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Check if let expr usage in manual_flatten

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`manual_flatten` should not trigger when match expression in `if let` is
going to be used.
This commit is contained in:
dswij 2021-08-14 17:43:28 +08:00
parent 711c5cb6d2
commit a09bc1b6fe
1 changed files with 5 additions and 2 deletions
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7
clippy_lints/src/loops/manual_flatten.rs
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@ -1,6 +1,7 @@
use super::utils::make_iterator_snippet;
use super::MANUAL_FLATTEN;
use clippy_utils::diagnostics::span_lint_and_then;
use clippy_utils::visitors::LocalUsedVisitor;
use clippy_utils::{is_lang_ctor, path_to_local_id};
use if_chain::if_chain;
use rustc_errors::Applicability;
@ -37,16 +38,18 @@ pub(super) fn check<'tcx>(
if_chain! {
if let Some(inner_expr) = inner_expr;
if let ExprKind::Match(
match_expr, match_arms, MatchSource::IfLetDesugar{ contains_else_clause: false }
match_expr, [true_arm, _else_arm], MatchSource::IfLetDesugar{ contains_else_clause: false }
) = inner_expr.kind;
// Ensure match_expr in `if let` statement is the same as the pat from the for-loop
if let PatKind::Binding(_, pat_hir_id, _, _) = pat.kind;
if path_to_local_id(match_expr, pat_hir_id);
// Ensure the `if let` statement is for the `Some` variant of `Option` or the `Ok` variant of `Result`
if let PatKind::TupleStruct(ref qpath, _, _) = match_arms[0].pat.kind;
if let PatKind::TupleStruct(ref qpath, _, _) = true_arm.pat.kind;
let some_ctor = is_lang_ctor(cx, qpath, OptionSome);
let ok_ctor = is_lang_ctor(cx, qpath, ResultOk);
if some_ctor || ok_ctor;
// Ensure epxr in `if let` is not used afterwards
if !LocalUsedVisitor::new(cx, pat_hir_id).check_arm(true_arm);
then {
let if_let_type = if some_ctor { "Some" } else { "Ok" };
// Prepare the error message