Reuse -Zincremental_verify_ich.

Author: cjgillot

compiler/rustc_query_system/src/dep_graph/graph.rs

@@ -1109,7 +1109,7 @@ pub(super) struct CurrentDepGraph<K: DepKind> {
     forbidden_edge: Option<EdgeFilter<K>>,
 
     /// Used to verify the absence of hash collisions among DepNodes.
-    /// This field is only `Some` if the `-Z incremental_verify_depnodes` option is present.
+    /// This field is only `Some` if the `-Z incremental_verify_ich` option is present.
     #[cfg(debug_assertions)]
     seen_dep_nodes: Option<Lock<FxHashSet<DepNode<K>>>>,
 
@@ -1195,7 +1195,7 @@ impl<K: DepKind> CurrentDepGraph<K> {
             #[cfg(debug_assertions)]
             fingerprints: Lock::new(IndexVec::from_elem_n(None, new_node_count_estimate)),
             #[cfg(debug_assertions)]
-            seen_dep_nodes: session.opts.unstable_opts.incremental_verify_depnodes.then(|| {
+            seen_dep_nodes: session.opts.unstable_opts.incremental_verify_ich.then(|| {
                 Lock::new(FxHashSet::with_capacity_and_hasher(
                     new_node_count_estimate,
                     Default::default(),

compiler/rustc_session/src/options.rs

@@ -1483,10 +1483,10 @@ options! {
     #[rustc_lint_opt_deny_field_access("use `Session::incremental_relative_spans` instead of this field")]
     incremental_relative_spans: bool = (false, parse_bool, [TRACKED],
         "hash spans relative to their parent item for incr. comp. (default: no)"),
-    incremental_verify_depnodes: bool = (false, parse_bool, [UNTRACKED],
-        "verify incr. comp. dep-nodes for hash collisions (default: no)"),
     incremental_verify_ich: bool = (false, parse_bool, [UNTRACKED],
-        "verify incr. comp. hashes of green query instances (default: no)"),
+        "verify extended properties for incr. comp. (default: no):
+        - hashes of green query instances;
+        - hash collisions when creating dep-nodes."),
     inline_in_all_cgus: Option<bool> = (None, parse_opt_bool, [TRACKED],
         "control whether `#[inline]` functions are in all CGUs"),
     inline_llvm: bool = (true, parse_bool, [TRACKED],