Split ast_region_to_region in two parts.

Author: cjgillot

compiler/rustc_typeck/src/astconv/mod.rs

@@ -205,12 +205,39 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
         def: Option<&ty::GenericParamDef>,
     ) -> ty::Region<'tcx> {
         let tcx = self.tcx();
+
+        let r = if let Some(rl) = tcx.named_region(lifetime.hir_id) {
+            self.ast_region_to_region_inner(rl)
+        } else {
+            self.re_infer(def, lifetime.span).unwrap_or_else(|| {
+                debug!(?lifetime, "unelided lifetime in signature");
+
+                // This indicates an illegal lifetime
+                // elision. `resolve_lifetime` should have
+                // reported an error in this case -- but if
+                // not, let's error out.
+                tcx.sess.delay_span_bug(lifetime.span, "unelided lifetime in signature");
+
+                // Supply some dummy value. We don't have an
+                // `re_error`, annoyingly, so use `'static`.
+                tcx.lifetimes.re_static
+            })
+        };
+
+        debug!("ast_region_to_region(lifetime={:?}) yields {:?}", lifetime, r);
+
+        r
+    }
+
+    #[tracing::instrument(level = "debug", skip(self))]
+    fn ast_region_to_region_inner(&self, lifetime: rl::Region) -> ty::Region<'tcx> {
+        let tcx = self.tcx();
         let lifetime_name = |def_id| tcx.hir().name(tcx.hir().local_def_id_to_hir_id(def_id));
 
-        let r = match tcx.named_region(lifetime.hir_id) {
-            Some(rl::Region::Static) => tcx.lifetimes.re_static,
+        let r = match lifetime {
+            rl::Region::Static => tcx.lifetimes.re_static,
 
-            Some(rl::Region::LateBound(debruijn, index, def_id)) => {
+            rl::Region::LateBound(debruijn, index, def_id) => {
                 let name = lifetime_name(def_id.expect_local());
                 let br = ty::BoundRegion {
                     var: ty::BoundVar::from_u32(index),
@@ -219,20 +246,20 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                 tcx.mk_region(ty::ReLateBound(debruijn, br))
             }
 
-            Some(rl::Region::LateBoundAnon(debruijn, index, anon_index)) => {
+            rl::Region::LateBoundAnon(debruijn, index, anon_index) => {
                 let br = ty::BoundRegion {
                     var: ty::BoundVar::from_u32(index),
                     kind: ty::BrAnon(anon_index),
                 };
                 tcx.mk_region(ty::ReLateBound(debruijn, br))
             }
 
-            Some(rl::Region::EarlyBound(index, id)) => {
+            rl::Region::EarlyBound(index, id) => {
                 let name = lifetime_name(id.expect_local());
                 tcx.mk_region(ty::ReEarlyBound(ty::EarlyBoundRegion { def_id: id, index, name }))
             }
 
-            Some(rl::Region::Free(scope, id)) => {
+            rl::Region::Free(scope, id) => {
                 let name = lifetime_name(id.expect_local());
                 tcx.mk_region(ty::ReFree(ty::FreeRegion {
                     scope,
@@ -241,22 +268,6 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
 
                 // (*) -- not late-bound, won't change
             }
-
-            None => {
-                self.re_infer(def, lifetime.span).unwrap_or_else(|| {
-                    debug!(?lifetime, "unelided lifetime in signature");
-
-                    // This indicates an illegal lifetime
-                    // elision. `resolve_lifetime` should have
-                    // reported an error in this case -- but if
-                    // not, let's error out.
-                    tcx.sess.delay_span_bug(lifetime.span, "unelided lifetime in signature");
-
-                    // Supply some dummy value. We don't have an
-                    // `re_error`, annoyingly, so use `'static`.
-                    tcx.lifetimes.re_static
-                })
-            }
         };
 
         debug!("ast_region_to_region(lifetime={:?}) yields {:?}", lifetime, r);