diff options
| -rw-r--r-- | clippy_lints/src/matches/match_ref_pats.rs | 66 | ||||
| -rw-r--r-- | clippy_lints/src/matches/mod.rs | 69 |
2 files changed, 71 insertions, 64 deletions
diff --git a/clippy_lints/src/matches/match_ref_pats.rs b/clippy_lints/src/matches/match_ref_pats.rs new file mode 100644 index 00000000000..80f964ba1b7 --- /dev/null +++ b/clippy_lints/src/matches/match_ref_pats.rs @@ -0,0 +1,66 @@ +use clippy_utils::diagnostics::{multispan_sugg, span_lint_and_then}; +use clippy_utils::source::snippet; +use clippy_utils::sugg::Sugg; +use core::iter::once; +use rustc_hir::{BorrowKind, Expr, ExprKind, Mutability, Pat, PatKind}; +use rustc_lint::LateContext; + +use super::MATCH_REF_PATS; + +pub(crate) fn check<'a, 'b, I>(cx: &LateContext<'_>, ex: &Expr<'_>, pats: I, expr: &Expr<'_>) +where + 'b: 'a, + I: Clone + Iterator<Item = &'a Pat<'b>>, +{ + if !has_multiple_ref_pats(pats.clone()) { + return; + } + + let (first_sugg, msg, title); + let span = ex.span.source_callsite(); + if let ExprKind::AddrOf(BorrowKind::Ref, Mutability::Not, inner) = ex.kind { + first_sugg = once((span, Sugg::hir_with_macro_callsite(cx, inner, "..").to_string())); + msg = "try"; + title = "you don't need to add `&` to both the expression and the patterns"; + } else { + first_sugg = once((span, Sugg::hir_with_macro_callsite(cx, ex, "..").deref().to_string())); + msg = "instead of prefixing all patterns with `&`, you can dereference the expression"; + title = "you don't need to add `&` to all patterns"; + } + + let remaining_suggs = pats.filter_map(|pat| { + if let PatKind::Ref(refp, _) = pat.kind { + Some((pat.span, snippet(cx, refp.span, "..").to_string())) + } else { + None + } + }); + + span_lint_and_then(cx, MATCH_REF_PATS, expr.span, title, |diag| { + if !expr.span.from_expansion() { + multispan_sugg(diag, msg, first_sugg.chain(remaining_suggs)); + } + }); +} + +fn has_multiple_ref_pats<'a, 'b, I>(pats: I) -> bool +where + 'b: 'a, + I: Iterator<Item = &'a Pat<'b>>, +{ + let mut ref_count = 0; + for opt in pats.map(|pat| match pat.kind { + PatKind::Ref(..) => Some(true), // &-patterns + PatKind::Wild => Some(false), // an "anything" wildcard is also fine + _ => None, // any other pattern is not fine + }) { + if let Some(inner) = opt { + if inner { + ref_count += 1; + } + } else { + return false; + } + } + ref_count > 1 +} diff --git a/clippy_lints/src/matches/mod.rs b/clippy_lints/src/matches/mod.rs index c2bf2aa6c9d..56f1031f9b9 100644 --- a/clippy_lints/src/matches/mod.rs +++ b/clippy_lints/src/matches/mod.rs @@ -1,11 +1,9 @@ -use clippy_utils::diagnostics::{multispan_sugg, span_lint_and_help, span_lint_and_sugg, span_lint_and_then}; -use clippy_utils::source::{snippet, snippet_with_applicability}; -use clippy_utils::sugg::Sugg; +use clippy_utils::diagnostics::{span_lint_and_help, span_lint_and_sugg}; +use clippy_utils::source::snippet_with_applicability; use clippy_utils::{is_wild, meets_msrv, msrvs, path_to_local_id, peel_blocks, strip_pat_refs}; -use core::iter::once; use if_chain::if_chain; use rustc_errors::Applicability; -use rustc_hir::{Arm, BorrowKind, Expr, ExprKind, Local, MatchSource, Mutability, Pat, PatKind, QPath}; +use rustc_hir::{Arm, Expr, ExprKind, Local, MatchSource, Pat, PatKind, QPath}; use rustc_lint::{LateContext, LateLintPass}; use rustc_middle::ty; use rustc_semver::RustcVersion; @@ -14,6 +12,7 @@ use rustc_session::{declare_tool_lint, impl_lint_pass}; mod match_as_ref; mod match_bool; mod match_like_matches; +mod match_ref_pats; mod match_same_arms; mod match_single_binding; mod match_wild_enum; @@ -633,7 +632,7 @@ impl<'tcx> LateLintPass<'tcx> for Matches { } } if let ExprKind::Match(ex, arms, _) = expr.kind { - check_match_ref_pats(cx, ex, arms.iter().map(|el| el.pat), expr); + match_ref_pats::check(cx, ex, arms.iter().map(|el| el.pat), expr); } } @@ -698,42 +697,6 @@ impl<'tcx> LateLintPass<'tcx> for Matches { extract_msrv_attr!(LateContext); } -fn check_match_ref_pats<'a, 'b, I>(cx: &LateContext<'_>, ex: &Expr<'_>, pats: I, expr: &Expr<'_>) -where - 'b: 'a, - I: Clone + Iterator<Item = &'a Pat<'b>>, -{ - if !has_multiple_ref_pats(pats.clone()) { - return; - } - - let (first_sugg, msg, title); - let span = ex.span.source_callsite(); - if let ExprKind::AddrOf(BorrowKind::Ref, Mutability::Not, inner) = ex.kind { - first_sugg = once((span, Sugg::hir_with_macro_callsite(cx, inner, "..").to_string())); - msg = "try"; - title = "you don't need to add `&` to both the expression and the patterns"; - } else { - first_sugg = once((span, Sugg::hir_with_macro_callsite(cx, ex, "..").deref().to_string())); - msg = "instead of prefixing all patterns with `&`, you can dereference the expression"; - title = "you don't need to add `&` to all patterns"; - } - - let remaining_suggs = pats.filter_map(|pat| { - if let PatKind::Ref(refp, _) = pat.kind { - Some((pat.span, snippet(cx, refp.span, "..").to_string())) - } else { - None - } - }); - - span_lint_and_then(cx, MATCH_REF_PATS, expr.span, title, |diag| { - if !expr.span.from_expansion() { - multispan_sugg(diag, msg, first_sugg.chain(remaining_suggs)); - } - }); -} - fn check_wild_in_or_pats(cx: &LateContext<'_>, arms: &[Arm<'_>]) { for arm in arms { if let PatKind::Or(fields) = arm.pat.kind { @@ -751,25 +714,3 @@ fn check_wild_in_or_pats(cx: &LateContext<'_>, arms: &[Arm<'_>]) { } } } - -fn has_multiple_ref_pats<'a, 'b, I>(pats: I) -> bool -where - 'b: 'a, - I: Iterator<Item = &'a Pat<'b>>, -{ - let mut ref_count = 0; - for opt in pats.map(|pat| match pat.kind { - PatKind::Ref(..) => Some(true), // &-patterns - PatKind::Wild => Some(false), // an "anything" wildcard is also fine - _ => None, // any other pattern is not fine - }) { - if let Some(inner) = opt { - if inner { - ref_count += 1; - } - } else { - return false; - } - } - ref_count > 1 -} |