Introduce more fine-grained borrowed locals analysis for generators

Cargo.lock

@@ -3760,6 +3760,7 @@ dependencies = [
 name = "rustc_mir_dataflow"
 version = "0.0.0"
 dependencies = [
+ "either",
  "polonius-engine",
  "regex",
  "rustc_ast",

compiler/rustc_data_structures/src/graph/implementation/mod.rs

@@ -22,6 +22,7 @@
 
 use crate::snapshot_vec::{SnapshotVec, SnapshotVecDelegate};
 use rustc_index::bit_set::BitSet;
+use rustc_index::Idx;
 use std::fmt::Debug;
 
 #[cfg(test)]
@@ -59,9 +60,19 @@ impl<N> SnapshotVecDelegate for Edge<N> {
     fn reverse(_: &mut Vec<Edge<N>>, _: ()) {}
 }
 
-#[derive(Copy, Clone, PartialEq, Debug)]
+#[derive(Copy, Clone, PartialEq, Eq, Hash, Debug, Ord, PartialOrd)]
 pub struct NodeIndex(pub usize);
 
+impl Idx for NodeIndex {
+    fn new(idx: usize) -> Self {
+        NodeIndex(idx)
+    }
+
+    fn index(self) -> usize {
+        self.0
+    }
+}
+
 #[derive(Copy, Clone, PartialEq, Debug)]
 pub struct EdgeIndex(pub usize);
 

compiler/rustc_mir_dataflow/Cargo.toml

@@ -22,3 +22,4 @@ rustc_middle = { path = "../rustc_middle" }
 rustc_serialize = { path = "../rustc_serialize" }
 rustc_target = { path = "../rustc_target" }
 rustc_span = { path = "../rustc_span" }
+either = "1"

compiler/rustc_mir_dataflow/src/framework/cursor.rs

@@ -140,7 +140,6 @@ where
     }
 
     /// Allows inspection of unreachable basic blocks even with `debug_assertions` enabled.
-    #[cfg(test)]
     pub(crate) fn allow_unreachable(&mut self) {
         #[cfg(debug_assertions)]
         self.reachable_blocks.insert_all()