fix a couple nits

- remove unneeded type ascription
- fix variable name
- fix typo in comment
- fix `var_origins` var and function name: these are `VarInfos`

compiler/rustc_borrowck/src/lib.rs

@@ -120,11 +120,10 @@ fn mir_borrowck(tcx: TyCtxt<'_>, def: LocalDefId) -> &BorrowCheckResult<'_> {
         return tcx.arena.alloc(result);
     }
 
-    let promoted: &IndexSlice<_, _> = &promoted.borrow();
-    let opt_closure_req = do_mir_borrowck(tcx, input_body, promoted, None).0;
+    let borrowck_result = do_mir_borrowck(tcx, input_body, &*promoted.borrow(), None).0;
     debug!("mir_borrowck done");
 
-    tcx.arena.alloc(opt_closure_req)
+    tcx.arena.alloc(borrowck_result)
 }
 
 /// Perform the actual borrow checking.
@@ -215,7 +214,7 @@ fn do_mir_borrowck<'tcx>(
         consumer_options,
     );
 
-    // Dump MIR results into a file, if that is enabled. This let us
+    // Dump MIR results into a file, if that is enabled. This lets us
     // write unit-tests, as well as helping with debugging.
     nll::dump_nll_mir(&infcx, body, &regioncx, &opt_closure_req, &borrow_set);
 

compiler/rustc_borrowck/src/nll.rs

@@ -121,7 +121,7 @@ pub(crate) fn compute_regions<'a, 'tcx>(
     // Create the region inference context, taking ownership of the
     // region inference data that was contained in `infcx`, and the
     // base constraints generated by the type-check.
-    let var_origins = infcx.get_region_var_origins();
+    let var_infos = infcx.get_region_var_infos();
 
     // If requested, emit legacy polonius facts.
     polonius::legacy::emit_facts(
@@ -137,7 +137,7 @@ pub(crate) fn compute_regions<'a, 'tcx>(
 
     let mut regioncx = RegionInferenceContext::new(
         infcx,
-        var_origins,
+        var_infos,
         constraints,
         universal_region_relations,
         elements,

compiler/rustc_infer/src/infer/mod.rs

@@ -945,7 +945,7 @@ impl<'tcx> InferCtxt<'tcx> {
 
     /// Clone the list of variable regions. This is used only during NLL processing
     /// to put the set of region variables into the NLL region context.
-    pub fn get_region_var_origins(&self) -> VarInfos {
+    pub fn get_region_var_infos(&self) -> VarInfos {
         let inner = self.inner.borrow();
         assert!(!UndoLogs::<UndoLog<'_>>::in_snapshot(&inner.undo_log));
         let storage = inner.region_constraint_storage.as_ref().expect("regions already resolved");