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rustc_trait_selection: adopt let else in more places

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This commit is contained in:
est31
2022-02-19 00:48:31 +01:00
parent b8c56fa8c3
commit dab5c44800
10 changed files with 75 additions and 117 deletions
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16
compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs
View File

@@ -436,11 +436,8 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
obligation: &TraitObligation<'tcx>,
candidates: &mut SelectionCandidateSet<'tcx>,
) {
let kind = match self.tcx().fn_trait_kind_from_lang_item(obligation.predicate.def_id()) {
Some(k) => k,
None => {
return;
}
let Some(kind) = self.tcx().fn_trait_kind_from_lang_item(obligation.predicate.def_id()) else {
return;
};
// Okay to skip binder because the substs on closure types never
@@ -763,12 +760,9 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
// T: Trait
// so it seems ok if we (conservatively) fail to accept that `Unsize`
// obligation above. Should be possible to extend this in the future.
let source = match obligation.self_ty().no_bound_vars() {
Some(t) => t,
None => {
// Don't add any candidates if there are bound regions.
return;
}
let Some(source) = obligation.self_ty().no_bound_vars() else {
// Don't add any candidates if there are bound regions.
return;
};
let target = obligation.predicate.skip_binder().trait_ref.substs.type_at(1);

20
compiler/rustc_trait_selection/src/traits/select/confirmation.rs
View File

@@ -272,9 +272,8 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
} else {
bug!("unexpected builtin trait {:?}", trait_def)
};
let nested = match conditions {
BuiltinImplConditions::Where(nested) => nested,
_ => bug!("obligation {:?} had matched a builtin impl but now doesn't", obligation),
let BuiltinImplConditions::Where(nested) = conditions else {
bug!("obligation {:?} had matched a builtin impl but now doesn't", obligation);
};
let cause = obligation.derived_cause(BuiltinDerivedObligation);
@@ -421,9 +420,8 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
let trait_predicate = self.infcx.replace_bound_vars_with_placeholders(obligation.predicate);
let self_ty = self.infcx.shallow_resolve(trait_predicate.self_ty());
let obligation_trait_ref = ty::Binder::dummy(trait_predicate.trait_ref);
let data = match *self_ty.kind() {
ty::Dynamic(data, ..) => data,
_ => span_bug!(obligation.cause.span, "object candidate with non-object"),
let ty::Dynamic(data, ..) = *self_ty.kind() else {
span_bug!(obligation.cause.span, "object candidate with non-object");
};
let object_trait_ref = data.principal().unwrap_or_else(|| {
@@ -608,9 +606,8 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
// touch bound regions, they just capture the in-scope
// type/region parameters.
let self_ty = self.infcx.shallow_resolve(obligation.self_ty().skip_binder());
let (generator_def_id, substs) = match *self_ty.kind() {
ty::Generator(id, substs, _) => (id, substs),
_ => bug!("closure candidate for non-closure {:?}", obligation),
let ty::Generator(generator_def_id, substs, _) = *self_ty.kind() else {
bug!("closure candidate for non-closure {:?}", obligation);
};
debug!(?obligation, ?generator_def_id, ?substs, "confirm_generator_candidate");
@@ -652,9 +649,8 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
// touch bound regions, they just capture the in-scope
// type/region parameters.
let self_ty = self.infcx.shallow_resolve(obligation.self_ty().skip_binder());
let (closure_def_id, substs) = match *self_ty.kind() {
ty::Closure(id, substs) => (id, substs),
_ => bug!("closure candidate for non-closure {:?}", obligation),
let ty::Closure(closure_def_id, substs) = *self_ty.kind() else {
bug!("closure candidate for non-closure {:?}", obligation);
};
let obligation_predicate = obligation.predicate;