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authorFlorian Diebold <[email protected]>2021-04-07 20:26:37 +0100
committerFlorian Diebold <[email protected]>2021-04-08 13:08:55 +0100
commitcaee3b6c2d9a7dbcf678cc06d0c1832a4bf19be4 (patch)
treedf770a02d0474c985cfb283c4386fb3711bae80f /crates/hir_ty/src/lib.rs
parentb25b147e8604f62a5620a5833112e358ebeeb287 (diff)
Replace some `fold` calls
Diffstat (limited to 'crates/hir_ty/src/lib.rs')
-rw-r--r--crates/hir_ty/src/lib.rs26
1 files changed, 26 insertions, 0 deletions
diff --git a/crates/hir_ty/src/lib.rs b/crates/hir_ty/src/lib.rs
index 7d4793c2f..60680ec86 100644
--- a/crates/hir_ty/src/lib.rs
+++ b/crates/hir_ty/src/lib.rs
@@ -302,3 +302,29 @@ pub fn dummy_usize_const() -> Const {
302 } 302 }
303 .intern(&Interner) 303 .intern(&Interner)
304} 304}
305
306pub(crate) fn fold_free_vars<T: HasInterner<Interner = Interner> + Fold<Interner>>(
307 t: T,
308 f: impl FnMut(BoundVar, DebruijnIndex) -> Ty,
309) -> T::Result {
310 use chalk_ir::{fold::Folder, Fallible};
311 struct FreeVarFolder<F>(F);
312 impl<'i, F: FnMut(BoundVar, DebruijnIndex) -> Ty + 'i> Folder<'i, Interner> for FreeVarFolder<F> {
313 fn as_dyn(&mut self) -> &mut dyn Folder<'i, Interner> {
314 self
315 }
316
317 fn interner(&self) -> &'i Interner {
318 &Interner
319 }
320
321 fn fold_free_var_ty(
322 &mut self,
323 bound_var: BoundVar,
324 outer_binder: DebruijnIndex,
325 ) -> Fallible<Ty> {
326 Ok(self.0(bound_var, outer_binder))
327 }
328 }
329 t.fold_with(&mut FreeVarFolder(f), DebruijnIndex::INNERMOST).expect("fold failed unexpectedly")
330}