extend existing local predicate skeletons in LoadState::compile

src/machine/compile.rs

@@ -1099,6 +1099,29 @@ impl<'a> LoadState<'a> {
                 }
             }
 
+            match self
+                .wam
+                .indices
+                .get_local_predicate_skeleton_mut(
+                    &self.compilation_target,
+                    predicates.compilation_target.clone(),
+                    key.clone(),
+                )
+            {
+                Some(skeleton) => {
+                    self.retraction_info
+                        .push_record(RetractionRecord::SkeletonLocalClauseTruncateBack(
+                            self.compilation_target.clone(),
+                            predicates.compilation_target.clone(),
+                            key.clone(),
+                            skeleton.clause_clause_locs.len(),
+                        ));
+
+                    skeleton.clause_clause_locs.extend_from_slice(
+                        &clause_clause_locs[0 ..]
+                    );
+                }
+                None => {
                     let mut skeleton = PredicateSkeleton::new();
                     skeleton.clause_clause_locs = clause_clause_locs;
 
@@ -1108,6 +1131,8 @@ impl<'a> LoadState<'a> {
                         skeleton,
                     );
                 }
+            }
+        }
 
         set_code_index(
             &mut self.retraction_info,

src/machine/loader.rs

@@ -76,6 +76,7 @@ pub(crate) enum RetractionRecord {
     SkeletonClausePopFront(CompilationTarget, PredicateKey),
     SkeletonLocalClauseClausePopBack(CompilationTarget, CompilationTarget, PredicateKey),
     SkeletonLocalClauseClausePopFront(CompilationTarget, CompilationTarget, PredicateKey),
+    SkeletonLocalClauseTruncateBack(CompilationTarget, CompilationTarget, PredicateKey, usize),
     SkeletonClauseTruncateBack(CompilationTarget, PredicateKey, usize),
     SkeletonClauseStartReplaced(CompilationTarget, PredicateKey, usize, usize),
     RemovedSkeletonClause(
@@ -519,6 +520,27 @@ impl<'a> Drop for LoadState<'a> {
                         None => {}
                     }
                 }
+                RetractionRecord::SkeletonLocalClauseTruncateBack(
+                    src_compilation_target,
+                    local_compilation_target,
+                    key,
+                    len,
+                ) => {
+                    match self
+                        .wam
+                        .indices
+                        .get_local_predicate_skeleton_mut(
+                            &src_compilation_target,
+                            local_compilation_target,
+                            key,
+                        )
+                    {
+                        Some(skeleton) => {
+                            skeleton.clause_clause_locs.truncate_back(len);
+                        }
+                        None => {}
+                    }
+                }
                 RetractionRecord::SkeletonClauseTruncateBack(compilation_target, key, len) => {
                     match self
                         .wam