diff --git a/Sources/JExtractSwiftLib/Swift2Java.swift b/Sources/JExtractSwiftLib/Swift2Java.swift
index 6952f3b1e..e07338101 100644
--- a/Sources/JExtractSwiftLib/Swift2Java.swift
+++ b/Sources/JExtractSwiftLib/Swift2Java.swift
@@ -201,18 +201,22 @@ public func collectAllFiles(suffix: String, in inputPaths: [URL], log: Logger) -
   ]
 
   for path in inputPaths {
+    var filesInPath: OrderedSet<URL> = []
     do {
       try collectFilesFromPath(
         path,
         suffix: suffix,
         fileManager: fileManager,
         resourceKeys: resourceKeys,
-        into: &allFiles,
+        into: &filesInPath,
         log: log
       )
     } catch {
       log.trace("Failed to collect paths in: \(path), skipping.")
     }
+    // Directory enumeration order is filesystem-dependent (e.g. hash-ordered on APFS);
+    // sort so that extraction output is deterministic across machines.
+    allFiles.append(contentsOf: filesInPath.sorted { $0.path < $1.path })
   }
 
   return allFiles
diff --git a/Sources/SwiftExtract/SwiftTypes/SwiftParsedModuleSymbolTableBuilder.swift b/Sources/SwiftExtract/SwiftTypes/SwiftParsedModuleSymbolTableBuilder.swift
index 08bc4e146..773b7b00f 100644
--- a/Sources/SwiftExtract/SwiftTypes/SwiftParsedModuleSymbolTableBuilder.swift
+++ b/Sources/SwiftExtract/SwiftTypes/SwiftParsedModuleSymbolTableBuilder.swift
@@ -27,8 +27,16 @@ package struct SwiftParsedModuleSymbolTableBuilder {
   /// The build configuration used to resolve #if conditional compilation blocks.
   package let buildConfig: any BuildConfiguration
 
-  /// Extension decls their extended type hasn't been resolved.
-  package var unresolvedExtensions: [ExtensionDeclSyntax]
+  /// An extension decl whose extended type hasn't been resolved yet, paired with
+  /// the path of the source file it was declared in.
+  package struct UnresolvedExtension {
+    package var node: ExtensionDeclSyntax
+    package var sourceFilePath: String
+  }
+
+  /// Extension decls their extended type hasn't been resolved, paired with
+  /// the path of the source file they were declared in.
+  package var unresolvedExtensions: [UnresolvedExtension]
 
   package init(
     moduleName: String,
@@ -213,7 +221,7 @@ extension SwiftParsedModuleSymbolTableBuilder {
     sourceFilePath: String
   ) {
     if !self.tryHandle(extension: node, sourceFilePath: sourceFilePath) {
-      self.unresolvedExtensions.append(node)
+      self.unresolvedExtensions.append(UnresolvedExtension(node: node, sourceFilePath: sourceFilePath))
     }
   }
 
@@ -273,7 +281,7 @@ extension SwiftParsedModuleSymbolTableBuilder {
     while !unresolvedExtensions.isEmpty {
       var extensions = self.unresolvedExtensions
       extensions.removeAll(where: {
-        self.tryHandle(extension: $0, sourceFilePath: "FIXME_MISSING_FILEPATH.swift") // FIXME: missing filepath here in finalize
+        self.tryHandle(extension: $0.node, sourceFilePath: $0.sourceFilePath)
       })
 
       // If we didn't resolve anything, we're done.
diff --git a/Tests/SwiftExtractTests/SwiftSymbolTableTests.swift b/Tests/SwiftExtractTests/SwiftSymbolTableTests.swift
index 4b8e44dbd..8648a95df 100644
--- a/Tests/SwiftExtractTests/SwiftSymbolTableTests.swift
+++ b/Tests/SwiftExtractTests/SwiftSymbolTableTests.swift
@@ -54,6 +54,37 @@ struct SwiftSymbolTableSuite {
     #expect(symbolTable.lookupType("Z", parent: nil) == nil)
   }
 
+  @Test func deferredExtensionKeepsSourceFilePath() throws {
+    // The extension is visited before the file declaring the extended type,
+    // so it is resolved late (in `finalize()`); nested types must still be
+    // attributed to the file they were declared in.
+    let extensionFile: SourceFileSyntax = """
+      extension Outer.Inner {
+        public struct Deferred {}
+      }
+      """
+    let declarationFile: SourceFileSyntax = """
+      public enum Outer {
+        public enum Inner {}
+      }
+      """
+    let symbolTable = SwiftSymbolTable.setup(
+      moduleName: "MyModule",
+      [
+        .init(syntax: extensionFile, path: "Feature/Feature+Model.swift"),
+        .init(syntax: declarationFile, path: "Core/Outer.swift"),
+      ],
+      config: nil,
+      sourceDependencies: SourceDependencies(),
+    )
+
+    let outer = try #require(symbolTable.lookupType("Outer", parent: nil))
+    let inner = try #require(symbolTable.lookupType("Inner", parent: outer))
+    let deferred = try #require(symbolTable.lookupType("Deferred", parent: inner))
+    #expect(deferred.sourceFilePath == "Feature/Feature+Model.swift")
+    #expect(inner.sourceFilePath == "Core/Outer.swift")
+  }
+
   @Test func moduleScopedLookup() throws {
     let symbolTable = makeSymbolTable(
       moduleName: "MyModule",