Detect implicitly defined late bound lifetime parameters as well

Author: petrochenkov

src/librustc_typeck/collect.rs

@@ -772,6 +772,92 @@ fn trait_def<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
     tcx.alloc_trait_def(def)
 }
 
+fn has_late_bound_regions<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
+                                    node: hir_map::Node<'tcx>)
+                                    -> bool {
+    struct LateBoundRegionsDetector<'a, 'tcx: 'a> {
+        tcx: TyCtxt<'a, 'tcx, 'tcx>,
+        binder_depth: usize,
+        has_late_bound_regions: bool,
+    }
+
+    impl<'a, 'tcx> Visitor<'tcx> for LateBoundRegionsDetector<'a, 'tcx> {
+        fn nested_visit_map<'this>(&'this mut self) -> NestedVisitorMap<'this, 'tcx> {
+            NestedVisitorMap::None
+        }
+
+        fn visit_ty(&mut self, ty: &'tcx hir::Ty) {
+            if self.has_late_bound_regions { return }
+            match ty.node {
+                hir::TyBareFn(..) => {
+                    self.binder_depth += 1;
+                    intravisit::walk_ty(self, ty);
+                    self.binder_depth -= 1;
+                }
+                _ => intravisit::walk_ty(self, ty)
+            }
+        }
+
+        fn visit_poly_trait_ref(&mut self,
+                                tr: &'tcx hir::PolyTraitRef,
+                                m: hir::TraitBoundModifier) {
+            if self.has_late_bound_regions { return }
+            self.binder_depth += 1;
+            intravisit::walk_poly_trait_ref(self, tr, m);
+            self.binder_depth -= 1;
+        }
+
+        fn visit_lifetime(&mut self, lt: &'tcx hir::Lifetime) {
+            if self.has_late_bound_regions { return }
+
+            match self.tcx.named_region_map.defs.get(&lt.id).cloned() {
+                Some(rl::Region::Static) | Some(rl::Region::EarlyBound(..)) => {}
+                _ => self.has_late_bound_regions = true
+            }
+        }
+    }
+
+    fn has_late_bound_regions<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
+                                        generics: &'tcx hir::Generics,
+                                        decl: &'tcx hir::FnDecl)
+                                        -> bool {
+        let mut visitor = LateBoundRegionsDetector {
+            tcx, binder_depth: 0, has_late_bound_regions: false
+        };
+        for lifetime in &generics.lifetimes {
+            if tcx.named_region_map.late_bound.contains(&lifetime.lifetime.id) {
+                return true;
+            }
+        }
+        visitor.visit_fn_decl(decl);
+        visitor.has_late_bound_regions
+    }
+
+    match node {
+        hir_map::NodeTraitItem(item) => match item.node {
+            hir::TraitItemKind::Method(ref sig, _) =>
+                has_late_bound_regions(tcx, &sig.generics, &sig.decl),
+            _ => false,
+        },
+        hir_map::NodeImplItem(item) => match item.node {
+            hir::ImplItemKind::Method(ref sig, _) =>
+                has_late_bound_regions(tcx, &sig.generics, &sig.decl),
+            _ => false,
+        },
+        hir_map::NodeForeignItem(item) => match item.node {
+            hir::ForeignItemFn(ref fn_decl, _, ref generics) =>
+                has_late_bound_regions(tcx, generics, fn_decl),
+            _ => false,
+        },
+        hir_map::NodeItem(item) => match item.node {
+            hir::ItemFn(ref fn_decl, .., ref generics, _) =>
+                has_late_bound_regions(tcx, generics, fn_decl),
+            _ => false,
+        },
+        _ => false
+    }
+}
+
 fn generics_of<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
                          def_id: DefId)
                          -> &'tcx ty::Generics {
@@ -876,13 +962,11 @@ fn generics_of<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
 
     let has_self = opt_self.is_some();
     let mut parent_has_self = false;
-    let mut parent_has_late_bound_regions = false;
     let mut own_start = has_self as u32;
     let (parent_regions, parent_types) = parent_def_id.map_or((0, 0), |def_id| {
         let generics = tcx.generics_of(def_id);
         assert_eq!(has_self, false);
         parent_has_self = generics.has_self;
-        parent_has_late_bound_regions = generics.has_late_bound_regions;
         own_start = generics.count() as u32;
         (generics.parent_regions + generics.regions.len() as u32,
             generics.parent_types + generics.types.len() as u32)
@@ -900,7 +984,6 @@ fn generics_of<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
         }
     }).collect::<Vec<_>>();
 
-    let has_late_bound_regions = regions.len() != ast_generics.lifetimes.len();
     let object_lifetime_defaults =
         tcx.named_region_map.object_lifetime_defaults.get(&node_id);
 
@@ -963,7 +1046,7 @@ fn generics_of<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
         types: types,
         type_param_to_index: type_param_to_index,
         has_self: has_self || parent_has_self,
-        has_late_bound_regions: has_late_bound_regions || parent_has_late_bound_regions,
+        has_late_bound_regions: has_late_bound_regions(tcx, node),
     })
 }
 

src/test/compile-fail/constructor-lifetime-args.rs

@@ -0,0 +1,36 @@
+// Copyright 2017 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+// All lifetime parameters in struct constructors are currently considered early bound,
+// i.e. `S::<ARGS>` is interpreted kinda like an associated item `S::<ARGS>::ctor`.
+// This behavior is a bit weird, because if equivalent constructor were written manually
+// it would get late bound lifetime parameters.
+// Variant constructors behave in the same way, lifetime parameters are considered
+// belonging to the enum and being early bound.
+// https://github.com/rust-lang/rust/issues/30904
+
+struct S<'a, 'b>(&'a u8, &'b u8);
+enum E<'a, 'b> {
+    V(&'a u8),
+    U(&'b u8),
+}
+
+fn main() {
+    S(&0, &0); // OK
+    S::<'static>(&0, &0);
+    //~^ ERROR expected 2 lifetime parameters, found 1 lifetime parameter
+    S::<'static, 'static, 'static>(&0, &0);
+    //~^ ERROR expected at most 2 lifetime parameters, found 3 lifetime parameters
+    E::V(&0); // OK
+    E::V::<'static>(&0);
+    //~^ ERROR expected 2 lifetime parameters, found 1 lifetime parameter
+    E::V::<'static, 'static, 'static>(&0);
+    //~^ ERROR expected at most 2 lifetime parameters, found 3 lifetime parameters
+}

src/test/compile-fail/method-call-lifetime-args-lint.rs

@@ -42,25 +42,25 @@ fn method_call() {
     //~| WARN this was previously accepted
 
     S.late_implicit(&0, &0); // OK
-    // S.late_implicit::<'static>(&0, &0);
-    //FIXME ERROR cannot specify lifetime arguments explicitly
-    //FIXME WARN this was previously accepted
-    // S.late_implicit::<'static, 'static>(&0, &0);
-    //FIXME ERROR cannot specify lifetime arguments explicitly
-    //FIXME WARN this was previously accepted
-    // S.late_implicit::<'static, 'static, 'static>(&0, &0);
-    //FIXME ERROR cannot specify lifetime arguments explicitly
-    //FIXME WARN this was previously accepted
+    S.late_implicit::<'static>(&0, &0);
+    //~^ ERROR cannot specify lifetime arguments explicitly
+    //~| WARN this was previously accepted
+    S.late_implicit::<'static, 'static>(&0, &0);
+    //~^ ERROR cannot specify lifetime arguments explicitly
+    //~| WARN this was previously accepted
+    S.late_implicit::<'static, 'static, 'static>(&0, &0);
+    //~^ ERROR cannot specify lifetime arguments explicitly
+    //~| WARN this was previously accepted
     S.late_implicit_early(&0); // OK
     S.late_implicit_early::<'static>(&0);
-    //FIXME ERROR cannot specify lifetime arguments explicitly
-    //FIXME WARN this was previously accepted
-    // S.late_implicit_early::<'static, 'static>(&0);
-    //FIXME ERROR cannot specify lifetime arguments explicitly
-    //FIXME WARN this was previously accepted
-    // S.late_implicit_early::<'static, 'static, 'static>(&0);
-    //FIXME ERROR cannot specify lifetime arguments explicitly
-    //FIXME WARN this was previously accepted
+    //~^ ERROR cannot specify lifetime arguments explicitly
+    //~| WARN this was previously accepted
+    S.late_implicit_early::<'static, 'static>(&0);
+    //~^ ERROR cannot specify lifetime arguments explicitly
+    //~| WARN this was previously accepted
+    S.late_implicit_early::<'static, 'static, 'static>(&0);
+    //~^ ERROR cannot specify lifetime arguments explicitly
+    //~| WARN this was previously accepted
 }
 
 fn ufcs() {
@@ -69,8 +69,8 @@ fn ufcs() {
     //~| WARN this was previously accepted
 
     S::late_implicit_early::<'static>(S, &0);
-    //FIXME ERROR cannot specify lifetime arguments explicitly
-    //FIXME WARN this was previously accepted
+    //~^ ERROR cannot specify lifetime arguments explicitly
+    //~| WARN this was previously accepted
 }
 
 fn main() {}

src/test/compile-fail/method-call-lifetime-args.rs

@@ -16,7 +16,17 @@ impl S {
     fn early<'a, 'b>(self) -> (&'a u8, &'b u8) { loop {} }
     fn late_early<'a, 'b>(self, _: &'a u8) -> &'b u8 { loop {} }
     fn late_implicit_early<'b>(self, _: &u8) -> &'b u8 { loop {} }
+    fn late_implicit_self_early<'b>(&self) -> &'b u8 { loop {} }
+    fn late_unused_early<'a, 'b>(self) -> &'b u8 { loop {} }
     fn life_and_type<'a, T>(self) -> &'a T { loop {} }
+
+    // 'late lifetimes here belong to nested types not to the tested functions.
+    fn early_tricky_explicit<'a>(_: for<'late> fn(&'late u8),
+                                 _: Box<for<'late> Fn(&'late u8)>)
+                                 -> &'a u8 { loop {} }
+    fn early_tricky_implicit<'a>(_: fn(&u8),
+                                 _: Box<Fn(&u8)>)
+                                 -> &'a u8 { loop {} }
 }
 
 fn method_call() {
@@ -46,21 +56,26 @@ fn ufcs() {
 
     S::late_implicit(S, &0, &0); // OK
     S::late_implicit::<'static>(S, &0, &0);
-    //~^ ERROR expected at most 0 lifetime parameters, found 1 lifetime parameter
-    //FIXME ERROR cannot specify lifetime arguments explicitly
+    //~^ ERROR cannot specify lifetime arguments explicitly
     S::late_implicit::<'static, 'static>(S, &0, &0);
-    //~^ ERROR expected at most 0 lifetime parameters, found 2 lifetime parameters
-    //FIXME ERROR cannot specify lifetime arguments explicitly
+    //~^ ERROR cannot specify lifetime arguments explicitly
     S::late_implicit::<'static, 'static, 'static>(S, &0, &0);
-    //~^ ERROR expected at most 0 lifetime parameters, found 3 lifetime parameters
-    //FIXME ERROR cannot specify lifetime arguments explicitly
+    //~^ ERROR cannot specify lifetime arguments explicitly
     S::late_implicit_early(S, &0); // OK
     S::late_implicit_early::<'static, 'static>(S, &0);
-    //~^ ERROR expected at most 1 lifetime parameter, found 2 lifetime parameters
-    //FIXME ERROR cannot specify lifetime arguments explicitly
+    //~^ ERROR cannot specify lifetime arguments explicitly
     S::late_implicit_early::<'static, 'static, 'static>(S, &0);
-    //~^ ERROR expected at most 1 lifetime parameter, found 3 lifetime parameters
-    //FIXME ERROR cannot specify lifetime arguments explicitly
+    //~^ ERROR cannot specify lifetime arguments explicitly
+    S::late_implicit_self_early(&S); // OK
+    S::late_implicit_self_early::<'static, 'static>(&S);
+    //~^ ERROR cannot specify lifetime arguments explicitly
+    S::late_implicit_self_early::<'static, 'static, 'static>(&S);
+    //~^ ERROR cannot specify lifetime arguments explicitly
+    S::late_unused_early(S); // OK
+    S::late_unused_early::<'static, 'static>(S);
+    //~^ ERROR cannot specify lifetime arguments explicitly
+    S::late_unused_early::<'static, 'static, 'static>(S);
+    //~^ ERROR cannot specify lifetime arguments explicitly
 
     S::early(S); // OK
     S::early::<'static>(S);
@@ -70,6 +85,9 @@ fn ufcs() {
     let _: &u8 = S::life_and_type::<'static>(S);
     S::life_and_type::<u8>(S);
     S::life_and_type::<'static, u8>(S);
+
+    S::early_tricky_explicit::<'static>(loop {}, loop {}); // OK
+    S::early_tricky_implicit::<'static>(loop {}, loop {}); // OK
 }
 
 fn main() {}

src/test/incremental/hashes/inherent_impls.rs

@@ -369,7 +369,7 @@ impl Foo {
 impl Foo {
     #[rustc_dirty(label="Hir", cfg="cfail2")]
     #[rustc_clean(label="Hir", cfg="cfail3")]
-    #[rustc_metadata_dirty(cfg="cfail2")]
+    #[rustc_metadata_clean(cfg="cfail2")]
     #[rustc_metadata_clean(cfg="cfail3")]
     pub fn add_lifetime_parameter_to_method<'a>(&self) { }
 }