4 files changed, 9 insertions, 24 deletions
diff --git a/compiler/rustc_mir_transform/src/coverage/counters.rs b/compiler/rustc_mir_transform/src/coverage/counters.rs
index 69dc4f2ddea..6e73a476421 100644
--- a/compiler/rustc_mir_transform/src/coverage/counters.rs
+++ b/compiler/rustc_mir_transform/src/coverage/counters.rs
@@ -2,7 +2,7 @@ use std::fmt::{self, Debug};
 
 use rustc_data_structures::captures::Captures;
 use rustc_data_structures::fx::FxHashMap;
-use rustc_data_structures::graph::WithNumNodes;
+use rustc_data_structures::graph::DirectedGraph;
 use rustc_index::IndexVec;
 use rustc_middle::mir::coverage::{CounterId, CovTerm, Expression, ExpressionId, Op};
 
diff --git a/compiler/rustc_mir_transform/src/coverage/graph.rs b/compiler/rustc_mir_transform/src/coverage/graph.rs
index ed8c4d8283d..1895735ab35 100644
--- a/compiler/rustc_mir_transform/src/coverage/graph.rs
+++ b/compiler/rustc_mir_transform/src/coverage/graph.rs
@@ -1,7 +1,7 @@
 use rustc_data_structures::captures::Captures;
 use rustc_data_structures::fx::FxHashSet;
 use rustc_data_structures::graph::dominators::{self, Dominators};
-use rustc_data_structures::graph::{self, GraphSuccessors, WithNumNodes, WithStartNode};
+use rustc_data_structures::graph::{self, DirectedGraph, StartNode};
 use rustc_index::bit_set::BitSet;
 use rustc_index::IndexVec;
 use rustc_middle::mir::{self, BasicBlock, Terminator, TerminatorKind};
@@ -193,16 +193,14 @@ impl IndexMut<BasicCoverageBlock> for CoverageGraph {
 
 impl graph::DirectedGraph for CoverageGraph {
     type Node = BasicCoverageBlock;
-}
 
-impl graph::WithNumNodes for CoverageGraph {
     #[inline]
     fn num_nodes(&self) -> usize {
         self.bcbs.len()
     }
 }
 
-impl graph::WithStartNode for CoverageGraph {
+impl graph::StartNode for CoverageGraph {
     #[inline]
     fn start_node(&self) -> Self::Node {
         self.bcb_from_bb(mir::START_BLOCK)
@@ -210,28 +208,16 @@ impl graph::WithStartNode for CoverageGraph {
     }
 }
 
-type BcbSuccessors<'graph> = std::slice::Iter<'graph, BasicCoverageBlock>;
-
-impl<'graph> graph::GraphSuccessors<'graph> for CoverageGraph {
-    type Item = BasicCoverageBlock;
-    type Iter = std::iter::Cloned<BcbSuccessors<'graph>>;
-}
-
-impl graph::WithSuccessors for CoverageGraph {
+impl graph::Successors for CoverageGraph {
     #[inline]
-    fn successors(&self, node: Self::Node) -> <Self as GraphSuccessors<'_>>::Iter {
+    fn successors(&self, node: Self::Node) -> impl Iterator<Item = Self::Node> {
         self.successors[node].iter().cloned()
     }
 }
 
-impl<'graph> graph::GraphPredecessors<'graph> for CoverageGraph {
-    type Item = BasicCoverageBlock;
-    type Iter = std::iter::Copied<std::slice::Iter<'graph, BasicCoverageBlock>>;
-}
-
-impl graph::WithPredecessors for CoverageGraph {
+impl graph::Predecessors for CoverageGraph {
     #[inline]
-    fn predecessors(&self, node: Self::Node) -> <Self as graph::GraphPredecessors<'_>>::Iter {
+    fn predecessors(&self, node: Self::Node) -> impl Iterator<Item = Self::Node> {
         self.predecessors[node].iter().copied()
     }
 }
diff --git a/compiler/rustc_mir_transform/src/coverage/spans.rs b/compiler/rustc_mir_transform/src/coverage/spans.rs
index 672de1fbe60..03ede886688 100644
--- a/compiler/rustc_mir_transform/src/coverage/spans.rs
+++ b/compiler/rustc_mir_transform/src/coverage/spans.rs
@@ -1,4 +1,4 @@
-use rustc_data_structures::graph::WithNumNodes;
+use rustc_data_structures::graph::DirectedGraph;
 use rustc_index::bit_set::BitSet;
 use rustc_middle::mir;
 use rustc_span::{BytePos, Span};
diff --git a/compiler/rustc_mir_transform/src/coverage/tests.rs b/compiler/rustc_mir_transform/src/coverage/tests.rs
index 569998de35e..cf1a2b399f9 100644
--- a/compiler/rustc_mir_transform/src/coverage/tests.rs
+++ b/compiler/rustc_mir_transform/src/coverage/tests.rs
@@ -28,8 +28,7 @@ use super::counters;
 use super::graph::{self, BasicCoverageBlock};
 
 use itertools::Itertools;
-use rustc_data_structures::graph::WithNumNodes;
-use rustc_data_structures::graph::WithSuccessors;
+use rustc_data_structures::graph::{DirectedGraph, Successors};
 use rustc_index::{Idx, IndexVec};
 use rustc_middle::mir::*;
 use rustc_middle::ty;