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Fix formatting of if let chain
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parent
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commit
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@ -77,53 +77,54 @@ impl<'tcx> LateLintPass<'tcx> for ManualLetElse {
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local.els.is_none() &&
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local.ty.is_none() &&
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init.span.ctxt() == stmt.span.ctxt() &&
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let Some(if_let_or_match) = IfLetOrMatch::parse(cx, init) {
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match if_let_or_match {
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IfLetOrMatch::IfLet(if_let_expr, let_pat, if_then, if_else) => if_chain! {
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if expr_is_simple_identity(let_pat, if_then);
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if let Some(if_else) = if_else;
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if expr_diverges(cx, if_else);
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then {
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emit_manual_let_else(cx, stmt.span, if_let_expr, local.pat, let_pat, if_else);
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}
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},
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IfLetOrMatch::Match(match_expr, arms, source) => {
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if self.matches_behaviour == MatchLintBehaviour::Never {
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return;
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}
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if source != MatchSource::Normal {
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return;
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}
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// Any other number than two arms doesn't (necessarily)
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// have a trivial mapping to let else.
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if arms.len() != 2 {
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return;
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}
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// Guards don't give us an easy mapping either
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if arms.iter().any(|arm| arm.guard.is_some()) {
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return;
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}
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let check_types = self.matches_behaviour == MatchLintBehaviour::WellKnownTypes;
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let diverging_arm_opt = arms
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.iter()
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.enumerate()
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.find(|(_, arm)| expr_diverges(cx, arm.body) && pat_allowed_for_else(cx, arm.pat, check_types));
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let Some((idx, diverging_arm)) = diverging_arm_opt else { return; };
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// If the non-diverging arm is the first one, its pattern can be reused in a let/else statement.
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// However, if it arrives in second position, its pattern may cover some cases already covered
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// by the diverging one.
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// TODO: accept the non-diverging arm as a second position if patterns are disjointed.
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if idx == 0 {
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return;
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}
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let pat_arm = &arms[1 - idx];
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if !expr_is_simple_identity(pat_arm.pat, pat_arm.body) {
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return;
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}
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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) => if_chain! {
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if expr_is_simple_identity(let_pat, if_then);
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if let Some(if_else) = if_else;
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if expr_diverges(cx, if_else);
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then {
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emit_manual_let_else(cx, stmt.span, if_let_expr, local.pat, let_pat, if_else);
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}
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},
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IfLetOrMatch::Match(match_expr, arms, source) => {
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if self.matches_behaviour == MatchLintBehaviour::Never {
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return;
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}
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if source != MatchSource::Normal {
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return;
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}
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// Any other number than two arms doesn't (necessarily)
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// have a trivial mapping to let else.
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if arms.len() != 2 {
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return;
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}
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// Guards don't give us an easy mapping either
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if arms.iter().any(|arm| arm.guard.is_some()) {
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return;
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}
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let check_types = self.matches_behaviour == MatchLintBehaviour::WellKnownTypes;
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let diverging_arm_opt = arms
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.iter()
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.enumerate()
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.find(|(_, arm)| expr_diverges(cx, arm.body) && pat_allowed_for_else(cx, arm.pat, check_types));
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let Some((idx, diverging_arm)) = diverging_arm_opt else { return; };
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// If the non-diverging arm is the first one, its pattern can be reused in a let/else statement.
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// However, if it arrives in second position, its pattern may cover some cases already covered
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// by the diverging one.
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// TODO: accept the non-diverging arm as a second position if patterns are disjointed.
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if idx == 0 {
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return;
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}
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let pat_arm = &arms[1 - idx];
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if !expr_is_simple_identity(pat_arm.pat, pat_arm.body) {
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return;
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}
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emit_manual_let_else(cx, stmt.span, match_expr, local.pat, pat_arm.pat, diverging_arm.body);
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},
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}
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emit_manual_let_else(cx, stmt.span, match_expr, local.pat, pat_arm.pat, diverging_arm.body);
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},
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}
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};
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}
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