diff options
| -rw-r--r-- | clippy_lints/src/matches/collapsible_match.rs | 49 | ||||
| -rw-r--r-- | clippy_lints/src/matches/mod.rs | 11 | ||||
| -rw-r--r-- | clippy_utils/src/lib.rs | 18 | ||||
| -rw-r--r-- | tests/ui/collapsible_match.rs | 41 | ||||
| -rw-r--r-- | tests/ui/collapsible_match.stderr | 71 | ||||
| -rw-r--r-- | tests/ui/collapsible_match2.stderr | 2 |
6 files changed, 184 insertions, 8 deletions
diff --git a/clippy_lints/src/matches/collapsible_match.rs b/clippy_lints/src/matches/collapsible_match.rs index 5b50efad3e4..aaf559fc443 100644 --- a/clippy_lints/src/matches/collapsible_match.rs +++ b/clippy_lints/src/matches/collapsible_match.rs @@ -4,20 +4,22 @@ use clippy_utils::msrvs::Msrv; use clippy_utils::source::snippet; use clippy_utils::visitors::is_local_used; use clippy_utils::{ - SpanlessEq, is_res_lang_ctor, is_unit_expr, path_to_local, peel_blocks_with_stmt, peel_ref_operators, + SpanlessEq, get_ref_operators, is_res_lang_ctor, is_unit_expr, path_to_local, peel_blocks_with_stmt, + peel_ref_operators, }; +use rustc_ast::BorrowKind; use rustc_errors::MultiSpan; use rustc_hir::LangItem::OptionNone; -use rustc_hir::{Arm, Expr, HirId, Pat, PatExpr, PatExprKind, PatKind}; +use rustc_hir::{Arm, Expr, ExprKind, HirId, Pat, PatExpr, PatExprKind, PatKind}; use rustc_lint::LateContext; use rustc_span::Span; use super::{COLLAPSIBLE_MATCH, pat_contains_disallowed_or}; -pub(super) fn check_match<'tcx>(cx: &LateContext<'tcx>, arms: &'tcx [Arm<'_>], msrv: Msrv) { +pub(super) fn check_match<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>, arms: &'tcx [Arm<'_>], msrv: Msrv) { if let Some(els_arm) = arms.iter().rfind(|arm| arm_is_wild_like(cx, arm)) { for arm in arms { - check_arm(cx, true, arm.pat, arm.body, arm.guard, Some(els_arm.body), msrv); + check_arm(cx, true, arm.pat, expr, arm.body, arm.guard, Some(els_arm.body), msrv); } } } @@ -27,15 +29,18 @@ pub(super) fn check_if_let<'tcx>( pat: &'tcx Pat<'_>, body: &'tcx Expr<'_>, else_expr: Option<&'tcx Expr<'_>>, + let_expr: &'tcx Expr<'_>, msrv: Msrv, ) { - check_arm(cx, false, pat, body, None, else_expr, msrv); + check_arm(cx, false, pat, let_expr, body, None, else_expr, msrv); } +#[allow(clippy::too_many_arguments)] fn check_arm<'tcx>( cx: &LateContext<'tcx>, outer_is_match: bool, outer_pat: &'tcx Pat<'tcx>, + outer_cond: &'tcx Expr<'tcx>, outer_then_body: &'tcx Expr<'tcx>, outer_guard: Option<&'tcx Expr<'tcx>>, outer_else_body: Option<&'tcx Expr<'tcx>>, @@ -82,6 +87,9 @@ fn check_arm<'tcx>( }, IfLetOrMatch::Match(_, arms, ..) => !arms.iter().any(|arm| is_local_used(cx, arm, binding_id)), } + // Check if the inner expression contains any borrows/dereferences + && let ref_types = get_ref_operators(cx, inner_scrutinee) + && let Some(method) = build_ref_method_chain(ref_types) { let msg = format!( "this `{}` can be collapsed into the outer `{}`", @@ -103,6 +111,10 @@ fn check_arm<'tcx>( let mut help_span = MultiSpan::from_spans(vec![binding_span, inner_then_pat.span]); help_span.push_span_label(binding_span, "replace this binding"); help_span.push_span_label(inner_then_pat.span, format!("with this pattern{replace_msg}")); + if !method.is_empty() { + let outer_cond_msg = format!("use: `{}{}`", snippet(cx, outer_cond.span, ".."), method); + help_span.push_span_label(outer_cond.span, outer_cond_msg); + } diag.span_help( help_span, "the outer pattern can be modified to include the inner pattern", @@ -148,3 +160,30 @@ fn find_pat_binding_and_is_innermost_parent_pat_struct(pat: &Pat<'_>, hir_id: Hi }); (span, is_innermost_parent_pat_struct) } + +/// Builds a chain of reference-manipulation method calls (e.g., `.as_ref()`, `.as_mut()`, +/// `.copied()`) based on reference operators +fn build_ref_method_chain(expr: Vec<&Expr<'_>>) -> Option<String> { + let mut req_method_calls = String::new(); + + for ref_operator in expr { + match ref_operator.kind { + ExprKind::AddrOf(BorrowKind::Raw, _, _) => { + return None; + }, + ExprKind::AddrOf(_, m, _) if m.is_mut() => { + req_method_calls.push_str(".as_mut()"); + }, + ExprKind::AddrOf(_, _, _) => { + req_method_calls.push_str(".as_ref()"); + }, + // Deref operator is the only operator that this function should have received + ExprKind::Unary(_, _) => { + req_method_calls.push_str(".copied()"); + }, + _ => (), + } + } + + Some(req_method_calls) +} diff --git a/clippy_lints/src/matches/mod.rs b/clippy_lints/src/matches/mod.rs index c128fc40b73..6f49c552411 100644 --- a/clippy_lints/src/matches/mod.rs +++ b/clippy_lints/src/matches/mod.rs @@ -1073,7 +1073,7 @@ impl<'tcx> LateLintPass<'tcx> for Matches { significant_drop_in_scrutinee::check_match(cx, expr, ex, arms, source); } - collapsible_match::check_match(cx, arms, self.msrv); + collapsible_match::check_match(cx, ex, arms, self.msrv); if !from_expansion { // These don't depend on a relationship between multiple arms match_wild_err_arm::check(cx, ex, arms); @@ -1137,7 +1137,14 @@ impl<'tcx> LateLintPass<'tcx> for Matches { match_ref_pats::check(cx, ex, arms.iter().map(|el| el.pat), expr); } } else if let Some(if_let) = higher::IfLet::hir(cx, expr) { - collapsible_match::check_if_let(cx, if_let.let_pat, if_let.if_then, if_let.if_else, self.msrv); + collapsible_match::check_if_let( + cx, + if_let.let_pat, + if_let.if_then, + if_let.if_else, + if_let.let_expr, + self.msrv, + ); significant_drop_in_scrutinee::check_if_let(cx, expr, if_let.let_expr, if_let.if_then, if_let.if_else); if !from_expansion { if let Some(else_expr) = if_let.if_else { diff --git a/clippy_utils/src/lib.rs b/clippy_utils/src/lib.rs index df47b9f7e33..0bb19dab1f7 100644 --- a/clippy_utils/src/lib.rs +++ b/clippy_utils/src/lib.rs @@ -2404,6 +2404,24 @@ pub fn peel_ref_operators<'hir>(cx: &LateContext<'_>, mut expr: &'hir Expr<'hir> expr } +/// Returns a `Vec` of `Expr`s containing `AddrOf` operators (`&`) or deref operators (`*`) of a +/// given expression. +pub fn get_ref_operators<'hir>(cx: &LateContext<'_>, expr: &'hir Expr<'hir>) -> Vec<&'hir Expr<'hir>> { + let mut operators = Vec::new(); + peel_hir_expr_while(expr, |expr| match expr.kind { + ExprKind::AddrOf(_, _, e) => { + operators.push(expr); + Some(e) + }, + ExprKind::Unary(UnOp::Deref, e) if cx.typeck_results().expr_ty(e).is_ref() => { + operators.push(expr); + Some(e) + }, + _ => None, + }); + operators +} + pub fn is_hir_ty_cfg_dependant(cx: &LateContext<'_>, ty: &hir::Ty<'_>) -> bool { if let TyKind::Path(QPath::Resolved(_, path)) = ty.kind && let Res::Def(_, def_id) = path.res diff --git a/tests/ui/collapsible_match.rs b/tests/ui/collapsible_match.rs index 71b82040ff6..8931a3aa09c 100644 --- a/tests/ui/collapsible_match.rs +++ b/tests/ui/collapsible_match.rs @@ -316,6 +316,47 @@ fn lint_emitted_at_right_node(opt: Option<Result<u64, String>>) { }; } +pub fn issue_14155() { + let mut arr = ["a", "b", "c"]; + if let Some(last) = arr.last() { + match *last { + //~^ collapsible_match + "a" | "b" => { + unimplemented!() + }, + _ => (), + } + } + + if let Some(last) = arr.last() { + match &last { + //~^ collapsible_match + &&"a" | &&"b" => { + unimplemented!() + }, + _ => (), + } + } + + if let Some(mut last) = arr.last_mut() { + match &mut last { + //~^ collapsible_match + &mut &mut "a" | &mut &mut "b" => { + unimplemented!() + }, + _ => (), + } + } + + const NULL_PTR: *const &'static str = std::ptr::null(); + if let Some(last) = arr.last() { + match &raw const *last { + NULL_PTR => unimplemented!(), + _ => (), + } + } +} + fn make<T>() -> T { unimplemented!() } diff --git a/tests/ui/collapsible_match.stderr b/tests/ui/collapsible_match.stderr index c290d84ec29..14b1c1b187e 100644 --- a/tests/ui/collapsible_match.stderr +++ b/tests/ui/collapsible_match.stderr @@ -250,5 +250,74 @@ LL | if let Issue9647::A { a: Some(a), .. } = x { LL | if let Some(u) = a { | ^^^^^^^ with this pattern -error: aborting due to 13 previous errors +error: this `match` can be collapsed into the outer `if let` + --> tests/ui/collapsible_match.rs:322:9 + | +LL | / match *last { +LL | | +LL | | "a" | "b" => { +LL | | unimplemented!() +LL | | }, +LL | | _ => (), +LL | | } + | |_________^ + | +help: the outer pattern can be modified to include the inner pattern + --> tests/ui/collapsible_match.rs:321:17 + | +LL | if let Some(last) = arr.last() { + | ^^^^ ---------- use: `arr.last().copied()` + | | + | replace this binding +... +LL | "a" | "b" => { + | ^^^^^^^^^ with this pattern + +error: this `match` can be collapsed into the outer `if let` + --> tests/ui/collapsible_match.rs:332:9 + | +LL | / match &last { +LL | | +LL | | &&"a" | &&"b" => { +LL | | unimplemented!() +LL | | }, +LL | | _ => (), +LL | | } + | |_________^ + | +help: the outer pattern can be modified to include the inner pattern + --> tests/ui/collapsible_match.rs:331:17 + | +LL | if let Some(last) = arr.last() { + | ^^^^ ---------- use: `arr.last().as_ref()` + | | + | replace this binding +... +LL | &&"a" | &&"b" => { + | ^^^^^^^^^^^^^ with this pattern + +error: this `match` can be collapsed into the outer `if let` + --> tests/ui/collapsible_match.rs:342:9 + | +LL | / match &mut last { +LL | | +LL | | &mut &mut "a" | &mut &mut "b" => { +LL | | unimplemented!() +LL | | }, +LL | | _ => (), +LL | | } + | |_________^ + | +help: the outer pattern can be modified to include the inner pattern + --> tests/ui/collapsible_match.rs:341:17 + | +LL | if let Some(mut last) = arr.last_mut() { + | ^^^^^^^^ -------------- use: `arr.last_mut().as_mut()` + | | + | replace this binding +... +LL | &mut &mut "a" | &mut &mut "b" => { + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ with this pattern + +error: aborting due to 16 previous errors diff --git a/tests/ui/collapsible_match2.stderr b/tests/ui/collapsible_match2.stderr index 7b273063752..25970670999 100644 --- a/tests/ui/collapsible_match2.stderr +++ b/tests/ui/collapsible_match2.stderr @@ -77,6 +77,8 @@ LL | | }, help: the outer pattern can be modified to include the inner pattern --> tests/ui/collapsible_match2.rs:54:14 | +LL | match Some(&[1]) { + | ---------- use: `Some(&[1]).copied()` LL | Some(s) => match *s { | ^ replace this binding LL | |