Incorporate `iter_nodes` into `graph::DirectedGraph`

This assumes that the set of valid node IDs is exactly `0..num_nodes`.

In practice, we have a lot of graph-algorithm code that already assumes that
nodes are densely numbered, by using `num_nodes` to allocate per-node indexed
data structures.

3 files changed, 0 insertions, 19 deletions

diff --git a/compiler/rustc_mir_transform/src/coverage/counters/balanced_flow.rs b/compiler/rustc_mir_transform/src/coverage/counters/balanced_flow.rs
index c108f96a564..4c20722a043 100644
--- a/compiler/rustc_mir_transform/src/coverage/counters/balanced_flow.rs
+++ b/compiler/rustc_mir_transform/src/coverage/counters/balanced_flow.rs
@@ -20,8 +20,6 @@ use rustc_data_structures::graph::reversed::ReversedGraph;
 use rustc_index::Idx;
 use rustc_index::bit_set::DenseBitSet;
 
-use crate::coverage::counters::iter_nodes::IterNodes;
-
 /// A view of an underlying graph that has been augmented to have “balanced flow”.
 /// This means that the flow (execution count) of each node is equal to the
 /// sum of its in-edge flows, and also equal to the sum of its out-edge flows.
diff --git a/compiler/rustc_mir_transform/src/coverage/counters/iter_nodes.rs b/compiler/rustc_mir_transform/src/coverage/counters/iter_nodes.rs
deleted file mode 100644
index 9d87f7af1b0..00000000000
--- a/compiler/rustc_mir_transform/src/coverage/counters/iter_nodes.rs
+++ /dev/null
@@ -1,16 +0,0 @@
-use rustc_data_structures::graph;
-use rustc_index::Idx;
-
-pub(crate) trait IterNodes: graph::DirectedGraph {
-    /// Iterates over all nodes of a graph in ascending numeric order.
-    /// Assumes that nodes are densely numbered, i.e. every index in
-    /// `0..num_nodes` is a valid node.
-    ///
-    /// FIXME: Can this just be part of [`graph::DirectedGraph`]?
-    fn iter_nodes(
-        &self,
-    ) -> impl Iterator<Item = Self::Node> + DoubleEndedIterator + ExactSizeIterator {
-        (0..self.num_nodes()).map(<Self::Node as Idx>::new)
-    }
-}
-impl<G: graph::DirectedGraph> IterNodes for G {}
diff --git a/compiler/rustc_mir_transform/src/coverage/counters/node_flow.rs b/compiler/rustc_mir_transform/src/coverage/counters/node_flow.rs
index 3647c889937..9d80b3af42d 100644
--- a/compiler/rustc_mir_transform/src/coverage/counters/node_flow.rs
+++ b/compiler/rustc_mir_transform/src/coverage/counters/node_flow.rs
@@ -11,7 +11,6 @@ use rustc_index::bit_set::DenseBitSet;
 use rustc_index::{Idx, IndexSlice, IndexVec};
 use rustc_middle::mir::coverage::Op;
 
-use crate::coverage::counters::iter_nodes::IterNodes;
 use crate::coverage::counters::union_find::UnionFind;
 
 #[cfg(test)]