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Auto merge of #13324 - WeiTheShinobi:single_match, r=dswij

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[`single_match`, `single_match_else`] fix suggestion when match irrefutable

fixes #13012

changelog:[`single_match`, `single_match_else`]: fix suggestion when `match` irrefutable
This commit is contained in:
bors 2024-09-08 15:02:35 +00:00
commit bcf528bdef
7 changed files with 184 additions and 4 deletions
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27
clippy_lints/src/matches/single_match.rs
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@ -1,5 +1,5 @@
use clippy_utils::diagnostics::span_lint_and_sugg;
use clippy_utils::source::{expr_block, snippet, SpanRangeExt};
use clippy_utils::source::{expr_block, snippet, snippet_block_with_context, SpanRangeExt};
use clippy_utils::ty::implements_trait;
use clippy_utils::{
is_lint_allowed, is_unit_expr, peel_blocks, peel_hir_pat_refs, peel_middle_ty_refs, peel_n_hir_expr_refs,
@ -9,7 +9,7 @@ use rustc_arena::DroplessArena;
use rustc_errors::Applicability;
use rustc_hir::def::{DefKind, Res};
use rustc_hir::intravisit::{walk_pat, Visitor};
use rustc_hir::{Arm, Expr, ExprKind, HirId, Pat, PatKind, QPath};
use rustc_hir::{Arm, Expr, ExprKind, HirId, Node, Pat, PatKind, QPath, StmtKind};
use rustc_lint::LateContext;
use rustc_middle::ty::{self, AdtDef, ParamEnv, TyCtxt, TypeckResults, VariantDef};
use rustc_span::{sym, Span};
@ -91,6 +91,29 @@ fn report_single_pattern(cx: &LateContext<'_>, ex: &Expr<'_>, arm: &Arm<'_>, exp
format!(" else {}", expr_block(cx, els, ctxt, "..", Some(expr.span), &mut app))
});
if snippet(cx, ex.span, "..") == snippet(cx, arm.pat.span, "..") {
let msg = "this pattern is irrefutable, `match` is useless";
let (sugg, help) = if is_unit_expr(arm.body) {
(String::new(), "`match` expression can be removed")
} else {
let mut sugg = snippet_block_with_context(cx, arm.body.span, ctxt, "..", Some(expr.span), &mut app)
.0
.to_string();
if let Node::Stmt(stmt) = cx.tcx.parent_hir_node(expr.hir_id)
&& let StmtKind::Expr(_) = stmt.kind
&& match arm.body.kind {
ExprKind::Block(block, _) => block.span.from_expansion(),
_ => true,
}
{
sugg.push(';');
}
(sugg, "try")
};
span_lint_and_sugg(cx, lint, expr.span, msg, help, sugg.to_string(), app);
return;
}
let (pat, pat_ref_count) = peel_hir_pat_refs(arm.pat);
let (msg, sugg) = if let PatKind::Path(_) | PatKind::Lit(_) = pat.kind
&& let (ty, ty_ref_count) = peel_middle_ty_refs(cx.typeck_results().expr_ty(ex))