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authorbors[bot] <26634292+bors[bot]@users.noreply.github.com>2020-12-20 11:47:01 +0000
committerGitHub <[email protected]>2020-12-20 11:47:01 +0000
commiteefbae7ed4fca97281bbcd8e5738311be3a31dc6 (patch)
tree2d979ad92fc4a6a2000518feb545f72b88e36cf4 /crates/hir_def/src
parentf3125555a8de6fad4529408436800a6b1243a442 (diff)
parentfa65d6ba855fb2da68840b987bfdec258239a59b (diff)
Merge #6921
6921: Higher-ranked trait bounds for where clauses r=flodiebold a=Veykril There is a slight problem with this which is also noted in a FIXME now but `LifetimeParameters` of these ForLifetime where clauses allocate the lifetimes in the corresponding arena as if they were lifetimes of the item itself and not just the clause they belong to. I wasn't entirely sure what I could do about this but given nothing really uses lifetimes like that currently I figured it might be fine? Open to suggestions for that problem. Co-authored-by: Lukas Wirth <[email protected]>
Diffstat (limited to 'crates/hir_def/src')
-rw-r--r--crates/hir_def/src/generics.rs37
1 files changed, 31 insertions, 6 deletions
diff --git a/crates/hir_def/src/generics.rs b/crates/hir_def/src/generics.rs
index 41134d23b..bb8fca009 100644
--- a/crates/hir_def/src/generics.rs
+++ b/crates/hir_def/src/generics.rs
@@ -62,6 +62,7 @@ pub struct GenericParams {
62pub enum WherePredicate { 62pub enum WherePredicate {
63 TypeBound { target: WherePredicateTypeTarget, bound: TypeBound }, 63 TypeBound { target: WherePredicateTypeTarget, bound: TypeBound },
64 Lifetime { target: LifetimeRef, bound: LifetimeRef }, 64 Lifetime { target: LifetimeRef, bound: LifetimeRef },
65 ForLifetime { lifetimes: Box<[Name]>, target: WherePredicateTypeTarget, bound: TypeBound },
65} 66}
66 67
67#[derive(Clone, PartialEq, Eq, Debug)] 68#[derive(Clone, PartialEq, Eq, Debug)]
@@ -69,7 +70,6 @@ pub enum WherePredicateTypeTarget {
69 TypeRef(TypeRef), 70 TypeRef(TypeRef),
70 /// For desugared where predicates that can directly refer to a type param. 71 /// For desugared where predicates that can directly refer to a type param.
71 TypeParam(LocalTypeParamId), 72 TypeParam(LocalTypeParamId),
72 // FIXME: ForLifetime(Vec<LifetimeParamId>, TypeRef)
73} 73}
74 74
75#[derive(Default)] 75#[derive(Default)]
@@ -234,7 +234,7 @@ impl GenericParams {
234 for bound in 234 for bound in
235 node.type_bound_list().iter().flat_map(|type_bound_list| type_bound_list.bounds()) 235 node.type_bound_list().iter().flat_map(|type_bound_list| type_bound_list.bounds())
236 { 236 {
237 self.add_where_predicate_from_bound(lower_ctx, bound, target.clone()); 237 self.add_where_predicate_from_bound(lower_ctx, bound, None, target.clone());
238 } 238 }
239 } 239 }
240 240
@@ -279,8 +279,25 @@ impl GenericParams {
279 } else { 279 } else {
280 continue; 280 continue;
281 }; 281 };
282
283 let lifetimes: Option<Box<_>> = pred.generic_param_list().map(|param_list| {
284 // Higher-Ranked Trait Bounds
285 param_list
286 .lifetime_params()
287 .map(|lifetime_param| {
288 lifetime_param
289 .lifetime()
290 .map_or_else(Name::missing, |lt| Name::new_lifetime(&lt))
291 })
292 .collect()
293 });
282 for bound in pred.type_bound_list().iter().flat_map(|l| l.bounds()) { 294 for bound in pred.type_bound_list().iter().flat_map(|l| l.bounds()) {
283 self.add_where_predicate_from_bound(lower_ctx, bound, target.clone()); 295 self.add_where_predicate_from_bound(
296 lower_ctx,
297 bound,
298 lifetimes.as_ref(),
299 target.clone(),
300 );
284 } 301 }
285 } 302 }
286 } 303 }
@@ -289,6 +306,7 @@ impl GenericParams {
289 &mut self, 306 &mut self,
290 lower_ctx: &LowerCtx, 307 lower_ctx: &LowerCtx,
291 bound: ast::TypeBound, 308 bound: ast::TypeBound,
309 hrtb_lifetimes: Option<&Box<[Name]>>,
292 target: Either<TypeRef, LifetimeRef>, 310 target: Either<TypeRef, LifetimeRef>,
293 ) { 311 ) {
294 if bound.question_mark_token().is_some() { 312 if bound.question_mark_token().is_some() {
@@ -297,9 +315,16 @@ impl GenericParams {
297 } 315 }
298 let bound = TypeBound::from_ast(lower_ctx, bound); 316 let bound = TypeBound::from_ast(lower_ctx, bound);
299 let predicate = match (target, bound) { 317 let predicate = match (target, bound) {
300 (Either::Left(type_ref), bound) => WherePredicate::TypeBound { 318 (Either::Left(type_ref), bound) => match hrtb_lifetimes {
301 target: WherePredicateTypeTarget::TypeRef(type_ref), 319 Some(hrtb_lifetimes) => WherePredicate::ForLifetime {
302 bound, 320 lifetimes: hrtb_lifetimes.clone(),
321 target: WherePredicateTypeTarget::TypeRef(type_ref),
322 bound,
323 },
324 None => WherePredicate::TypeBound {
325 target: WherePredicateTypeTarget::TypeRef(type_ref),
326 bound,
327 },
303 }, 328 },
304 (Either::Right(lifetime), TypeBound::Lifetime(bound)) => { 329 (Either::Right(lifetime), TypeBound::Lifetime(bound)) => {
305 WherePredicate::Lifetime { target: lifetime, bound } 330 WherePredicate::Lifetime { target: lifetime, bound }