
|
|
|
enum Kind<'a, T> {
|
2015-12-23 00:14:10 +00:00
|
|
|
|
Start(T, &'a SpannedRange<T>),
|
2017-01-30 11:30:16 +00:00
|
|
|
|
End(Bound<T>, &'a SpannedRange<T>),
|
2015-12-23 00:14:10 +00:00
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
impl<'a, T: Copy> Kind<'a, T> {
|
|
|
|
|
fn range(&self) -> &'a SpannedRange<T> {
|
|
|
|
|
match *self {
|
2017-09-05 09:33:04 +00:00
|
|
|
|
Kind::Start(_, r) | Kind::End(_, r) => r,
|
2015-12-23 00:14:10 +00:00
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
|
2017-01-30 11:30:16 +00:00
|
|
|
|
fn value(self) -> Bound<T> {
|
2015-12-23 00:14:10 +00:00
|
|
|
|
match self {
|
2017-01-30 11:30:16 +00:00
|
|
|
|
Kind::Start(t, _) => Bound::Included(t),
|
2016-04-14 18:14:03 +00:00
|
|
|
|
Kind::End(t, _) => t,
|
2015-12-23 00:14:10 +00:00
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
impl<'a, T: Copy + Ord> PartialOrd for Kind<'a, T> {
|
|
|
|
|
fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
|
|
|
|
|
Some(self.cmp(other))
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
impl<'a, T: Copy + Ord> Ord for Kind<'a, T> {
|
|
|
|
|
fn cmp(&self, other: &Self) -> Ordering {
|
2017-01-30 11:30:16 +00:00
|
|
|
|
match (self.value(), other.value()) {
|
2017-09-05 09:33:04 +00:00
|
|
|
|
(Bound::Included(a), Bound::Included(b)) | (Bound::Excluded(a), Bound::Excluded(b)) => a.cmp(&b),
|
2017-01-31 07:08:54 +00:00
|
|
|
|
// Range patterns cannot be unbounded (yet)
|
2017-09-05 09:33:04 +00:00
|
|
|
|
(Bound::Unbounded, _) | (_, Bound::Unbounded) => unimplemented!(),
|
|
|
|
|
(Bound::Included(a), Bound::Excluded(b)) => match a.cmp(&b) {
|
|
|
|
|
Ordering::Equal => Ordering::Greater,
|
|
|
|
|
other => other,
|
2017-01-30 11:30:16 +00:00
|
|
|
|
},
|
2017-09-05 09:33:04 +00:00
|
|
|
|
(Bound::Excluded(a), Bound::Included(b)) => match a.cmp(&b) {
|
|
|
|
|
Ordering::Equal => Ordering::Less,
|
|
|
|
|
other => other,
|
2017-01-30 11:30:16 +00:00
|
|
|
|
},
|
|
|
|
|
}
|
2015-12-23 00:14:10 +00:00
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
|
2016-01-04 04:26:12 +00:00
|
|
|
|
let mut values = Vec::with_capacity(2 * ranges.len());
|
2015-12-23 00:14:10 +00:00
|
|
|
|
|
|
|
|
|
for r in ranges {
|
2016-04-26 15:05:39 +00:00
|
|
|
|
values.push(Kind::Start(r.node.0, r));
|
|
|
|
|
values.push(Kind::End(r.node.1, r));
|
2015-12-23 00:14:10 +00:00
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
values.sort();
|
|
|
|
|
|
|
|
|
|
for (a, b) in values.iter().zip(values.iter().skip(1)) {
|
|
|
|
|
match (a, b) {
|
2018-11-27 20:14:15 +00:00
|
|
|
|
(&Kind::Start(_, ra), &Kind::End(_, rb)) => {
|
|
|
|
|
if ra.node != rb.node {
|
|
|
|
|
return Some((ra, rb));
|
|
|
|
|
}
|
2016-12-20 17:21:30 +00:00
|
|
|
|
},
|
2017-01-30 11:30:16 +00:00
|
|
|
|
(&Kind::End(a, _), &Kind::Start(b, _)) if a != Bound::Included(b) => (),
|
2016-04-26 15:05:39 +00:00
|
|
|
|
_ => return Some((a.range(), b.range())),
|
2015-12-23 00:14:10 +00:00
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
None
|
|
|
|
|
}
|
2020-04-03 19:31:47 +00:00
|
|
|
|
|
2020-07-14 12:59:59 +00:00
|
|
|
|
mod redundant_pattern_match {
|
|
|
|
|
use super::REDUNDANT_PATTERN_MATCHING;
|
2020-09-20 22:00:33 +00:00
|
|
|
|
use crate::utils::{match_qpath, match_trait_method, paths, snippet, span_lint_and_then};
|
2020-07-14 12:59:59 +00:00
|
|
|
|
use if_chain::if_chain;
|
|
|
|
|
use rustc_ast::ast::LitKind;
|
|
|
|
|
use rustc_errors::Applicability;
|
2020-09-20 22:00:33 +00:00
|
|
|
|
use rustc_hir::{Arm, Expr, ExprKind, MatchSource, PatKind, QPath};
|
2020-07-14 12:59:59 +00:00
|
|
|
|
use rustc_lint::LateContext;
|
2020-11-02 16:32:55 +00:00
|
|
|
|
use rustc_span::sym;
|
2020-07-14 12:59:59 +00:00
|
|
|
|
|
|
|
|
|
pub fn check<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
|
|
|
|
|
if let ExprKind::Match(op, arms, ref match_source) = &expr.kind {
|
|
|
|
|
match match_source {
|
|
|
|
|
MatchSource::Normal => find_sugg_for_match(cx, expr, op, arms),
|
|
|
|
|
MatchSource::IfLetDesugar { .. } => find_sugg_for_if_let(cx, expr, op, arms, "if"),
|
|
|
|
|
MatchSource::WhileLetDesugar => find_sugg_for_if_let(cx, expr, op, arms, "while"),
|
|
|
|
|
_ => {},
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
fn find_sugg_for_if_let<'tcx>(
|
|
|
|
|
cx: &LateContext<'tcx>,
|
|
|
|
|
expr: &'tcx Expr<'_>,
|
|
|
|
|
op: &Expr<'_>,
|
|
|
|
|
arms: &[Arm<'_>],
|
|
|
|
|
keyword: &'static str,
|
|
|
|
|
) {
|
|
|
|
|
let good_method = match arms[0].pat.kind {
|
|
|
|
|
PatKind::TupleStruct(ref path, ref patterns, _) if patterns.len() == 1 => {
|
|
|
|
|
if let PatKind::Wild = patterns[0].kind {
|
2020-09-20 22:00:33 +00:00
|
|
|
|
if match_qpath(path, &paths::RESULT_OK) {
|
|
|
|
|
"is_ok()"
|
|
|
|
|
} else if match_qpath(path, &paths::RESULT_ERR) {
|
|
|
|
|
"is_err()"
|
|
|
|
|
} else if match_qpath(path, &paths::OPTION_SOME) {
|
|
|
|
|
"is_some()"
|
2020-11-17 21:34:39 +00:00
|
|
|
|
} else if match_qpath(path, &paths::POLL_READY) {
|
|
|
|
|
"is_ready()"
|
2020-11-25 01:01:05 +00:00
|
|
|
|
} else if match_qpath(path, &paths::IPADDR_V4) {
|
|
|
|
|
"is_ipv4()"
|
|
|
|
|
} else if match_qpath(path, &paths::IPADDR_V6) {
|
|
|
|
|
"is_ipv6()"
|
2020-09-20 22:00:33 +00:00
|
|
|
|
} else {
|
|
|
|
|
return;
|
|
|
|
|
}
|
2020-07-14 12:59:59 +00:00
|
|
|
|
} else {
|
2020-09-20 22:00:33 +00:00
|
|
|
|
return;
|
2020-07-14 12:59:59 +00:00
|
|
|
|
}
|
|
|
|
|
},
|
2020-11-17 21:34:39 +00:00
|
|
|
|
PatKind::Path(ref path) => {
|
|
|
|
|
if match_qpath(path, &paths::OPTION_NONE) {
|
|
|
|
|
"is_none()"
|
|
|
|
|
} else if match_qpath(path, &paths::POLL_PENDING) {
|
|
|
|
|
"is_pending()"
|
|
|
|
|
} else {
|
|
|
|
|
return;
|
|
|
|
|
}
|
|
|
|
|
},
|
2020-09-20 22:00:33 +00:00
|
|
|
|
_ => return,
|
2020-07-14 12:59:59 +00:00
|
|
|
|
};
|
|
|
|
|
|
|
|
|
|
// check that `while_let_on_iterator` lint does not trigger
|
|
|
|
|
if_chain! {
|
|
|
|
|
if keyword == "while";
|
|
|
|
|
if let ExprKind::MethodCall(method_path, _, _, _) = op.kind;
|
2020-11-02 16:32:55 +00:00
|
|
|
|
if method_path.ident.name == sym::next;
|
2020-07-14 12:59:59 +00:00
|
|
|
|
if match_trait_method(cx, op, &paths::ITERATOR);
|
|
|
|
|
then {
|
|
|
|
|
return;
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
|
2020-07-26 19:07:07 +00:00
|
|
|
|
let result_expr = match &op.kind {
|
|
|
|
|
ExprKind::AddrOf(_, _, borrowed) => borrowed,
|
|
|
|
|
_ => op,
|
|
|
|
|
};
|
2020-07-14 12:59:59 +00:00
|
|
|
|
span_lint_and_then(
|
|
|
|
|
cx,
|
|
|
|
|
REDUNDANT_PATTERN_MATCHING,
|
|
|
|
|
arms[0].pat.span,
|
|
|
|
|
&format!("redundant pattern matching, consider using `{}`", good_method),
|
|
|
|
|
|diag| {
|
|
|
|
|
// while let ... = ... { ... }
|
|
|
|
|
// ^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
|
|
|
|
let expr_span = expr.span;
|
|
|
|
|
|
|
|
|
|
// while let ... = ... { ... }
|
|
|
|
|
// ^^^
|
2020-07-26 19:07:07 +00:00
|
|
|
|
let op_span = result_expr.span.source_callsite();
|
2020-07-14 12:59:59 +00:00
|
|
|
|
|
|
|
|
|
// while let ... = ... { ... }
|
|
|
|
|
// ^^^^^^^^^^^^^^^^^^^
|
|
|
|
|
let span = expr_span.until(op_span.shrink_to_hi());
|
|
|
|
|
diag.span_suggestion(
|
|
|
|
|
span,
|
|
|
|
|
"try this",
|
|
|
|
|
format!("{} {}.{}", keyword, snippet(cx, op_span, "_"), good_method),
|
|
|
|
|
Applicability::MachineApplicable, // snippet
|
|
|
|
|
);
|
|
|
|
|
},
|
|
|
|
|
);
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
fn find_sugg_for_match<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>, op: &Expr<'_>, arms: &[Arm<'_>]) {
|
|
|
|
|
if arms.len() == 2 {
|
|
|
|
|
let node_pair = (&arms[0].pat.kind, &arms[1].pat.kind);
|
|
|
|
|
|
|
|
|
|
let found_good_method = match node_pair {
|
|
|
|
|
(
|
|
|
|
|
PatKind::TupleStruct(ref path_left, ref patterns_left, _),
|
|
|
|
|
PatKind::TupleStruct(ref path_right, ref patterns_right, _),
|
|
|
|
|
) if patterns_left.len() == 1 && patterns_right.len() == 1 => {
|
|
|
|
|
if let (PatKind::Wild, PatKind::Wild) = (&patterns_left[0].kind, &patterns_right[0].kind) {
|
|
|
|
|
find_good_method_for_match(
|
|
|
|
|
arms,
|
|
|
|
|
path_left,
|
|
|
|
|
path_right,
|
|
|
|
|
&paths::RESULT_OK,
|
|
|
|
|
&paths::RESULT_ERR,
|
|
|
|
|
"is_ok()",
|
|
|
|
|
"is_err()",
|
|
|
|
|
)
|
2020-11-25 01:01:05 +00:00
|
|
|
|
.or_else(|| {
|
|
|
|
|
find_good_method_for_match(
|
|
|
|
|
arms,
|
|
|
|
|
path_left,
|
|
|
|
|
path_right,
|
|
|
|
|
&paths::IPADDR_V4,
|
|
|
|
|
&paths::IPADDR_V6,
|
|
|
|
|
"is_ipv4()",
|
|
|
|
|
"is_ipv6()",
|
|
|
|
|
)
|
|
|
|
|
})
|
2020-07-14 12:59:59 +00:00
|
|
|
|
} else {
|
|
|
|
|
None
|
|
|
|
|
}
|
|
|
|
|
},
|
|
|
|
|
(PatKind::TupleStruct(ref path_left, ref patterns, _), PatKind::Path(ref path_right))
|
|
|
|
|
| (PatKind::Path(ref path_left), PatKind::TupleStruct(ref path_right, ref patterns, _))
|
|
|
|
|
if patterns.len() == 1 =>
|
|
|
|
|
{
|
|
|
|
|
if let PatKind::Wild = patterns[0].kind {
|
|
|
|
|
find_good_method_for_match(
|
|
|
|
|
arms,
|
|
|
|
|
path_left,
|
|
|
|
|
path_right,
|
|
|
|
|
&paths::OPTION_SOME,
|
|
|
|
|
&paths::OPTION_NONE,
|
|
|
|
|
"is_some()",
|
|
|
|
|
"is_none()",
|
|
|
|
|
)
|
2020-11-17 21:34:39 +00:00
|
|
|
|
.or_else(|| {
|
|
|
|
|
find_good_method_for_match(
|
|
|
|
|
arms,
|
|
|
|
|
path_left,
|
|
|
|
|
path_right,
|
|
|
|
|
&paths::POLL_READY,
|
|
|
|
|
&paths::POLL_PENDING,
|
|
|
|
|
"is_ready()",
|
|
|
|
|
"is_pending()",
|
|
|
|
|
)
|
|
|
|
|
})
|
2020-07-14 12:59:59 +00:00
|
|
|
|
} else {
|
|
|
|
|
None
|
|
|
|
|
}
|
|
|
|
|
},
|
|
|
|
|
_ => None,
|
|
|
|
|
};
|
|
|
|
|
|
|
|
|
|
if let Some(good_method) = found_good_method {
|
2020-07-26 19:07:07 +00:00
|
|
|
|
let span = expr.span.to(op.span);
|
|
|
|
|
let result_expr = match &op.kind {
|
|
|
|
|
ExprKind::AddrOf(_, _, borrowed) => borrowed,
|
|
|
|
|
_ => op,
|
|
|
|
|
};
|
2020-07-14 12:59:59 +00:00
|
|
|
|
span_lint_and_then(
|
|
|
|
|
cx,
|
|
|
|
|
REDUNDANT_PATTERN_MATCHING,
|
|
|
|
|
expr.span,
|
|
|
|
|
&format!("redundant pattern matching, consider using `{}`", good_method),
|
|
|
|
|
|diag| {
|
|
|
|
|
diag.span_suggestion(
|
|
|
|
|
span,
|
|
|
|
|
"try this",
|
2020-07-26 19:07:07 +00:00
|
|
|
|
format!("{}.{}", snippet(cx, result_expr.span, "_"), good_method),
|
2020-07-14 12:59:59 +00:00
|
|
|
|
Applicability::MaybeIncorrect, // snippet
|
|
|
|
|
);
|
|
|
|
|
},
|
|
|
|
|
);
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
fn find_good_method_for_match<'a>(
|
|
|
|
|
arms: &[Arm<'_>],
|
|
|
|
|
path_left: &QPath<'_>,
|
|
|
|
|
path_right: &QPath<'_>,
|
|
|
|
|
expected_left: &[&str],
|
|
|
|
|
expected_right: &[&str],
|
|
|
|
|
should_be_left: &'a str,
|
|
|
|
|
should_be_right: &'a str,
|
|
|
|
|
) -> Option<&'a str> {
|
|
|
|
|
let body_node_pair = if match_qpath(path_left, expected_left) && match_qpath(path_right, expected_right) {
|
|
|
|
|
(&(*arms[0].body).kind, &(*arms[1].body).kind)
|
|
|
|
|
} else if match_qpath(path_right, expected_left) && match_qpath(path_left, expected_right) {
|
|
|
|
|
(&(*arms[1].body).kind, &(*arms[0].body).kind)
|
|
|
|
|
} else {
|
|
|
|
|
return None;
|
|
|
|
|
};
|
|
|
|
|
|
|
|
|
|
match body_node_pair {
|
|
|
|
|
(ExprKind::Lit(ref lit_left), ExprKind::Lit(ref lit_right)) => match (&lit_left.node, &lit_right.node) {
|
2020-09-20 22:00:33 +00:00
|
|
|
|
(LitKind::Bool(true), LitKind::Bool(false)) => Some(should_be_left),
|
|
|
|
|
(LitKind::Bool(false), LitKind::Bool(true)) => Some(should_be_right),
|
2020-07-14 12:59:59 +00:00
|
|
|
|
_ => None,
|
|
|
|
|
},
|
|
|
|
|
_ => None,
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
|
2020-04-03 19:31:47 +00:00
|
|
|
|
#[test]
|
|
|
|
|
fn test_overlapping() {
|
|
|
|
|
use rustc_span::source_map::DUMMY_SP;
|
|
|
|
|
|
|
|
|
|
let sp = |s, e| SpannedRange {
|
|
|
|
|
span: DUMMY_SP,
|
|
|
|
|
node: (s, e),
|
|
|
|
|
};
|
|
|
|
|
|
|
|
|
|
assert_eq!(None, overlapping::<u8>(&[]));
|
|
|
|
|
assert_eq!(None, overlapping(&[sp(1, Bound::Included(4))]));
|
|
|
|
|
assert_eq!(
|
|
|
|
|
None,
|
|
|
|
|
overlapping(&[sp(1, Bound::Included(4)), sp(5, Bound::Included(6))])
|
|
|
|
|
);
|
|
|
|
|
assert_eq!(
|
|
|
|
|
None,
|
|
|
|
|
overlapping(&[
|
|
|
|
|
sp(1, Bound::Included(4)),
|
|
|
|
|
sp(5, Bound::Included(6)),
|
|
|
|
|
sp(10, Bound::Included(11))
|
|
|
|
|
],)
|
|
|
|
|
);
|
|
|
|
|
assert_eq!(
|
|
|
|
|
Some((&sp(1, Bound::Included(4)), &sp(3, Bound::Included(6)))),
|
|
|
|
|
overlapping(&[sp(1, Bound::Included(4)), sp(3, Bound::Included(6))])
|
|
|
|
|
);
|
|
|
|
|
assert_eq!(
|
|
|
|
|
Some((&sp(5, Bound::Included(6)), &sp(6, Bound::Included(11)))),
|
|
|
|
|
overlapping(&[
|
|
|
|
|
sp(1, Bound::Included(4)),
|
|
|
|
|
sp(5, Bound::Included(6)),
|
|
|
|
|
sp(6, Bound::Included(11))
|
|
|
|
|
],)
|
|
|
|
|
);
|
|
|
|
|
}
|
2020-10-24 15:06:07 +00:00
|
|
|
|
|
|
|
|
|
/// Implementation of `MATCH_SAME_ARMS`.
|
|
|
|
|
fn lint_match_arms<'tcx>(cx: &LateContext<'tcx>, expr: &Expr<'_>) {
|
|
|
|
|
fn same_bindings<'tcx>(lhs: &FxHashMap<Symbol, Ty<'tcx>>, rhs: &FxHashMap<Symbol, Ty<'tcx>>) -> bool {
|
|
|
|
|
lhs.len() == rhs.len()
|
|
|
|
|
&& lhs
|
|
|
|
|
.iter()
|
|
|
|
|
.all(|(name, l_ty)| rhs.get(name).map_or(false, |r_ty| TyS::same_type(l_ty, r_ty)))
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
if let ExprKind::Match(_, ref arms, MatchSource::Normal) = expr.kind {
|
|
|
|
|
let hash = |&(_, arm): &(usize, &Arm<'_>)| -> u64 {
|
|
|
|
|
let mut h = SpanlessHash::new(cx);
|
|
|
|
|
h.hash_expr(&arm.body);
|
|
|
|
|
h.finish()
|
|
|
|
|
};
|
|
|
|
|
|
|
|
|
|
let eq = |&(lindex, lhs): &(usize, &Arm<'_>), &(rindex, rhs): &(usize, &Arm<'_>)| -> bool {
|
|
|
|
|
let min_index = usize::min(lindex, rindex);
|
|
|
|
|
let max_index = usize::max(lindex, rindex);
|
|
|
|
|
|
|
|
|
|
// Arms with a guard are ignored, those can’t always be merged together
|
|
|
|
|
// This is also the case for arms in-between each there is an arm with a guard
|
|
|
|
|
(min_index..=max_index).all(|index| arms[index].guard.is_none()) &&
|
|
|
|
|
SpanlessEq::new(cx).eq_expr(&lhs.body, &rhs.body) &&
|
|
|
|
|
// all patterns should have the same bindings
|
|
|
|
|
same_bindings(&bindings(cx, &lhs.pat), &bindings(cx, &rhs.pat))
|
|
|
|
|
};
|
|
|
|
|
|
|
|
|
|
let indexed_arms: Vec<(usize, &Arm<'_>)> = arms.iter().enumerate().collect();
|
|
|
|
|
for (&(_, i), &(_, j)) in search_same(&indexed_arms, hash, eq) {
|
|
|
|
|
span_lint_and_then(
|
|
|
|
|
cx,
|
|
|
|
|
MATCH_SAME_ARMS,
|
|
|
|
|
j.body.span,
|
|
|
|
|
"this `match` has identical arm bodies",
|
|
|
|
|
|diag| {
|
|
|
|
|
diag.span_note(i.body.span, "same as this");
|
|
|
|
|
|
|
|
|
|
// Note: this does not use `span_suggestion` on purpose:
|
|
|
|
|
// there is no clean way
|
|
|
|
|
// to remove the other arm. Building a span and suggest to replace it to ""
|
|
|
|
|
// makes an even more confusing error message. Also in order not to make up a
|
|
|
|
|
// span for the whole pattern, the suggestion is only shown when there is only
|
|
|
|
|
// one pattern. The user should know about `|` if they are already using it…
|
|
|
|
|
|
|
|
|
|
let lhs = snippet(cx, i.pat.span, "<pat1>");
|
|
|
|
|
let rhs = snippet(cx, j.pat.span, "<pat2>");
|
|
|
|
|
|
|
|
|
|
if let PatKind::Wild = j.pat.kind {
|
|
|
|
|
// if the last arm is _, then i could be integrated into _
|
|
|
|
|
// note that i.pat cannot be _, because that would mean that we're
|
|
|
|
|
// hiding all the subsequent arms, and rust won't compile
|
|
|
|
|
diag.span_note(
|
|
|
|
|
i.body.span,
|
|
|
|
|
&format!(
|
|
|
|
|
"`{}` has the same arm body as the `_` wildcard, consider removing it",
|
|
|
|
|
lhs
|
|
|
|
|
),
|
|
|
|
|
);
|
|
|
|
|
} else {
|
|
|
|
|
diag.span_help(i.pat.span, &format!("consider refactoring into `{} | {}`", lhs, rhs));
|
|
|
|
|
}
|
|
|
|
|
},
|
|
|
|
|
);
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
/// Returns the list of bindings in a pattern.
|
|
|
|
|
fn bindings<'tcx>(cx: &LateContext<'tcx>, pat: &Pat<'_>) -> FxHashMap<Symbol, Ty<'tcx>> {
|
|
|
|
|
fn bindings_impl<'tcx>(cx: &LateContext<'tcx>, pat: &Pat<'_>, map: &mut FxHashMap<Symbol, Ty<'tcx>>) {
|
|
|
|
|
match pat.kind {
|
|
|
|
|
PatKind::Box(ref pat) | PatKind::Ref(ref pat, _) => bindings_impl(cx, pat, map),
|
|
|
|
|
PatKind::TupleStruct(_, pats, _) => {
|
|
|
|
|
for pat in pats {
|
|
|
|
|
bindings_impl(cx, pat, map);
|
|
|
|
|
}
|
|
|
|
|
},
|
|
|
|
|
PatKind::Binding(.., ident, ref as_pat) => {
|
|
|
|
|
if let Entry::Vacant(v) = map.entry(ident.name) {
|
|
|
|
|
v.insert(cx.typeck_results().pat_ty(pat));
|
|
|
|
|
}
|
|
|
|
|
if let Some(ref as_pat) = *as_pat {
|
|
|
|
|
bindings_impl(cx, as_pat, map);
|
|
|
|
|
}
|
|
|
|
|
},
|
|
|
|
|
PatKind::Or(fields) | PatKind::Tuple(fields, _) => {
|
|
|
|
|
for pat in fields {
|
|
|
|
|
bindings_impl(cx, pat, map);
|
|
|
|
|
}
|
|
|
|
|
},
|
|
|
|
|
PatKind::Struct(_, fields, _) => {
|
|
|
|
|
for pat in fields {
|
|
|
|
|
bindings_impl(cx, &pat.pat, map);
|
|
|
|
|
}
|
|
|
|
|
},
|
|
|
|
|
PatKind::Slice(lhs, ref mid, rhs) => {
|
|
|
|
|
for pat in lhs {
|
|
|
|
|
bindings_impl(cx, pat, map);
|
|
|
|
|
}
|
|
|
|
|
if let Some(ref mid) = *mid {
|
|
|
|
|
bindings_impl(cx, mid, map);
|
|
|
|
|
}
|
|
|
|
|
for pat in rhs {
|
|
|
|
|
bindings_impl(cx, pat, map);
|
|
|
|
|
}
|
|
|
|
|
},
|
|
|
|
|
PatKind::Lit(..) | PatKind::Range(..) | PatKind::Wild | PatKind::Path(..) => (),
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
let mut result = FxHashMap::default();
|
|
|
|
|
bindings_impl(cx, pat, &mut result);
|
|
|
|
|
result
|
|
|
|
|
}
|