Check Repeat Rvalue

Author: spastorino

src/librustc/infer/mod.rs

@@ -1201,6 +1201,10 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
     /// translate them into the form that the NLL solver
     /// understands. See the NLL module for mode details.
     pub fn take_and_reset_region_constraints(&self) -> RegionConstraintData<'tcx> {
+        assert!(self.region_obligations.borrow().is_empty(),
+                "region_obligations not empty: {:#?}",
+                self.region_obligations.borrow());
+
         self.borrow_region_constraints().take_and_reset_data()
     }
 

src/librustc_mir/transform/type_check.rs

@@ -17,7 +17,7 @@ use rustc::infer::region_constraints::RegionConstraintData;
 use rustc::traits::{self, FulfillmentContext};
 use rustc::ty::error::TypeError;
 use rustc::ty::fold::TypeFoldable;
-use rustc::ty::{self, Ty, TyCtxt, TypeVariants};
+use rustc::ty::{self, Ty, TyCtxt, TypeVariants, ToPolyTraitRef};
 use rustc::middle::const_val::ConstVal;
 use rustc::mir::*;
 use rustc::mir::tcx::PlaceTy;
@@ -545,6 +545,13 @@ impl<'a, 'gcx, 'tcx> TypeChecker<'a, 'gcx, 'tcx> {
             span_mirbug!(self, "", "errors selecting obligation: {:?}", e);
         }
 
+        self.infcx.process_registered_region_obligations(
+            &[],
+            None,
+            self.param_env,
+            self.body_id,
+        );
+
         let data = self.infcx.take_and_reset_region_constraints();
         if !data.is_empty() {
             self.constraints
@@ -1110,13 +1117,28 @@ impl<'a, 'gcx, 'tcx> TypeChecker<'a, 'gcx, 'tcx> {
     }
 
     fn check_rvalue(&mut self, mir: &Mir<'tcx>, rvalue: &Rvalue<'tcx>, location: Location) {
+        let tcx = self.tcx();
+
         match rvalue {
             Rvalue::Aggregate(ak, ops) => {
                 self.check_aggregate_rvalue(mir, rvalue, ak, ops, location)
             }
+
+            Rvalue::Repeat(operand, const_usize) => {
+                if const_usize.as_u64() > 1 {
+                    let operand_ty = operand.ty(mir, tcx);
+
+                    let trait_ref = ty::TraitRef {
+                        def_id: tcx.lang_items().copy_trait().unwrap(),
+                        substs: tcx.mk_substs_trait(operand_ty, &[]),
+                    };
+
+                    self.prove_trait_ref(trait_ref, location);
+                }
+            }
+
             // FIXME: These other cases have to be implemented in future PRs
             Rvalue::Use(..) |
-            Rvalue::Repeat(..) |
             Rvalue::Ref(..) |
             Rvalue::Len(..) |
             Rvalue::Cast(..) |
@@ -1205,6 +1227,31 @@ impl<'a, 'gcx, 'tcx> TypeChecker<'a, 'gcx, 'tcx> {
         }
     }
 
+    fn prove_trait_ref(&mut self, trait_ref: ty::TraitRef<'tcx>, location: Location) {
+        self.prove_predicates(
+            &[
+                ty::Predicate::Trait(trait_ref.to_poly_trait_ref().to_poly_trait_predicate()),
+            ],
+            location,
+        );
+    }
+
+    fn prove_predicates(&mut self, predicates: &[ty::Predicate<'tcx>], location: Location) {
+        self.fully_perform_op(location.at_self(), |this| {
+            let cause = this.misc(this.last_span);
+            let obligations = predicates
+                .iter()
+                .map(|&p| {
+                    traits::Obligation::new(cause.clone(), this.param_env, p)
+                })
+                .collect();
+            Ok(InferOk {
+                value: (),
+                obligations,
+            })
+        }).unwrap()
+    }
+
     fn typeck_mir(&mut self, mir: &Mir<'tcx>) {
         self.last_span = mir.span;
         debug!("run_on_mir: {:?}", mir.span);
@@ -1237,7 +1284,7 @@ impl<'a, 'gcx, 'tcx> TypeChecker<'a, 'gcx, 'tcx> {
     {
         self.fully_perform_op(location.at_self(), |this| {
             let mut selcx = traits::SelectionContext::new(this.infcx);
-            let cause = traits::ObligationCause::misc(this.last_span, ast::CRATE_NODE_ID);
+            let cause = this.misc(this.last_span);
             let traits::Normalized { value, obligations } =
                 traits::normalize(&mut selcx, this.param_env, cause, value);
             Ok(InferOk { value, obligations })

src/test/compile-fail/nll/where_clauses_in_repeat_rvalue.rs

@@ -0,0 +1,39 @@
+// 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.
+
+// compile-flags: -Z borrowck=mir -Z nll
+
+#![allow(warnings)]
+
+struct Foo<T> {
+    t: T,
+}
+
+impl<T: 'static + Copy> Copy for Foo<T> {}
+impl<T: 'static + Copy> Clone for Foo<T> {
+    fn clone(&self) -> Self {
+        *self
+    }
+}
+
+fn main() {
+    let mut x = 22;
+
+    {
+        let p = &x; //~ ERROR borrowed value does not live long enough
+        let w = Foo { t: p };
+
+        let v = [w; 22];
+    }
+
+    x += 1;
+    //~^ ERROR cannot assign to `x` because it is borrowed [E0506]
+}
+//~^ ERROR borrowed value does not live long enough [E0597]