diff options
Diffstat (limited to 'crates/ra_hir_ty/src/lower.rs')
-rw-r--r-- | crates/ra_hir_ty/src/lower.rs | 43 |
1 files changed, 35 insertions, 8 deletions
diff --git a/crates/ra_hir_ty/src/lower.rs b/crates/ra_hir_ty/src/lower.rs index d5154f436..3dc154e92 100644 --- a/crates/ra_hir_ty/src/lower.rs +++ b/crates/ra_hir_ty/src/lower.rs | |||
@@ -578,11 +578,13 @@ fn substs_from_path_segment( | |||
578 | // (i.e. defaults aren't used). | 578 | // (i.e. defaults aren't used). |
579 | if !infer_args || had_explicit_args { | 579 | if !infer_args || had_explicit_args { |
580 | if let Some(def_generic) = def_generic { | 580 | if let Some(def_generic) = def_generic { |
581 | let default_substs = ctx.db.generic_defaults(def_generic); | 581 | let defaults = ctx.db.generic_defaults(def_generic); |
582 | assert_eq!(total_len, default_substs.len()); | 582 | assert_eq!(total_len, defaults.len()); |
583 | 583 | ||
584 | for default_ty in default_substs.iter().skip(substs.len()) { | 584 | for default_ty in defaults.iter().skip(substs.len()) { |
585 | substs.push(default_ty.clone()); | 585 | // each default can depend on the previous parameters |
586 | let substs_so_far = Substs(substs.clone().into()); | ||
587 | substs.push(default_ty.clone().subst(&substs_so_far)); | ||
586 | } | 588 | } |
587 | } | 589 | } |
588 | } | 590 | } |
@@ -945,17 +947,42 @@ pub(crate) fn generic_predicates_query( | |||
945 | } | 947 | } |
946 | 948 | ||
947 | /// Resolve the default type params from generics | 949 | /// Resolve the default type params from generics |
948 | pub(crate) fn generic_defaults_query(db: &dyn HirDatabase, def: GenericDefId) -> Substs { | 950 | pub(crate) fn generic_defaults_query( |
951 | db: &dyn HirDatabase, | ||
952 | def: GenericDefId, | ||
953 | ) -> Arc<[Binders<Ty>]> { | ||
949 | let resolver = def.resolver(db.upcast()); | 954 | let resolver = def.resolver(db.upcast()); |
950 | let ctx = TyLoweringContext::new(db, &resolver); | 955 | let ctx = |
956 | TyLoweringContext::new(db, &resolver).with_type_param_mode(TypeParamLoweringMode::Variable); | ||
951 | let generic_params = generics(db.upcast(), def); | 957 | let generic_params = generics(db.upcast(), def); |
952 | 958 | ||
953 | let defaults = generic_params | 959 | let defaults = generic_params |
954 | .iter() | 960 | .iter() |
955 | .map(|(_idx, p)| p.default.as_ref().map_or(Ty::Unknown, |t| Ty::from_hir(&ctx, t))) | 961 | .enumerate() |
962 | .map(|(idx, (_, p))| { | ||
963 | let mut ty = p.default.as_ref().map_or(Ty::Unknown, |t| Ty::from_hir(&ctx, t)); | ||
964 | |||
965 | // Each default can only refer to previous parameters. | ||
966 | ty.walk_mut_binders( | ||
967 | &mut |ty, binders| match ty { | ||
968 | Ty::Bound(BoundVar { debruijn, index }) if *debruijn == binders => { | ||
969 | if *index >= idx { | ||
970 | // type variable default referring to parameter coming | ||
971 | // after it. This is forbidden (FIXME: report | ||
972 | // diagnostic) | ||
973 | *ty = Ty::Unknown; | ||
974 | } | ||
975 | } | ||
976 | _ => {} | ||
977 | }, | ||
978 | DebruijnIndex::INNERMOST, | ||
979 | ); | ||
980 | |||
981 | Binders::new(idx, ty) | ||
982 | }) | ||
956 | .collect(); | 983 | .collect(); |
957 | 984 | ||
958 | Substs(defaults) | 985 | defaults |
959 | } | 986 | } |
960 | 987 | ||
961 | fn fn_sig_for_fn(db: &dyn HirDatabase, def: FunctionId) -> PolyFnSig { | 988 | fn fn_sig_for_fn(db: &dyn HirDatabase, def: FunctionId) -> PolyFnSig { |