Projection cache and better warnings for #32330

src/librustc/diagnostics.rs

@@ -1647,5 +1647,5 @@ register_diagnostics! {
     E0490, // a value of type `..` is borrowed for too long
     E0491, // in type `..`, reference has a longer lifetime than the data it...
     E0495, // cannot infer an appropriate lifetime due to conflicting requirements
-    E0525, // expected a closure that implements `..` but this closure only implements `..`
+    E0525  // expected a closure that implements `..` but this closure only implements `..`
 }

src/librustc/hir/intravisit.rs

@@ -132,6 +132,9 @@ pub trait Visitor<'v> : Sized {
     fn visit_generics(&mut self, g: &'v Generics) {
         walk_generics(self, g)
     }
+    fn visit_where_predicate(&mut self, predicate: &'v WherePredicate) {
+        walk_where_predicate(self, predicate)
+    }
     fn visit_fn(&mut self, fk: FnKind<'v>, fd: &'v FnDecl, b: &'v Block, s: Span, _: NodeId) {
         walk_fn(self, fk, fd, b, s)
     }
@@ -529,29 +532,34 @@ pub fn walk_generics<'v, V: Visitor<'v>>(visitor: &mut V, generics: &'v Generics
         walk_list!(visitor, visit_ty, &param.default);
     }
     walk_list!(visitor, visit_lifetime_def, &generics.lifetimes);
-    for predicate in &generics.where_clause.predicates {
-        match predicate {
-            &WherePredicate::BoundPredicate(WhereBoundPredicate{ref bounded_ty,
-                                                                          ref bounds,
-                                                                          ref bound_lifetimes,
-                                                                          ..}) => {
-                visitor.visit_ty(bounded_ty);
-                walk_list!(visitor, visit_ty_param_bound, bounds);
-                walk_list!(visitor, visit_lifetime_def, bound_lifetimes);
-            }
-            &WherePredicate::RegionPredicate(WhereRegionPredicate{ref lifetime,
-                                                                            ref bounds,
-                                                                            ..}) => {
-                visitor.visit_lifetime(lifetime);
-                walk_list!(visitor, visit_lifetime, bounds);
-            }
-            &WherePredicate::EqPredicate(WhereEqPredicate{id,
-                                                                    ref path,
-                                                                    ref ty,
-                                                                    ..}) => {
-                visitor.visit_path(path, id);
-                visitor.visit_ty(ty);
-            }
+    walk_list!(visitor, visit_where_predicate, &generics.where_clause.predicates);
+}
+
+pub fn walk_where_predicate<'v, V: Visitor<'v>>(
+    visitor: &mut V,
+    predicate: &'v WherePredicate)
+{
+    match predicate {
+        &WherePredicate::BoundPredicate(WhereBoundPredicate{ref bounded_ty,
+                                                            ref bounds,
+                                                            ref bound_lifetimes,
+                                                            ..}) => {
+            visitor.visit_ty(bounded_ty);
+            walk_list!(visitor, visit_ty_param_bound, bounds);
+            walk_list!(visitor, visit_lifetime_def, bound_lifetimes);
+        }
+        &WherePredicate::RegionPredicate(WhereRegionPredicate{ref lifetime,
+                                                              ref bounds,
+                                                              ..}) => {
+            visitor.visit_lifetime(lifetime);
+            walk_list!(visitor, visit_lifetime, bounds);
+        }
+        &WherePredicate::EqPredicate(WhereEqPredicate{id,
+                                                      ref path,
+                                                      ref ty,
+                                                      ..}) => {
+            visitor.visit_path(path, id);
+            visitor.visit_ty(ty);
         }
     }
 }

src/librustc/infer/error_reporting.rs

@@ -77,6 +77,7 @@ use hir::map as ast_map;
 use hir;
 use hir::print as pprust;
 
+use lint;
 use hir::def::Def;
 use hir::def_id::DefId;
 use infer::{self, TypeOrigin};
@@ -1017,6 +1018,27 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
         let (fn_decl, generics) = rebuilder.rebuild();
         self.give_expl_lifetime_param(err, &fn_decl, unsafety, constness, name, &generics, span);
     }
+
+    pub fn issue_32330_warnings(&self, span: Span, issue32330s: &[ty::Issue32330]) {
+        for issue32330 in issue32330s {
+            match *issue32330 {
+                ty::Issue32330::WontChange => { }
+                ty::Issue32330::WillChange { fn_def_id, region_name } => {
+                    self.tcx.sess.add_lint(
+                        lint::builtin::HR_LIFETIME_IN_ASSOC_TYPE,
+                        ast::CRATE_NODE_ID,
+                        span,
+                        format!("lifetime parameter `{0}` declared on fn `{1}` \
+                                 appears only in the return type, \
+                                 but here is required to be higher-ranked, \
+                                 which means that `{0}` must appear in both \
+                                 argument and return types",
+                                region_name,
+                                self.tcx.item_path_str(fn_def_id)));
+                }
+            }
+        }
+    }
 }
 
 struct RebuildPathInfo<'a> {
@@ -1129,7 +1151,7 @@ impl<'a, 'gcx, 'tcx> Rebuilder<'a, 'gcx, 'tcx> {
                 ty::BrAnon(i) => {
                     anon_nums.insert(i);
                 }
-                ty::BrNamed(_, name) => {
+                ty::BrNamed(_, name, _) => {
                     region_names.insert(name);
                 }
                 _ => ()
@@ -1143,7 +1165,7 @@ impl<'a, 'gcx, 'tcx> Rebuilder<'a, 'gcx, 'tcx> {
         for sr in self.same_regions {
             for br in &sr.regions {
                 match *br {
-                    ty::BrNamed(_, name) => {
+                    ty::BrNamed(_, name, _) => {
                         all_region_names.insert(name);
                     }
                     _ => ()
@@ -1923,3 +1945,4 @@ fn name_to_dummy_lifetime(name: ast::Name) -> hir::Lifetime {
                     span: codemap::DUMMY_SP,
                     name: name }
 }
+