diff options
| -rw-r--r-- | src/librustc/ty/erase_regions.rs | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/src/librustc/ty/erase_regions.rs b/src/librustc/ty/erase_regions.rs index bbf71c62ca6..da7e021b2d5 100644 --- a/src/librustc/ty/erase_regions.rs +++ b/src/librustc/ty/erase_regions.rs @@ -1,4 +1,4 @@ -use ty::{self, Ty, TyCtxt}; +use ty::{self, Ty, TyCtxt, TypeFlags}; use ty::fold::{TypeFolder, TypeFoldable}; pub(super) fn provide(providers: &mut ty::query::Providers<'_>) { @@ -21,6 +21,11 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> { pub fn erase_regions<T>(self, value: &T) -> T where T : TypeFoldable<'tcx> { + // If there's nothing to erase avoid performing the query at all + if !value.has_type_flags(TypeFlags::HAS_RE_LATE_BOUND | TypeFlags::HAS_FREE_REGIONS) { + return value.clone(); + } + let value1 = value.fold_with(&mut RegionEraserVisitor { tcx: self }); debug!("erase_regions({:?}) = {:?}", value, value1); value1 |