Change DepNodeColorMap::insert to insert_red.

Because it's only ever used for inserting red. (`None` is only used as a
starting value, and `Green` is inserted by `try_mark_green` and
friends.)

Author: nnethercote

compiler/rustc_query_system/src/dep_graph/graph.rs

@@ -148,10 +148,9 @@ impl<D: Deps> DepGraph<D> {
         );
         assert_eq!(red_node_index, DepNodeIndex::FOREVER_RED_NODE);
         if prev_graph_node_count > 0 {
-            colors.insert(
-                SerializedDepNodeIndex::from_u32(DepNodeIndex::FOREVER_RED_NODE.as_u32()),
-                DepNodeColor::Red,
-            );
+            colors.insert_red(SerializedDepNodeIndex::from_u32(
+                DepNodeIndex::FOREVER_RED_NODE.as_u32(),
+            ));
         }
 
         DepGraph {
@@ -1384,14 +1383,8 @@ impl DepNodeColorMap {
     }
 
     #[inline]
-    pub(super) fn insert(&self, index: SerializedDepNodeIndex, color: DepNodeColor) {
-        self.values[index].store(
-            match color {
-                DepNodeColor::Red => COMPRESSED_RED,
-                DepNodeColor::Green(index) => index.as_u32(),
-            },
-            Ordering::Release,
-        )
+    pub(super) fn insert_red(&self, index: SerializedDepNodeIndex) {
+        self.values[index].store(COMPRESSED_RED, Ordering::Release)
     }
 }
 

compiler/rustc_query_system/src/dep_graph/serialized.rs

@@ -59,7 +59,7 @@ use rustc_serialize::{Decodable, Decoder, Encodable, Encoder};
 use rustc_session::Session;
 use tracing::{debug, instrument};
 
-use super::graph::{CurrentDepGraph, DepNodeColor, DepNodeColorMap};
+use super::graph::{CurrentDepGraph, DepNodeColorMap};
 use super::query::DepGraphQuery;
 use super::{DepKind, DepNode, DepNodeIndex, Deps};
 use crate::dep_graph::edges::EdgesVec;
@@ -906,7 +906,7 @@ impl<D: Deps> GraphEncoder<D> {
                 Err(dep_node_index) => return dep_node_index,
             }
         } else {
-            colors.insert(prev_index, DepNodeColor::Red);
+            colors.insert_red(prev_index);
         }
 
         self.status.bump_index(&mut *local);