(c2rust-analyze) Refactor out AnalysisCtxt::const_ref_perms (needed to add PhantomLifetime to get the lifetimes to work).

Author: kkysen

c2rust-analyze/src/context.rs

@@ -4,7 +4,7 @@ use crate::pointer_id::{
     GlobalPointerTable, LocalPointerTable, NextGlobalPointerId, NextLocalPointerId, PointerTable,
     PointerTableMut,
 };
-use crate::util::{self, describe_rvalue, RvalueDesc};
+use crate::util::{self, describe_rvalue, PhantomLifetime, RvalueDesc};
 use crate::AssignPointerIds;
 use bitflags::bitflags;
 use rustc_hir::def_id::DefId;
@@ -126,6 +126,13 @@ impl<'a, 'tcx> AnalysisCtxt<'_, 'tcx> {
         self.const_ref_locs.iter().map(|loc| self.rvalue_tys[loc])
     }
 
+    pub fn const_ref_perms(
+        &'a self,
+    ) -> impl Iterator<Item = (PointerId, PermissionSet)> + PhantomLifetime<'tcx> + 'a {
+        self.const_ref_tys()
+            .map(|lty| (lty.label, PermissionSet::for_const_ref_ty(lty.ty)))
+    }
+
     pub fn check_const_ref_perms(&self, asn: &Assignment) {
         for const_ref_lty in self.const_ref_tys() {
             let ptr_id = const_ref_lty.label;

c2rust-analyze/src/dataflow/type_check.rs

@@ -465,11 +465,8 @@ pub fn visit<'tcx>(
         equiv_constraints: Vec::new(),
     };
 
-    for const_ref_lty in acx.const_ref_tys() {
-        tc.constraints.add_all_perms(
-            const_ref_lty.label,
-            PermissionSet::for_const_ref_ty(const_ref_lty.ty),
-        );
+    for (ptr, perms) in acx.const_ref_perms() {
+        tc.constraints.add_all_perms(ptr, perms);
     }
 
     for (bb, bb_data) in mir.basic_blocks().iter_enumerated() {

c2rust-analyze/src/util.rs

@@ -348,3 +348,6 @@ pub fn is_null_const(constant: Constant) -> bool {
         _ => false,
     }
 }
+
+pub trait PhantomLifetime<'a> {}
+impl<'a, T: ?Sized> PhantomLifetime<'a> for T {}