2016-04-07 15:46:48 +00:00
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use rustc::hir::*;
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2015-08-21 17:32:21 +00:00
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use rustc::lint::*;
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2016-03-31 15:05:43 +00:00
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use rustc::middle::const_val::ConstVal;
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2016-03-27 18:59:02 +00:00
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use rustc::ty;
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2016-03-31 15:05:43 +00:00
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use rustc_const_eval::EvalHint::ExprTypeChecked;
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use rustc_const_eval::eval_const_expr_partial;
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use rustc_const_math::ConstInt;
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2015-12-23 00:14:10 +00:00
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use std::cmp::Ordering;
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2016-02-12 17:35:44 +00:00
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use syntax::ast::LitKind;
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2015-11-25 04:57:50 +00:00
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use syntax::codemap::Span;
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2016-04-14 16:13:15 +00:00
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use utils::paths;
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2016-03-09 15:22:31 +00:00
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use utils::{match_type, snippet, span_note_and_lint, span_lint_and_then, in_external_macro, expr_block};
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2016-06-29 19:50:21 +00:00
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use utils::sugg::Sugg;
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2015-08-21 17:32:21 +00:00
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2016-08-06 07:55:04 +00:00
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/// **What it does:** Checks for matches with a single arm where an `if let`
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/// will usually suffice.
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2015-12-11 00:22:27 +00:00
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///
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/// **Why is this bad?** Just readability – `if let` nests less than a `match`.
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///
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2016-08-06 07:55:04 +00:00
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/// **Known problems:** None.
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2015-12-11 00:22:27 +00:00
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///
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/// **Example:**
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2016-07-15 22:25:44 +00:00
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/// ```rust
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2015-12-11 00:22:27 +00:00
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/// match x {
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2016-09-18 11:17:25 +00:00
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/// Some(ref foo) => bar(foo),
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2015-12-11 00:22:27 +00:00
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/// _ => ()
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/// }
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/// ```
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2016-02-05 23:13:29 +00:00
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declare_lint! {
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2016-08-06 08:18:36 +00:00
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pub SINGLE_MATCH,
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Warn,
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2016-02-05 23:13:29 +00:00
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"a match statement with a single nontrivial arm (i.e, where the other arm \
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2016-08-06 08:18:36 +00:00
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is `_ => {}`) instead of `if let`"
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2016-02-05 23:13:29 +00:00
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}
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2015-12-23 00:14:10 +00:00
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2016-08-06 07:55:04 +00:00
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/// **What it does:** Checks for matches with a two arms where an `if let` will
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/// usually suffice.
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2016-01-24 11:24:16 +00:00
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///
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/// **Why is this bad?** Just readability – `if let` nests less than a `match`.
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///
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2016-08-06 07:55:04 +00:00
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/// **Known problems:** Personal style preferences may differ.
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2016-01-24 11:24:16 +00:00
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///
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/// **Example:**
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2016-07-15 22:25:44 +00:00
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/// ```rust
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2016-01-24 11:24:16 +00:00
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/// match x {
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2016-09-18 11:17:25 +00:00
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/// Some(ref foo) => bar(foo),
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2016-01-24 11:24:16 +00:00
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/// _ => bar(other_ref),
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/// }
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/// ```
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2016-02-05 23:13:29 +00:00
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declare_lint! {
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2016-08-06 08:18:36 +00:00
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pub SINGLE_MATCH_ELSE,
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Allow,
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"a match statement with a two arms where the second arm's pattern is a wildcard \
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instead of `if let`"
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2016-02-05 23:13:29 +00:00
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}
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2016-01-24 11:24:16 +00:00
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2016-08-06 07:55:04 +00:00
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/// **What it does:** Checks for matches where all arms match a reference,
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/// suggesting to remove the reference and deref the matched expression
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/// instead. It also checks for `if let &foo = bar` blocks.
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2015-12-11 00:22:27 +00:00
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///
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2016-08-06 07:55:04 +00:00
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/// **Why is this bad?** It just makes the code less readable. That reference
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/// destructuring adds nothing to the code.
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2015-12-11 00:22:27 +00:00
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///
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2016-08-06 07:55:04 +00:00
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/// **Known problems:** None.
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2015-12-11 00:22:27 +00:00
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///
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/// **Example:**
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2016-07-15 22:25:44 +00:00
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/// ```rust
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2015-12-11 00:22:27 +00:00
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/// match x {
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/// &A(ref y) => foo(y),
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/// &B => bar(),
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/// _ => frob(&x),
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/// }
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/// ```
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2016-02-05 23:13:29 +00:00
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declare_lint! {
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2016-08-06 08:18:36 +00:00
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pub MATCH_REF_PATS,
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Warn,
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"a match or `if let` with all arms prefixed with `&` instead of deref-ing the match expression"
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2016-02-05 23:13:29 +00:00
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}
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2015-12-23 00:14:10 +00:00
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2016-08-06 07:55:04 +00:00
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/// **What it does:** Checks for matches where match expression is a `bool`. It
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/// suggests to replace the expression with an `if...else` block.
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2015-12-11 00:22:27 +00:00
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///
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/// **Why is this bad?** It makes the code less readable.
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///
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2016-08-06 07:55:04 +00:00
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/// **Known problems:** None.
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2015-12-11 00:22:27 +00:00
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///
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/// **Example:**
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2016-07-15 22:25:44 +00:00
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/// ```rust
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2015-12-11 00:22:27 +00:00
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/// let condition: bool = true;
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/// match condition {
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/// true => foo(),
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/// false => bar(),
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/// }
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/// ```
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2016-02-05 23:13:29 +00:00
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declare_lint! {
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2016-08-06 08:18:36 +00:00
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pub MATCH_BOOL,
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Warn,
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"a match on a boolean expression instead of an `if..else` block"
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2016-02-05 23:13:29 +00:00
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}
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2015-08-21 17:32:21 +00:00
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2016-08-06 07:55:04 +00:00
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/// **What it does:** Checks for overlapping match arms.
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2015-12-23 00:14:10 +00:00
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///
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2016-08-06 07:55:04 +00:00
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/// **Why is this bad?** It is likely to be an error and if not, makes the code
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/// less obvious.
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2015-12-23 00:14:10 +00:00
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///
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2016-08-06 07:55:04 +00:00
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/// **Known problems:** None.
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2015-12-23 00:14:10 +00:00
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///
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/// **Example:**
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2016-07-15 22:25:44 +00:00
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/// ```rust
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2015-12-23 00:14:10 +00:00
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/// let x = 5;
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/// match x {
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/// 1 ... 10 => println!("1 ... 10"),
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/// 5 ... 15 => println!("5 ... 15"),
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/// _ => (),
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/// }
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/// ```
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2016-02-05 23:13:29 +00:00
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declare_lint! {
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2016-08-06 08:18:36 +00:00
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pub MATCH_OVERLAPPING_ARM,
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Warn,
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"a match with overlapping arms"
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2016-02-05 23:13:29 +00:00
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}
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2015-12-23 00:14:10 +00:00
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2015-08-21 17:32:21 +00:00
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#[allow(missing_copy_implementations)]
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pub struct MatchPass;
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impl LintPass for MatchPass {
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fn get_lints(&self) -> LintArray {
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2016-12-20 17:21:30 +00:00
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lint_array!(SINGLE_MATCH,
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MATCH_REF_PATS,
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MATCH_BOOL,
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SINGLE_MATCH_ELSE,
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MATCH_OVERLAPPING_ARM)
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2015-08-21 17:32:21 +00:00
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}
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2015-09-19 02:53:04 +00:00
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}
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2015-08-21 17:32:21 +00:00
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2016-12-07 12:13:40 +00:00
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impl<'a, 'tcx> LateLintPass<'a, 'tcx> for MatchPass {
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fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr) {
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2016-01-04 04:26:12 +00:00
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if in_external_macro(cx, expr.span) {
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return;
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}
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2015-09-03 14:42:17 +00:00
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if let ExprMatch(ref ex, ref arms, MatchSource::Normal) = expr.node {
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2015-12-23 01:19:32 +00:00
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check_single_match(cx, ex, arms, expr);
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check_match_bool(cx, ex, arms, expr);
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2015-12-23 10:25:44 +00:00
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check_overlapping_arms(cx, ex, arms);
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2015-12-23 01:19:32 +00:00
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}
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if let ExprMatch(ref ex, ref arms, source) = expr.node {
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check_match_ref_pats(cx, ex, arms, source, expr);
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}
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}
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}
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2015-08-21 17:49:00 +00:00
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2016-02-29 11:19:32 +00:00
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#[cfg_attr(rustfmt, rustfmt_skip)]
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2015-12-23 01:19:32 +00:00
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fn check_single_match(cx: &LateContext, ex: &Expr, arms: &[Arm], expr: &Expr) {
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2016-01-13 00:19:27 +00:00
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if arms.len() == 2 &&
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2016-02-29 11:19:32 +00:00
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arms[0].pats.len() == 1 && arms[0].guard.is_none() &&
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arms[1].pats.len() == 1 && arms[1].guard.is_none() {
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2016-02-24 16:38:57 +00:00
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let els = if is_unit_expr(&arms[1].body) {
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None
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} else if let ExprBlock(_) = arms[1].body.node {
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// matches with blocks that contain statements are prettier as `if let + else`
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Some(&*arms[1].body)
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} else {
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// allow match arms with just expressions
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return;
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};
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2016-11-16 20:57:56 +00:00
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let ty = cx.tcx.tables().expr_ty(ex);
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2016-02-24 16:38:57 +00:00
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if ty.sty != ty::TyBool || cx.current_level(MATCH_BOOL) == Allow {
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check_single_match_single_pattern(cx, ex, arms, expr, els);
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check_single_match_opt_like(cx, ex, arms, expr, ty, els);
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}
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2016-01-13 00:19:27 +00:00
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}
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}
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2016-01-24 11:24:16 +00:00
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fn check_single_match_single_pattern(cx: &LateContext, ex: &Expr, arms: &[Arm], expr: &Expr, els: Option<&Expr>) {
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2016-02-18 20:16:39 +00:00
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if arms[1].pats[0].node == PatKind::Wild {
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2016-01-24 11:24:16 +00:00
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let lint = if els.is_some() {
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SINGLE_MATCH_ELSE
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} else {
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SINGLE_MATCH
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};
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let els_str = els.map_or(String::new(), |els| format!(" else {}", expr_block(cx, els, None, "..")));
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2016-01-13 11:57:44 +00:00
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span_lint_and_then(cx,
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2016-01-24 11:24:16 +00:00
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lint,
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2016-01-04 04:26:12 +00:00
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expr.span,
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2016-01-13 11:57:44 +00:00
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"you seem to be trying to use match for destructuring a single pattern. \
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2016-02-29 11:19:32 +00:00
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Consider using `if let`",
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|db| {
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2016-06-05 23:42:39 +00:00
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db.span_suggestion(expr.span,
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"try this",
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format!("if let {} = {} {}{}",
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snippet(cx, arms[0].pats[0].span, ".."),
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snippet(cx, ex.span, ".."),
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expr_block(cx, &arms[0].body, None, ".."),
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els_str));
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});
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2015-12-23 01:19:32 +00:00
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}
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}
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2016-12-21 11:14:54 +00:00
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fn check_single_match_opt_like(
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cx: &LateContext,
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ex: &Expr,
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arms: &[Arm],
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expr: &Expr,
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ty: ty::Ty,
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els: Option<&Expr>
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) {
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2016-01-24 11:24:16 +00:00
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// list of candidate Enums we know will never get any more members
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2016-04-14 16:13:15 +00:00
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let candidates = &[(&paths::COW, "Borrowed"),
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(&paths::COW, "Cow::Borrowed"),
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(&paths::COW, "Cow::Owned"),
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(&paths::COW, "Owned"),
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(&paths::OPTION, "None"),
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(&paths::RESULT, "Err"),
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(&paths::RESULT, "Ok")];
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2016-01-13 00:19:27 +00:00
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let path = match arms[1].pats[0].node {
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2016-05-27 12:24:28 +00:00
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PatKind::TupleStruct(ref path, ref inner, _) => {
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2016-01-24 11:24:16 +00:00
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// contains any non wildcard patterns? e.g. Err(err)
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2016-02-24 16:38:57 +00:00
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if inner.iter().any(|pat| pat.node != PatKind::Wild) {
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2016-01-24 11:24:16 +00:00
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return;
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}
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path.to_string()
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2016-12-20 17:21:30 +00:00
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},
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2016-12-01 21:31:56 +00:00
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PatKind::Binding(BindByValue(MutImmutable), _, ident, None) => ident.node.to_string(),
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PatKind::Path(ref path) => path.to_string(),
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2016-01-30 12:48:39 +00:00
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_ => return,
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2016-01-13 00:19:27 +00:00
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};
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for &(ty_path, pat_path) in candidates {
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if &path == pat_path && match_type(cx, ty, ty_path) {
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2016-01-24 11:24:16 +00:00
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let lint = if els.is_some() {
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SINGLE_MATCH_ELSE
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} else {
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SINGLE_MATCH
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};
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let els_str = els.map_or(String::new(), |els| format!(" else {}", expr_block(cx, els, None, "..")));
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2016-01-13 11:57:44 +00:00
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span_lint_and_then(cx,
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2016-01-24 11:24:16 +00:00
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lint,
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2016-01-13 00:19:27 +00:00
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expr.span,
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2016-01-30 12:48:39 +00:00
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"you seem to be trying to use match for destructuring a single pattern. Consider \
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using `if let`",
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|db| {
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2016-06-05 23:42:39 +00:00
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db.span_suggestion(expr.span,
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"try this",
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format!("if let {} = {} {}{}",
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snippet(cx, arms[0].pats[0].span, ".."),
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snippet(cx, ex.span, ".."),
|
|
|
|
|
expr_block(cx, &arms[0].body, None, ".."),
|
|
|
|
|
els_str));
|
|
|
|
|
});
|
2016-01-13 00:19:27 +00:00
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
|
2015-12-23 01:19:32 +00:00
|
|
|
|
fn check_match_bool(cx: &LateContext, ex: &Expr, arms: &[Arm], expr: &Expr) {
|
|
|
|
|
// type of expression == bool
|
2016-11-16 20:57:56 +00:00
|
|
|
|
if cx.tcx.tables().expr_ty(ex).sty == ty::TyBool {
|
2016-07-03 17:13:01 +00:00
|
|
|
|
span_lint_and_then(cx,
|
|
|
|
|
MATCH_BOOL,
|
|
|
|
|
expr.span,
|
|
|
|
|
"you seem to be trying to match on a boolean expression",
|
|
|
|
|
move |db| {
|
|
|
|
|
if arms.len() == 2 && arms[0].pats.len() == 1 {
|
|
|
|
|
// no guards
|
|
|
|
|
let exprs = if let PatKind::Lit(ref arm_bool) = arms[0].pats[0].node {
|
|
|
|
|
if let ExprLit(ref lit) = arm_bool.node {
|
|
|
|
|
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
|
2015-12-23 01:19:32 +00:00
|
|
|
|
}
|
2016-01-04 04:26:12 +00:00
|
|
|
|
} else {
|
|
|
|
|
None
|
2016-07-03 17:13:01 +00:00
|
|
|
|
};
|
2016-01-13 11:57:44 +00:00
|
|
|
|
|
2016-08-01 14:59:14 +00:00
|
|
|
|
if let Some((true_expr, false_expr)) = exprs {
|
2016-07-03 17:13:01 +00:00
|
|
|
|
let sugg = match (is_unit_expr(true_expr), is_unit_expr(false_expr)) {
|
|
|
|
|
(false, false) => {
|
|
|
|
|
Some(format!("if {} {} else {}",
|
|
|
|
|
snippet(cx, ex.span, "b"),
|
|
|
|
|
expr_block(cx, true_expr, None, ".."),
|
|
|
|
|
expr_block(cx, false_expr, None, "..")))
|
2016-12-20 17:21:30 +00:00
|
|
|
|
},
|
2016-07-03 17:13:01 +00:00
|
|
|
|
(false, true) => {
|
|
|
|
|
Some(format!("if {} {}", snippet(cx, ex.span, "b"), expr_block(cx, true_expr, None, "..")))
|
2016-12-20 17:21:30 +00:00
|
|
|
|
},
|
2016-07-03 17:13:01 +00:00
|
|
|
|
(true, false) => {
|
|
|
|
|
let test = Sugg::hir(cx, ex, "..");
|
2016-12-20 17:21:30 +00:00
|
|
|
|
Some(format!("if {} {}", !test, expr_block(cx, false_expr, None, "..")))
|
|
|
|
|
},
|
2016-07-03 17:13:01 +00:00
|
|
|
|
(true, true) => None,
|
|
|
|
|
};
|
|
|
|
|
|
|
|
|
|
if let Some(sugg) = sugg {
|
|
|
|
|
db.span_suggestion(expr.span, "consider using an if/else expression", sugg);
|
2016-04-14 18:14:03 +00:00
|
|
|
|
}
|
2015-10-21 06:24:56 +00:00
|
|
|
|
}
|
2015-10-20 17:18:48 +00:00
|
|
|
|
}
|
2016-01-13 11:57:44 +00:00
|
|
|
|
|
2016-12-20 17:21:30 +00:00
|
|
|
|
});
|
2015-12-23 01:19:32 +00:00
|
|
|
|
}
|
|
|
|
|
}
|
2015-12-23 00:14:10 +00:00
|
|
|
|
|
2015-12-23 10:25:44 +00:00
|
|
|
|
fn check_overlapping_arms(cx: &LateContext, ex: &Expr, arms: &[Arm]) {
|
2016-11-16 20:57:56 +00:00
|
|
|
|
if arms.len() >= 2 && cx.tcx.tables().expr_ty(ex).is_integral() {
|
2015-12-23 01:19:32 +00:00
|
|
|
|
let ranges = all_ranges(cx, arms);
|
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) {
|
|
|
|
|
span_note_and_lint(cx,
|
|
|
|
|
MATCH_OVERLAPPING_ARM,
|
|
|
|
|
start.span,
|
|
|
|
|
"some ranges overlap",
|
|
|
|
|
end.span,
|
|
|
|
|
"overlaps with this");
|
|
|
|
|
}
|
2015-08-21 17:32:21 +00:00
|
|
|
|
}
|
2015-12-23 01:19:32 +00:00
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
fn check_match_ref_pats(cx: &LateContext, ex: &Expr, arms: &[Arm], source: MatchSource, expr: &Expr) {
|
|
|
|
|
if has_only_ref_pats(arms) {
|
|
|
|
|
if let ExprAddrOf(Mutability::MutImmutable, ref inner) = ex.node {
|
2016-03-09 15:22:31 +00:00
|
|
|
|
span_lint_and_then(cx,
|
|
|
|
|
MATCH_REF_PATS,
|
|
|
|
|
expr.span,
|
|
|
|
|
"you don't need to add `&` to both the expression and the patterns",
|
|
|
|
|
|db| {
|
2016-12-21 09:25:14 +00:00
|
|
|
|
let inner = Sugg::hir(cx, inner, "..");
|
|
|
|
|
let template = match_template(expr.span, source, inner);
|
|
|
|
|
db.span_suggestion(expr.span, "try", template);
|
|
|
|
|
});
|
2015-12-23 01:19:32 +00:00
|
|
|
|
} else {
|
2016-03-09 15:22:31 +00:00
|
|
|
|
span_lint_and_then(cx,
|
|
|
|
|
MATCH_REF_PATS,
|
|
|
|
|
expr.span,
|
|
|
|
|
"you don't need to add `&` to all patterns",
|
|
|
|
|
|db| {
|
2016-07-03 17:13:01 +00:00
|
|
|
|
let ex = Sugg::hir(cx, ex, "..");
|
|
|
|
|
let template = match_template(expr.span, source, ex.deref());
|
|
|
|
|
db.span_suggestion(expr.span,
|
2016-12-21 09:25:14 +00:00
|
|
|
|
"instead of prefixing all patterns with `&`, you can dereference the expression",
|
2016-07-03 17:13:01 +00:00
|
|
|
|
template);
|
|
|
|
|
});
|
2015-11-24 17:47:17 +00:00
|
|
|
|
}
|
2015-08-21 17:32:21 +00:00
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
|
2016-03-19 16:48:29 +00:00
|
|
|
|
/// Get all arms that are unbounded `PatRange`s.
|
2015-12-23 00:14:10 +00:00
|
|
|
|
fn all_ranges(cx: &LateContext, arms: &[Arm]) -> Vec<SpannedRange<ConstVal>> {
|
|
|
|
|
arms.iter()
|
2016-06-21 11:51:44 +00:00
|
|
|
|
.flat_map(|arm| {
|
2015-12-23 00:14:10 +00:00
|
|
|
|
if let Arm { ref pats, guard: None, .. } = *arm {
|
2016-12-20 17:21:30 +00:00
|
|
|
|
pats.iter()
|
|
|
|
|
} else {
|
|
|
|
|
[].iter()
|
|
|
|
|
}
|
|
|
|
|
.filter_map(|pat| {
|
|
|
|
|
if_let_chain! {[
|
2016-06-21 11:51:44 +00:00
|
|
|
|
let PatKind::Range(ref lhs, ref rhs) = pat.node,
|
|
|
|
|
let Ok(lhs) = eval_const_expr_partial(cx.tcx, lhs, ExprTypeChecked, None),
|
|
|
|
|
let Ok(rhs) = eval_const_expr_partial(cx.tcx, rhs, ExprTypeChecked, None)
|
|
|
|
|
], {
|
|
|
|
|
return Some(SpannedRange { span: pat.span, node: (lhs, rhs) });
|
|
|
|
|
}}
|
2015-12-23 00:14:10 +00:00
|
|
|
|
|
2016-12-20 17:21:30 +00:00
|
|
|
|
if_let_chain! {[
|
2016-06-21 11:51:44 +00:00
|
|
|
|
let PatKind::Lit(ref value) = pat.node,
|
|
|
|
|
let Ok(value) = eval_const_expr_partial(cx.tcx, value, ExprTypeChecked, None)
|
|
|
|
|
], {
|
|
|
|
|
return Some(SpannedRange { span: pat.span, node: (value.clone(), value) });
|
|
|
|
|
}}
|
2015-12-23 01:06:18 +00:00
|
|
|
|
|
2016-12-20 17:21:30 +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,
|
|
|
|
|
pub node: (T, T),
|
2015-12-23 00:14:10 +00:00
|
|
|
|
}
|
|
|
|
|
|
2016-03-15 19:09:53 +00:00
|
|
|
|
type TypedRanges = Vec<SpannedRange<ConstInt>>;
|
2015-12-23 00:14:10 +00:00
|
|
|
|
|
|
|
|
|
/// Get all `Int` ranges or all `Uint` ranges. Mixed types are an error anyway and other types than
|
|
|
|
|
/// `Uint` and `Int` probably don't make sense.
|
|
|
|
|
fn type_ranges(ranges: &[SpannedRange<ConstVal>]) -> TypedRanges {
|
2016-04-14 18:14:03 +00:00
|
|
|
|
ranges.iter()
|
2016-12-20 17:21:30 +00:00
|
|
|
|
.filter_map(|range| {
|
|
|
|
|
if let (ConstVal::Integral(start), ConstVal::Integral(end)) = range.node {
|
|
|
|
|
Some(SpannedRange {
|
|
|
|
|
span: range.span,
|
|
|
|
|
node: (start, end),
|
|
|
|
|
})
|
|
|
|
|
} else {
|
|
|
|
|
None
|
|
|
|
|
}
|
|
|
|
|
})
|
|
|
|
|
.collect()
|
2015-12-23 00:14:10 +00:00
|
|
|
|
}
|
|
|
|
|
|
2015-08-21 17:32:21 +00:00
|
|
|
|
fn is_unit_expr(expr: &Expr) -> bool {
|
|
|
|
|
match expr.node {
|
|
|
|
|
ExprTup(ref v) if v.is_empty() => true,
|
|
|
|
|
ExprBlock(ref b) if b.stmts.is_empty() && b.expr.is_none() => true,
|
|
|
|
|
_ => false,
|
|
|
|
|
}
|
|
|
|
|
}
|
2015-08-21 17:49:00 +00:00
|
|
|
|
|
|
|
|
|
fn has_only_ref_pats(arms: &[Arm]) -> bool {
|
2016-01-04 04:26:12 +00:00
|
|
|
|
let mapped = arms.iter()
|
2016-12-20 17:21:30 +00:00
|
|
|
|
.flat_map(|a| &a.pats)
|
|
|
|
|
.map(|p| {
|
|
|
|
|
match p.node {
|
|
|
|
|
PatKind::Ref(..) => Some(true), // &-patterns
|
|
|
|
|
PatKind::Wild => Some(false), // an "anything" wildcard is also fine
|
|
|
|
|
_ => None, // any other pattern is not fine
|
|
|
|
|
}
|
|
|
|
|
})
|
|
|
|
|
.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
|
|
|
|
|
2016-07-03 17:13:01 +00:00
|
|
|
|
fn match_template(span: Span, source: MatchSource, expr: Sugg) -> String {
|
2015-11-24 17:47:17 +00:00
|
|
|
|
match source {
|
2016-07-03 17:13:01 +00:00
|
|
|
|
MatchSource::Normal => format!("match {} {{ .. }}", expr),
|
|
|
|
|
MatchSource::IfLetDesugar { .. } => format!("if let .. = {} {{ .. }}", expr),
|
|
|
|
|
MatchSource::WhileLetDesugar => format!("while let .. = {} {{ .. }}", expr),
|
2016-04-03 15:16:53 +00:00
|
|
|
|
MatchSource::ForLoopDesugar => span_bug!(span, "for loop desugared to match with &-patterns!"),
|
2016-04-14 18:14:03 +00:00
|
|
|
|
MatchSource::TryDesugar => span_bug!(span, "`?` operator desugared to match with &-patterns!"),
|
2015-11-24 17:47:17 +00:00
|
|
|
|
}
|
|
|
|
|
}
|
2015-12-23 00:14:10 +00:00
|
|
|
|
|
2015-12-23 16:48:30 +00:00
|
|
|
|
pub fn overlapping<T>(ranges: &[SpannedRange<T>]) -> Option<(&SpannedRange<T>, &SpannedRange<T>)>
|
2016-01-04 04:26:12 +00:00
|
|
|
|
where T: Copy + Ord
|
|
|
|
|
{
|
2015-12-23 00:14:10 +00:00
|
|
|
|
#[derive(Copy, Clone, Debug, Eq, PartialEq)]
|
|
|
|
|
enum Kind<'a, T: 'a> {
|
|
|
|
|
Start(T, &'a SpannedRange<T>),
|
|
|
|
|
End(T, &'a SpannedRange<T>),
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
impl<'a, T: Copy> Kind<'a, T> {
|
|
|
|
|
fn range(&self) -> &'a SpannedRange<T> {
|
|
|
|
|
match *self {
|
2016-04-14 18:14:03 +00:00
|
|
|
|
Kind::Start(_, r) |
|
|
|
|
|
Kind::End(_, r) => r,
|
2015-12-23 00:14:10 +00:00
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
fn value(self) -> T {
|
|
|
|
|
match self {
|
2016-04-14 18:14:03 +00:00
|
|
|
|
Kind::Start(t, _) |
|
|
|
|
|
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 {
|
|
|
|
|
self.value().cmp(&other.value())
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
|
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) {
|
2016-01-04 04:26:12 +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
|
|
|
|
},
|
2015-12-23 00:14:10 +00:00
|
|
|
|
(&Kind::End(a, _), &Kind::Start(b, _)) if a != b => (),
|
2016-04-26 15:05:39 +00:00
|
|
|
|
_ => return Some((a.range(), b.range())),
|
2015-12-23 00:14:10 +00:00
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
None
|
|
|
|
|
}
|