diff --git a/Package.resolved b/Package.resolved
index fb51d24..45337e9 100644
--- a/Package.resolved
+++ b/Package.resolved
@@ -14,8 +14,8 @@
       "kind" : "remoteSourceControl",
       "location" : "https://github.com/swiftlang/swift-syntax.git",
       "state" : {
-        "revision" : "cb53fa1bd3219b0b23ded7dfdd3b2baff266fd25",
-        "version" : "600.0.0"
+        "revision" : "0687f71944021d616d34d922343dcef086855920",
+        "version" : "600.0.1"
       }
     },
     {
diff --git a/Sources/CodableToTypeScript/Generator/PackageGenerator.swift b/Sources/CodableToTypeScript/Generator/PackageGenerator.swift
index 89f733e..5de8b75 100644
--- a/Sources/CodableToTypeScript/Generator/PackageGenerator.swift
+++ b/Sources/CodableToTypeScript/Generator/PackageGenerator.swift
@@ -87,7 +87,10 @@ public final class PackageGenerator {
 
         try withErrorCollector { collect in
             while let source = targetSources.popLast() {
-                generatedSources.insert(source)
+                guard generatedSources.insert(source).inserted else {
+                    continue
+                }
+
                 collect(at: source.file.lastPathComponent) {
                     let tsSource = try convertedSources[source] ?? (codeGenerator.convert(source: source))
 
@@ -96,23 +99,25 @@ public final class PackageGenerator {
                         source: tsSource
                     )
                     try didConvertSource?(source, entry)
+                    if entry.isEmpty {
+                        return
+                    }
+
+                    generatedEntries.append(.init(
+                        file: entry.file,
+                        source: entry.source
+                    ))
 
-                    if !entry.source.elements.isEmpty {
-                        generatedEntries.append(.init(
-                            file: entry.file,
-                            source: entry.source
-                        ))
-
-                        let imports = try tsSource.buildAutoImportDecls(
-                            from: entry.file,
-                            symbolTable: allSymbols,
-                            fileExtension: importFileExtension
-                        )
-                        tsSource.replaceImportDecls(imports)
-                        for importedDecl in imports.flatMap(\.names) {
-                            if let source = symbolToSource[importedDecl], !generatedSources.contains(source) {
-                                targetSources.append(source)
-                            }
+                    let imports = try tsSource.buildAutoImportDecls(
+                        from: entry.file,
+                        symbolTable: allSymbols,
+                        fileExtension: importFileExtension
+                    )
+                    tsSource.replaceImportDecls(imports)
+                    for importedSymbolName in imports.flatMap(\.names) {
+                        // Add a file that is used but not included in the generation target
+                        if let source = symbolToSource[importedSymbolName], !generatedSources.contains(source) {
+                            targetSources.append(source)
                         }
                     }
                 }
@@ -166,3 +171,9 @@ public final class PackageGenerator {
     }
 }
 #endif
+
+extension PackageEntry {
+    fileprivate var isEmpty: Bool {
+        source.elements.isEmpty
+    }
+}
diff --git a/Tests/CodableToTypeScriptTests/PackageGeneratorTests.swift b/Tests/CodableToTypeScriptTests/PackageGeneratorTests.swift
index d7e86a7..6751534 100644
--- a/Tests/CodableToTypeScriptTests/PackageGeneratorTests.swift
+++ b/Tests/CodableToTypeScriptTests/PackageGeneratorTests.swift
@@ -148,4 +148,44 @@ final class PackageGeneratorTests: XCTestCase {
         })
         XCTAssertFalse(hasTSAbsoluteURL)
     }
+
+    func testGenerationsNotDuplicates() throws {
+        let context = Context()
+
+        let aModule = Reader(
+            context: context,
+            module: context.getOrCreateModule(name: "A")
+        ).read(source: """
+        struct A: Codable {}
+        """, file: URL(fileURLWithPath: "A.swift")).module
+
+        let bModule = Reader(
+            context: context,
+            module: context.getOrCreateModule(name: "B")
+        ).read(source: """
+        import A
+        
+        struct B: Codable {
+            var a: A
+        }
+        """, file: URL(fileURLWithPath: "B.swift")).module
+
+        let generator = PackageGenerator(
+            context: context,
+            symbols: SymbolTable(),
+            importFileExtension: .js,
+            outputDirectory: URL(fileURLWithPath: "/dev/null", isDirectory: true)
+        )
+
+        var convertedEntries: [PackageEntry] = []
+        generator.didConvertSource = { (source, entry) in
+            convertedEntries.append(entry)
+        }
+        _ = try generator.generate(modules: [aModule, bModule]) // the order is important!
+
+        XCTAssertEqual(convertedEntries.map(\.file.lastPathComponent), [
+            "B.ts",
+            "A.ts",
+        ])
+    }
 }