Make ui/borrowck/borrowck-reborrow-from-mut.rs robust w.r.t. NLL.

src/test/ui/borrowck/borrowck-reborrow-from-mut.nll.stderr

@@ -1,3 +1,107 @@
+error[E0499]: cannot borrow `foo.bar1` as mutable more than once at a time
+  --> $DIR/borrowck-reborrow-from-mut.rs:23:17
+   |
+LL |     let _bar1 = &mut foo.bar1;
+   |                 ------------- first mutable borrow occurs here
+LL |     let _bar2 = &mut foo.bar1;  //~ ERROR cannot borrow
+   |                 ^^^^^^^^^^^^^ second mutable borrow occurs here
+LL |     use_mut(_bar1);
+   |             ----- first borrow later used here
+
+error[E0502]: cannot borrow `foo.bar1` as immutable because it is also borrowed as mutable
+  --> $DIR/borrowck-reborrow-from-mut.rs:28:17
+   |
+LL |     let _bar1 = &mut foo.bar1;
+   |                 ------------- mutable borrow occurs here
+LL |     let _bar2 = &foo.bar1;  //~ ERROR cannot borrow
+   |                 ^^^^^^^^^ immutable borrow occurs here
+LL |     use_mut(_bar1);
+   |             ----- mutable borrow later used here
+
+error[E0502]: cannot borrow `foo.bar1` as mutable because it is also borrowed as immutable
+  --> $DIR/borrowck-reborrow-from-mut.rs:33:17
+   |
+LL |     let _bar1 = &foo.bar1;
+   |                 --------- immutable borrow occurs here
+LL |     let _bar2 = &mut foo.bar1;  //~ ERROR cannot borrow
+   |                 ^^^^^^^^^^^^^ mutable borrow occurs here
+LL |     use_imm(_bar1);
+   |             ----- immutable borrow later used here
+
+error[E0499]: cannot borrow `foo.bar1` as mutable more than once at a time
+  --> $DIR/borrowck-reborrow-from-mut.rs:55:21
+   |
+LL |     let _bar1 = &mut foo.bar1;
+   |                 ------------- first mutable borrow occurs here
+LL |     match *foo {
+LL |         Foo { bar1: ref mut _bar1, bar2: _ } => {}
+   |                     ^^^^^^^^^^^^^ second mutable borrow occurs here
+...
+LL |     use_mut(_bar1);
+   |             ----- first borrow later used here
+
+error[E0502]: cannot borrow `foo.bar1` as immutable because it is also borrowed as mutable
+  --> $DIR/borrowck-reborrow-from-mut.rs:62:17
+   |
+LL |     let _bar1 = &mut foo.bar1.int1;
+   |                 ------------------ mutable borrow occurs here
+LL |     let _foo1 = &foo.bar1; //~ ERROR cannot borrow
+   |                 ^^^^^^^^^ immutable borrow occurs here
+LL |     let _foo2 = &*foo; //~ ERROR cannot borrow
+LL |     use_mut(_bar1);
+   |             ----- mutable borrow later used here
+
+error[E0502]: cannot borrow `*foo` as immutable because it is also borrowed as mutable
+  --> $DIR/borrowck-reborrow-from-mut.rs:63:17
+   |
+LL |     let _bar1 = &mut foo.bar1.int1;
+   |                 ------------------ mutable borrow occurs here
+LL |     let _foo1 = &foo.bar1; //~ ERROR cannot borrow
+LL |     let _foo2 = &*foo; //~ ERROR cannot borrow
+   |                 ^^^^^ immutable borrow occurs here
+LL |     use_mut(_bar1);
+   |             ----- mutable borrow later used here
+
+error[E0499]: cannot borrow `foo.bar1` as mutable more than once at a time
+  --> $DIR/borrowck-reborrow-from-mut.rs:68:17
+   |
+LL |     let _bar1 = &mut foo.bar1.int1;
+   |                 ------------------ first mutable borrow occurs here
+LL |     let _foo1 = &mut foo.bar1; //~ ERROR cannot borrow
+   |                 ^^^^^^^^^^^^^ second mutable borrow occurs here
+LL |     use_mut(_bar1);
+   |             ----- first borrow later used here
+
+error[E0499]: cannot borrow `*foo` as mutable more than once at a time
+  --> $DIR/borrowck-reborrow-from-mut.rs:73:17
+   |
+LL |     let _bar1 = &mut foo.bar1.int1;
+   |                 ------------------ first mutable borrow occurs here
+LL |     let _foo2 = &mut *foo; //~ ERROR cannot borrow
+   |                 ^^^^^^^^^ second mutable borrow occurs here
+LL |     use_mut(_bar1);
+   |             ----- first borrow later used here
+
+error[E0502]: cannot borrow `foo.bar1` as mutable because it is also borrowed as immutable
+  --> $DIR/borrowck-reborrow-from-mut.rs:78:17
+   |
+LL |     let _bar1 = &foo.bar1.int1;
+   |                 -------------- immutable borrow occurs here
+LL |     let _foo1 = &mut foo.bar1; //~ ERROR cannot borrow
+   |                 ^^^^^^^^^^^^^ mutable borrow occurs here
+LL |     use_imm(_bar1);
+   |             ----- immutable borrow later used here
+
+error[E0502]: cannot borrow `*foo` as mutable because it is also borrowed as immutable
+  --> $DIR/borrowck-reborrow-from-mut.rs:83:17
+   |
+LL |     let _bar1 = &foo.bar1.int1;
+   |                 -------------- immutable borrow occurs here
+LL |     let _foo2 = &mut *foo; //~ ERROR cannot borrow
+   |                 ^^^^^^^^^ mutable borrow occurs here
+LL |     use_imm(_bar1);
+   |             ----- immutable borrow later used here
+
 error[E0596]: cannot borrow `foo.bar1` as mutable, as it is behind a `&` reference
   --> $DIR/borrowck-reborrow-from-mut.rs:98:17
    |
@@ -6,6 +110,7 @@ LL | fn borrow_mut_from_imm(foo: &Foo) {
 LL |     let _bar1 = &mut foo.bar1; //~ ERROR cannot borrow
    |                 ^^^^^^^^^^^^^ `foo` is a `&` reference, so the data it refers to cannot be borrowed as mutable
 
-error: aborting due to previous error
+error: aborting due to 11 previous errors
 
-For more information about this error, try `rustc --explain E0596`.
+Some errors occurred: E0499, E0502, E0596.
+For more information about an error, try `rustc --explain E0499`.

src/test/ui/borrowck/borrowck-reborrow-from-mut.rs

@@ -21,79 +21,79 @@ struct Bar {
 fn borrow_same_field_twice_mut_mut(foo: &mut Foo) {
     let _bar1 = &mut foo.bar1;
     let _bar2 = &mut foo.bar1;  //~ ERROR cannot borrow
+    use_mut(_bar1);
 }
-
 fn borrow_same_field_twice_mut_imm(foo: &mut Foo) {
     let _bar1 = &mut foo.bar1;
     let _bar2 = &foo.bar1;  //~ ERROR cannot borrow
+    use_mut(_bar1);
 }
-
 fn borrow_same_field_twice_imm_mut(foo: &mut Foo) {
     let _bar1 = &foo.bar1;
     let _bar2 = &mut foo.bar1;  //~ ERROR cannot borrow
+    use_imm(_bar1);
 }
-
 fn borrow_same_field_twice_imm_imm(foo: &mut Foo) {
     let _bar1 = &foo.bar1;
     let _bar2 = &foo.bar1;
+    use_imm(_bar1);
 }
-
 fn borrow_both_mut(foo: &mut Foo) {
     let _bar1 = &mut foo.bar1;
     let _bar2 = &mut foo.bar2;
+    use_mut(_bar1);
 }
-
 fn borrow_both_mut_pattern(foo: &mut Foo) {
     match *foo {
-        Foo { bar1: ref mut _bar1, bar2: ref mut _bar2 } => {}
+        Foo { bar1: ref mut _bar1, bar2: ref mut _bar2 } =>
+        { use_mut(_bar1); use_mut(_bar2); }
     }
 }
-
 fn borrow_var_and_pattern(foo: &mut Foo) {
     let _bar1 = &mut foo.bar1;
     match *foo {
         Foo { bar1: ref mut _bar1, bar2: _ } => {}
         //~^ ERROR cannot borrow
     }
+    use_mut(_bar1);
 }
-
 fn borrow_mut_and_base_imm(foo: &mut Foo) {
     let _bar1 = &mut foo.bar1.int1;
     let _foo1 = &foo.bar1; //~ ERROR cannot borrow
     let _foo2 = &*foo; //~ ERROR cannot borrow
+    use_mut(_bar1);
 }
-
 fn borrow_mut_and_base_mut(foo: &mut Foo) {
     let _bar1 = &mut foo.bar1.int1;
     let _foo1 = &mut foo.bar1; //~ ERROR cannot borrow
+    use_mut(_bar1);
 }
-
 fn borrow_mut_and_base_mut2(foo: &mut Foo) {
     let _bar1 = &mut foo.bar1.int1;
     let _foo2 = &mut *foo; //~ ERROR cannot borrow
+    use_mut(_bar1);
 }
-
 fn borrow_imm_and_base_mut(foo: &mut Foo) {
     let _bar1 = &foo.bar1.int1;
     let _foo1 = &mut foo.bar1; //~ ERROR cannot borrow
+    use_imm(_bar1);
 }
-
 fn borrow_imm_and_base_mut2(foo: &mut Foo) {
     let _bar1 = &foo.bar1.int1;
     let _foo2 = &mut *foo; //~ ERROR cannot borrow
+    use_imm(_bar1);
 }
-
 fn borrow_imm_and_base_imm(foo: &mut Foo) {
     let _bar1 = &foo.bar1.int1;
     let _foo1 = &foo.bar1;
     let _foo2 = &*foo;
+    use_imm(_bar1);
 }
-
 fn borrow_mut_and_imm(foo: &mut Foo) {
     let _bar1 = &mut foo.bar1;
     let _foo1 = &foo.bar2;
+    use_mut(_bar1);
 }
-
 fn borrow_mut_from_imm(foo: &Foo) {
     let _bar1 = &mut foo.bar1; //~ ERROR cannot borrow
 }
@@ -101,6 +101,9 @@ fn borrow_mut_from_imm(foo: &Foo) {
 fn borrow_long_path_both_mut(foo: &mut Foo) {
     let _bar1 = &mut foo.bar1.int1;
     let _foo1 = &mut foo.bar2.int2;
+    use_mut(_bar1);
 }
-
 fn main() {}
+
+fn use_mut<T>(_: &mut T) { }
+fn use_imm<T>(_: &T) { }

src/test/ui/borrowck/borrowck-reborrow-from-mut.stderr

@@ -5,6 +5,7 @@ LL |     let _bar1 = &mut foo.bar1;
    |                      -------- first mutable borrow occurs here
 LL |     let _bar2 = &mut foo.bar1;  //~ ERROR cannot borrow
    |                      ^^^^^^^^ second mutable borrow occurs here
+LL |     use_mut(_bar1);
 LL | }
    | - first borrow ends here
 
@@ -15,6 +16,7 @@ LL |     let _bar1 = &mut foo.bar1;
    |                      -------- mutable borrow occurs here
 LL |     let _bar2 = &foo.bar1;  //~ ERROR cannot borrow
    |                  ^^^^^^^^ immutable borrow occurs here
+LL |     use_mut(_bar1);
 LL | }
    | - mutable borrow ends here
 
@@ -25,6 +27,7 @@ LL |     let _bar1 = &foo.bar1;
    |                  -------- immutable borrow occurs here
 LL |     let _bar2 = &mut foo.bar1;  //~ ERROR cannot borrow
    |                      ^^^^^^^^ mutable borrow occurs here
+LL |     use_imm(_bar1);
 LL | }
    | - immutable borrow ends here
 
@@ -47,7 +50,7 @@ LL |     let _bar1 = &mut foo.bar1.int1;
    |                      ------------- mutable borrow occurs here
 LL |     let _foo1 = &foo.bar1; //~ ERROR cannot borrow
    |                  ^^^^^^^^ immutable borrow occurs here
-LL |     let _foo2 = &*foo; //~ ERROR cannot borrow
+...
 LL | }
    | - mutable borrow ends here
 
@@ -59,6 +62,7 @@ LL |     let _bar1 = &mut foo.bar1.int1;
 LL |     let _foo1 = &foo.bar1; //~ ERROR cannot borrow
 LL |     let _foo2 = &*foo; //~ ERROR cannot borrow
    |                  ^^^^ immutable borrow occurs here
+LL |     use_mut(_bar1);
 LL | }
    | - mutable borrow ends here
 
@@ -69,6 +73,7 @@ LL |     let _bar1 = &mut foo.bar1.int1;
    |                      ------------- first mutable borrow occurs here
 LL |     let _foo1 = &mut foo.bar1; //~ ERROR cannot borrow
    |                      ^^^^^^^^ second mutable borrow occurs here
+LL |     use_mut(_bar1);
 LL | }
    | - first borrow ends here
 
@@ -79,6 +84,7 @@ LL |     let _bar1 = &mut foo.bar1.int1;
    |                      ------------- first mutable borrow occurs here
 LL |     let _foo2 = &mut *foo; //~ ERROR cannot borrow
    |                      ^^^^ second mutable borrow occurs here
+LL |     use_mut(_bar1);
 LL | }
    | - first borrow ends here
 
@@ -89,6 +95,7 @@ LL |     let _bar1 = &foo.bar1.int1;
    |                  ------------- immutable borrow occurs here
 LL |     let _foo1 = &mut foo.bar1; //~ ERROR cannot borrow
    |                      ^^^^^^^^ mutable borrow occurs here
+LL |     use_imm(_bar1);
 LL | }
    | - immutable borrow ends here
 
@@ -99,6 +106,7 @@ LL |     let _bar1 = &foo.bar1.int1;
    |                  ------------- immutable borrow occurs here
 LL |     let _foo2 = &mut *foo; //~ ERROR cannot borrow
    |                      ^^^^ mutable borrow occurs here
+LL |     use_imm(_bar1);
 LL | }
    | - immutable borrow ends here