@@ -76,7 +76,7 @@ export const transformModuleDeclaration: FunctionVisitor<ts.ModuleDeclaration> =
     const isFirstDeclaration =
         symbol === undefined ||
         (!symbol.declarations.some(d => ts.isClassLike(d) || ts.isFunctionDeclaration(d)) &&
-            node === symbol.declarations.find(ts.isModuleDeclaration));
+            ts.getOriginalNode(node) === symbol.declarations.find(ts.isModuleDeclaration));
 
     if (isNonModuleMergeable) {
         // 'local NS = NS or {}' or 'exportTable.NS = exportTable.NS or {}'
 
@@ -40,3 +40,23 @@ test("statement comments", () => {
         .setOptions({ luaPlugins: [{ name: path.join(__dirname, "add-comments.ts") }] })
         .expectLuaToMatchSnapshot();
 });
+
+// https://github.com/TypeScriptToLua/TypeScriptToLua/issues/1013
+test.each(["namespace", "module"])("%s with TS transformer plugin", moduleOrNamespace => {
+    util.testModule`
+        import { ns } from "module";
+        export const result = ns.returnsBool();
+    `
+        .addExtraFile(
+            "module.ts",
+            `
+            export ${moduleOrNamespace} ns {
+                export function returnsBool() {
+                    return false;
+                }
+            }
+        `
+        )
+        .setOptions({ plugins: [{ transform: path.join(__dirname, "transformer-plugin.ts") }] })
+        .expectNoExecutionError();
+});
@@ -0,0 +1,15 @@
+/**
+ * This is a TS tranformer plugin that replaces any return statement to 'return true'.
+ */
+import * as ts from "typescript";
+
+const replaceNode = (node: ts.Node) => {
+    if (ts.isReturnStatement(node)) {
+        return ts.factory.createReturnStatement(ts.factory.createTrue());
+    }
+};
+const createTransformer = () => (context: ts.TransformationContext) => {
+    const visit = (node: ts.Node): ts.Node => replaceNode(node) ?? ts.visitEachChild(node, visit, context);
+    return (file: ts.SourceFile) => ts.visitNode(file, visit);
+};
+exports.default = createTransformer;