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Use let chains in the new solver #143066

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66ea349
Use let chains in the new solver
compiler-errors Jun 27, 2025
ccbe983
Use one more let chain
compiler-errors Jun 27, 2025
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8 changes: 4 additions & 4 deletions compiler/rustc_next_trait_solver/src/solve/assembly/mod.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -383,10 +383,10 @@ where

let mut candidates = vec![];

if let TypingMode::Coherence = self.typing_mode() {
if let Ok(candidate) = self.consider_coherence_unknowable_candidate(goal) {
return vec![candidate];
}
if let TypingMode::Coherence = self.typing_mode()
&& let Ok(candidate) = self.consider_coherence_unknowable_candidate(goal)
{
return vec![candidate];
}

self.assemble_alias_bound_candidates(goal, &mut candidates);
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12 changes: 6 additions & 6 deletions compiler/rustc_next_trait_solver/src/solve/assembly/structural_traits.rs
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Expand Up @@ -997,12 +997,12 @@ where
}

fn try_fold_ty(&mut self, ty: I::Ty) -> Result<I::Ty, Ambiguous> {
if let ty::Alias(ty::Projection, alias_ty) = ty.kind() {
if let Some(term) = self.try_eagerly_replace_alias(alias_ty.into())? {
return Ok(term.expect_ty());
}
if let ty::Alias(ty::Projection, alias_ty) = ty.kind()
&& let Some(term) = self.try_eagerly_replace_alias(alias_ty.into())?
{
Ok(term.expect_ty())
} else {
ty.try_super_fold_with(self)
}
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@lcnr lcnr Jun 27, 2025 •
edited
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vibe, no longer early return, just use else?


ty.try_super_fold_with(self)
}
}
24 changes: 11 additions & 13 deletions compiler/rustc_next_trait_solver/src/solve/effect_goals.rs
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Expand Up @@ -42,20 +42,18 @@ where
goal: Goal<I, Self>,
assumption: I::Clause,
) -> Result<(), NoSolution> {
if let Some(host_clause) = assumption.as_host_effect_clause() {
if host_clause.def_id() == goal.predicate.def_id()
&& host_clause.constness().satisfies(goal.predicate.constness)
{
if DeepRejectCtxt::relate_rigid_rigid(ecx.cx()).args_may_unify(
goal.predicate.trait_ref.args,
host_clause.skip_binder().trait_ref.args,
) {
return Ok(());
}
}
if let Some(host_clause) = assumption.as_host_effect_clause()
&& host_clause.def_id() == goal.predicate.def_id()
&& host_clause.constness().satisfies(goal.predicate.constness)
&& DeepRejectCtxt::relate_rigid_rigid(ecx.cx()).args_may_unify(
goal.predicate.trait_ref.args,
host_clause.skip_binder().trait_ref.args,
)
{
Ok(())
} else {
Err(NoSolution)
}

Err(NoSolution)
}

fn match_assumption(
Expand Down
59 changes: 26 additions & 33 deletions compiler/rustc_next_trait_solver/src/solve/eval_ctxt/mod.rs
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Expand Up @@ -429,22 +429,21 @@ where
// If we have run this goal before, and it was stalled, check that any of the goal's
// args have changed. Otherwise, we don't need to re-run the goal because it'll remain
// stalled, since it'll canonicalize the same way and evaluation is pure.
if let Some(stalled_on) = stalled_on {
if !stalled_on.stalled_vars.iter().any(|value| self.delegate.is_changed_arg(*value))
&& !self
.delegate
.opaque_types_storage_num_entries()
.needs_reevaluation(stalled_on.num_opaques)
{
return Ok((
NestedNormalizationGoals::empty(),
GoalEvaluation {
certainty: Certainty::Maybe(stalled_on.stalled_cause),
has_changed: HasChanged::No,
stalled_on: Some(stalled_on),
},
));
}
if let Some(stalled_on) = stalled_on
&& !stalled_on.stalled_vars.iter().any(|value| self.delegate.is_changed_arg(*value))
&& !self
.delegate
.opaque_types_storage_num_entries()
.needs_reevaluation(stalled_on.num_opaques)
{
return Ok((
NestedNormalizationGoals::empty(),
GoalEvaluation {
certainty: Certainty::Maybe(stalled_on.stalled_cause),
has_changed: HasChanged::No,
stalled_on: Some(stalled_on),
},
));
}

let (orig_values, canonical_goal) = self.canonicalize_goal(goal);
Expand Down Expand Up @@ -833,14 +832,11 @@ where

match t.kind() {
ty::Infer(ty::TyVar(vid)) => {
if let ty::TermKind::Ty(term) = self.term.kind() {
if let ty::Infer(ty::TyVar(term_vid)) = term.kind() {
if self.delegate.root_ty_var(vid)
== self.delegate.root_ty_var(term_vid)
{
return ControlFlow::Break(());
}
}
if let ty::TermKind::Ty(term) = self.term.kind()
&& let ty::Infer(ty::TyVar(term_vid)) = term.kind()
&& self.delegate.root_ty_var(vid) == self.delegate.root_ty_var(term_vid)
{
return ControlFlow::Break(());
}

self.check_nameable(self.delegate.universe_of_ty(vid).unwrap())?;
Expand All @@ -860,15 +856,12 @@ where
fn visit_const(&mut self, c: I::Const) -> Self::Result {
match c.kind() {
ty::ConstKind::Infer(ty::InferConst::Var(vid)) => {
if let ty::TermKind::Const(term) = self.term.kind() {
if let ty::ConstKind::Infer(ty::InferConst::Var(term_vid)) = term.kind()
{
if self.delegate.root_const_var(vid)
== self.delegate.root_const_var(term_vid)
{
return ControlFlow::Break(());
}
}
if let ty::TermKind::Const(term) = self.term.kind()
&& let ty::ConstKind::Infer(ty::InferConst::Var(term_vid)) = term.kind()
&& self.delegate.root_const_var(vid)
== self.delegate.root_const_var(term_vid)
{
return ControlFlow::Break(());
}

self.check_nameable(self.delegate.universe_of_ct(vid).unwrap())
Expand Down
21 changes: 10 additions & 11 deletions compiler/rustc_next_trait_solver/src/solve/normalizes_to/mod.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -112,18 +112,17 @@ where
goal: Goal<I, Self>,
assumption: I::Clause,
) -> Result<(), NoSolution> {
if let Some(projection_pred) = assumption.as_projection_clause() {
if projection_pred.item_def_id() == goal.predicate.def_id() {
if DeepRejectCtxt::relate_rigid_rigid(ecx.cx()).args_may_unify(
goal.predicate.alias.args,
projection_pred.skip_binder().projection_term.args,
) {
return Ok(());
}
}
if let Some(projection_pred) = assumption.as_projection_clause()
&& projection_pred.item_def_id() == goal.predicate.def_id()
&& DeepRejectCtxt::relate_rigid_rigid(ecx.cx()).args_may_unify(
goal.predicate.alias.args,
projection_pred.skip_binder().projection_term.args,
)
{
Ok(())
} else {
Err(NoSolution)
}

Err(NoSolution)
}

fn match_assumption(
Expand Down
47 changes: 23 additions & 24 deletions compiler/rustc_next_trait_solver/src/solve/trait_goals.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -127,33 +127,32 @@ where
goal: Goal<I, Self>,
assumption: I::Clause,
) -> Result<(), NoSolution> {
if let Some(trait_clause) = assumption.as_trait_clause() {
if trait_clause.polarity() != goal.predicate.polarity {
return Err(NoSolution);
}

if trait_clause.def_id() == goal.predicate.def_id() {
if DeepRejectCtxt::relate_rigid_rigid(ecx.cx()).args_may_unify(
goal.predicate.trait_ref.args,
trait_clause.skip_binder().trait_ref.args,
) {
return Ok(());
}
}

fn trait_def_id_matches<I: Interner>(
cx: I,
clause_def_id: I::DefId,
goal_def_id: I::DefId,
) -> bool {
clause_def_id == goal_def_id
// PERF(sized-hierarchy): Sizedness supertraits aren't elaborated to improve perf, so
// check for a `Sized` subtrait when looking for `MetaSized`. `PointeeSized` bounds
// are syntactic sugar for a lack of bounds so don't need this.
if ecx.cx().is_lang_item(goal.predicate.def_id(), TraitSolverLangItem::MetaSized)
&& ecx.cx().is_lang_item(trait_clause.def_id(), TraitSolverLangItem::Sized)
{
let meta_sized_clause =
trait_predicate_with_def_id(ecx.cx(), trait_clause, goal.predicate.def_id());
return Self::fast_reject_assumption(ecx, goal, meta_sized_clause);
}
// check for a `MetaSized` supertrait being matched against a `Sized` assumption.
//
// `PointeeSized` bounds are syntactic sugar for a lack of bounds so don't need this.
|| (cx.is_lang_item(clause_def_id, TraitSolverLangItem::Sized)
&& cx.is_lang_item(goal_def_id, TraitSolverLangItem::MetaSized))
}

Err(NoSolution)
if let Some(trait_clause) = assumption.as_trait_clause()
&& trait_clause.polarity() == goal.predicate.polarity
&& trait_def_id_matches(ecx.cx(), trait_clause.def_id(), goal.predicate.def_id())
&& DeepRejectCtxt::relate_rigid_rigid(ecx.cx()).args_may_unify(
goal.predicate.trait_ref.args,
trait_clause.skip_binder().trait_ref.args,
)
{
return Ok(());
} else {
Err(NoSolution)
}
}

fn match_assumption(
Expand Down
8 changes: 4 additions & 4 deletions compiler/rustc_type_ir/src/elaborate.rs
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Expand Up @@ -320,10 +320,10 @@ pub fn supertrait_def_ids<I: Interner>(
let trait_def_id = stack.pop()?;

for (predicate, _) in cx.explicit_super_predicates_of(trait_def_id).iter_identity() {
if let ty::ClauseKind::Trait(data) = predicate.kind().skip_binder() {
if set.insert(data.def_id()) {
stack.push(data.def_id());
}
if let ty::ClauseKind::Trait(data) = predicate.kind().skip_binder()
&& set.insert(data.def_id())
{
stack.push(data.def_id());
}
}

Expand Down
12 changes: 6 additions & 6 deletions compiler/rustc_type_ir/src/relate/solver_relating.rs
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Expand Up @@ -284,12 +284,12 @@ where
}

// If they have no bound vars, relate normally.
if let Some(a_inner) = a.no_bound_vars() {
if let Some(b_inner) = b.no_bound_vars() {
self.relate(a_inner, b_inner)?;
return Ok(a);
}
};
if let Some(a_inner) = a.no_bound_vars()
&& let Some(b_inner) = b.no_bound_vars()
{
self.relate(a_inner, b_inner)?;
return Ok(a);
}

match self.ambient_variance {
// Checks whether `for<..> sub <: for<..> sup` holds.
Expand Down
36 changes: 17 additions & 19 deletions compiler/rustc_type_ir/src/search_graph/global_cache.rs
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Expand Up @@ -80,31 +80,29 @@ impl<X: Cx> GlobalCache<X> {
mut candidate_is_applicable: impl FnMut(&NestedGoals<X>) -> bool,
) -> Option<CacheData<'a, X>> {
let entry = self.map.get(&input)?;
if let Some(Success { required_depth, ref nested_goals, ref result }) = entry.success {
if available_depth.cache_entry_is_applicable(required_depth)
&& candidate_is_applicable(nested_goals)
{
return Some(CacheData {
result: cx.get_tracked(&result),
required_depth,
encountered_overflow: false,
nested_goals,
});
}
if let Some(Success { required_depth, ref nested_goals, ref result }) = entry.success
&& available_depth.cache_entry_is_applicable(required_depth)
&& candidate_is_applicable(nested_goals)
{
return Some(CacheData {
result: cx.get_tracked(&result),
required_depth,
encountered_overflow: false,
nested_goals,
});
}

let additional_depth = available_depth.0;
if let Some(WithOverflow { nested_goals, result }) =
entry.with_overflow.get(&additional_depth)
&& candidate_is_applicable(nested_goals)
{
if candidate_is_applicable(nested_goals) {
return Some(CacheData {
result: cx.get_tracked(result),
required_depth: additional_depth,
encountered_overflow: true,
nested_goals,
});
}
return Some(CacheData {
result: cx.get_tracked(result),
required_depth: additional_depth,
encountered_overflow: true,
nested_goals,
});
}

None
Expand Down
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