Rollup merge of #55745 - nnethercote:outlives_components-SmallVec, r=matthewjasper

[rust.git] / src / librustc / ty / sty.rs

diff --git a/src/librustc/ty/sty.rs b/src/librustc/ty/sty.rs
index 5c8549cba2333e3a37a5a7ee43a69709d16af263..a4130bf15cb8272f2bd726ae061b5f758a03a042 100644 (file)
--- a/src/librustc/ty/sty.rs
+++ b/src/librustc/ty/sty.rs
@@ -22,6 +22,7 @@
 use util::captures::Captures;
 use mir::interpret::{Scalar, Pointer};
 
+use smallvec::SmallVec;
 use std::iter;
 use std::cmp::Ordering;
 use rustc_target::spec::abi;
@@ -1846,28 +1847,27 @@ pub fn ty_adt_def(&self) -> Option<&'tcx AdtDef> {
         }
     }
 
-    /// Returns the regions directly referenced from this type (but
-    /// not types reachable from this type via `walk_tys`). This
-    /// ignores late-bound regions binders.
-    pub fn regions(&self) -> Vec<ty::Region<'tcx>> {
+    /// Push onto `out` the regions directly referenced from this type (but not
+    /// types reachable from this type via `walk_tys`). This ignores late-bound
+    /// regions binders.
+    pub fn push_regions(&self, out: &mut SmallVec<[ty::Region<'tcx>; 4]>) {
         match self.sty {
             Ref(region, _, _) => {
-                vec![region]
+                out.push(region);
             }
             Dynamic(ref obj, region) => {
-                let mut v = vec![region];
-                v.extend(obj.principal().skip_binder().substs.regions());
-                v
+                out.push(region);
+                out.extend(obj.principal().skip_binder().substs.regions());
             }
             Adt(_, substs) | Opaque(_, substs) => {
-                substs.regions().collect()
+                out.extend(substs.regions())
             }
             Closure(_, ClosureSubsts { ref substs }) |
             Generator(_, GeneratorSubsts { ref substs }, _) => {
-                substs.regions().collect()
+                out.extend(substs.regions())
             }
             Projection(ref data) | UnnormalizedProjection(ref data) => {
-                data.substs.regions().collect()
+                out.extend(data.substs.regions())
             }
             FnDef(..) |
             FnPtr(_) |
@@ -1887,9 +1887,7 @@ pub fn regions(&self) -> Vec<ty::Region<'tcx>> {
             Param(_) |
             Bound(..) |
             Infer(_) |
-            Error => {
-                vec![]
-            }
+            Error => {}
         }
     }