diff --git a/CHANGELOG.md b/CHANGELOG.md
index cd80ba7de..9717021ac 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -10,7 +10,7 @@
 
 ##### Bug Fixes
 
-- None.
+- Fix another crash while indexing.
 
 ## 2.8.5 (2022-01-03)
 
diff --git a/Sources/PeripheryKit/Indexer/SourceGraph.swift b/Sources/PeripheryKit/Indexer/SourceGraph.swift
index e4454ae42..756cddcda 100644
--- a/Sources/PeripheryKit/Indexer/SourceGraph.swift
+++ b/Sources/PeripheryKit/Indexer/SourceGraph.swift
@@ -93,10 +93,14 @@ public final class SourceGraph {
 
     func markRetained(_ declaration: Declaration) {
         mutationQueue.sync {
-            _ = retainedDeclarations.insert(declaration)
+            markRetainedUnsafe(declaration)
         }
     }
 
+    func markRetainedUnsafe(_ declaration: Declaration) {
+        _ = retainedDeclarations.insert(declaration)
+    }
+
     func markPotentialAssignOnlyProperty(_ declaration: Declaration) {
         mutationQueue.sync {
             _ = potentialAssignOnlyProperties.insert(declaration)
@@ -117,12 +121,16 @@ public final class SourceGraph {
 
     func add(_ declaration: Declaration) {
         mutationQueue.sync {
-            allDeclarations.insert(declaration)
-            allDeclarationsByKind[declaration.kind, default: []].insert(declaration)
+            addUnsafe(declaration)
+        }
+    }
 
-            if !declaration.isImplicit {
-                declaration.usrs.forEach { allExplicitDeclarationsByUsr[$0] = declaration }
-            }
+    func addUnsafe(_ declaration: Declaration) {
+        allDeclarations.insert(declaration)
+        allDeclarationsByKind[declaration.kind, default: []].insert(declaration)
+
+        if !declaration.isImplicit {
+            declaration.usrs.forEach { allExplicitDeclarationsByUsr[$0] = declaration }
         }
     }
 
diff --git a/Sources/PeripheryKit/Indexer/SwiftIndexer.swift b/Sources/PeripheryKit/Indexer/SwiftIndexer.swift
index 0b3e3bd26..a3e7b1cd2 100644
--- a/Sources/PeripheryKit/Indexer/SwiftIndexer.swift
+++ b/Sources/PeripheryKit/Indexer/SwiftIndexer.swift
@@ -280,14 +280,13 @@ public final class SwiftIndexer {
 
         private func associateLatentReferences() {
             for (usr, refs) in referencesByUsr {
-                guard let decl = graph.explicitDeclaration(withUsr: usr) else {
-                    danglingReferences.append(contentsOf: refs)
-                    continue
-                }
-
                 graph.mutating {
-                    for ref in refs {
-                        associateUnsafe(ref, with: decl)
+                    if let decl = graph.explicitDeclaration(withUsr: usr) {
+                        for ref in refs {
+                            associateUnsafe(ref, with: decl)
+                        }
+                    } else {
+                        danglingReferences.append(contentsOf: refs)
                     }
                 }
             }
@@ -433,15 +432,16 @@ public final class SwiftIndexer {
                     }
                 }
 
-                for param in params {
-                    let paramDecl = param.declaration
-                    paramDecl.parent = functionDecl
-                    functionDecl.unusedParameters.insert(paramDecl)
-                    graph.add(paramDecl)
-
-                    if ignoredParamNames.contains(param.name) ||
-                        (functionDecl.isObjcAccessible && configuration.retainObjcAccessible) {
-                        graph.markRetained(paramDecl)
+                graph.mutating {
+                    for param in params {
+                        let paramDecl = param.declaration
+                        paramDecl.parent = functionDecl
+                        functionDecl.unusedParameters.insert(paramDecl)
+                        graph.addUnsafe(paramDecl)
+
+                        if (functionDecl.isObjcAccessible && configuration.retainObjcAccessible) || ignoredParamNames.contains(param.name) {
+                            graph.markRetainedUnsafe(paramDecl)
+                        }
                     }
                 }
             }