[redundant_pattern_matching
]: catch if let true
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@ -57,7 +57,7 @@ fn is_format(cx: &LateContext<'_>, e: &Expr<'_>) -> bool {
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Some(higher::IfLetOrMatch::Match(_, arms, MatchSource::Normal)) => {
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arms.iter().any(|arm| is_format(cx, arm.body))
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},
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Some(higher::IfLetOrMatch::IfLet(_, _, then, r#else)) => {
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Some(higher::IfLetOrMatch::IfLet(_, _, then, r#else, _)) => {
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is_format(cx, then) || r#else.is_some_and(|e| is_format(cx, e))
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},
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_ => false,
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@ -20,7 +20,7 @@ pub(super) fn check<'tcx>(
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span: Span,
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) {
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let inner_expr = peel_blocks_with_stmt(body);
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if let Some(higher::IfLet { let_pat, let_expr, if_then, if_else: None })
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if let Some(higher::IfLet { let_pat, let_expr, if_then, if_else: None, .. })
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= higher::IfLet::hir(cx, inner_expr)
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// Ensure match_expr in `if let` statement is the same as the pat from the for-loop
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&& let PatKind::Binding(_, pat_hir_id, _, _) = pat.kind
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@ -61,7 +61,7 @@ pub(crate) fn check_manual_let_else(&mut self, cx: &LateContext<'tcx>, stmt: &'t
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&& let Some(if_let_or_match) = IfLetOrMatch::parse(cx, init)
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{
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match if_let_or_match {
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IfLetOrMatch::IfLet(if_let_expr, let_pat, if_then, if_else) => {
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IfLetOrMatch::IfLet(if_let_expr, let_pat, if_then, if_else, ..) => {
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if let Some(ident_map) = expr_simple_identity_map(local.pat, let_pat, if_then)
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&& let Some(if_else) = if_else
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&& is_never_expr(cx, if_else).is_some()
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@ -41,7 +41,7 @@ fn check_arm<'tcx>(
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let inner_expr = peel_blocks_with_stmt(outer_then_body);
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if let Some(inner) = IfLetOrMatch::parse(cx, inner_expr)
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&& let Some((inner_scrutinee, inner_then_pat, inner_else_body)) = match inner {
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IfLetOrMatch::IfLet(scrutinee, pat, _, els) => Some((scrutinee, pat, els)),
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IfLetOrMatch::IfLet(scrutinee, pat, _, els, _) => Some((scrutinee, pat, els)),
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IfLetOrMatch::Match(scrutinee, arms, ..) => if arms.len() == 2 && arms.iter().all(|a| a.guard.is_none())
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// if there are more than two arms, collapsing would be non-trivial
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// one of the arms must be "wild-like"
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@ -75,7 +75,7 @@ fn check_arm<'tcx>(
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)
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// ...or anywhere in the inner expression
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&& match inner {
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IfLetOrMatch::IfLet(_, _, body, els) => {
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IfLetOrMatch::IfLet(_, _, body, els, _) => {
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!is_local_used(cx, body, binding_id) && els.map_or(true, |e| !is_local_used(cx, e, binding_id))
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},
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IfLetOrMatch::Match(_, arms, ..) => !arms.iter().any(|arm| is_local_used(cx, arm, binding_id)),
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@ -1104,6 +1104,7 @@ fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
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if_let.let_pat,
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if_let.let_expr,
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if_let.if_else.is_some(),
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if_let.let_span,
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);
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needless_match::check_if_let(cx, expr, &if_let);
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}
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@ -12,13 +12,13 @@
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use rustc_hir::{Arm, Expr, ExprKind, Guard, Node, Pat, PatKind, QPath, UnOp};
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use rustc_lint::LateContext;
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use rustc_middle::ty::{self, GenericArgKind, Ty};
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use rustc_span::{sym, Symbol};
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use rustc_span::{sym, Span, Symbol};
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use std::fmt::Write;
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use std::ops::ControlFlow;
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pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
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if let Some(higher::WhileLet { let_pat, let_expr, .. }) = higher::WhileLet::hir(expr) {
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find_sugg_for_if_let(cx, expr, let_pat, let_expr, "while", false);
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find_method_sugg_for_if_let(cx, expr, let_pat, let_expr, "while", false);
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}
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}
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@ -28,8 +28,34 @@ pub(super) fn check_if_let<'tcx>(
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pat: &'tcx Pat<'_>,
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scrutinee: &'tcx Expr<'_>,
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has_else: bool,
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let_span: Span,
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) {
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find_sugg_for_if_let(cx, expr, pat, scrutinee, "if", has_else);
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find_if_let_true(cx, pat, scrutinee, let_span);
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find_method_sugg_for_if_let(cx, expr, pat, scrutinee, "if", has_else);
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}
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fn find_if_let_true<'tcx>(cx: &LateContext<'tcx>, pat: &'tcx Pat<'_>, scrutinee: &'tcx Expr<'_>, let_span: Span) {
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if let PatKind::Lit(lit) = pat.kind
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&& let ExprKind::Lit(lit) = lit.kind
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&& let LitKind::Bool(is_true) = lit.node
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{
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let mut snip = snippet(cx, scrutinee.span, "..").into_owned();
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if !is_true {
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// Invert condition for `if let false = ...`
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snip.insert(0, '!');
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}
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span_lint_and_sugg(
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cx,
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REDUNDANT_PATTERN_MATCHING,
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let_span,
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"using `if let` to pattern match a boolean",
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"consider using a regular `if` expression",
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snip,
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Applicability::MachineApplicable,
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);
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}
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}
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// Extract the generic arguments out of a type
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@ -100,7 +126,7 @@ fn find_method_and_type<'tcx>(
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}
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}
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fn find_sugg_for_if_let<'tcx>(
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fn find_method_sugg_for_if_let<'tcx>(
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cx: &LateContext<'tcx>,
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expr: &'tcx Expr<'_>,
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let_pat: &Pat<'_>,
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@ -186,7 +186,7 @@ pub fn check_map_call(
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match higher::IfLetOrMatch::parse(cx, map_body.value) {
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// For `if let` we want to check that the variant matching arm references the local created by
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// its pattern
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Some(higher::IfLetOrMatch::IfLet(sc, pat, then, Some(else_)))
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Some(higher::IfLetOrMatch::IfLet(sc, pat, then, Some(else_), ..))
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if let Some((ident, span)) = expr_uses_local(pat, then) =>
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{
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(sc, else_, ident, span)
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@ -238,6 +238,7 @@ fn detect_option_if_let_else<'tcx>(cx: &LateContext<'tcx>, expr: &Expr<'tcx>) ->
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let_expr,
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if_then,
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if_else: Some(if_else),
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..
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}) = higher::IfLet::hir(cx, expr)
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&& !cx.typeck_results().expr_ty(expr).is_unit()
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&& !is_else_clause(cx.tcx, expr)
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@ -256,6 +256,7 @@ fn check_if_let_some_or_err_and_early_return<'tcx>(&self, cx: &LateContext<'tcx>
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let_expr,
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if_then,
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if_else,
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..
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}) = higher::IfLet::hir(cx, expr)
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&& !is_else_clause(cx.tcx, expr)
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&& let PatKind::TupleStruct(ref path1, [field], ddpos) = let_pat.kind
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@ -91,6 +91,9 @@ pub struct IfLet<'hir> {
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pub if_then: &'hir Expr<'hir>,
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/// `if let` else expression
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pub if_else: Option<&'hir Expr<'hir>>,
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/// `if let PAT = EXPR`
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/// ^^^^^^^^^^^^^^
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pub let_span: Span,
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}
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impl<'hir> IfLet<'hir> {
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@ -99,9 +102,10 @@ pub fn hir(cx: &LateContext<'_>, expr: &Expr<'hir>) -> Option<Self> {
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if let ExprKind::If(
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Expr {
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kind:
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ExprKind::Let(hir::Let {
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ExprKind::Let(&hir::Let {
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pat: let_pat,
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init: let_expr,
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span: let_span,
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..
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}),
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..
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@ -129,6 +133,7 @@ pub fn hir(cx: &LateContext<'_>, expr: &Expr<'hir>) -> Option<Self> {
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let_expr,
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if_then,
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if_else,
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let_span,
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});
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}
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None
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@ -146,6 +151,9 @@ pub enum IfLetOrMatch<'hir> {
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&'hir Pat<'hir>,
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&'hir Expr<'hir>,
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Option<&'hir Expr<'hir>>,
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/// `if let PAT = EXPR`
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/// ^^^^^^^^^^^^^^
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Span,
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),
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}
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@ -160,7 +168,8 @@ pub fn parse(cx: &LateContext<'_>, expr: &Expr<'hir>) -> Option<Self> {
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let_pat,
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if_then,
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if_else,
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}| { Self::IfLet(let_expr, let_pat, if_then, if_else) },
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let_span,
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}| { Self::IfLet(let_expr, let_pat, if_then, if_else, let_span) },
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),
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}
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}
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