diff options
Diffstat (limited to 'compiler/rustc_infer/src/infer/sub.rs')
| -rw-r--r-- | compiler/rustc_infer/src/infer/sub.rs | 17 |
1 files changed, 14 insertions, 3 deletions
diff --git a/compiler/rustc_infer/src/infer/sub.rs b/compiler/rustc_infer/src/infer/sub.rs index b27571275..b7eab5d43 100644 --- a/compiler/rustc_infer/src/infer/sub.rs +++ b/compiler/rustc_infer/src/infer/sub.rs @@ -4,6 +4,7 @@ use super::SubregionOrigin; use crate::infer::combine::ConstEquateRelation; use crate::infer::{TypeVariableOrigin, TypeVariableOriginKind}; use crate::traits::Obligation; +use rustc_middle::ty::error::{ExpectedFound, TypeError}; use rustc_middle::ty::relate::{Cause, Relate, RelateResult, TypeRelation}; use rustc_middle::ty::visit::TypeVisitable; use rustc_middle::ty::TyVar; @@ -141,17 +142,27 @@ impl<'tcx> TypeRelation<'tcx> for Sub<'_, '_, 'tcx> { Ok(infcx.tcx.mk_ty_var(var)) }; let (a, b) = if self.a_is_expected { (a, b) } else { (b, a) }; - let (a, b) = match (a.kind(), b.kind()) { + let (ga, gb) = match (a.kind(), b.kind()) { (&ty::Opaque(..), _) => (a, generalize(b, true)?), (_, &ty::Opaque(..)) => (generalize(a, false)?, b), _ => unreachable!(), }; self.fields.obligations.extend( infcx - .handle_opaque_type(a, b, true, &self.fields.trace.cause, self.param_env())? + .handle_opaque_type(ga, gb, true, &self.fields.trace.cause, self.param_env()) + // Don't leak any generalized type variables out of this + // subtyping relation in the case of a type error. + .map_err(|err| { + let (ga, gb) = self.fields.infcx.resolve_vars_if_possible((ga, gb)); + if let TypeError::Sorts(sorts) = err && sorts.expected == ga && sorts.found == gb { + TypeError::Sorts(ExpectedFound { expected: a, found: b }) + } else { + err + } + })? .obligations, ); - Ok(a) + Ok(ga) } _ => { |