diff options
| -rw-r--r-- | compiler/rustc_infer/src/infer/mod.rs | 83 |
1 files changed, 39 insertions, 44 deletions
diff --git a/compiler/rustc_infer/src/infer/mod.rs b/compiler/rustc_infer/src/infer/mod.rs index 2524bd78355..e1cad1a4f6c 100644 --- a/compiler/rustc_infer/src/infer/mod.rs +++ b/compiler/rustc_infer/src/infer/mod.rs @@ -1659,49 +1659,6 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> { self.tcx.const_eval_resolve(param_env_erased, unevaluated, span) } - /// If `typ` is a type variable of some kind, resolve it one level - /// (but do not resolve types found in the result). If `typ` is - /// not a type variable, just return it unmodified. - // FIXME(eddyb) inline into `ShallowResolver::visit_ty`. - fn shallow_resolve_ty(&self, typ: Ty<'tcx>) -> Ty<'tcx> { - match *typ.kind() { - ty::Infer(ty::TyVar(v)) => { - // Not entirely obvious: if `typ` is a type variable, - // it can be resolved to an int/float variable, which - // can then be recursively resolved, hence the - // recursion. Note though that we prevent type - // variables from unifying to other type variables - // directly (though they may be embedded - // structurally), and we prevent cycles in any case, - // so this recursion should always be of very limited - // depth. - // - // Note: if these two lines are combined into one we get - // dynamic borrow errors on `self.inner`. - let known = self.inner.borrow_mut().type_variables().probe(v).known(); - known.map_or(typ, |t| self.shallow_resolve_ty(t)) - } - - ty::Infer(ty::IntVar(v)) => self - .inner - .borrow_mut() - .int_unification_table() - .probe_value(v) - .map(|v| v.to_type(self.tcx)) - .unwrap_or(typ), - - ty::Infer(ty::FloatVar(v)) => self - .inner - .borrow_mut() - .float_unification_table() - .probe_value(v) - .map(|v| v.to_type(self.tcx)) - .unwrap_or(typ), - - _ => typ, - } - } - /// `ty_or_const_infer_var_changed` is equivalent to one of these two: /// * `shallow_resolve(ty) != ty` (where `ty.kind = ty::Infer(_)`) /// * `shallow_resolve(ct) != ct` (where `ct.kind = ty::ConstKind::Infer(_)`) @@ -1831,8 +1788,46 @@ impl<'a, 'tcx> TypeFolder<'tcx> for ShallowResolver<'a, 'tcx> { self.infcx.tcx } + /// If `ty` is a type variable of some kind, resolve it one level + /// (but do not resolve types found in the result). If `typ` is + /// not a type variable, just return it unmodified. fn fold_ty(&mut self, ty: Ty<'tcx>) -> Ty<'tcx> { - self.infcx.shallow_resolve_ty(ty) + match *ty.kind() { + ty::Infer(ty::TyVar(v)) => { + // Not entirely obvious: if `typ` is a type variable, + // it can be resolved to an int/float variable, which + // can then be recursively resolved, hence the + // recursion. Note though that we prevent type + // variables from unifying to other type variables + // directly (though they may be embedded + // structurally), and we prevent cycles in any case, + // so this recursion should always be of very limited + // depth. + // + // Note: if these two lines are combined into one we get + // dynamic borrow errors on `self.inner`. + let known = self.infcx.inner.borrow_mut().type_variables().probe(v).known(); + known.map_or(ty, |t| self.fold_ty(t)) + } + + ty::Infer(ty::IntVar(v)) => self + .infcx + .inner + .borrow_mut() + .int_unification_table() + .probe_value(v) + .map_or(ty, |v| v.to_type(self.infcx.tcx)), + + ty::Infer(ty::FloatVar(v)) => self + .infcx + .inner + .borrow_mut() + .float_unification_table() + .probe_value(v) + .map_or(ty, |v| v.to_type(self.infcx.tcx)), + + _ => ty, + } } fn fold_const(&mut self, ct: ty::Const<'tcx>) -> ty::Const<'tcx> { |