Visit the mir basic blocks in reverse-postfix order

src/librustc_mir/dataflow/mod.rs

@@ -16,6 +16,7 @@ use rustc_data_structures::bitslice::{bitwise, BitwiseOperator};
 
 use rustc::ty::{self, TyCtxt};
 use rustc::mir::{self, Mir, BasicBlock, BasicBlockData, Location, Statement, Terminator};
+use rustc::mir::traversal;
 use rustc::session::Session;
 
 use std::borrow::Borrow;
@@ -333,7 +334,7 @@ pub(crate) trait DataflowResultsConsumer<'a, 'tcx: 'a> {
 
     fn analyze_results(&mut self, flow_uninit: &mut Self::FlowState) {
         let flow = flow_uninit;
-        for bb in self.mir().basic_blocks().indices() {
+        for (bb, _) in traversal::reverse_postorder(self.mir()) {
             flow.reset_to_entry_of(bb);
             self.process_basic_block(bb, flow);
         }

src/test/ui/issue-47184.stderr

@@ -2,10 +2,9 @@ error[E0597]: borrowed value does not live long enough
   --> $DIR/issue-47184.rs:14:44
    |
 LL |     let _vec: Vec<&'static String> = vec![&String::new()];
-   |                                            ^^^^^^^^^^^^^ temporary value does not live long enough
-LL |     //~^ ERROR borrowed value does not live long enough [E0597]
-LL | }
-   | - temporary value only lives until here
+   |                                            ^^^^^^^^^^^^^ - temporary value only lives until here
+   |                                            |
+   |                                            temporary value does not live long enough
    |
    = note: borrowed value must be valid for the static lifetime...
 

src/test/ui/nll/get_default.stderr

@@ -55,6 +55,18 @@ LL | |     }
 LL | | }
    | |_^
 
+error[E0502]: cannot borrow `*map` as mutable because it is also borrowed as immutable (Mir)
+  --> $DIR/get_default.rs:45:17
+   |
+LL |         match map.get() {
+   |               --- immutable borrow occurs here
+LL |             Some(v) => {
+LL |                 map.set(String::new()); // Both AST and MIR error here
+   |                 ^^^ mutable borrow occurs here
+...
+LL |                 return v;
+   |                        - borrow later used here
+
 error[E0502]: cannot borrow `*map` as mutable because it is also borrowed as immutable (Mir)
   --> $DIR/get_default.rs:51:17
    |
@@ -76,18 +88,6 @@ LL | |     }
 LL | | }
    | |_^
 
-error[E0502]: cannot borrow `*map` as mutable because it is also borrowed as immutable (Mir)
-  --> $DIR/get_default.rs:45:17
-   |
-LL |         match map.get() {
-   |               --- immutable borrow occurs here
-LL |             Some(v) => {
-LL |                 map.set(String::new()); // Both AST and MIR error here
-   |                 ^^^ mutable borrow occurs here
-...
-LL |                 return v;
-   |                        - borrow later used here
-
 error: aborting due to 6 previous errors
 
 For more information about this error, try `rustc --explain E0502`.

src/test/ui/span/dropck_arr_cycle_checked.nll.stderr

@@ -1,7 +1,7 @@
-error[E0597]: `b1` does not live long enough
-  --> $DIR/dropck_arr_cycle_checked.rs:111:24
+error[E0597]: `b3` does not live long enough
+  --> $DIR/dropck_arr_cycle_checked.rs:105:24
    |
-LL |     b3.a[0].v.set(Some(&b1));
+LL |     b1.a[1].v.set(Some(&b3));
    |                        ^^^ borrowed value does not live long enough
 ...
 LL | }
@@ -22,10 +22,10 @@ LL | }
    | borrowed value only lives until here
    | borrow later used here, when `b1` is dropped
 
-error[E0597]: `b3` does not live long enough
-  --> $DIR/dropck_arr_cycle_checked.rs:105:24
+error[E0597]: `b1` does not live long enough
+  --> $DIR/dropck_arr_cycle_checked.rs:111:24
    |
-LL |     b1.a[1].v.set(Some(&b3));
+LL |     b3.a[0].v.set(Some(&b1));
    |                        ^^^ borrowed value does not live long enough
 ...
 LL | }

src/test/ui/span/dropck_direct_cycle_with_drop.nll.stderr

@@ -1,9 +1,9 @@
-error[E0597]: `d1` does not live long enough
-  --> $DIR/dropck_direct_cycle_with_drop.rs:48:19
+error[E0597]: `d2` does not live long enough
+  --> $DIR/dropck_direct_cycle_with_drop.rs:46:19
    |
-LL |     d2.p.set(Some(&d1));
+LL |     d1.p.set(Some(&d2));
    |                   ^^^ borrowed value does not live long enough
-LL |     //~^ ERROR `d1` does not live long enough
+...
 LL | }
    | -
    | |
@@ -12,12 +12,12 @@ LL | }
    |
    = note: values in a scope are dropped in the opposite order they are defined
 
-error[E0597]: `d2` does not live long enough
-  --> $DIR/dropck_direct_cycle_with_drop.rs:46:19
+error[E0597]: `d1` does not live long enough
+  --> $DIR/dropck_direct_cycle_with_drop.rs:48:19
    |
-LL |     d1.p.set(Some(&d2));
+LL |     d2.p.set(Some(&d1));
    |                   ^^^ borrowed value does not live long enough
-...
+LL |     //~^ ERROR `d1` does not live long enough
 LL | }
    | -
    | |

src/test/ui/span/dropck_vec_cycle_checked.nll.stderr

@@ -1,7 +1,7 @@
-error[E0597]: `c1` does not live long enough
-  --> $DIR/dropck_vec_cycle_checked.rs:121:24
+error[E0597]: `c3` does not live long enough
+  --> $DIR/dropck_vec_cycle_checked.rs:115:24
    |
-LL |     c3.v[0].v.set(Some(&c1));
+LL |     c1.v[1].v.set(Some(&c3));
    |                        ^^^ borrowed value does not live long enough
 ...
 LL | }
@@ -22,10 +22,10 @@ LL | }
    | borrowed value only lives until here
    | borrow later used here, when `c1` is dropped
 
-error[E0597]: `c3` does not live long enough
-  --> $DIR/dropck_vec_cycle_checked.rs:115:24
+error[E0597]: `c1` does not live long enough
+  --> $DIR/dropck_vec_cycle_checked.rs:121:24
    |
-LL |     c1.v[1].v.set(Some(&c3));
+LL |     c3.v[0].v.set(Some(&c1));
    |                        ^^^ borrowed value does not live long enough
 ...
 LL | }

src/test/ui/span/vec-must-not-hide-type-from-dropck.nll.stderr

@@ -1,21 +1,21 @@
-error[E0597]: `c1` does not live long enough
-  --> $DIR/vec-must-not-hide-type-from-dropck.rs:129:24
+error[E0597]: `c2` does not live long enough
+  --> $DIR/vec-must-not-hide-type-from-dropck.rs:127:24
    |
-LL |     c2.v[0].v.set(Some(&c1));
+LL |     c1.v[0].v.set(Some(&c2));
    |                        ^^^ borrowed value does not live long enough
-LL |     //~^ ERROR `c1` does not live long enough
+...
 LL | }
    | -
    | |
    | borrowed value only lives until here
    | borrow later used here, when `c1` is dropped
 
-error[E0597]: `c2` does not live long enough
-  --> $DIR/vec-must-not-hide-type-from-dropck.rs:127:24
+error[E0597]: `c1` does not live long enough
+  --> $DIR/vec-must-not-hide-type-from-dropck.rs:129:24
    |
-LL |     c1.v[0].v.set(Some(&c2));
+LL |     c2.v[0].v.set(Some(&c1));
    |                        ^^^ borrowed value does not live long enough
-...
+LL |     //~^ ERROR `c1` does not live long enough
 LL | }
    | -
    | |