Rust: Rename predicates.

Author: geoffw0

rust/ql/src/queries/unusedentities/UnreachableCode.ql

@@ -15,38 +15,40 @@ import codeql.rust.controlflow.internal.ControlFlowGraphImpl as ControlFlowGraph
 /**
  * Successor relation that includes unreachable AST nodes.
  */
-predicate succFull(AstNode a, AstNode b) {
+private predicate succ(AstNode a, AstNode b) {
   exists(ControlFlowGraphImpl::ControlFlowTree cft | cft.succ(a, b, _))
 }
 
 /**
- * Gets a node we'd prefer not to report as unreachable.
+ * Gets a node we'd prefer not to report as unreachable. These will be removed
+ * from the AST for the purposes of this query, with successor links being
+ * made across them where appropriate.
  */
-predicate skipNode(AstNode n) {
+predicate hiddenNode(AstNode n) {
   // isolated node (not intended to be part of the CFG)
-  not succFull(n, _) and
-  not succFull(_, n)
+  not succ(n, _) and
+  not succ(_, n)
   or
   n instanceof ControlFlowGraphImpl::PostOrderTree // location is counter-intuitive
 }
 
 /**
- * Successor relation for edges out of `skipNode`s.
+ * Successor relation for edges out of `hiddenNode`s.
  */
-predicate succSkip(AstNode a, AstNode b) {
-  skipNode(a) and
-  succFull(a, b)
+private predicate succHidden(AstNode a, AstNode b) {
+  hiddenNode(a) and
+  succ(a, b)
 }
 
 /**
- * Successor relation that skips over `skipNode`s.
+ * Successor relation that removes / links over `hiddenNode`s.
  */
-predicate succSkipping(AstNode a, AstNode b) {
+private predicate succWithHiding(AstNode a, AstNode b) {
   exists(AstNode mid |
-    not skipNode(a) and
-    succFull(a, mid) and
-    succSkip*(mid, b) and
-    not skipNode(b)
+    not hiddenNode(a) and
+    succ(a, mid) and
+    succHidden*(mid, b) and
+    not hiddenNode(b)
   )
 }
 
@@ -61,8 +63,8 @@ predicate reachable(AstNode n) { n = any(CfgNode cfn).getAstNode() }
  */
 private predicate firstUnreachable(AstNode n) {
   not reachable(n) and
-  not skipNode(n) and
-  forall(AstNode pred | succSkipping(pred, n) | reachable(pred))
+  not hiddenNode(n) and
+  forall(AstNode pred | succWithHiding(pred, n) | reachable(pred))
 }
 
 from AstNode n